MPI4PY(3)

NAME
mpi4py - MPI for Python

    Author
        Lisandro Dalcin

    Contact
        <dalcinl@gmail.com>

    Date
        March 20, 2026

  Abstract

MPI for Python provides Python bindings for the Message Passing Interface (MPI) standard, allowing Python applications to exploit multiple processors on workstations, clusters and supercomputers.

This package builds on the MPI specification and provides an object oriented interface resembling the MPI-2 C++ bindings. It supports point-to-point (sends, receives) and collective (broadcasts, scatters, gathers) communication of any picklable Python object, as well as efficient communication of Python objects exposing the Python buffer interface (e.g. NumPy arrays and builtin bytes/array/memoryview objects).

INTRODUCTION

Over the last years, high performance computing has become an affordable resource to many more researchers in the scientific community than ever before. The conjunction of quality open source software and commodity hardware strongly influenced the now widespread popularity of Beowulf <https://www.beowulf.org/> class clusters and cluster of workstations.

Among many parallel computational models, message-passing has proven to be an effective one. This paradigm is specially suited for (but not limited to) distributed memory architectures and is used in today’s most demanding scientific and engineering application related to modeling, simulation, design, and signal processing. However, portable message-passing parallel programming used to be a nightmare in the past because of the many incompatible options developers were faced to. Fortunately, this situation definitely changed after the MPI Forum released its standard specification.

High performance computing is traditionally associated with software development using compiled languages. However, in typical applications programs, only a small part of the code is time-critical enough to require the efficiency of compiled languages. The rest of the code is generally related to memory management, error handling, input/output, and user interaction, and those are usually the most error prone and time-consuming lines of code to write and debug in the whole development process. Interpreted high-level languages can be really advantageous for this kind of tasks.

For implementing general-purpose numerical computations, MATLAB [1] is the dominant interpreted programming language. In the open source side, Octave and Scilab are well known, freely distributed software packages providing compatibility with the MATLAB language. In this work, we present MPI for Python, a new package enabling applications to exploit multiple processors using standard MPI “look and feel” in Python scripts.

[1] MATLAB is a registered trademark of The MathWorks, Inc.

  What is MPI?

MPI <https://www.mpi-forum.org/>, [mpi-using] <#mpi-using> [mpi-ref] <#mpi-ref> the Message Passing Interface, is a standardized and portable message-passing system designed to function on a wide variety of parallel computers. The standard defines the syntax and semantics of library routines and allows users to write portable programs in the main scientific programming languages (Fortran, C, or C++).

Since its release, the MPI specification [mpi-std1] <#mpi-std1> [mpi-std2] <#mpi-std2> has become the leading standard for message-passing libraries for parallel computers. Implementations are available from vendors of high-performance computers and from well known open source projects like MPICH <https://www.mpich.org/> [mpi-mpich] <#mpi-mpich> and Open MPI <https://www.open-mpi.org/> [mpi-openmpi] <#mpi-openmpi>.

  What is Python?

Python <https://www.python.org/> is a modern, easy to learn, powerful programming language. It has efficient high-level data structures and a simple but effective approach to object-oriented programming with dynamic typing and dynamic binding. It supports modules and packages, which encourages program modularity and code reuse. Python’s elegant syntax, together with its interpreted nature, make it an ideal language for scripting and rapid application development in many areas on most platforms.

The Python interpreter and the extensive standard library are available in source or binary form without charge for all major platforms, and can be freely distributed. It is easily extended with new functions and data types implemented in C or C++. Python is also suitable as an extension language for customizable applications.

Python is an ideal candidate for writing the higher-level parts of large-scale scientific applications [Hinsen97] <#hinsen97> and driving simulations in parallel architectures [Beazley97] <#beazley97> like clusters of PC’s or SMP’s. Python codes are quickly developed, easily maintained, and can achieve a high degree of integration with other libraries written in compiled languages.

  Related Projects

As this work started and evolved, some ideas were borrowed from well known MPI and Python related open source projects from the Internet.

    •   OOMPI <https://web.archive.org/web/20100614170656/http://www.osl.iu.edu/research/oompi/overview.php>

        •   It has no relation with Python, but is an excellent object oriented approach to MPI.

        •   It is a C++ class library specification layered on top of the C bindings that encapsulates MPI into a functional class hierarchy.

        •   It provides a flexible and intuitive interface by adding some abstractions, like Ports and Messages, which enrich and simplify the syntax.

    •   Pypar <https://github.com/daleroberts/pypar>

        •   Its interface is rather minimal. There is no support for communicators or process topologies.

        •   It does not require the Python interpreter to be modified or recompiled, but does not permit interactive parallel runs.

        •   General (picklable) Python objects of any type can be communicated. There is good support for numeric arrays, practically full MPI bandwidth can be achieved.

    •   pyMPI <https://sourceforge.net/projects/pympi/>

        •   It rebuilds the Python interpreter providing a built-in module for message passing. It does permit interactive parallel runs, which are useful for learning and debugging.

        •   It provides an interface suitable for basic parallel programming. There is not full support for defining new communicators or process topologies.

        •   General (picklable) Python objects can be messaged between processors. There is native support for numeric arrays.

    •   Scientific Python <http://dirac.cnrs-orleans.fr/ScientificPython.html>

        •   It provides a collection of Python modules that are useful for scientific computing.

        •   There is an interface to MPI and BSP (Bulk Synchronous Parallel programming).

        •   The interface is simple but incomplete and does not resemble the MPI specification. There is support for numeric arrays.

Additionally, we would like to mention some available tools for scientific computing and software development with Python.

    •   NumPy <https://numpy.org/> is a package that provides array manipulation and computational capabilities similar to those found in IDL, MATLAB, or Octave. Using NumPy, it is possible to write many efficient numerical data processing applications directly in Python without using any C, C++ or Fortran code.

    •   SciPy <https://scipy.org/> is an open source library of scientific tools for Python, gathering a variety of high level science and engineering modules together as a single package. It includes modules for graphics and plotting, optimization, integration, special functions, signal and image processing, genetic algorithms, ODE solvers, and others.

    •   Cython <https://cython.org/> is a language that makes writing C extensions for the Python language as easy as Python itself. The Cython language is very close to the Python language, but Cython additionally supports calling C functions and declaring C types on variables and class attributes. This allows the compiler to generate very efficient C code from Cython code. This makes Cython the ideal language for wrapping for external C libraries, and for fast C modules that speed up the execution of Python code.

    •   SWIG <https://www.swig.org/> is a software development tool that connects programs written in C and C++ with a variety of high-level programming languages like Perl, Tcl/Tk, Ruby and Python. Issuing header files to SWIG is the simplest approach to interfacing C/C++ libraries from a Python module.

[mpi-std1]
    MPI Forum. MPI: A Message Passing Interface Standard. International Journal of Supercomputer Applications, volume 8, number 3-4, pages 159-416, 1994.

[mpi-std2]
    MPI Forum. MPI: A Message Passing Interface Standard. High Performance Computing Applications, volume 12, number 1-2, pages 1-299, 1998.

[mpi-using]
    William Gropp, Ewing Lusk, and Anthony Skjellum. Using MPI: portable parallel programming with the message-passing interface. MIT Press, 1994.

[mpi-ref]
    Mark Snir, Steve Otto, Steven Huss-Lederman, David Walker, and Jack Dongarra. MPI - The Complete Reference, volume 1, The MPI Core. MIT Press, 2nd. edition, 1998.

[mpi-mpich]
    W. Gropp, E. Lusk, N. Doss, and A. Skjellum. A high-performance, portable implementation of the MPI message passing interface standard. Parallel Computing, 22(6):789-828, September 1996.

[mpi-openmpi]
    Edgar Gabriel, Graham E. Fagg, George Bosilca, Thara Angskun, Jack J. Dongarra, Jeffrey M. Squyres, Vishal Sahay, Prabhanjan Kambadur, Brian Barrett, Andrew Lumsdaine, Ralph H. Castain, David J. Daniel, Richard L. Graham, and Timothy S. Woodall. Open MPI: Goals, Concept, and Design of a Next Generation MPI Implementation. In Proceedings, 11th European PVM/MPI Users’ Group Meeting, Budapest, Hungary, September 2004.

[Hinsen97]
    Konrad Hinsen. The Molecular Modelling Toolkit: a case study of a large scientific application in Python. In Proceedings of the 6th International Python Conference, pages 29-35, San Jose, Ca., October 1997.

[Beazley97]
    David M. Beazley and Peter S. Lomdahl. Feeding a large-scale physics application to Python. In Proceedings of the 6th International Python Conference, pages 21-29, San Jose, Ca., October 1997.

OVERVIEW

MPI for Python provides an object oriented approach to message passing which grounds on the standard MPI-2 C++ bindings. The interface was designed with focus in translating MPI syntax and semantics of standard MPI-2 bindings for C++ to Python. Any user of the standard C/C++ MPI bindings should be able to use this module without need of learning a new interface.

  Communicating Python Objects and Array Data

The Python standard library supports different mechanisms for data persistence. Many of them rely on disk storage, but pickling and marshaling can also work with memory buffers.

The pickle <https://docs.python.org/3/library/pickle.html#module-pickle> modules provide user-extensible facilities to serialize general Python objects using ASCII or binary formats. The marshal <https://docs.python.org/3/library/marshal.html#module-marshal> module provides facilities to serialize built-in Python objects using a binary format specific to Python, but independent of machine architecture issues.

MPI for Python can communicate any built-in or user-defined Python object taking advantage of the features provided by the pickle <https://docs.python.org/3/library/pickle.html#module-pickle> module. These facilities will be routinely used to build binary representations of objects to communicate (at sending processes), and restoring them back (at receiving processes).

Although simple and general, the serialization approach (i.e., pickling and unpickling) previously discussed imposes important overheads in memory as well as processor usage, especially in the scenario of objects with large memory footprints being communicated. Pickling general Python objects, ranging from primitive or container built-in types to user-defined classes, necessarily requires computer resources. Processing is also needed for dispatching the appropriate serialization method (that depends on the type of the object) and doing the actual packing. Additional memory is always needed, and if its total amount is not known a priori, many reallocations can occur. Indeed, in the case of large numeric arrays, this is certainly unacceptable and precludes communication of objects occupying half or more of the available memory resources.

MPI for Python supports direct communication of any object exporting the single-segment buffer interface. This interface is a standard Python mechanism provided by some types (e.g., strings and numeric arrays), allowing access in the C side to a contiguous memory buffer (i.e., address and length) containing the relevant data. This feature, in conjunction with the capability of constructing user-defined MPI datatypes describing complicated memory layouts, enables the implementation of many algorithms involving multidimensional numeric arrays (e.g., image processing, fast Fourier transforms, finite difference schemes on structured Cartesian grids) directly in Python, with negligible overhead, and almost as fast as compiled Fortran, C, or C++ codes.

  Communicators

In MPI for Python, Comm <#mpi4py.MPI.Comm> is the base class of communicators. The Intracomm <#mpi4py.MPI.Intracomm> and Intercomm <#mpi4py.MPI.Intercomm> classes are subclasses of the Comm <#mpi4py.MPI.Comm> class. The Comm.Is_inter <#mpi4py.MPI.Comm.Is_inter> method (and Comm.Is_intra <#mpi4py.MPI.Comm.Is_intra>, provided for convenience but not part of the MPI specification) is defined for communicator objects and can be used to determine the particular communicator class.

The two predefined intracommunicator instances are available: COMM_SELF <#mpi4py.MPI.COMM_SELF> and COMM_WORLD <#mpi4py.MPI.COMM_WORLD>. From them, new communicators can be created as needed.

The number of processes in a communicator and the calling process rank can be respectively obtained with methods Comm.Get_size <#mpi4py.MPI.Comm.Get_size> and Comm.Get_rank <#mpi4py.MPI.Comm.Get_rank>. The associated process group can be retrieved from a communicator by calling the Comm.Get_group <#mpi4py.MPI.Comm.Get_group> method, which returns an instance of the Group <#mpi4py.MPI.Group> class. Set operations with Group <#mpi4py.MPI.Group> objects like like Group.Union <#mpi4py.MPI.Group.Union>, Group.Intersection <#mpi4py.MPI.Group.Intersection> and Group.Difference <#mpi4py.MPI.Group.Difference> are fully supported, as well as the creation of new communicators from these groups using Comm.Create <#mpi4py.MPI.Comm.Create> and Intracomm.Create_group <#mpi4py.MPI.Intracomm.Create_group>.

New communicator instances can be obtained with the Comm.Clone <#mpi4py.MPI.Comm.Clone>, Comm.Dup <#mpi4py.MPI.Comm.Dup> and Comm.Split <#mpi4py.MPI.Comm.Split> methods, as well methods Intracomm.Create_intercomm <#mpi4py.MPI.Intracomm.Create_intercomm> and Intercomm.Merge <#mpi4py.MPI.Intercomm.Merge>.

Virtual topologies (Cartcomm <#mpi4py.MPI.Cartcomm>, Graphcomm <#mpi4py.MPI.Graphcomm> and Distgraphcomm <#mpi4py.MPI.Distgraphcomm> classes, which are specializations of the Intracomm <#mpi4py.MPI.Intracomm> class) are fully supported. New instances can be obtained from intracommunicator instances with factory methods Intracomm.Create_cart <#mpi4py.MPI.Intracomm.Create_cart> and Intracomm.Create_graph <#mpi4py.MPI.Intracomm.Create_graph>.

  Point-to-Point Communications

Point to point communication is a fundamental capability of message passing systems. This mechanism enables the transmission of data between a pair of processes, one side sending, the other receiving.

MPI provides a set of send and receive functions allowing the communication of typed data with an associated tag. The type information enables the conversion of data representation from one architecture to another in the case of heterogeneous computing environments; additionally, it allows the representation of non-contiguous data layouts and user-defined datatypes, thus avoiding the overhead of (otherwise unavoidable) packing/unpacking operations. The tag information allows selectivity of messages at the receiving end.

  Blocking Communications

MPI provides basic send and receive functions that are blocking. These functions block the caller until the data buffers involved in the communication can be safely reused by the application program.

In MPI for Python, the Comm.Send <#mpi4py.MPI.Comm.Send>, Comm.Recv <#mpi4py.MPI.Comm.Recv> and Comm.Sendrecv <#mpi4py.MPI.Comm.Sendrecv> methods of communicator objects provide support for blocking point-to-point communications within Intracomm <#mpi4py.MPI.Intracomm> and Intercomm <#mpi4py.MPI.Intercomm> instances. These methods can communicate memory buffers. The variants Comm.send <#mpi4py.MPI.Comm.send>, Comm.recv <#mpi4py.MPI.Comm.recv> and Comm.sendrecv <#mpi4py.MPI.Comm.sendrecv> can communicate general Python objects.

  Nonblocking Communications

On many systems, performance can be significantly increased by overlapping communication and computation. This is particularly true on systems where communication can be executed autonomously by an intelligent, dedicated communication controller.

MPI provides nonblocking send and receive functions. They allow the possible overlap of communication and computation. Non-blocking communication always come in two parts: posting functions, which begin the requested operation; and test-for-completion functions, which allow to discover whether the requested operation has completed.

In MPI for Python, the Comm.Isend <#mpi4py.MPI.Comm.Isend> and Comm.Irecv <#mpi4py.MPI.Comm.Irecv> methods initiate send and receive operations, respectively. These methods return a Request <#mpi4py.MPI.Request> instance, uniquely identifying the started operation. Its completion can be managed using the Request.Test <#mpi4py.MPI.Request.Test>, Request.Wait <#mpi4py.MPI.Request.Wait>, and Request.Cancel <#mpi4py.MPI.Request.Cancel> methods. The management of Request <#mpi4py.MPI.Request> objects and associated memory buffers involved in communication requires a careful, rather low-level coordination. Users must ensure that objects exposing their memory buffers are not accessed at the Python level while they are involved in nonblocking message-passing operations.

  Persistent Communications

Often a communication with the same argument list is repeatedly executed within an inner loop. In such cases, communication can be further optimized by using persistent communication, a particular case of nonblocking communication allowing the reduction of the overhead between processes and communication controllers. Furthermore , this kind of optimization can also alleviate the extra call overheads associated to interpreted, dynamic languages like Python.

In MPI for Python, the Comm.Send_init <#mpi4py.MPI.Comm.Send_init> and Comm.Recv_init <#mpi4py.MPI.Comm.Recv_init> methods create persistent requests for a send and receive operation, respectively. These methods return an instance of the Prequest <#mpi4py.MPI.Prequest> class, a subclass of the Request <#mpi4py.MPI.Request> class. The actual communication can be effectively started using the Prequest.Start <#mpi4py.MPI.Prequest.Start> method, and its completion can be managed as previously described.

  Collective Communications

Collective communications allow the transmittal of data between multiple processes of a group simultaneously. The syntax and semantics of collective functions is consistent with point-to-point communication. Collective functions communicate typed data, but messages are not paired with an associated tag; selectivity of messages is implied in the calling order.

The more commonly used collective communication operations are the following.

    •   Barrier synchronization across all group members.

    •   Global communication functions

        •   Broadcast data from one member to all members of a group.

        •   Gather data from all members to one member of a group.

        •   Scatter data from one member to all members of a group.

    •   Global reduction operations such as sum, maximum, minimum, etc.

In MPI for Python, the Comm.Bcast <#mpi4py.MPI.Comm.Bcast>, Comm.Scatter <#mpi4py.MPI.Comm.Scatter>, Comm.Gather <#mpi4py.MPI.Comm.Gather>, Comm.Allgather <#mpi4py.MPI.Comm.Allgather>, Comm.Alltoall <#mpi4py.MPI.Comm.Alltoall> methods provide support for collective communications of memory buffers. The lower-case variants Comm.bcast <#mpi4py.MPI.Comm.bcast>, Comm.scatter <#mpi4py.MPI.Comm.scatter>, Comm.gather <#mpi4py.MPI.Comm.gather>, Comm.allgather <#mpi4py.MPI.Comm.allgather> and Comm.alltoall <#mpi4py.MPI.Comm.alltoall> can communicate general Python objects. The vector variants (which can communicate different amounts of data to each process) Comm.Scatterv <#mpi4py.MPI.Comm.Scatterv>, Comm.Gatherv <#mpi4py.MPI.Comm.Gatherv>, Comm.Allgatherv <#mpi4py.MPI.Comm.Allgatherv>, Comm.Alltoallv <#mpi4py.MPI.Comm.Alltoallv> and Comm.Alltoallw <#mpi4py.MPI.Comm.Alltoallw> are also supported, they can only communicate objects exposing memory buffers.

Global reduction operations on memory buffers are accessible through the Comm.Reduce <#mpi4py.MPI.Comm.Reduce>, Comm.Reduce_scatter <#mpi4py.MPI.Comm.Reduce_scatter>, Comm.Allreduce <#mpi4py.MPI.Comm.Allreduce>, Intracomm.Scan <#mpi4py.MPI.Intracomm.Scan> and Intracomm.Exscan <#mpi4py.MPI.Intracomm.Exscan> methods. The lower-case variants Comm.reduce <#mpi4py.MPI.Comm.reduce>, Comm.allreduce <#mpi4py.MPI.Comm.allreduce>, Intracomm.scan <#mpi4py.MPI.Intracomm.scan> and Intracomm.exscan <#mpi4py.MPI.Intracomm.exscan> can communicate general Python objects; however, the actual required reduction computations are performed sequentially at some process. All the predefined (i.e., SUM <#mpi4py.MPI.SUM>, PROD <#mpi4py.MPI.PROD>, MAX <#mpi4py.MPI.MAX>, etc.) reduction operations can be applied.

  Support for GPU-aware MPI

Several MPI implementations, including Open MPI and MVAPICH, support passing GPU pointers to MPI calls to avoid explicit data movement between host and device. On the Python side, support for handling GPU arrays have been implemented in many libraries related GPU computation such as CuPy <https://cupy.dev/>, Numba <https://numba.pydata.org/>, PyTorch <https://pytorch.org/>, and PyArrow <https://arrow.apache.org/docs/python/>. To maximize interoperability across library boundaries, two kinds of zero-copy data exchange protocols have been defined and agreed upon: DLPack and CUDA Array Interface (CAI).

MPI for Python provides an experimental support for GPU-aware MPI. This feature requires:

    1.  mpi4py is built against a GPU-aware MPI library.

    2.  The Python GPU arrays are compliant with either of the protocols.

See the Tutorial <> section for further information. We note that

    •   Whether or not a MPI call can work for GPU arrays depends on the underlying MPI implementation, not on mpi4py.

    •   This support is currently experimental and subject to change in the future.

  Dynamic Process Management

In the context of the MPI-1 specification, a parallel application is static; that is, no processes can be added to or deleted from a running application after it has been started. Fortunately, this limitation was addressed in MPI-2. The new specification added a process management model providing a basic interface between an application and external resources and process managers.

This MPI-2 extension can be really useful, especially for sequential applications built on top of parallel modules, or parallel applications with a client/server model. The MPI-2 process model provides a mechanism to create new processes and establish communication between them and the existing MPI application. It also provides mechanisms to establish communication between two existing MPI applications, even when one did not start the other.

In MPI for Python, new independent process groups can be created by calling the Intracomm.Spawn <#mpi4py.MPI.Intracomm.Spawn> method within an intracommunicator. This call returns a new intercommunicator (i.e., an Intercomm <#mpi4py.MPI.Intercomm> instance) at the parent process group. The child process group can retrieve the matching intercommunicator by calling the Comm.Get_parent <#mpi4py.MPI.Comm.Get_parent> class method. At each side, the new intercommunicator can be used to perform point to point and collective communications between the parent and child groups of processes.

Alternatively, disjoint groups of processes can establish communication using a client/server approach. Any server application must first call the Open_port <#mpi4py.MPI.Open_port> function to open a port and the Publish_name <#mpi4py.MPI.Publish_name> function to publish a provided service, and next call the Intracomm.Accept <#mpi4py.MPI.Intracomm.Accept> method. Any client applications can first find a published service by calling the Lookup_name <#mpi4py.MPI.Lookup_name> function, which returns the port where a server can be contacted; and next call the Intracomm.Connect <#mpi4py.MPI.Intracomm.Connect> method. Both Intracomm.Accept <#mpi4py.MPI.Intracomm.Accept> and Intracomm.Connect <#mpi4py.MPI.Intracomm.Connect> methods return an Intercomm <#mpi4py.MPI.Intercomm> instance. When connection between client/server processes is no longer needed, all of them must cooperatively call the Comm.Disconnect <#mpi4py.MPI.Comm.Disconnect> method. Additionally, server applications should release resources by calling the Unpublish_name <#mpi4py.MPI.Unpublish_name> and Close_port <#mpi4py.MPI.Close_port> functions.

  One-Sided Communications

One-sided communications (also called Remote Memory Access, RMA) supplements the traditional two-sided, send/receive based MPI communication model with a one-sided, put/get based interface. One-sided communication that can take advantage of the capabilities of highly specialized network hardware. Additionally, this extension lowers latency and software overhead in applications written using a shared-memory-like paradigm.

The MPI specification revolves around the use of objects called windows; they intuitively specify regions of a process’s memory that have been made available for remote read and write operations. The published memory blocks can be accessed through three functions for put (remote send), get (remote write), and accumulate (remote update or reduction) data items. A much larger number of functions support different synchronization styles; the semantics of these synchronization operations are fairly complex.

In MPI for Python, one-sided operations are available by using instances of the Win <#mpi4py.MPI.Win> class. New window objects are created by calling the Win.Create <#mpi4py.MPI.Win.Create> method at all processes within a communicator and specifying a memory buffer . When a window instance is no longer needed, the Win.Free <#mpi4py.MPI.Win.Free> method should be called.

The three one-sided MPI operations for remote write, read and reduction are available through calling the methods Win.Put <#mpi4py.MPI.Win.Put>, Win.Get <#mpi4py.MPI.Win.Get>, and Win.Accumulate <#mpi4py.MPI.Win.Accumulate> respectively within a Win <#mpi4py.MPI.Win> instance. These methods need an integer rank identifying the target process and an integer offset relative the base address of the remote memory block being accessed.

The one-sided operations read, write, and reduction are implicitly nonblocking, and must be synchronized by using two primary modes. Active target synchronization requires the origin process to call the Win.Start <#mpi4py.MPI.Win.Start> and Win.Complete <#mpi4py.MPI.Win.Complete> methods at the origin process, and target process cooperates by calling the Win.Post <#mpi4py.MPI.Win.Post> and Win.Wait <#mpi4py.MPI.Win.Wait> methods. There is also a collective variant provided by the Win.Fence <#mpi4py.MPI.Win.Fence> method. Passive target synchronization is more lenient, only the origin process calls the Win.Lock <#mpi4py.MPI.Win.Lock> and Win.Unlock <#mpi4py.MPI.Win.Unlock> methods. Locks are used to protect remote accesses to the locked remote window and to protect local load/store accesses to a locked local window.

  Parallel Input/Output

The POSIX standard provides a model of a widely portable file system. However, the optimization needed for parallel input/output cannot be achieved with this generic interface. In order to ensure efficiency and scalability, the underlying parallel input/output system must provide a high-level interface supporting partitioning of file data among processes and a collective interface supporting complete transfers of global data structures between process memories and files. Additionally, further efficiencies can be gained via support for asynchronous input/output, strided accesses to data, and control over physical file layout on storage devices. This scenario motivated the inclusion in the MPI-2 standard of a custom interface in order to support more elaborated parallel input/output operations.

The MPI specification for parallel input/output revolves around the use objects called files. As defined by MPI, files are not just contiguous byte streams. Instead, they are regarded as ordered collections of typed data items. MPI supports sequential or random access to any integral set of these items. Furthermore, files are opened collectively by a group of processes.

The common patterns for accessing a shared file (broadcast, scatter, gather, reduction) is expressed by using user-defined datatypes. Compared to the communication patterns of point-to-point and collective communications, this approach has the advantage of added flexibility and expressiveness. Data access operations (read and write) are defined for different kinds of positioning (using explicit offsets, individual file pointers, and shared file pointers), coordination (non-collective and collective), and synchronism (blocking, nonblocking, and split collective with begin/end phases).

In MPI for Python, all MPI input/output operations are performed through instances of the File <#mpi4py.MPI.File> class. File handles are obtained by calling the File.Open <#mpi4py.MPI.File.Open> method at all processes within a communicator and providing a file name and the intended access mode. After use, they must be closed by calling the File.Close <#mpi4py.MPI.File.Close> method. Files even can be deleted by calling method File.Delete <#mpi4py.MPI.File.Delete>.

After creation, files are typically associated with a per-process view. The view defines the current set of data visible and accessible from an open file as an ordered set of elementary datatypes. This data layout can be set and queried with the File.Set_view <#mpi4py.MPI.File.Set_view> and File.Get_view <#mpi4py.MPI.File.Get_view> methods respectively.

Actual input/output operations are achieved by many methods combining read and write calls with different behavior regarding positioning, coordination, and synchronism. Summing up, MPI for Python provides the thirty (30) methods defined in MPI-2 for reading from or writing to files using explicit offsets or file pointers (individual or shared), in blocking or nonblocking and collective or noncollective versions.

  Environmental Management

  Initialization and Exit

Module functions Init <#mpi4py.MPI.Init> or Init_thread <#mpi4py.MPI.Init_thread> and Finalize <#mpi4py.MPI.Finalize> provide MPI initialization and finalization respectively. Module functions Is_initialized <#mpi4py.MPI.Is_initialized> and Is_finalized <#mpi4py.MPI.Is_finalized> provide the respective tests for initialization and finalization.

Note:
        MPI_Init() or MPI_Init_thread() is actually called when you import the MPI <#module-mpi4py.MPI> module from the mpi4py <#module-mpi4py> package, but only if MPI is not already initialized. In such case, calling Init <#mpi4py.MPI.Init> or Init_thread <#mpi4py.MPI.Init_thread> from Python is expected to generate an MPI error, and in turn an exception will be raised.

Note:
        MPI_Finalize() is registered (by using Python C/API function Py_AtExit() <https://docs.python.org/3/c-api/sys.html#c.Py_AtExit>) for being automatically called when Python processes exit, but only if mpi4py <#module-mpi4py> actually initialized MPI. Therefore, there is no need to call Finalize <#mpi4py.MPI.Finalize> from Python to ensure MPI finalization.

  Implementation Information

    •   The MPI version number can be retrieved from module function Get_version <#mpi4py.MPI.Get_version>. It returns a two-integer tuple (version, subversion).

    •   The Get_processor_name <#mpi4py.MPI.Get_processor_name> function can be used to access the processor name.

    •   The values of predefined attributes attached to the world communicator can be obtained by calling the Comm.Get_attr <#mpi4py.MPI.Comm.Get_attr> method within the COMM_WORLD <#mpi4py.MPI.COMM_WORLD> instance.

  Timers

MPI timer functionalities are available through the Wtime <#mpi4py.MPI.Wtime> and Wtick <#mpi4py.MPI.Wtick> functions.

  Error Handling

In order to facilitate handle sharing with other Python modules interfacing MPI-based parallel libraries, the predefined MPI error handlers ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN> and ERRORS_ARE_FATAL <#mpi4py.MPI.ERRORS_ARE_FATAL> can be assigned to and retrieved from communicators using methods Comm.Set_errhandler <#mpi4py.MPI.Comm.Set_errhandler> and Comm.Get_errhandler <#mpi4py.MPI.Comm.Get_errhandler>, and similarly for windows and files. New custom error handlers can be created with Comm.Create_errhandler <#mpi4py.MPI.Comm.Create_errhandler>.

When the predefined error handler ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN> is set, errors returned from MPI calls within Python code will raise an instance of the exception class Exception <#mpi4py.MPI.Exception>, which is a subclass of the standard Python exception RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>.

Note:
        After import, mpi4py overrides the default MPI rules governing inheritance of error handlers. The ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN> error handler is set in the predefined COMM_SELF <#mpi4py.MPI.COMM_SELF> and COMM_WORLD <#mpi4py.MPI.COMM_WORLD> communicators, as well as any new Comm <#mpi4py.MPI.Comm>, Win <#mpi4py.MPI.Win>, or File <#mpi4py.MPI.File> instance created through mpi4py. If you ever pass such handles to C/C++/Fortran library code, it is recommended to set the ERRORS_ARE_FATAL <#mpi4py.MPI.ERRORS_ARE_FATAL> error handler on them to ensure MPI errors do not pass silently.

Warning:
        Importing with from mpi4py.MPI import * will cause a name clashing with the standard Python Exception <https://docs.python.org/3/library/exceptions.html#Exception> base class.

TUTORIAL

Warning:
        Under construction. Contributions very welcome!

Tip:
        Rolf Rabenseifner <https://www.hlrs.de/people/rolf-rabenseifner> at HLRS <https://www.hlrs.de/> developed a comprehensive MPI-3.1/4.0 course with slides and a large set of exercises including solutions. This material is available online <https://www.hlrs.de/training/self-study-materials/mpi-course-material> for self-study. The slides and exercises show the C, Fortran, and Python (mpi4py) interfaces. For performance reasons, most Python exercises use NumPy arrays and communication routines involving buffer-like objects.

Tip:
        Victor Eijkhout <https://tacc.utexas.edu/about/staff-directory/victor-eijkhout> at TACC <https://tacc.utexas.edu/> authored the book Parallel Programming for Science and Engineering. This book is available online <https://theartofhpc.com/pcse.html> in PDF and HTML <https://theartofhpc.com/pcse/index.html> formats. The book covers parallel programming with MPI and OpenMP in C/C++ and Fortran, and MPI in Python using mpi4py.

MPI for Python supports convenient, pickle-based communication of generic Python object as well as fast, near C-speed, direct array data communication of buffer-provider objects (e.g., NumPy arrays).

    •   Communication of generic Python objects

        You have to use methods with all-lowercase names, like Comm.send <#mpi4py.MPI.Comm.send>, Comm.recv <#mpi4py.MPI.Comm.recv>, Comm.bcast <#mpi4py.MPI.Comm.bcast>, Comm.scatter <#mpi4py.MPI.Comm.scatter>, Comm.gather <#mpi4py.MPI.Comm.gather> . An object to be sent is passed as a parameter to the communication call, and the received object is simply the return value.

        The Comm.isend <#mpi4py.MPI.Comm.isend> and Comm.irecv <#mpi4py.MPI.Comm.irecv> methods return Request <#mpi4py.MPI.Request> instances; completion of these methods can be managed using the Request.test <#mpi4py.MPI.Request.test> and Request.wait <#mpi4py.MPI.Request.wait> methods.

        The Comm.recv <#mpi4py.MPI.Comm.recv> and Comm.irecv <#mpi4py.MPI.Comm.irecv> methods may be passed a buffer object that can be repeatedly used to receive messages avoiding internal memory allocation. This buffer must be sufficiently large to accommodate the transmitted messages; hence, any buffer passed to Comm.recv <#mpi4py.MPI.Comm.recv> or Comm.irecv <#mpi4py.MPI.Comm.irecv> must be at least as long as the pickled data transmitted to the receiver.

        Collective calls like Comm.scatter <#mpi4py.MPI.Comm.scatter>, Comm.gather <#mpi4py.MPI.Comm.gather>, Comm.allgather <#mpi4py.MPI.Comm.allgather>, Comm.alltoall <#mpi4py.MPI.Comm.alltoall> expect a single value or a sequence of Comm.size <#mpi4py.MPI.Comm.size> elements at the root or all process. They return a single value, a list of Comm.size <#mpi4py.MPI.Comm.size> elements, or None <https://docs.python.org/3/library/constants.html#None>.

        Note:
            MPI for Python uses the highest protocol version <https://docs.python.org/3/library/pickle.html#pickle-protocols> available in the Python runtime (see the HIGHEST_PROTOCOL <https://docs.python.org/3/library/pickle.html#pickle.HIGHEST_PROTOCOL> constant in the pickle <https://docs.python.org/3/library/pickle.html#module-pickle> module). The default protocol can be changed at import time by setting the MPI4PY_PICKLE_PROTOCOL <#envvar-MPI4PY_PICKLE_PROTOCOL> environment variable, or at runtime by assigning a different value to the PROTOCOL <#mpi4py.MPI.Pickle.PROTOCOL> attribute of the pickle <#mpi4py.MPI.pickle> object within the MPI <#module-mpi4py.MPI> module.

    •   Communication of buffer-like objects

        You have to use method names starting with an upper-case letter, like Comm.Send <#mpi4py.MPI.Comm.Send>, Comm.Recv <#mpi4py.MPI.Comm.Recv>, Comm.Bcast <#mpi4py.MPI.Comm.Bcast>, Comm.Scatter <#mpi4py.MPI.Comm.Scatter>, Comm.Gather <#mpi4py.MPI.Comm.Gather>.

        In general, buffer arguments to these calls must be explicitly specified by using a 2/3-list/tuple like [data, MPI.DOUBLE], or [data, count, MPI.DOUBLE] (the former one uses the byte-size of data and the extent of the MPI datatype to define count).

        For vector collectives communication operations like Comm.Scatterv <#mpi4py.MPI.Comm.Scatterv> and Comm.Gatherv <#mpi4py.MPI.Comm.Gatherv>, buffer arguments are specified as [data, count, displ, datatype], where count and displ are sequences of integral values.

        Automatic MPI datatype discovery for NumPy/GPU arrays and PEP-3118 buffers is supported, but limited to basic C types (all C/C99-native signed/unsigned integral types and single/double precision real/complex floating types) and availability of matching datatypes in the underlying MPI implementation. In this case, the buffer-provider object can be passed directly as a buffer argument, the count and MPI datatype will be inferred.

        If mpi4py is built against a GPU-aware MPI implementation, GPU arrays can be passed to upper-case methods as long as they have either the __dlpack__ and __dlpack_device__ methods or the __cuda_array_interface__ attribute that are compliant with the respective standard specifications. Moreover, only C-contiguous or Fortran-contiguous GPU arrays are supported. It is important to note that GPU buffers must be fully ready before any MPI routines operate on them to avoid race conditions. This can be ensured by using the synchronization API of your array library. mpi4py does not have access to any GPU-specific functionality and thus cannot perform this operation automatically for users.

  Running Python scripts with MPI

Most MPI programs can be run with the command mpiexec. In practice, running Python programs looks like:

            $ mpiexec -n 4 python script.py

to run the program with 4 processors.

  Point-to-Point Communication

    •   Python objects (pickle <https://docs.python.org/3/library/pickle.html#module-pickle> under the hood):

                from mpi4py import MPI

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                if rank == 0:
                    data = {'a': 7, 'b': 3.14}
                    comm.send(data, dest=1, tag=11)
                elif rank == 1:
                    data = comm.recv(source=0, tag=11)

    •   Python objects with non-blocking communication:

                from mpi4py import MPI

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                if rank == 0:
                    data = {'a': 7, 'b': 3.14}
                    req = comm.isend(data, dest=1, tag=11)
                    req.wait()
                elif rank == 1:
                    req = comm.irecv(source=0, tag=11)
                    data = req.wait()

    •   NumPy arrays (the fast way!):

                from mpi4py import MPI
                import numpy

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                # passing MPI datatypes explicitly
                if rank == 0:
                    data = numpy.arange(1000, dtype='i')
                    comm.Send([data, MPI.INT], dest=1, tag=77)
                elif rank == 1:
                    data = numpy.empty(1000, dtype='i')
                    comm.Recv([data, MPI.INT], source=0, tag=77)

                # automatic MPI datatype discovery
                if rank == 0:
                    data = numpy.arange(100, dtype=numpy.float64)
                    comm.Send(data, dest=1, tag=13)
                elif rank == 1:
                    data = numpy.empty(100, dtype=numpy.float64)
                    comm.Recv(data, source=0, tag=13)

  Collective Communication

    •   Broadcasting a Python dictionary:

                from mpi4py import MPI

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                if rank == 0:
                    data = {'key1' : [7, 2.72, 2+3j],
                            'key2' : ( 'abc', 'xyz')}
                else:
                    data = None
                data = comm.bcast(data, root=0)

    •   Scattering Python objects:

                from mpi4py import MPI

                comm = MPI.COMM_WORLD
                size = comm.Get_size()
                rank = comm.Get_rank()

                if rank == 0:
                    data = [(i+1)**2 for i in range(size)]
                else:
                    data = None
                data = comm.scatter(data, root=0)
                assert data == (rank+1)**2

    •   Gathering Python objects:

                from mpi4py import MPI

                comm = MPI.COMM_WORLD
                size = comm.Get_size()
                rank = comm.Get_rank()

                data = (rank+1)**2
                data = comm.gather(data, root=0)
                if rank == 0:
                    for i in range(size):
                        assert data[i] == (i+1)**2
                else:
                    assert data is None

    •   Broadcasting a NumPy array:

                from mpi4py import MPI
                import numpy as np

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                if rank == 0:
                    data = np.arange(100, dtype='i')
                else:
                    data = np.empty(100, dtype='i')
                comm.Bcast(data, root=0)
                for i in range(100):
                    assert data[i] == i

    •   Scattering NumPy arrays:

                from mpi4py import MPI
                import numpy as np

                comm = MPI.COMM_WORLD
                size = comm.Get_size()
                rank = comm.Get_rank()

                sendbuf = None
                if rank == 0:
                    sendbuf = np.empty([size, 100], dtype='i')
                    sendbuf.T[:,:] = range(size)
                recvbuf = np.empty(100, dtype='i')
                comm.Scatter(sendbuf, recvbuf, root=0)
                assert np.allclose(recvbuf, rank)

    •   Gathering NumPy arrays:

                from mpi4py import MPI
                import numpy as np

                comm = MPI.COMM_WORLD
                size = comm.Get_size()
                rank = comm.Get_rank()

                sendbuf = np.zeros(100, dtype='i') + rank
                recvbuf = None
                if rank == 0:
                    recvbuf = np.empty([size, 100], dtype='i')
                comm.Gather(sendbuf, recvbuf, root=0)
                if rank == 0:
                    for i in range(size):
                        assert np.allclose(recvbuf[i,:], i)

    •   Parallel matrix-vector product:

                from mpi4py import MPI
                import numpy

                def matvec(comm, A, x):
                    m = A.shape[0] # local rows
                    p = comm.Get_size()
                    xg = numpy.zeros(m*p, dtype='d')
                    comm.Allgather([x,  MPI.DOUBLE],
                                   [xg, MPI.DOUBLE])
                    y = numpy.dot(A, xg)
                    return y

  Input/Output (MPI-IO)

    •   Collective I/O with NumPy arrays:

                from mpi4py import MPI
                import numpy as np

                amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
                comm = MPI.COMM_WORLD
                fh = MPI.File.Open(comm, "./datafile.contig", amode)

                buffer = np.empty(10, dtype=np.int)
                buffer[:] = comm.Get_rank()

                offset = comm.Get_rank()*buffer.nbytes
                fh.Write_at_all(offset, buffer)

                fh.Close()

    •   Non-contiguous Collective I/O with NumPy arrays and datatypes:

                from mpi4py import MPI
                import numpy as np

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()
                size = comm.Get_size()

                amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
                fh = MPI.File.Open(comm, "./datafile.noncontig", amode)

                item_count = 10

                buffer = np.empty(item_count, dtype='i')
                buffer[:] = rank

                filetype = MPI.INT.Create_vector(item_count, 1, size)
                filetype.Commit()

                displacement = MPI.INT.Get_size()*rank
                fh.Set_view(displacement, filetype=filetype)

                fh.Write_all(buffer)
                filetype.Free()
                fh.Close()

  Dynamic Process Management

    •   Compute Pi - Master (or parent, or client) side:

                #!/usr/bin/env python
                from mpi4py import MPI
                import numpy
                import sys

                comm = MPI.COMM_SELF.Spawn(sys.executable,
                                           args=['cpi.py'],
                                           maxprocs=5)

                N = numpy.array(100, 'i')
                comm.Bcast([N, MPI.INT], root=MPI.ROOT)
                PI = numpy.array(0.0, 'd')
                comm.Reduce(None, [PI, MPI.DOUBLE],
                            op=MPI.SUM, root=MPI.ROOT)
                print(PI)

                comm.Disconnect()

    •   Compute Pi - Worker (or child, or server) side:

                #!/usr/bin/env python
                from mpi4py import MPI
                import numpy

                comm = MPI.Comm.Get_parent()
                size = comm.Get_size()
                rank = comm.Get_rank()

                N = numpy.array(0, dtype='i')
                comm.Bcast([N, MPI.INT], root=0)
                h = 1.0 / N; s = 0.0
                for i in range(rank, N, size):
                    x = h * (i + 0.5)
                    s += 4.0 / (1.0 + x**2)
                PI = numpy.array(s * h, dtype='d')
                comm.Reduce([PI, MPI.DOUBLE], None,
                            op=MPI.SUM, root=0)

                comm.Disconnect()

  GPU-aware MPI + Python GPU arrays

    •   Reduce-to-all CuPy arrays:

                from mpi4py import MPI
                import cupy as cp

                comm = MPI.COMM_WORLD
                size = comm.Get_size()
                rank = comm.Get_rank()

                sendbuf = cp.arange(10, dtype='i')
                recvbuf = cp.empty_like(sendbuf)
                cp.cuda.get_current_stream().synchronize()
                comm.Allreduce(sendbuf, recvbuf)

                assert cp.allclose(recvbuf, sendbuf*size)

  One-Sided Communication (RMA)

    •   Read from (write to) the entire RMA window:

                import numpy as np
                from mpi4py import MPI
                from mpi4py.util import dtlib

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                datatype = MPI.FLOAT
                np_dtype = dtlib.to_numpy_dtype(datatype)
                itemsize = datatype.Get_size()

                N = 10
                win_size = N * itemsize if rank == 0 else 0
                win = MPI.Win.Allocate(win_size, comm=comm)

                buf = np.empty(N, dtype=np_dtype)
                if rank == 0:
                    buf.fill(42)
                    win.Lock(rank=0)
                    win.Put(buf, target_rank=0)
                    win.Unlock(rank=0)
                    comm.Barrier()
                else:
                    comm.Barrier()
                    win.Lock(rank=0)
                    win.Get(buf, target_rank=0)
                    win.Unlock(rank=0)
                    assert np.all(buf == 42)

    •   Accessing a part of the RMA window using the target argument, which is defined as (offset, count, datatype):

                import numpy as np
                from mpi4py import MPI
                from mpi4py.util import dtlib

                comm = MPI.COMM_WORLD
                rank = comm.Get_rank()

                datatype = MPI.FLOAT
                np_dtype = dtlib.to_numpy_dtype(datatype)
                itemsize = datatype.Get_size()

                N = comm.Get_size() + 1
                win_size = N * itemsize if rank == 0 else 0
                win = MPI.Win.Allocate(
                    size=win_size,
                    disp_unit=itemsize,
                    comm=comm,
                )
                if rank == 0:
                    mem = np.frombuffer(win, dtype=np_dtype)
                    mem[:] = np.arange(len(mem), dtype=np_dtype)
                comm.Barrier()

                buf = np.zeros(3, dtype=np_dtype)
                target = (rank, 2, datatype)
                win.Lock(rank=0)
                win.Get(buf, target_rank=0, target=target)
                win.Unlock(rank=0)
                assert np.all(buf == [rank, rank+1, 0])

  Wrapping with SWIG

    •   C source:

                /* file: helloworld.c */
                void sayhello(MPI_Comm comm)
                {
                  int size, rank;
                  MPI_Comm_size(comm, &size);
                  MPI_Comm_rank(comm, &rank);
                  printf("Hello, World! "
                         "I am process %d of %d.\n",
                         rank, size);
                }

    •   SWIG interface file:

                // file: helloworld.i
                %module helloworld
                %{
                #include <mpi.h>
                #include "helloworld.c"
                }%

                %include mpi4py/mpi4py.i
                %mpi4py_typemap(Comm, MPI_Comm);
                void sayhello(MPI_Comm comm);

    •   Try it in the Python prompt:

                >>> from mpi4py import MPI
                >>> import helloworld
                >>> helloworld.sayhello(MPI.COMM_WORLD)
                Hello, World! I am process 0 of 1.

  Wrapping with F2Py

    •   Fortran 90 source:

                ! file: helloworld.f90
                subroutine sayhello(comm)
                  use mpi
                  implicit none
                  integer :: comm, rank, size, ierr
                  call MPI_Comm_size(comm, size, ierr)
                  call MPI_Comm_rank(comm, rank, ierr)
                  print *, 'Hello, World! I am process ',rank,' of ',size,'.'
                end subroutine sayhello

    •   Compiling example using f2py

                $ f2py -c --f90exec=mpif90 helloworld.f90 -m helloworld

    •   Try it in the Python prompt:

                >>> from mpi4py import MPI
                >>> import helloworld
                >>> fcomm = MPI.COMM_WORLD.py2f()
                >>> helloworld.sayhello(fcomm)
                Hello, World! I am process 0 of 1.

MPI4PY

The MPI for Python package.

The Message Passing Interface (MPI) is a standardized and portable message-passing system designed to function on a wide variety of parallel computers. The MPI standard defines the syntax and semantics of library routines and allows users to write portable programs in the main scientific programming languages (Fortran, C, or C++). Since its release, the MPI specification has become the leading standard for message-passing libraries for parallel computers.

MPI for Python provides MPI bindings for the Python programming language, allowing any Python program to exploit multiple processors. This package build on the MPI specification and provides an object oriented interface which closely follows MPI-2 C++ bindings.

  Runtime configuration options

    mpi4py.rc
        This object has attributes exposing runtime configuration options that become effective at import time of the MPI <#module-mpi4py.MPI> module.

Attributes Summary
initialize | Automatic MPI initialization at import
threads | Request initialization with thread support
thread_level | Level of thread support to request
finalize | Automatic MPI finalization at exit
fast_reduce | Use tree-based reductions for objects
recv_mprobe | Use matched probes to receive objects
irecv_bufsz | Default buffer size in bytes for irecv() <#mpi4py.MPI.Comm.irecv>
errors | Error handling policy

Attributes Documentation

    mpi4py.rc.initialize
        Automatic MPI initialization at import.

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    See also:
            MPI4PY_RC_INITIALIZE

    mpi4py.rc.threads
        Request initialization with thread support.

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    See also:
            MPI4PY_RC_THREADS

    mpi4py.rc.thread_level
        Level of thread support to request.

        Type
            str <https://docs.python.org/3/library/stdtypes.html#str>

        Default
            "multiple"

        Choices
            "multiple", "serialized", "funneled", "single"

    See also:
            MPI4PY_RC_THREAD_LEVEL

    mpi4py.rc.finalize
        Automatic MPI finalization at exit.

        If set to None <https://docs.python.org/3/library/constants.html#None>, the value of mpi4py.rc.initialize is used.

        Type
            None <https://docs.python.org/3/library/constants.html#None> or bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            None <https://docs.python.org/3/library/constants.html#None>

    See also:
            MPI4PY_RC_FINALIZE

    mpi4py.rc.fast_reduce
        Use tree-based reductions for objects.

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    See also:
            MPI4PY_RC_FAST_REDUCE

    mpi4py.rc.recv_mprobe
        Use matched probes to receive objects.

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    See also:
            MPI4PY_RC_RECV_MPROBE

    mpi4py.rc.irecv_bufsz
        Default buffer size in bytes for irecv() <#mpi4py.MPI.Comm.irecv>.

        Type
            int <https://docs.python.org/3/library/functions.html#int>

        Default
            32768

    See also:
            MPI4PY_RC_IRECV_BUFSZ

    Added in version 4.0.0.

    mpi4py.rc.errors
        Error handling policy.

        Type
            str <https://docs.python.org/3/library/stdtypes.html#str>

        Default
            "exception"

        Choices
            "exception", "default", "abort", "fatal"

    See also:
            MPI4PY_RC_ERRORS

Example

MPI for Python features automatic initialization and finalization of the MPI execution environment. By using the mpi4py.rc object, MPI initialization and finalization can be handled programmatically:

            import mpi4py
            mpi4py.rc.initialize = False  # do not initialize MPI automatically
            mpi4py.rc.finalize = False    # do not finalize MPI automatically

            from mpi4py import MPI # import the 'MPI' module

            MPI.Init()      # manual initialization of the MPI environment
            ...             # your finest code here ...
            MPI.Finalize()  # manual finalization of the MPI environment

  Environment variables

The following environment variables override the corresponding attributes of the mpi4py.rc and MPI.pickle <#mpi4py.MPI.pickle> objects at import time of the MPI <#module-mpi4py.MPI> module.

Note:
        For variables of boolean type, accepted values are 0 and 1 (interpreted as False <https://docs.python.org/3/library/constants.html#False> and True <https://docs.python.org/3/library/constants.html#True>, respectively), and strings specifying a YAML boolean <https://yaml.org/type/bool.html> value (case-insensitive).

    MPI4PY_RC_INITIALIZE

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    Whether to automatically initialize MPI at import time of the mpi4py.MPI <#module-mpi4py.MPI> module.

    See also:
            mpi4py.rc.initialize

    Added in version 4.0.0.

    MPI4PY_RC_FINALIZE

        Type
            None <https://docs.python.org/3/library/constants.html#None> | bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            None <https://docs.python.org/3/library/constants.html#None>

        Choices
            None <https://docs.python.org/3/library/constants.html#None>, True <https://docs.python.org/3/library/constants.html#True>, False <https://docs.python.org/3/library/constants.html#False>

    Whether to automatically finalize MPI at exit time of the Python process.

    See also:
            mpi4py.rc.finalize

    Added in version 4.0.0.

    MPI4PY_RC_THREADS

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    Whether to initialize MPI with thread support.

    See also:
            mpi4py.rc.threads

    Added in version 3.1.0.

    MPI4PY_RC_THREAD_LEVEL

        Default
            "multiple"

        Choices
            "single", "funneled", "serialized", "multiple"

    The level of required thread support.

    See also:
            mpi4py.rc.thread_level

    Added in version 3.1.0.

    MPI4PY_RC_FAST_REDUCE

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    Whether to use tree-based reductions for objects.

    See also:
            mpi4py.rc.fast_reduce

    Added in version 3.1.0.

    MPI4PY_RC_RECV_MPROBE

        Type
            bool <https://docs.python.org/3/library/functions.html#bool>

        Default
            True <https://docs.python.org/3/library/constants.html#True>

    Whether to use matched probes to receive objects.

    See also:
            mpi4py.rc.recv_mprobe

    MPI4PY_RC_IRECV_BUFSZ

        Type
            int <https://docs.python.org/3/library/functions.html#int>

        Default
            32768

    Default buffer size in bytes for irecv() <#mpi4py.MPI.Comm.irecv>.

    See also:
            mpi4py.rc.irecv_bufsz

    Added in version 4.0.0.

    MPI4PY_RC_ERRORS

        Default
            "exception"

        Choices
            "exception", "default", "abort", "fatal"

    Controls default MPI error handling policy.

    See also:
            mpi4py.rc.errors

    Added in version 3.1.0.

    MPI4PY_PICKLE_PROTOCOL

        Type
            int <https://docs.python.org/3/library/functions.html#int>

        Default
            pickle.HIGHEST_PROTOCOL <https://docs.python.org/3/library/pickle.html#pickle.HIGHEST_PROTOCOL>

    Controls the default pickle protocol to use when communicating Python objects.

    See also:
            PROTOCOL <#mpi4py.MPI.Pickle.PROTOCOL> attribute of the MPI.pickle <#mpi4py.MPI.pickle> object within the MPI <#module-mpi4py.MPI> module.

    Added in version 3.1.0.

    MPI4PY_PICKLE_THRESHOLD

        Type
            int <https://docs.python.org/3/library/functions.html#int>

        Default
            262144

    Controls the default buffer size threshold for switching from in-band to out-of-band buffer handling when using pickle protocol version 5 or higher.

    See also:
            THRESHOLD <#mpi4py.MPI.Pickle.THRESHOLD> attribute of the MPI.pickle <#mpi4py.MPI.pickle> object within the MPI <#module-mpi4py.MPI> module.

    Added in version 3.1.2.

  Miscellaneous functions

    mpi4py.profile(name, *, path=None)
        Support for the MPI profiling interface.

        Parameters

            •   name (str <https://docs.python.org/3/library/stdtypes.html#str>) – Name of the profiler library to load.

            •   path (sequence <https://docs.python.org/3/glossary.html#term-sequence> of str <https://docs.python.org/3/library/stdtypes.html#str>, optional) – Additional paths to search for the profiler.

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

    mpi4py.get_include()
        Return the directory in the package that contains header files.

        Extension modules that need to compile against mpi4py should use this function to locate the appropriate include directory. Using Python distutils (or perhaps NumPy distutils):

                import mpi4py
                Extension('extension_name', ...
                          include_dirs=[..., mpi4py.get_include()])

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

    mpi4py.get_config()
        Return a dictionary with information about MPI.

        Changed in version 4.0.0: By default, this function returns an empty dictionary. However, downstream packagers and distributors may alter such behavior. To that end, MPI information must be provided under an mpi section within a UTF-8 encoded INI-style configuration file mpi.cfg located at the top-level package directory. The configuration file is read and parsed using the configparser <https://docs.python.org/3/library/configparser.html#module-configparser> module.

        Return type
            dict <https://docs.python.org/3/library/stdtypes.html#dict>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>]

MPI4PY.MPI

  Classes

Ancillary
Datatype <#mpi4py.MPI.Datatype> | Datatype object.
Status <#mpi4py.MPI.Status> | Status object.
Request <#mpi4py.MPI.Request> | Request handler.
Prequest <#mpi4py.MPI.Prequest> | Persistent request handler.
Grequest <#mpi4py.MPI.Grequest> | Generalized request handler.
Op <#mpi4py.MPI.Op> | Reduction operation.
Group <#mpi4py.MPI.Group> | Group of processes.
Info <#mpi4py.MPI.Info> | Info object.
Session <#mpi4py.MPI.Session> | Session context.

Communication
Comm <#mpi4py.MPI.Comm> | Communication context.
Intracomm <#mpi4py.MPI.Intracomm> | Intracommunicator.
Topocomm <#mpi4py.MPI.Topocomm> | Topology intracommunicator.
Cartcomm <#mpi4py.MPI.Cartcomm> | Cartesian topology intracommunicator.
Graphcomm <#mpi4py.MPI.Graphcomm> | General graph topology intracommunicator.
Distgraphcomm <#mpi4py.MPI.Distgraphcomm> | Distributed graph topology intracommunicator.
Intercomm <#mpi4py.MPI.Intercomm> | Intercommunicator.
Message <#mpi4py.MPI.Message> | Matched message.

One-sided operations
Win <#mpi4py.MPI.Win> | Remote memory access context.

Input/Output
File <#mpi4py.MPI.File> | File I/O context.

Error handling
Errhandler <#mpi4py.MPI.Errhandler> | Error handler.
Exception <#mpi4py.MPI.Exception> | Exception class.

Auxiliary
Pickle <#mpi4py.MPI.Pickle> | Pickle/unpickle Python objects.
buffer <#mpi4py.MPI.buffer> | Buffer.

  Functions

Version inquiry
Get_version <#mpi4py.MPI.Get_version>() | Obtain the version number of the MPI standard.
Get_library_version <#mpi4py.MPI.Get_library_version>() | Obtain the version string of the MPI library.

Initialization and finalization
Init <#mpi4py.MPI.Init>() | Initialize the MPI execution environment.
Init_thread <#mpi4py.MPI.Init_thread>([required]) | Initialize the MPI execution environment.
Finalize <#mpi4py.MPI.Finalize>() | Terminate the MPI execution environment.
Is_initialized <#mpi4py.MPI.Is_initialized>() | Indicate whether Init <#mpi4py.MPI.Init> has been called.
Is_finalized <#mpi4py.MPI.Is_finalized>() | Indicate whether Finalize <#mpi4py.MPI.Finalize> has completed.
Query_thread <#mpi4py.MPI.Query_thread>() | Return the level of thread support provided by the MPI library.
Is_thread_main <#mpi4py.MPI.Is_thread_main>() | Indicate whether this thread called Init <#mpi4py.MPI.Init> or Init_thread <#mpi4py.MPI.Init_thread>.

Memory allocation
Alloc_mem <#mpi4py.MPI.Alloc_mem>(size[, info]) | Allocate memory for message passing and remote memory access.
Free_mem <#mpi4py.MPI.Free_mem>(mem) | Free memory allocated with Alloc_mem <#mpi4py.MPI.Alloc_mem>.

Address manipulation
Get_address <#mpi4py.MPI.Get_address>(location) | Get the address of a location in memory.
Aint_add <#mpi4py.MPI.Aint_add>(base, disp) | Return the sum of base address and displacement.
Aint_diff <#mpi4py.MPI.Aint_diff>(addr1, addr2) | Return the difference between absolute addresses.

Timer
Wtick <#mpi4py.MPI.Wtick>() | Return the resolution of Wtime <#mpi4py.MPI.Wtime>.
Wtime <#mpi4py.MPI.Wtime>() | Return an elapsed time on the calling processor.

Error handling
Get_error_class <#mpi4py.MPI.Get_error_class>(errorcode) | Convert an error code into an error class.
Get_error_string <#mpi4py.MPI.Get_error_string>(errorcode) | Return the error string for a given error class or error code.
Add_error_class <#mpi4py.MPI.Add_error_class>() | Add an error class to the known error classes.
Add_error_code <#mpi4py.MPI.Add_error_code>(errorclass) | Add an error code to an error class.
Add_error_string <#mpi4py.MPI.Add_error_string>(errorcode, string) | Associate an error string with an error class or error code.
Remove_error_class <#mpi4py.MPI.Remove_error_class>(errorclass) | Remove an error class from the known error classes.
Remove_error_code <#mpi4py.MPI.Remove_error_code>(errorcode) | Remove an error code from the known error codes.
Remove_error_string <#mpi4py.MPI.Remove_error_string>(errorcode) | Remove error string association from error class or error code.

Dynamic process management
Open_port <#mpi4py.MPI.Open_port>([info]) | Return an address used to connect group of processes.
Close_port <#mpi4py.MPI.Close_port>(port_name) | Close a port.
Publish_name <#mpi4py.MPI.Publish_name>(service_name, port_name[, info]) | Publish a service name.
Unpublish_name <#mpi4py.MPI.Unpublish_name>(service_name, port_name[, info]) | Unpublish a service name.
Lookup_name <#mpi4py.MPI.Lookup_name>(service_name[, info]) | Lookup a port name given a service name.

Miscellanea
Attach_buffer <#mpi4py.MPI.Attach_buffer>(buf) | Attach a user-provided buffer for sending in buffered mode.
Detach_buffer <#mpi4py.MPI.Detach_buffer>() | Remove an existing attached buffer.
Flush_buffer <#mpi4py.MPI.Flush_buffer>() | Block until all buffered messages have been transmitted.
Iflush_buffer <#mpi4py.MPI.Iflush_buffer>() | Nonblocking flush for buffered messages.
Compute_dims <#mpi4py.MPI.Compute_dims>(nnodes, dims) | Return a balanced distribution of processes per coordinate direction.
Get_processor_name <#mpi4py.MPI.Get_processor_name>() | Obtain the name of the calling processor.
Register_datarep <#mpi4py.MPI.Register_datarep>(datarep, read_fn, write_fn, ...) | Register user-defined data representations.
Pcontrol <#mpi4py.MPI.Pcontrol>(level) | Control profiling.

Utilities
get_vendor <#mpi4py.MPI.get_vendor>() | Information about the underlying MPI implementation.

  Attributes
UNDEFINED <#mpi4py.MPI.UNDEFINED> | Constant UNDEFINED of type int <https://docs.python.org/3/library/functions.html#int>
ANY_SOURCE <#mpi4py.MPI.ANY_SOURCE> | Constant ANY_SOURCE of type int <https://docs.python.org/3/library/functions.html#int>
ANY_TAG <#mpi4py.MPI.ANY_TAG> | Constant ANY_TAG of type int <https://docs.python.org/3/library/functions.html#int>
PROC_NULL <#mpi4py.MPI.PROC_NULL> | Constant PROC_NULL of type int <https://docs.python.org/3/library/functions.html#int>
ROOT <#mpi4py.MPI.ROOT> | Constant ROOT of type int <https://docs.python.org/3/library/functions.html#int>
BOTTOM <#mpi4py.MPI.BOTTOM> | Object BOTTOM of type BottomType <#mpi4py.MPI.BottomType>
IN_PLACE <#mpi4py.MPI.IN_PLACE> | Object IN_PLACE of type InPlaceType <#mpi4py.MPI.InPlaceType>
BUFFER_AUTOMATIC <#mpi4py.MPI.BUFFER_AUTOMATIC> | Object BUFFER_AUTOMATIC of type BufferAutomaticType <#mpi4py.MPI.BufferAutomaticType>
KEYVAL_INVALID <#mpi4py.MPI.KEYVAL_INVALID> | Constant KEYVAL_INVALID of type int <https://docs.python.org/3/library/functions.html#int>
TAG_UB <#mpi4py.MPI.TAG_UB> | Constant TAG_UB of type int <https://docs.python.org/3/library/functions.html#int>
IO <#mpi4py.MPI.IO> | Constant IO of type int <https://docs.python.org/3/library/functions.html#int>
WTIME_IS_GLOBAL <#mpi4py.MPI.WTIME_IS_GLOBAL> | Constant WTIME_IS_GLOBAL of type int <https://docs.python.org/3/library/functions.html#int>
UNIVERSE_SIZE <#mpi4py.MPI.UNIVERSE_SIZE> | Constant UNIVERSE_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
APPNUM <#mpi4py.MPI.APPNUM> | Constant APPNUM of type int <https://docs.python.org/3/library/functions.html#int>
LASTUSEDCODE <#mpi4py.MPI.LASTUSEDCODE> | Constant LASTUSEDCODE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_BASE <#mpi4py.MPI.WIN_BASE> | Constant WIN_BASE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_SIZE <#mpi4py.MPI.WIN_SIZE> | Constant WIN_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_DISP_UNIT <#mpi4py.MPI.WIN_DISP_UNIT> | Constant WIN_DISP_UNIT of type int <https://docs.python.org/3/library/functions.html#int>
WIN_CREATE_FLAVOR <#mpi4py.MPI.WIN_CREATE_FLAVOR> | Constant WIN_CREATE_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR <#mpi4py.MPI.WIN_FLAVOR> | Constant WIN_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
WIN_MODEL <#mpi4py.MPI.WIN_MODEL> | Constant WIN_MODEL of type int <https://docs.python.org/3/library/functions.html#int>
SUCCESS <#mpi4py.MPI.SUCCESS> | Constant SUCCESS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_LASTCODE <#mpi4py.MPI.ERR_LASTCODE> | Constant ERR_LASTCODE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_COMM <#mpi4py.MPI.ERR_COMM> | Constant ERR_COMM of type int <https://docs.python.org/3/library/functions.html#int>
ERR_GROUP <#mpi4py.MPI.ERR_GROUP> | Constant ERR_GROUP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TYPE <#mpi4py.MPI.ERR_TYPE> | Constant ERR_TYPE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_REQUEST <#mpi4py.MPI.ERR_REQUEST> | Constant ERR_REQUEST of type int <https://docs.python.org/3/library/functions.html#int>
ERR_OP <#mpi4py.MPI.ERR_OP> | Constant ERR_OP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ERRHANDLER <#mpi4py.MPI.ERR_ERRHANDLER> | Constant ERR_ERRHANDLER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BUFFER <#mpi4py.MPI.ERR_BUFFER> | Constant ERR_BUFFER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_COUNT <#mpi4py.MPI.ERR_COUNT> | Constant ERR_COUNT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TAG <#mpi4py.MPI.ERR_TAG> | Constant ERR_TAG of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RANK <#mpi4py.MPI.ERR_RANK> | Constant ERR_RANK of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ROOT <#mpi4py.MPI.ERR_ROOT> | Constant ERR_ROOT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TRUNCATE <#mpi4py.MPI.ERR_TRUNCATE> | Constant ERR_TRUNCATE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_IN_STATUS <#mpi4py.MPI.ERR_IN_STATUS> | Constant ERR_IN_STATUS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PENDING <#mpi4py.MPI.ERR_PENDING> | Constant ERR_PENDING of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TOPOLOGY <#mpi4py.MPI.ERR_TOPOLOGY> | Constant ERR_TOPOLOGY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DIMS <#mpi4py.MPI.ERR_DIMS> | Constant ERR_DIMS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ARG <#mpi4py.MPI.ERR_ARG> | Constant ERR_ARG of type int <https://docs.python.org/3/library/functions.html#int>
ERR_OTHER <#mpi4py.MPI.ERR_OTHER> | Constant ERR_OTHER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNKNOWN <#mpi4py.MPI.ERR_UNKNOWN> | Constant ERR_UNKNOWN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INTERN <#mpi4py.MPI.ERR_INTERN> | Constant ERR_INTERN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO <#mpi4py.MPI.ERR_INFO> | Constant ERR_INFO of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE <#mpi4py.MPI.ERR_FILE> | Constant ERR_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_WIN <#mpi4py.MPI.ERR_WIN> | Constant ERR_WIN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_KEYVAL <#mpi4py.MPI.ERR_KEYVAL> | Constant ERR_KEYVAL of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_KEY <#mpi4py.MPI.ERR_INFO_KEY> | Constant ERR_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_VALUE <#mpi4py.MPI.ERR_INFO_VALUE> | Constant ERR_INFO_VALUE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_NOKEY <#mpi4py.MPI.ERR_INFO_NOKEY> | Constant ERR_INFO_NOKEY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ACCESS <#mpi4py.MPI.ERR_ACCESS> | Constant ERR_ACCESS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_AMODE <#mpi4py.MPI.ERR_AMODE> | Constant ERR_AMODE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BAD_FILE <#mpi4py.MPI.ERR_BAD_FILE> | Constant ERR_BAD_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE_EXISTS <#mpi4py.MPI.ERR_FILE_EXISTS> | Constant ERR_FILE_EXISTS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE_IN_USE <#mpi4py.MPI.ERR_FILE_IN_USE> | Constant ERR_FILE_IN_USE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_SPACE <#mpi4py.MPI.ERR_NO_SPACE> | Constant ERR_NO_SPACE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_SUCH_FILE <#mpi4py.MPI.ERR_NO_SUCH_FILE> | Constant ERR_NO_SUCH_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_IO <#mpi4py.MPI.ERR_IO> | Constant ERR_IO of type int <https://docs.python.org/3/library/functions.html#int>
ERR_READ_ONLY <#mpi4py.MPI.ERR_READ_ONLY> | Constant ERR_READ_ONLY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_CONVERSION <#mpi4py.MPI.ERR_CONVERSION> | Constant ERR_CONVERSION of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DUP_DATAREP <#mpi4py.MPI.ERR_DUP_DATAREP> | Constant ERR_DUP_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNSUPPORTED_DATAREP <#mpi4py.MPI.ERR_UNSUPPORTED_DATAREP> | Constant ERR_UNSUPPORTED_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNSUPPORTED_OPERATION <#mpi4py.MPI.ERR_UNSUPPORTED_OPERATION> | Constant ERR_UNSUPPORTED_OPERATION of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NAME <#mpi4py.MPI.ERR_NAME> | Constant ERR_NAME of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_MEM <#mpi4py.MPI.ERR_NO_MEM> | Constant ERR_NO_MEM of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NOT_SAME <#mpi4py.MPI.ERR_NOT_SAME> | Constant ERR_NOT_SAME of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PORT <#mpi4py.MPI.ERR_PORT> | Constant ERR_PORT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_QUOTA <#mpi4py.MPI.ERR_QUOTA> | Constant ERR_QUOTA of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SERVICE <#mpi4py.MPI.ERR_SERVICE> | Constant ERR_SERVICE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SPAWN <#mpi4py.MPI.ERR_SPAWN> | Constant ERR_SPAWN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BASE <#mpi4py.MPI.ERR_BASE> | Constant ERR_BASE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SIZE <#mpi4py.MPI.ERR_SIZE> | Constant ERR_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DISP <#mpi4py.MPI.ERR_DISP> | Constant ERR_DISP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ASSERT <#mpi4py.MPI.ERR_ASSERT> | Constant ERR_ASSERT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_LOCKTYPE <#mpi4py.MPI.ERR_LOCKTYPE> | Constant ERR_LOCKTYPE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_CONFLICT <#mpi4py.MPI.ERR_RMA_CONFLICT> | Constant ERR_RMA_CONFLICT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_SYNC <#mpi4py.MPI.ERR_RMA_SYNC> | Constant ERR_RMA_SYNC of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_RANGE <#mpi4py.MPI.ERR_RMA_RANGE> | Constant ERR_RMA_RANGE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_ATTACH <#mpi4py.MPI.ERR_RMA_ATTACH> | Constant ERR_RMA_ATTACH of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_SHARED <#mpi4py.MPI.ERR_RMA_SHARED> | Constant ERR_RMA_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_FLAVOR <#mpi4py.MPI.ERR_RMA_FLAVOR> | Constant ERR_RMA_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_C <#mpi4py.MPI.ORDER_C> | Constant ORDER_C of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_F <#mpi4py.MPI.ORDER_F> | Constant ORDER_F of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_FORTRAN <#mpi4py.MPI.ORDER_FORTRAN> | Constant ORDER_FORTRAN of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_INTEGER <#mpi4py.MPI.TYPECLASS_INTEGER> | Constant TYPECLASS_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_REAL <#mpi4py.MPI.TYPECLASS_REAL> | Constant TYPECLASS_REAL of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_COMPLEX <#mpi4py.MPI.TYPECLASS_COMPLEX> | Constant TYPECLASS_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_NONE <#mpi4py.MPI.DISTRIBUTE_NONE> | Constant DISTRIBUTE_NONE of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_BLOCK <#mpi4py.MPI.DISTRIBUTE_BLOCK> | Constant DISTRIBUTE_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_CYCLIC <#mpi4py.MPI.DISTRIBUTE_CYCLIC> | Constant DISTRIBUTE_CYCLIC of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_DFLT_DARG <#mpi4py.MPI.DISTRIBUTE_DFLT_DARG> | Constant DISTRIBUTE_DFLT_DARG of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_NAMED <#mpi4py.MPI.COMBINER_NAMED> | Constant COMBINER_NAMED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_DUP <#mpi4py.MPI.COMBINER_DUP> | Constant COMBINER_DUP of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_CONTIGUOUS <#mpi4py.MPI.COMBINER_CONTIGUOUS> | Constant COMBINER_CONTIGUOUS of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_VECTOR <#mpi4py.MPI.COMBINER_VECTOR> | Constant COMBINER_VECTOR of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HVECTOR <#mpi4py.MPI.COMBINER_HVECTOR> | Constant COMBINER_HVECTOR of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_INDEXED <#mpi4py.MPI.COMBINER_INDEXED> | Constant COMBINER_INDEXED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HINDEXED <#mpi4py.MPI.COMBINER_HINDEXED> | Constant COMBINER_HINDEXED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_INDEXED_BLOCK <#mpi4py.MPI.COMBINER_INDEXED_BLOCK> | Constant COMBINER_INDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HINDEXED_BLOCK <#mpi4py.MPI.COMBINER_HINDEXED_BLOCK> | Constant COMBINER_HINDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_STRUCT <#mpi4py.MPI.COMBINER_STRUCT> | Constant COMBINER_STRUCT of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_SUBARRAY <#mpi4py.MPI.COMBINER_SUBARRAY> | Constant COMBINER_SUBARRAY of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_DARRAY <#mpi4py.MPI.COMBINER_DARRAY> | Constant COMBINER_DARRAY of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_RESIZED <#mpi4py.MPI.COMBINER_RESIZED> | Constant COMBINER_RESIZED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_VALUE_INDEX <#mpi4py.MPI.COMBINER_VALUE_INDEX> | Constant COMBINER_VALUE_INDEX of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_REAL <#mpi4py.MPI.COMBINER_F90_REAL> | Constant COMBINER_F90_REAL of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_COMPLEX <#mpi4py.MPI.COMBINER_F90_COMPLEX> | Constant COMBINER_F90_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_INTEGER <#mpi4py.MPI.COMBINER_F90_INTEGER> | Constant COMBINER_F90_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>
IDENT <#mpi4py.MPI.IDENT> | Constant IDENT of type int <https://docs.python.org/3/library/functions.html#int>
CONGRUENT <#mpi4py.MPI.CONGRUENT> | Constant CONGRUENT of type int <https://docs.python.org/3/library/functions.html#int>
SIMILAR <#mpi4py.MPI.SIMILAR> | Constant SIMILAR of type int <https://docs.python.org/3/library/functions.html#int>
UNEQUAL <#mpi4py.MPI.UNEQUAL> | Constant UNEQUAL of type int <https://docs.python.org/3/library/functions.html#int>
CART <#mpi4py.MPI.CART> | Constant CART of type int <https://docs.python.org/3/library/functions.html#int>
GRAPH <#mpi4py.MPI.GRAPH> | Constant GRAPH of type int <https://docs.python.org/3/library/functions.html#int>
DIST_GRAPH <#mpi4py.MPI.DIST_GRAPH> | Constant DIST_GRAPH of type int <https://docs.python.org/3/library/functions.html#int>
UNWEIGHTED <#mpi4py.MPI.UNWEIGHTED> | Constant UNWEIGHTED of type int <https://docs.python.org/3/library/functions.html#int>
WEIGHTS_EMPTY <#mpi4py.MPI.WEIGHTS_EMPTY> | Constant WEIGHTS_EMPTY of type int <https://docs.python.org/3/library/functions.html#int>
COMM_TYPE_SHARED <#mpi4py.MPI.COMM_TYPE_SHARED> | Constant COMM_TYPE_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
BSEND_OVERHEAD <#mpi4py.MPI.BSEND_OVERHEAD> | Constant BSEND_OVERHEAD of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_CREATE <#mpi4py.MPI.WIN_FLAVOR_CREATE> | Constant WIN_FLAVOR_CREATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_ALLOCATE <#mpi4py.MPI.WIN_FLAVOR_ALLOCATE> | Constant WIN_FLAVOR_ALLOCATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_DYNAMIC <#mpi4py.MPI.WIN_FLAVOR_DYNAMIC> | Constant WIN_FLAVOR_DYNAMIC of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_SHARED <#mpi4py.MPI.WIN_FLAVOR_SHARED> | Constant WIN_FLAVOR_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
WIN_SEPARATE <#mpi4py.MPI.WIN_SEPARATE> | Constant WIN_SEPARATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_UNIFIED <#mpi4py.MPI.WIN_UNIFIED> | Constant WIN_UNIFIED of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOCHECK <#mpi4py.MPI.MODE_NOCHECK> | Constant MODE_NOCHECK of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOSTORE <#mpi4py.MPI.MODE_NOSTORE> | Constant MODE_NOSTORE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOPUT <#mpi4py.MPI.MODE_NOPUT> | Constant MODE_NOPUT of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOPRECEDE <#mpi4py.MPI.MODE_NOPRECEDE> | Constant MODE_NOPRECEDE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOSUCCEED <#mpi4py.MPI.MODE_NOSUCCEED> | Constant MODE_NOSUCCEED of type int <https://docs.python.org/3/library/functions.html#int>
LOCK_EXCLUSIVE <#mpi4py.MPI.LOCK_EXCLUSIVE> | Constant LOCK_EXCLUSIVE of type int <https://docs.python.org/3/library/functions.html#int>
LOCK_SHARED <#mpi4py.MPI.LOCK_SHARED> | Constant LOCK_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
MODE_RDONLY <#mpi4py.MPI.MODE_RDONLY> | Constant MODE_RDONLY of type int <https://docs.python.org/3/library/functions.html#int>
MODE_WRONLY <#mpi4py.MPI.MODE_WRONLY> | Constant MODE_WRONLY of type int <https://docs.python.org/3/library/functions.html#int>
MODE_RDWR <#mpi4py.MPI.MODE_RDWR> | Constant MODE_RDWR of type int <https://docs.python.org/3/library/functions.html#int>
MODE_CREATE <#mpi4py.MPI.MODE_CREATE> | Constant MODE_CREATE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_EXCL <#mpi4py.MPI.MODE_EXCL> | Constant MODE_EXCL of type int <https://docs.python.org/3/library/functions.html#int>
MODE_DELETE_ON_CLOSE <#mpi4py.MPI.MODE_DELETE_ON_CLOSE> | Constant MODE_DELETE_ON_CLOSE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_UNIQUE_OPEN <#mpi4py.MPI.MODE_UNIQUE_OPEN> | Constant MODE_UNIQUE_OPEN of type int <https://docs.python.org/3/library/functions.html#int>
MODE_SEQUENTIAL <#mpi4py.MPI.MODE_SEQUENTIAL> | Constant MODE_SEQUENTIAL of type int <https://docs.python.org/3/library/functions.html#int>
MODE_APPEND <#mpi4py.MPI.MODE_APPEND> | Constant MODE_APPEND of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_SET <#mpi4py.MPI.SEEK_SET> | Constant SEEK_SET of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_CUR <#mpi4py.MPI.SEEK_CUR> | Constant SEEK_CUR of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_END <#mpi4py.MPI.SEEK_END> | Constant SEEK_END of type int <https://docs.python.org/3/library/functions.html#int>
DISPLACEMENT_CURRENT <#mpi4py.MPI.DISPLACEMENT_CURRENT> | Constant DISPLACEMENT_CURRENT of type int <https://docs.python.org/3/library/functions.html#int>
DISP_CUR <#mpi4py.MPI.DISP_CUR> | Constant DISP_CUR of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_SINGLE <#mpi4py.MPI.THREAD_SINGLE> | Constant THREAD_SINGLE of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_FUNNELED <#mpi4py.MPI.THREAD_FUNNELED> | Constant THREAD_FUNNELED of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_SERIALIZED <#mpi4py.MPI.THREAD_SERIALIZED> | Constant THREAD_SERIALIZED of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_MULTIPLE <#mpi4py.MPI.THREAD_MULTIPLE> | Constant THREAD_MULTIPLE of type int <https://docs.python.org/3/library/functions.html#int>
VERSION <#mpi4py.MPI.VERSION> | Constant VERSION of type int <https://docs.python.org/3/library/functions.html#int>
SUBVERSION <#mpi4py.MPI.SUBVERSION> | Constant SUBVERSION of type int <https://docs.python.org/3/library/functions.html#int>
MAX_PROCESSOR_NAME <#mpi4py.MPI.MAX_PROCESSOR_NAME> | Constant MAX_PROCESSOR_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_ERROR_STRING <#mpi4py.MPI.MAX_ERROR_STRING> | Constant MAX_ERROR_STRING of type int <https://docs.python.org/3/library/functions.html#int>
MAX_PORT_NAME <#mpi4py.MPI.MAX_PORT_NAME> | Constant MAX_PORT_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_INFO_KEY <#mpi4py.MPI.MAX_INFO_KEY> | Constant MAX_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>
MAX_INFO_VAL <#mpi4py.MPI.MAX_INFO_VAL> | Constant MAX_INFO_VAL of type int <https://docs.python.org/3/library/functions.html#int>
MAX_OBJECT_NAME <#mpi4py.MPI.MAX_OBJECT_NAME> | Constant MAX_OBJECT_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_DATAREP_STRING <#mpi4py.MPI.MAX_DATAREP_STRING> | Constant MAX_DATAREP_STRING of type int <https://docs.python.org/3/library/functions.html#int>
MAX_LIBRARY_VERSION_STRING <#mpi4py.MPI.MAX_LIBRARY_VERSION_STRING> | Constant MAX_LIBRARY_VERSION_STRING of type int <https://docs.python.org/3/library/functions.html#int>
DATATYPE_NULL <#mpi4py.MPI.DATATYPE_NULL> | Object DATATYPE_NULL of type Datatype <#mpi4py.MPI.Datatype>
PACKED <#mpi4py.MPI.PACKED> | Object PACKED of type Datatype <#mpi4py.MPI.Datatype>
BYTE <#mpi4py.MPI.BYTE> | Object BYTE of type Datatype <#mpi4py.MPI.Datatype>
AINT <#mpi4py.MPI.AINT> | Object AINT of type Datatype <#mpi4py.MPI.Datatype>
OFFSET <#mpi4py.MPI.OFFSET> | Object OFFSET of type Datatype <#mpi4py.MPI.Datatype>
COUNT <#mpi4py.MPI.COUNT> | Object COUNT of type Datatype <#mpi4py.MPI.Datatype>
CHAR <#mpi4py.MPI.CHAR> | Object CHAR of type Datatype <#mpi4py.MPI.Datatype>
WCHAR <#mpi4py.MPI.WCHAR> | Object WCHAR of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_CHAR <#mpi4py.MPI.SIGNED_CHAR> | Object SIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>
SHORT <#mpi4py.MPI.SHORT> | Object SHORT of type Datatype <#mpi4py.MPI.Datatype>
INT <#mpi4py.MPI.INT> | Object INT of type Datatype <#mpi4py.MPI.Datatype>
LONG <#mpi4py.MPI.LONG> | Object LONG of type Datatype <#mpi4py.MPI.Datatype>
LONG_LONG <#mpi4py.MPI.LONG_LONG> | Object LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_CHAR <#mpi4py.MPI.UNSIGNED_CHAR> | Object UNSIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_SHORT <#mpi4py.MPI.UNSIGNED_SHORT> | Object UNSIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED <#mpi4py.MPI.UNSIGNED> | Object UNSIGNED of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_LONG <#mpi4py.MPI.UNSIGNED_LONG> | Object UNSIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_LONG_LONG <#mpi4py.MPI.UNSIGNED_LONG_LONG> | Object UNSIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
FLOAT <#mpi4py.MPI.FLOAT> | Object FLOAT of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE <#mpi4py.MPI.DOUBLE> | Object DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
LONG_DOUBLE <#mpi4py.MPI.LONG_DOUBLE> | Object LONG_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
C_BOOL <#mpi4py.MPI.C_BOOL> | Object C_BOOL of type Datatype <#mpi4py.MPI.Datatype>
INT8_T <#mpi4py.MPI.INT8_T> | Object INT8_T of type Datatype <#mpi4py.MPI.Datatype>
INT16_T <#mpi4py.MPI.INT16_T> | Object INT16_T of type Datatype <#mpi4py.MPI.Datatype>
INT32_T <#mpi4py.MPI.INT32_T> | Object INT32_T of type Datatype <#mpi4py.MPI.Datatype>
INT64_T <#mpi4py.MPI.INT64_T> | Object INT64_T of type Datatype <#mpi4py.MPI.Datatype>
UINT8_T <#mpi4py.MPI.UINT8_T> | Object UINT8_T of type Datatype <#mpi4py.MPI.Datatype>
UINT16_T <#mpi4py.MPI.UINT16_T> | Object UINT16_T of type Datatype <#mpi4py.MPI.Datatype>
UINT32_T <#mpi4py.MPI.UINT32_T> | Object UINT32_T of type Datatype <#mpi4py.MPI.Datatype>
UINT64_T <#mpi4py.MPI.UINT64_T> | Object UINT64_T of type Datatype <#mpi4py.MPI.Datatype>
C_COMPLEX <#mpi4py.MPI.C_COMPLEX> | Object C_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_FLOAT_COMPLEX <#mpi4py.MPI.C_FLOAT_COMPLEX> | Object C_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_DOUBLE_COMPLEX <#mpi4py.MPI.C_DOUBLE_COMPLEX> | Object C_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_LONG_DOUBLE_COMPLEX <#mpi4py.MPI.C_LONG_DOUBLE_COMPLEX> | Object C_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_BOOL <#mpi4py.MPI.CXX_BOOL> | Object CXX_BOOL of type Datatype <#mpi4py.MPI.Datatype>
CXX_FLOAT_COMPLEX <#mpi4py.MPI.CXX_FLOAT_COMPLEX> | Object CXX_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_DOUBLE_COMPLEX <#mpi4py.MPI.CXX_DOUBLE_COMPLEX> | Object CXX_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_LONG_DOUBLE_COMPLEX <#mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX> | Object CXX_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
SHORT_INT <#mpi4py.MPI.SHORT_INT> | Object SHORT_INT of type Datatype <#mpi4py.MPI.Datatype>
INT_INT <#mpi4py.MPI.INT_INT> | Object INT_INT of type Datatype <#mpi4py.MPI.Datatype>
TWOINT <#mpi4py.MPI.TWOINT> | Object TWOINT of type Datatype <#mpi4py.MPI.Datatype>
LONG_INT <#mpi4py.MPI.LONG_INT> | Object LONG_INT of type Datatype <#mpi4py.MPI.Datatype>
FLOAT_INT <#mpi4py.MPI.FLOAT_INT> | Object FLOAT_INT of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_INT <#mpi4py.MPI.DOUBLE_INT> | Object DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>
LONG_DOUBLE_INT <#mpi4py.MPI.LONG_DOUBLE_INT> | Object LONG_DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>
CHARACTER <#mpi4py.MPI.CHARACTER> | Object CHARACTER of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL <#mpi4py.MPI.LOGICAL> | Object LOGICAL of type Datatype <#mpi4py.MPI.Datatype>
INTEGER <#mpi4py.MPI.INTEGER> | Object INTEGER of type Datatype <#mpi4py.MPI.Datatype>
REAL <#mpi4py.MPI.REAL> | Object REAL of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_PRECISION <#mpi4py.MPI.DOUBLE_PRECISION> | Object DOUBLE_PRECISION of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX <#mpi4py.MPI.COMPLEX> | Object COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_COMPLEX <#mpi4py.MPI.DOUBLE_COMPLEX> | Object DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL1 <#mpi4py.MPI.LOGICAL1> | Object LOGICAL1 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL2 <#mpi4py.MPI.LOGICAL2> | Object LOGICAL2 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL4 <#mpi4py.MPI.LOGICAL4> | Object LOGICAL4 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL8 <#mpi4py.MPI.LOGICAL8> | Object LOGICAL8 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER1 <#mpi4py.MPI.INTEGER1> | Object INTEGER1 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER2 <#mpi4py.MPI.INTEGER2> | Object INTEGER2 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER4 <#mpi4py.MPI.INTEGER4> | Object INTEGER4 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER8 <#mpi4py.MPI.INTEGER8> | Object INTEGER8 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER16 <#mpi4py.MPI.INTEGER16> | Object INTEGER16 of type Datatype <#mpi4py.MPI.Datatype>
REAL2 <#mpi4py.MPI.REAL2> | Object REAL2 of type Datatype <#mpi4py.MPI.Datatype>
REAL4 <#mpi4py.MPI.REAL4> | Object REAL4 of type Datatype <#mpi4py.MPI.Datatype>
REAL8 <#mpi4py.MPI.REAL8> | Object REAL8 of type Datatype <#mpi4py.MPI.Datatype>
REAL16 <#mpi4py.MPI.REAL16> | Object REAL16 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX4 <#mpi4py.MPI.COMPLEX4> | Object COMPLEX4 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX8 <#mpi4py.MPI.COMPLEX8> | Object COMPLEX8 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX16 <#mpi4py.MPI.COMPLEX16> | Object COMPLEX16 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX32 <#mpi4py.MPI.COMPLEX32> | Object COMPLEX32 of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_INT <#mpi4py.MPI.UNSIGNED_INT> | Object UNSIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_SHORT <#mpi4py.MPI.SIGNED_SHORT> | Object SIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_INT <#mpi4py.MPI.SIGNED_INT> | Object SIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_LONG <#mpi4py.MPI.SIGNED_LONG> | Object SIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_LONG_LONG <#mpi4py.MPI.SIGNED_LONG_LONG> | Object SIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
BOOL <#mpi4py.MPI.BOOL> | Object BOOL of type Datatype <#mpi4py.MPI.Datatype>
SINT8_T <#mpi4py.MPI.SINT8_T> | Object SINT8_T of type Datatype <#mpi4py.MPI.Datatype>
SINT16_T <#mpi4py.MPI.SINT16_T> | Object SINT16_T of type Datatype <#mpi4py.MPI.Datatype>
SINT32_T <#mpi4py.MPI.SINT32_T> | Object SINT32_T of type Datatype <#mpi4py.MPI.Datatype>
SINT64_T <#mpi4py.MPI.SINT64_T> | Object SINT64_T of type Datatype <#mpi4py.MPI.Datatype>
F_BOOL <#mpi4py.MPI.F_BOOL> | Object F_BOOL of type Datatype <#mpi4py.MPI.Datatype>
F_INT <#mpi4py.MPI.F_INT> | Object F_INT of type Datatype <#mpi4py.MPI.Datatype>
F_FLOAT <#mpi4py.MPI.F_FLOAT> | Object F_FLOAT of type Datatype <#mpi4py.MPI.Datatype>
F_DOUBLE <#mpi4py.MPI.F_DOUBLE> | Object F_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
F_COMPLEX <#mpi4py.MPI.F_COMPLEX> | Object F_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
F_FLOAT_COMPLEX <#mpi4py.MPI.F_FLOAT_COMPLEX> | Object F_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
F_DOUBLE_COMPLEX <#mpi4py.MPI.F_DOUBLE_COMPLEX> | Object F_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
REQUEST_NULL <#mpi4py.MPI.REQUEST_NULL> | Object REQUEST_NULL of type Request <#mpi4py.MPI.Request>
MESSAGE_NULL <#mpi4py.MPI.MESSAGE_NULL> | Object MESSAGE_NULL of type Message <#mpi4py.MPI.Message>
MESSAGE_NO_PROC <#mpi4py.MPI.MESSAGE_NO_PROC> | Object MESSAGE_NO_PROC of type Message <#mpi4py.MPI.Message>
OP_NULL <#mpi4py.MPI.OP_NULL> | Object OP_NULL of type Op <#mpi4py.MPI.Op>
MAX <#mpi4py.MPI.MAX> | Object MAX of type Op <#mpi4py.MPI.Op>
MIN <#mpi4py.MPI.MIN> | Object MIN of type Op <#mpi4py.MPI.Op>
SUM <#mpi4py.MPI.SUM> | Object SUM of type Op <#mpi4py.MPI.Op>
PROD <#mpi4py.MPI.PROD> | Object PROD of type Op <#mpi4py.MPI.Op>
LAND <#mpi4py.MPI.LAND> | Object LAND of type Op <#mpi4py.MPI.Op>
BAND <#mpi4py.MPI.BAND> | Object BAND of type Op <#mpi4py.MPI.Op>
LOR <#mpi4py.MPI.LOR> | Object LOR of type Op <#mpi4py.MPI.Op>
BOR <#mpi4py.MPI.BOR> | Object BOR of type Op <#mpi4py.MPI.Op>
LXOR <#mpi4py.MPI.LXOR> | Object LXOR of type Op <#mpi4py.MPI.Op>
BXOR <#mpi4py.MPI.BXOR> | Object BXOR of type Op <#mpi4py.MPI.Op>
MAXLOC <#mpi4py.MPI.MAXLOC> | Object MAXLOC of type Op <#mpi4py.MPI.Op>
MINLOC <#mpi4py.MPI.MINLOC> | Object MINLOC of type Op <#mpi4py.MPI.Op>
REPLACE <#mpi4py.MPI.REPLACE> | Object REPLACE of type Op <#mpi4py.MPI.Op>
NO_OP <#mpi4py.MPI.NO_OP> | Object NO_OP of type Op <#mpi4py.MPI.Op>
GROUP_NULL <#mpi4py.MPI.GROUP_NULL> | Object GROUP_NULL of type Group <#mpi4py.MPI.Group>
GROUP_EMPTY <#mpi4py.MPI.GROUP_EMPTY> | Object GROUP_EMPTY of type Group <#mpi4py.MPI.Group>
INFO_NULL <#mpi4py.MPI.INFO_NULL> | Object INFO_NULL of type Info <#mpi4py.MPI.Info>
INFO_ENV <#mpi4py.MPI.INFO_ENV> | Object INFO_ENV of type Info <#mpi4py.MPI.Info>
ERRHANDLER_NULL <#mpi4py.MPI.ERRHANDLER_NULL> | Object ERRHANDLER_NULL of type Errhandler <#mpi4py.MPI.Errhandler>
ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN> | Object ERRORS_RETURN of type Errhandler <#mpi4py.MPI.Errhandler>
ERRORS_ARE_FATAL <#mpi4py.MPI.ERRORS_ARE_FATAL> | Object ERRORS_ARE_FATAL of type Errhandler <#mpi4py.MPI.Errhandler>
COMM_NULL <#mpi4py.MPI.COMM_NULL> | Object COMM_NULL of type Comm <#mpi4py.MPI.Comm>
COMM_SELF <#mpi4py.MPI.COMM_SELF> | Object COMM_SELF of type Intracomm <#mpi4py.MPI.Intracomm>
COMM_WORLD <#mpi4py.MPI.COMM_WORLD> | Object COMM_WORLD of type Intracomm <#mpi4py.MPI.Intracomm>
WIN_NULL <#mpi4py.MPI.WIN_NULL> | Object WIN_NULL of type Win <#mpi4py.MPI.Win>
FILE_NULL <#mpi4py.MPI.FILE_NULL> | Object FILE_NULL of type File <#mpi4py.MPI.File>
pickle <#mpi4py.MPI.pickle> | Object pickle of type Pickle <#mpi4py.MPI.Pickle>

MPI4PY.TYPING

Added in version 4.0.0.

This module provides type aliases <https://docs.python.org/3/glossary.html#term-type-alias> used to add type hints <https://docs.python.org/3/glossary.html#term-type-hint> to the various functions and methods within the MPI <#module-mpi4py.MPI> module.

See also:

            Module typing <https://docs.python.org/3/library/typing.html#module-typing>
                Documentation of the typing <https://docs.python.org/3/library/typing.html#module-typing> standard module.

Types Summary
SupportsBuffer | Python buffer protocol.
SupportsDLPack | DLPack data interchange protocol.
SupportsCAI | CUDA Array Interface (CAI) protocol.
Buffer | Buffer-like object.
Bottom | Start of the address range.
InPlace | In-place buffer argument.
Aint | Address-sized integral type.
Count | Integral type for counts.
Displ | Integral type for displacements.
Offset | Integral type for offsets.
TypeSpec | Datatype specification.
BufSpec | Buffer specification.
BufSpecB | Buffer specification (block).
BufSpecV | Buffer specification (vector).
BufSpecW | Buffer specification (generalized).
TargetSpec | Target specification.

Types Documentation

    mpi4py.typing.SupportsBuffer = <class 'mpi4py.typing.SupportsBuffer'>
        Python buffer protocol.

        See also:
            Buffer Protocol <https://docs.python.org/3/c-api/buffer.html#bufferobjects>

    mpi4py.typing.SupportsDLPack = <class 'mpi4py.typing.SupportsDLPack'>
        DLPack data interchange protocol.

        See also:
            dlpack:python-spec

    mpi4py.typing.SupportsCAI = <class 'mpi4py.typing.SupportsCAI'>
        CUDA Array Interface (CAI) protocol.

        See also:
            numba:cuda-array-interface

    mpi4py.typing.Buffer = mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI
        Buffer-like object.

    mpi4py.typing.Bottom = mpi4py.MPI.BottomType | None
        Start of the address range.

    mpi4py.typing.InPlace = mpi4py.MPI.InPlaceType | None
        In-place buffer argument.

    mpi4py.typing.Aint = <class 'typing.SupportsIndex'>
        Address-sized integral type.

        alias of SupportsIndex <https://docs.python.org/3/library/typing.html#typing.SupportsIndex>

    mpi4py.typing.Count = <class 'typing.SupportsIndex'>
        Integral type for counts.

        alias of SupportsIndex <https://docs.python.org/3/library/typing.html#typing.SupportsIndex>

    mpi4py.typing.Displ = <class 'typing.SupportsIndex'>
        Integral type for displacements.

        alias of SupportsIndex <https://docs.python.org/3/library/typing.html#typing.SupportsIndex>

    mpi4py.typing.Offset = <class 'typing.SupportsIndex'>
        Integral type for offsets.

        alias of SupportsIndex <https://docs.python.org/3/library/typing.html#typing.SupportsIndex>

    mpi4py.typing.TypeSpec = mpi4py.MPI.Datatype | str
        Datatype specification.

    mpi4py.typing.BufSpec = mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.SupportsIndex] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.SupportsIndex, mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.MPI.BottomType | None, typing.SupportsIndex, mpi4py.MPI.Datatype] | typing.List[typing.Any]
        Buffer specification.

        •   Buffer

        •   Tuple[Buffer, Count]

        •   Tuple[Buffer, TypeSpec]

        •   Tuple[Buffer, Count, TypeSpec]

        •   Tuple[Bottom, Count, Datatype <#mpi4py.MPI.Datatype>]

    mpi4py.typing.BufSpecB = mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.SupportsIndex] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.SupportsIndex, mpi4py.MPI.Datatype | str] | typing.List[typing.Any]
        Buffer specification (block).

        •   Buffer

        •   Tuple[Buffer, Count]

        •   Tuple[Buffer, TypeSpec]

        •   Tuple[Buffer, Count, TypeSpec]

    mpi4py.typing.BufSpecV = mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Sequence[typing.SupportsIndex]] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Tuple[typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex]]] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Sequence[typing.SupportsIndex], mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Tuple[typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex]], mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex], mpi4py.MPI.Datatype | str] | typing.Tuple[mpi4py.MPI.BottomType | None, typing.Tuple[typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex]], mpi4py.MPI.Datatype] | typing.Tuple[mpi4py.MPI.BottomType | None, typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex], mpi4py.MPI.Datatype] | typing.List[typing.Any]
        Buffer specification (vector).

        •   Buffer

        •   Tuple[Buffer, Sequence[Count]]

        •   Tuple[Buffer, Tuple[Sequence[Count], Sequence[Displ]]]

        •   Tuple[Buffer, TypeSpec]

        •   Tuple[Buffer, Sequence[Count], TypeSpec]

        •   Tuple[Buffer, Tuple[Sequence[Count], Sequence[Displ]], TypeSpec]

        •   Tuple[Buffer, Sequence[Count], Sequence[Displ], TypeSpec]

        •   Tuple[Bottom, Tuple[Sequence[Count], Sequence[Displ]], Datatype <#mpi4py.MPI.Datatype>]

        •   Tuple[Bottom, Sequence[Count], Sequence[Displ], Datatype <#mpi4py.MPI.Datatype>]

    mpi4py.typing.BufSpecW = typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Sequence[mpi4py.MPI.Datatype]] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Tuple[typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex]], typing.Sequence[mpi4py.MPI.Datatype]] | typing.Tuple[mpi4py.typing.SupportsBuffer | mpi4py.typing.SupportsDLPack | mpi4py.typing.SupportsCAI, typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex], typing.Sequence[mpi4py.MPI.Datatype]] | typing.Tuple[mpi4py.MPI.BottomType | None, typing.Tuple[typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex]], typing.Sequence[mpi4py.MPI.Datatype]] | typing.Tuple[mpi4py.MPI.BottomType | None, typing.Sequence[typing.SupportsIndex], typing.Sequence[typing.SupportsIndex], typing.Sequence[mpi4py.MPI.Datatype]] | typing.List[typing.Any]
        Buffer specification (generalized).

        •   Tuple[Buffer, Sequence[Datatype <#mpi4py.MPI.Datatype>]]

        •   Tuple[Buffer, Tuple[Sequence[Count], Sequence[Displ]], Sequence[Datatype <#mpi4py.MPI.Datatype>]]

        •   Tuple[Buffer, Sequence[Count], Sequence[Displ], Sequence[Datatype <#mpi4py.MPI.Datatype>]]

        •   Tuple[Bottom, Tuple[Sequence[Count], Sequence[Displ]], Sequence[Datatype <#mpi4py.MPI.Datatype>]]

        •   Tuple[Bottom, Sequence[Count], Sequence[Displ], Sequence[Datatype <#mpi4py.MPI.Datatype>]]

    mpi4py.typing.TargetSpec = typing.SupportsIndex | typing.Tuple[()] | typing.Tuple[typing.SupportsIndex] | typing.Tuple[typing.SupportsIndex, typing.SupportsIndex] | typing.Tuple[typing.SupportsIndex, typing.SupportsIndex, mpi4py.MPI.Datatype | str] | typing.List[typing.Any]
        Target specification.

        •   Displ

        •   Tuple[()]

        •   Tuple[Displ]

        •   Tuple[Displ, Count]

        •   Tuple[Displ, Count, TypeSpec]

    mpi4py.typing.S = TypeVar("S")
        Invariant TypeVar <https://docs.python.org/3/library/typing.html#typing.TypeVar>.

    mpi4py.typing.T = TypeVar("T")
        Invariant TypeVar <https://docs.python.org/3/library/typing.html#typing.TypeVar>.

    mpi4py.typing.U = TypeVar("U")
        Invariant TypeVar <https://docs.python.org/3/library/typing.html#typing.TypeVar>.

    mpi4py.typing.V = TypeVar("V")
        Invariant TypeVar <https://docs.python.org/3/library/typing.html#typing.TypeVar>.

MPI4PY.FUTURES

Added in version 3.0.0.

This package provides a high-level interface for asynchronously executing callables on a pool of worker processes using MPI for inter-process communication.

The mpi4py.futures package is based on concurrent.futures <https://docs.python.org/3/library/concurrent.futures.html#module-concurrent.futures> from the Python standard library. More precisely, mpi4py.futures provides the MPIPoolExecutor class as a concrete implementation of the abstract class Executor <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Executor>. The submit() <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Executor.submit> interface schedules a callable to be executed asynchronously and returns a Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> object representing the execution of the callable. Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> instances can be queried for the call result or exception. Sets of Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> instances can be passed to the wait() <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.wait> and as_completed() <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.as_completed> functions.

See also:

            Module concurrent.futures <https://docs.python.org/3/library/concurrent.futures.html#module-concurrent.futures>
                Documentation of the concurrent.futures <https://docs.python.org/3/library/concurrent.futures.html#module-concurrent.futures> standard module.

  MPIPoolExecutor

The MPIPoolExecutor class uses a pool of MPI processes to execute calls asynchronously. By performing computations in separate processes, it allows to side-step the global interpreter lock <https://docs.python.org/3/glossary.html#term-global-interpreter-lock> but also means that only picklable objects can be executed and returned. The __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> module must be importable by worker processes, thus MPIPoolExecutor instances may not work in the interactive interpreter.

MPIPoolExecutor takes advantage of the dynamic process management features introduced in the MPI-2 standard. In particular, the MPI.Intracomm.Spawn <#mpi4py.MPI.Intracomm.Spawn> method of MPI.COMM_SELF <#mpi4py.MPI.COMM_SELF> is used in the master (or parent) process to spawn new worker (or child) processes running a Python interpreter. The master process uses a separate thread (one for each MPIPoolExecutor instance) to communicate back and forth with the workers. The worker processes serve the execution of tasks in the main (and only) thread until they are signaled for completion.

Note:
        The worker processes must import the main script in order to unpickle any callable defined in the __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> module and submitted from the master process. Furthermore, the callables may need access to other global variables. At the worker processes, mpi4py.futures executes the main script code (using the runpy <https://docs.python.org/3/library/runpy.html#module-runpy> module) under the __worker__ namespace to define the __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> module. The __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> and __worker__ modules are added to sys.modules <https://docs.python.org/3/library/sys.html#sys.modules> (both at the master and worker processes) to ensure proper pickling and unpickling.

Warning:
        During the initial import phase at the workers, the main script cannot create and use new MPIPoolExecutor instances. Otherwise, each worker would attempt to spawn a new pool of workers, leading to infinite recursion. mpi4py.futures detects such recursive attempts to spawn new workers and aborts the MPI execution environment. As the main script code is run under the __worker__ namespace, the easiest way to avoid spawn recursion is using the idiom if __name__ == '__main__': ... in the main script.

    class mpi4py.futures.MPIPoolExecutor(max_workers=None, initializer=None, initargs=(), **kwargs)
        An Executor <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Executor> subclass that executes calls asynchronously using a pool of at most max_workers processes. If max_workers is None <https://docs.python.org/3/library/constants.html#None> or not given, its value is determined from the MPI4PY_FUTURES_MAX_WORKERS environment variable if set, or the MPI universe size if set, otherwise a single worker process is spawned. If max_workers is lower than or equal to 0, then a ValueError <https://docs.python.org/3/library/exceptions.html#ValueError> will be raised.

        initializer is an optional callable that is called at the start of each worker process before executing any tasks; initargs is a tuple of arguments passed to the initializer. If initializer raises an exception, all pending tasks and any attempt to submit new tasks to the pool will raise a BrokenExecutor <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.BrokenExecutor> exception.

        Other parameters:

        •   python_exe: Path to the Python interpreter executable used to spawn worker processes, otherwise sys.executable <https://docs.python.org/3/library/sys.html#sys.executable> is used.

        •   python_args: list <https://docs.python.org/3/library/stdtypes.html#list> or iterable with additional command line flags to pass to the Python executable. Command line flags determined from inspection of sys.flags <https://docs.python.org/3/library/sys.html#sys.flags>, sys.warnoptions <https://docs.python.org/3/library/sys.html#sys.warnoptions> and sys._xoptions <https://docs.python.org/3/library/sys.html#sys._xoptions> in are passed unconditionally.

        •   mpi_info: dict <https://docs.python.org/3/library/stdtypes.html#dict> or iterable yielding (key, value) pairs. These (key, value) pairs are passed (through an MPI.Info <#mpi4py.MPI.Info> object) to the MPI.Intracomm.Spawn <#mpi4py.MPI.Intracomm.Spawn> call used to spawn worker processes. This mechanism allows telling the MPI runtime system where and how to start the processes. Check the documentation of the backend MPI implementation about the set of keys it interprets and the corresponding format for values.

        •   globals: dict <https://docs.python.org/3/library/stdtypes.html#dict> or iterable yielding (name, value) pairs to initialize the main module namespace in worker processes.

        •   main: If set to False <https://docs.python.org/3/library/constants.html#False>, do not import the __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> module in worker processes. Setting main to False <https://docs.python.org/3/library/constants.html#False> prevents worker processes from accessing definitions in the parent __main__ <https://docs.python.org/3/library/__main__.html#module-__main__> namespace.

        •   path: list <https://docs.python.org/3/library/stdtypes.html#list> or iterable with paths to append to sys.path <https://docs.python.org/3/library/sys.html#sys.path> in worker processes to extend the module search path <https://docs.python.org/3/tutorial/modules.html#tut-searchpath>.

        •   wdir: Path to set the current working directory in worker processes using os.chdir() <https://docs.python.org/3/library/os.html#os.chdir>. The initial working directory is set by the MPI implementation. Quality MPI implementations should honor a wdir info key passed through mpi_info, although such feature is not mandatory.

        •   env: dict <https://docs.python.org/3/library/stdtypes.html#dict> or iterable yielding (name, value) pairs with environment variables to update os.environ <https://docs.python.org/3/library/os.html#os.environ> in worker processes. The initial environment is set by the MPI implementation. MPI implementations may allow setting the initial environment through mpi_info, however such feature is not required nor recommended by the MPI standard.

        •   use_pkl5: If set to True <https://docs.python.org/3/library/constants.html#True>, use pickle <https://docs.python.org/3/library/pickle.html#module-pickle> with out-of-band buffers for interprocess communication. If use_pkl5 is set to None <https://docs.python.org/3/library/constants.html#None> or not given, its value is determined from the MPI4PY_FUTURES_USE_PKL5 environment variable. Using pickle <https://docs.python.org/3/library/pickle.html#module-pickle> with out-of-band buffers may benefit applications dealing with large buffer-like objects like NumPy arrays. See mpi4py.util.pkl5 <#module-mpi4py.util.pkl5> for additional information.

        •   backoff: float <https://docs.python.org/3/library/functions.html#float> value specifying the maximum number of seconds a worker thread or process suspends execution with time.sleep() <https://docs.python.org/3/library/time.html#time.sleep> while idle-waiting. If not set, its value is determined from the MPI4PY_FUTURES_BACKOFF environment variable if set, otherwise the default value of 0.001 seconds is used. Lower values will reduce latency and increase execution throughput for very short-lived tasks, albeit at the expense of spinning CPU cores and increased energy consumption.

        submit(fn, /, *args, **kwargs)
            Schedule the callable fn to be executed as fn(*args, **kwargs) and returns a Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> object representing the execution of the callable.

                    executor = MPIPoolExecutor(max_workers=1)
                    future = executor.submit(pow, 321, 1234)
                    print(future.result())

        map(fn, *iterables, timeout=None, chunksize=1, buffersize=None, **kwargs)
            Similar to map(fn, *iterables) <https://docs.python.org/3/library/functions.html#map> except:

            •   The iterables are consumed immediately rather than lazily, unless buffersize is specified to limit the number of submitted tasks whose results have not yet been yielded. If the task buffer is full, the caller blocks and iteration over the iterables pauses until a result is yielded from the buffer.

            •   fn is executed asynchronously and several calls to fn may be made concurrently, out-of-order, in separate processes.

        The returned iterator raises a TimeoutError <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.TimeoutError> if __next__() <https://docs.python.org/3/library/stdtypes.html#iterator.__next__> is called and the result isn’t available after timeout seconds from the original call to map(). timeout can be an int or a float. If timeout is not specified or None <https://docs.python.org/3/library/constants.html#None>, there is no limit to the wait time.

        If fn raises an exception, then that exception will be raised when its value is retrieved from the iterator.

        This method chops iterables into a number of chunks which it submits to the pool as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer. For very long iterables, using a large value for chunksize can significantly improve performance compared to the default size of one.

        By default, the returned iterator yields results in-order, waiting for successive tasks to complete . This behavior can be changed by passing the keyword argument unordered as True <https://docs.python.org/3/library/constants.html#True>, then the result iterator will yield a result as soon as any of the tasks complete.

                    executor = MPIPoolExecutor(max_workers=3)
                    for result in executor.map(pow, [2] * 32, range(32)):
                        print(result)

        Changed in version 4.1.0: Added the buffersize parameter.

        starmap(fn, iterable, timeout=None, chunksize=1, buffersize=None, **kwargs)
            Similar to itertools.starmap(fn, iterable) <https://docs.python.org/3/library/itertools.html#itertools.starmap>. Used instead of map() when argument parameters are already grouped in tuples from a single iterable (the data has been “pre-zipped”). map(fn, *iterable) is equivalent to starmap(fn, zip(*iterable)).

                    executor = MPIPoolExecutor(max_workers=3)
                    iterable = ((2, n) for n in range(32))
                    for result in executor.starmap(pow, iterable):
                        print(result)

        Changed in version 4.1.0: Added the buffersize parameter.

        shutdown(wait=True, cancel_futures=False)
            Signal the executor that it should free any resources that it is using when the currently pending futures are done executing. Calls to submit() and map() made after shutdown() will raise RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>.

            If wait is True <https://docs.python.org/3/library/constants.html#True> then this method will not return until all the pending futures are done executing and the resources associated with the executor have been freed. If wait is False <https://docs.python.org/3/library/constants.html#False> then this method will return immediately and the resources associated with the executor will be freed when all pending futures are done executing. Regardless of the value of wait, the entire Python program will not exit until all pending futures are done executing.

            If cancel_futures is True <https://docs.python.org/3/library/constants.html#True>, this method will cancel all pending futures that the executor has not started running. Any futures that are completed or running won’t be cancelled, regardless of the value of cancel_futures.

            You can avoid having to call this method explicitly if you use the with <https://docs.python.org/3/reference/compound_stmts.html#with> statement, which will shutdown the executor instance (waiting as if shutdown() were called with wait set to True <https://docs.python.org/3/library/constants.html#True>).

                    import time
                    with MPIPoolExecutor(max_workers=1) as executor:
                        future = executor.submit(time.sleep, 2)
                    assert future.done()

        bootup(wait=True)
            Signal the executor that it should allocate eagerly any required resources (in particular, MPI worker processes). If wait is True <https://docs.python.org/3/library/constants.html#True>, then bootup() will not return until the executor resources are ready to process submissions. Resources are automatically allocated in the first call to submit(), thus calling bootup() explicitly is seldom needed.

        num_workers
            Number or worker processes in the pool.

    MPI4PY_FUTURES_MAX_WORKERS
        If the max_workers parameter to MPIPoolExecutor is None <https://docs.python.org/3/library/constants.html#None> or not given, the MPI4PY_FUTURES_MAX_WORKERS environment variable provides a fallback value for the maximum number of MPI worker processes to spawn.

        Added in version 3.1.0.

    MPI4PY_FUTURES_USE_PKL5
        If the use_pkl5 keyword argument to MPIPoolExecutor is None <https://docs.python.org/3/library/constants.html#None> or not given, the MPI4PY_FUTURES_USE_PKL5 environment variable provides a fallback value for whether the executor should use pickle <https://docs.python.org/3/library/pickle.html#module-pickle> with out-of-band buffers for interprocess communication. Accepted values are 0 and 1 (interpreted as False <https://docs.python.org/3/library/constants.html#False> and True <https://docs.python.org/3/library/constants.html#True>, respectively), and strings specifying a YAML boolean <https://yaml.org/type/bool.html> value (case-insensitive). Using pickle <https://docs.python.org/3/library/pickle.html#module-pickle> with out-of-band buffers may benefit applications dealing with large buffer-like objects like NumPy arrays. See mpi4py.util.pkl5 <#module-mpi4py.util.pkl5> for additional information.

        Added in version 4.0.0.

    MPI4PY_FUTURES_BACKOFF
        If the backoff keyword argument to MPIPoolExecutor is not given, the MPI4PY_FUTURES_BACKOFF environment variable can be set to a float <https://docs.python.org/3/library/functions.html#float> value specifying the maximum number of seconds a worker thread or process suspends execution with time.sleep() <https://docs.python.org/3/library/time.html#time.sleep> while idle-waiting. If not set, the default backoff value is 0.001 seconds. Lower values will reduce latency and increase execution throughput for very short-lived tasks, albeit at the expense of spinning CPU cores and increased energy consumption.

        Added in version 4.0.0.

Note:
        As the master process uses a separate thread to perform MPI communication with the workers, the backend MPI implementation should provide support for MPI.THREAD_MULTIPLE <#mpi4py.MPI.THREAD_MULTIPLE>. However, some popular MPI implementations do not support yet concurrent MPI calls from multiple threads. Additionally, users may decide to initialize MPI with a lower level of thread support. If the level of thread support in the backend MPI is less than MPI.THREAD_MULTIPLE <#mpi4py.MPI.THREAD_MULTIPLE>, mpi4py.futures will use a global lock to serialize MPI calls. If the level of thread support is less than MPI.THREAD_SERIALIZED <#mpi4py.MPI.THREAD_SERIALIZED>, mpi4py.futures will emit a RuntimeWarning <https://docs.python.org/3/library/exceptions.html#RuntimeWarning>.

Warning:
        If the level of thread support in the backend MPI is less than MPI.THREAD_SERIALIZED <#mpi4py.MPI.THREAD_SERIALIZED> (i.e, it is either MPI.THREAD_SINGLE <#mpi4py.MPI.THREAD_SINGLE> or MPI.THREAD_FUNNELED <#mpi4py.MPI.THREAD_FUNNELED>), in theory mpi4py.futures cannot be used. Rather than raising an exception, mpi4py.futures emits a warning and takes a “cross-fingers” attitude to continue execution in the hope that serializing MPI calls with a global lock will actually work.

  MPICommExecutor

Legacy MPI-1 implementations (as well as some vendor MPI-2 implementations) do not support the dynamic process management features introduced in the MPI-2 standard. Additionally, job schedulers and batch systems in supercomputing facilities may pose additional complications to applications using the MPI_Comm_spawn() routine.

With these issues in mind, mpi4py.futures supports an additional, more traditional, SPMD-like usage pattern requiring MPI-1 calls only. Python applications are started the usual way, e.g., using the mpiexec command. Python code should make a collective call to the MPICommExecutor context manager to partition the set of MPI processes within a MPI communicator in one master processes and many workers processes. The master process gets access to an MPIPoolExecutor instance to submit tasks. Meanwhile, the worker process follow a different execution path and team-up to execute the tasks submitted from the master.

Besides alleviating the lack of dynamic process management features in legacy MPI-1 or partial MPI-2 implementations, the MPICommExecutor context manager may be useful in classic MPI-based Python applications willing to take advantage of the simple, task-based, master/worker approach available in the mpi4py.futures package.

    class mpi4py.futures.MPICommExecutor(comm=None, root=0)
        Context manager for MPIPoolExecutor. This context manager splits a MPI (intra)communicator comm (defaults to MPI.COMM_WORLD <#mpi4py.MPI.COMM_WORLD> if not provided or None <https://docs.python.org/3/library/constants.html#None>) in two disjoint sets: a single master process (with rank root in comm) and the remaining worker processes. These sets are then connected through an intercommunicator. The target of the with <https://docs.python.org/3/reference/compound_stmts.html#with> statement is assigned either an MPIPoolExecutor instance (at the master) or None <https://docs.python.org/3/library/constants.html#None> (at the workers).

                from mpi4py import MPI
                from mpi4py.futures import MPICommExecutor

                with MPICommExecutor(MPI.COMM_WORLD, root=0) as executor:
                    if executor is not None:
                       future = executor.submit(abs, -42)
                       assert future.result() == 42
                       answer = set(executor.map(abs, [-42, 42]))
                       assert answer == {42}

Warning:
        If MPICommExecutor is passed a communicator of size one (e.g., MPI.COMM_SELF <#mpi4py.MPI.COMM_SELF>), then the executor instance assigned to the target of the with <https://docs.python.org/3/reference/compound_stmts.html#with> statement will execute all submitted tasks in a single worker thread, thus ensuring that task execution still progress asynchronously. However, the GIL <https://docs.python.org/3/glossary.html#term-GIL> will prevent the main and worker threads from running concurrently in multicore processors. Moreover, the thread context switching may harm noticeably the performance of CPU-bound tasks. In case of I/O-bound tasks, the GIL <https://docs.python.org/3/glossary.html#term-GIL> is not usually an issue, however, as a single worker thread is used, it progress one task at a time. We advice against using MPICommExecutor with communicators of size one and suggest refactoring your code to use instead a ThreadPoolExecutor <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutor>.

  Command line

Recalling the issues related to the lack of support for dynamic process management features in MPI implementations, mpi4py.futures supports an alternative usage pattern where Python code (either from scripts, modules, or zip files) is run under command line control of the mpi4py.futures package by passing -m mpi4py.futures to the python executable. The mpi4py.futures invocation should be passed a pyfile path to a script (or a zipfile/directory containing a __main__.py file). Additionally, mpi4py.futures accepts -m mod to execute a module named mod, -c cmd to execute a command string cmd, or even - to read commands from standard input (sys.stdin <https://docs.python.org/3/library/sys.html#sys.stdin>). Summarizing, mpi4py.futures can be invoked in the following ways:

    •   $ mpiexec -n numprocs python -m mpi4py.futures pyfile [arg] ...

    •   $ mpiexec -n numprocs python -m mpi4py.futures -m mod [arg] ...

    •   $ mpiexec -n numprocs python -m mpi4py.futures -c cmd [arg] ...

    •   $ mpiexec -n numprocs python -m mpi4py.futures - [arg] ...

Before starting the main script execution, mpi4py.futures splits MPI.COMM_WORLD <#mpi4py.MPI.COMM_WORLD> in one master (the process with rank 0 in MPI.COMM_WORLD <#mpi4py.MPI.COMM_WORLD>) and numprocs - 1 workers and connects them through an MPI intercommunicator. Afterwards, the master process proceeds with the execution of the user script code, which eventually creates MPIPoolExecutor instances to submit tasks. Meanwhile, the worker processes follow a different execution path to serve the master. Upon successful termination of the main script at the master, the entire MPI execution environment exists gracefully. In case of any unhandled exception in the main script, the master process calls MPI.COMM_WORLD.Abort(1) to prevent deadlocks and force termination of entire MPI execution environment.

Warning:
        Running scripts under command line control of mpi4py.futures is quite similar to executing a single-process application that spawn additional workers as required. However, there is a very important difference users should be aware of. All MPIPoolExecutor instances created at the master will share the pool of workers. Tasks submitted at the master from many different executors will be scheduled for execution in random order as soon as a worker is idle. Any executor can easily starve all the workers (e.g., by calling MPIPoolExecutor.map() with long iterables). If that ever happens, submissions from other executors will not be serviced until free workers are available.

See also:

            Command line <https://docs.python.org/3/using/cmdline.html#using-on-cmdline>
                Documentation on Python command line interface.

  Parallel tasks

The mpi4py.futures package favors an embarrassingly parallel execution model involving a series of sequential tasks independent of each other and executed asynchronously. Albeit unnatural, MPIPoolExecutor can still be used for handling workloads involving parallel tasks, where worker processes communicate and coordinate each other via MPI.

    mpi4py.futures.get_comm_workers()
        Access an intracommunicator grouping MPI worker processes.

Executing parallel tasks with mpi4py.futures requires following some rules, cf. highlighted lines in example cpi.py :

    •   Use MPIPoolExecutor.num_workers to determine the number of worker processes in the executor and submit exactly one callable per worker process using the MPIPoolExecutor.submit() method.

    •   The submitted callable must use get_comm_workers() to access an intracommunicator grouping MPI worker processes. Afterwards, it is highly recommended calling the Barrier() <#mpi4py.MPI.Comm.Barrier> method on the communicator. The barrier synchronization ensures that every worker process is executing the submitted callable exactly once. Afterwards, the parallel task can safely perform any kind of point-to-point or collective operation using the returned communicator.

    •   The Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> instances returned by MPIPoolExecutor.submit() should be collected in a sequence. Use wait() <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.wait> with the sequence of Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> instances to ensure logical completion of the parallel task.

  Utilities

The mpi4py.futures package provides additional utilities for handling Future <https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Future> instances.

    mpi4py.futures.collect(fs)
        Gather a collection of futures in a new future.

        Parameters
            fs – Collection of futures.

        Returns
            New future producing as result a list with results from fs.

    mpi4py.futures.compose(future, resulthook=None, excepthook=None)
        Compose the completion of a future with result and exception handlers.

        Parameters

            •   future – Input future instance.

            •   resulthook – Function to be called once the input future completes with success. Once the input future finish running with success, its result value is the input argument for resulthook. The result of resulthook is set as the result of the output future. If resulthook is None, the output future is completed directly with the result of the input future.

            •   excepthook – Function to be called once the input future completes with failure. Once the input future finish running with failure, its exception value is the input argument for excepthook. If excepthook returns an Exception <https://docs.python.org/3/library/exceptions.html#Exception> instance, it is set as the exception of the output future. Otherwise, the result of excepthook is set as the result of the output future. If excepthook is None, the output future is set as failed with the exception from the input future.

        Returns
            Output future instance to be completed once the input future is completed and either resulthook or excepthook finish executing.

  Examples

  Computing the Julia set

The following julia.py script computes the Julia set <https://en.wikipedia.org/wiki/Julia_set> and dumps an image to disk in binary PGM <https://netpbm.sourceforge.net/doc/pgm.html> format. The code starts by importing MPIPoolExecutor from the mpi4py.futures package. Next, some global constants and functions implement the computation of the Julia set. The computations are protected with the standard if __name__ == '__main__': ... idiom. The image is computed by whole scanlines submitting all these tasks at once using the map method. The result iterator yields scanlines in-order as the tasks complete. Finally, each scanline is dumped to disk.

julia.py

            from mpi4py.futures import MPIPoolExecutor

            x0, x1, w = -2.0, +2.0, 640*2
            y0, y1, h = -1.5, +1.5, 480*2
            dx = (x1 - x0) / w
            dy = (y1 - y0) / h

            c = complex(0, 0.65)

            def julia(x, y):
                z = complex(x, y)
                n = 255
                while abs(z) < 3 and n > 1:
                    z = z**2 + c
                    n -= 1
                return n

            def julia_line(k):
                line = bytearray(w)
                y = y1 - k * dy
                for j in range(w):
                    x = x0 + j * dx
                    line[j] = julia(x, y)
                return line

            if __name__ == '__main__':

                with MPIPoolExecutor() as executor:
                    image = executor.map(julia_line, range(h))
                    with open('julia.pgm', 'wb') as f:
                        f.write(b'P5 %d %d %d\n' % (w, h, 255))
                        for line in image:
                            f.write(line)

The recommended way to execute the script is by using the mpiexec command specifying one MPI process (master) and (optional but recommended) the desired MPI universe size, which determines the number of additional dynamically spawned processes (workers). The MPI universe size is provided either by a batch system or set by the user via command-line arguments to mpiexec or environment variables. Below we provide examples for MPICH and Open MPI implementations [1]. In all of these examples, the mpiexec command launches a single master process running the Python interpreter and executing the main script. When required, mpi4py.futures spawns the pool of 16 worker processes. The master submits tasks to the workers and waits for the results. The workers receive incoming tasks, execute them, and send back the results to the master.

When using MPICH implementation or its derivatives based on the Hydra process manager, users can set the MPI universe size via the -usize argument to mpiexec:

            $ mpiexec -n 1 -usize 17 python julia.py

or, alternatively, by setting the MPIEXEC_UNIVERSE_SIZE environment variable:

            $ env MPIEXEC_UNIVERSE_SIZE=17 mpiexec -n 1 python julia.py

In the Open MPI implementation, the MPI universe size can be set via the -host argument to mpiexec:

            $ mpiexec -n 1 -host localhost:17 python julia.py

Another way to specify the number of workers is to use the mpi4py.futures-specific environment variable MPI4PY_FUTURES_MAX_WORKERS:

            $ env MPI4PY_FUTURES_MAX_WORKERS=16 mpiexec -n 1 python julia.py

Note that in this case, the MPI universe size is ignored.

Alternatively, users may decide to execute the script in a more traditional way, that is, all the MPI processes are started at once. The user script is run under command-line control of mpi4py.futures passing the -m <https://docs.python.org/3/using/cmdline.html#using-on-cmdline> flag to the python executable:

            $ mpiexec -n 17 python -m mpi4py.futures julia.py

As explained previously, the 17 processes are partitioned in one master and 16 workers. The master process executes the main script while the workers execute the tasks submitted by the master.

[1] When using an MPI implementation other than MPICH or Open MPI, please check the documentation of the implementation and/or batch system for the ways to specify the desired MPI universe size.

  Computing Pi (parallel task)

The number \pi can be approximated via numerical integration with the simple midpoint rule, that is:

\pi = \int_{0}^{1} \frac{4}{1+x^2} \,dx \approx \frac{1}{n} \sum_{i=1}^{n} \frac{4}{1 + \left[\frac{1}{n} \left(i-\frac{1}{2}\right) \right]^2} .

The following cpi.py script computes such approximations using mpi4py.futures with a parallel task involving a collective reduction operation. Highlighted lines correspond to the rules discussed in Parallel tasks.

cpi.py

            import math
            import sys
            from mpi4py.futures import MPIPoolExecutor, wait
            from mpi4py.futures import get_comm_workers

            def compute_pi(n):
                # Access intracommunicator and synchronize
                comm = get_comm_workers()
                comm.Barrier()

                rank = comm.Get_rank()
                size = comm.Get_size()

                # Local computation
                h = 1.0 / n
                s = 0.0
                for i in range(rank + 1, n + 1, size):
                    x = h * (i - 0.5)
                    s += 4.0 / (1.0 + x**2)
                pi_partial = s * h

                # Parallel reduce-to-all
                pi = comm.allreduce(pi_partial)

                # All workers return the same value
                return pi

            if __name__ == '__main__':
                n = int(sys.argv[1]) if len(sys.argv) > 1 else 256

                with MPIPoolExecutor() as executor:
                    # Submit exactly one callable per worker
                    P = executor.num_workers
                    fs = [executor.submit(compute_pi, n) for _ in range(P)]

                    # Wait for all workers to finish
                    wait(fs)

                    # Get result from the first future object.
                    # In this particular example, due to using reduce-to-all,
                    # all the other future objects hold the same result value.
                    pi = fs[0].result()
                    print(
                        f"pi: {pi:.16f}, error: {abs(pi - math.pi):.3e}",
                        f"({n:d} intervals, {P:d} workers)",
                    )

To run in modern MPI-2 mode:

            $ env MPI4PY_FUTURES_MAX_WORKERS=4 mpiexec -n 1 python cpi.py 128
            pi: 3.1415977398528137, error: 5.086e-06 (128 intervals, 4 workers)

            $ env MPI4PY_FUTURES_MAX_WORKERS=8 mpiexec -n 1 python cpi.py 512
            pi: 3.1415929714812316, error: 3.179e-07 (512 intervals, 8 workers)

To run in legacy MPI-1 mode:

            $ mpiexec -n 5 python -m mpi4py.futures cpi.py 128
            pi: 3.1415977398528137, error: 5.086e-06 (128 intervals, 4 workers)

            $ mpiexec -n 9 python -m mpi4py.futures cpi.py 512
            pi: 3.1415929714812316, error: 3.179e-07 (512 intervals, 8 workers)

  Citation

If mpi4py.futures been significant to a project that leads to an academic publication, please acknowledge our work by citing the following article [mpi4py-futures] <#id4>:

[mpi4py-futures]
    M. Rogowski, S. Aseeri, D. Keyes, and L. Dalcin, mpi4py.futures: MPI-Based Asynchronous Task Execution for Python, IEEE Transactions on Parallel and Distributed Systems, 34(2):611-622, 2023. <https://doi.org/10.1109/TPDS.2022.3225481>

MPI4PY.UTIL

Added in version 3.1.0.

The mpi4py.util package collects miscellaneous utilities within the intersection of Python and MPI.

  mpi4py.util.dtlib

Added in version 3.1.0.

The mpi4py.util.dtlib module provides converter routines between NumPy and MPI datatypes.

    mpi4py.util.dtlib.from_numpy_dtype(dtype)
        Convert NumPy datatype to MPI datatype.

        Parameters
            dtype (DTypeLike <https://numpy.org/doc/stable/reference/typing.html#numpy.typing.DTypeLike>) – NumPy dtype-like object.

        Return type
            Datatype <#mpi4py.MPI.Datatype>

    mpi4py.util.dtlib.to_numpy_dtype(datatype)
        Convert MPI datatype to NumPy datatype.

        Parameters
            datatype (Datatype <#mpi4py.MPI.Datatype>) – MPI datatype.

        Return type
            dtype <https://numpy.org/doc/stable/reference/generated/numpy.dtype.html#numpy.dtype>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

  mpi4py.util.pkl5

Added in version 3.1.0.

pickle <https://docs.python.org/3/library/pickle.html#module-pickle> protocol 5 (see PEP 574 <https://peps.python.org/pep-0574/>) introduced support for out-of-band buffers, allowing for more efficient handling of certain object types with large memory footprints.

MPI for Python uses the traditional in-band handling of buffers. This approach is appropriate for communicating non-buffer Python objects, or buffer-like objects with small memory footprints. For point-to-point communication, in-band buffer handling allows for the communication of a pickled stream with a single MPI message, at the expense of additional CPU and memory overhead in the pickling and unpickling steps.

The mpi4py.util.pkl5 module provides communicator wrapper classes reimplementing pickle-based point-to-point and collective communication methods using pickle protocol 5. Handling out-of-band buffers necessarily involves multiple MPI messages, thus increasing latency and hurting performance in case of small size data. However, in case of large size data, the zero-copy savings of out-of-band buffer handling more than offset the extra latency costs. Additionally, these wrapper methods overcome the infamous 2 GiB message count limit (MPI-1 to MPI-3).

    class mpi4py.util.pkl5.Request
        Request.

        Custom request class for nonblocking communications.

        Note:
            Request is not a subclass of mpi4py.MPI.Request <#mpi4py.MPI.Request>

        Free()
            Free a communication request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        free()
            Free a communication request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        cancel()
            Cancel a communication request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        get_status(status=None)
            Non-destructive test for the completion of a request.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        test(status=None)
            Test for the completion of a request.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[bool <https://docs.python.org/3/library/functions.html#bool>, Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>]

        wait(status=None)
            Wait for a request to complete.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        classmethod get_status_all(requests, statuses=None)
            Non-destructive test for the completion of all requests.

            Classmethod

        classmethod testall(requests, statuses=None)
            Test for the completion of all requests.

            Classmethod

        classmethod waitall(requests, statuses=None)
            Wait for all requests to complete.

            Classmethod

    class mpi4py.util.pkl5.Message
        Message.

        Custom message class for matching probes.

        Note:
            Message is not a subclass of mpi4py.MPI.Message <#mpi4py.MPI.Message>

        free()
            Do nothing.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        recv(status=None)
            Blocking receive of matched message.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        irecv()
            Nonblocking receive of matched message.

            Return type
                Request <#mpi4py.util.pkl5.Request>

        classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Classmethod

        classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Classmethod

    class mpi4py.util.pkl5.Comm
        Communicator.

        Base communicator wrapper class.

        send(obj, dest, tag=0)
            Blocking send in standard mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        bsend(obj, dest, tag=0)
            Blocking send in buffered mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        ssend(obj, dest, tag=0)
            Blocking send in synchronous mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        isend(obj, dest, tag=0)
            Nonblocking send in standard mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.util.pkl5.Request>

        ibsend(obj, dest, tag=0)
            Nonblocking send in buffered mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.util.pkl5.Request>

        issend(obj, dest, tag=0)
            Nonblocking send in synchronous mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.util.pkl5.Request>

        recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking receive.

            Parameters

                •   buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any

        irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
            Nonblocking receive.

            Warning:
                This method cannot be supported reliably and raises RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>.

            Parameters

                •   buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.util.pkl5.Request>

        sendrecv(sendobj, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
            Send and receive.

            Parameters

                •   sendobj (Any)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvbuf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any

        mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.util.pkl5.Message>

        improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.util.pkl5.Message> | None <https://docs.python.org/3/library/constants.html#None>

        bcast(obj, root=0)
            Broadcast.

            Added in version 3.1.0.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        gather(sendobj, root=0)
            Gather.

            Added in version 4.0.0.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>

        scatter(sendobj, root=0)
            Scatter.

            Added in version 4.0.0.

            Parameters

                •   sendobj (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        allgather(sendobj)
            Gather to All.

            Added in version 4.0.0.

            Parameters
                sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        alltoall(sendobj)
            All to All Scatter/Gather.

            Added in version 4.0.0.

            Parameters
                sendobj (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

    class mpi4py.util.pkl5.Intracomm
        Intracommunicator.

        Intracommunicator wrapper class.

    class mpi4py.util.pkl5.Intercomm
        Intercommunicator.

        Intercommunicator wrapper class.

  Examples

test-pkl5-1.py

            import numpy as np
            from mpi4py import MPI
            from mpi4py.util import pkl5

            comm = pkl5.Intracomm(MPI.COMM_WORLD)  # comm wrapper
            size = comm.Get_size()
            rank = comm.Get_rank()
            dst = (rank + 1) % size
            src = (rank - 1) % size

            sobj = np.full(1024**3, rank, dtype='i4')  # > 4 GiB
            sreq = comm.isend(sobj, dst, tag=42)
            robj = comm.recv (None, src, tag=42)
            sreq.Free()

            assert np.min(robj) == src
            assert np.max(robj) == src

test-pkl5-2.py

            import numpy as np
            from mpi4py import MPI
            from mpi4py.util import pkl5

            comm = pkl5.Intracomm(MPI.COMM_WORLD)  # comm wrapper
            size = comm.Get_size()
            rank = comm.Get_rank()
            dst = (rank + 1) % size
            src = (rank - 1) % size

            sobj = np.full(1024**3, rank, dtype='i4')  # > 4 GiB
            sreq = comm.isend(sobj, dst, tag=42)

            status = MPI.Status()
            rmsg = comm.mprobe(status=status)
            assert status.Get_source() == src
            assert status.Get_tag() == 42
            rreq = rmsg.irecv()
            robj = rreq.wait()

            sreq.Free()
            assert np.max(robj) == src
            assert np.min(robj) == src

  mpi4py.util.pool

Added in version 4.0.0.

See also:
        This module intends to be a drop-in replacement for the multiprocessing.pool <https://docs.python.org/3/library/multiprocessing.html#module-multiprocessing.pool> interface from the Python standard library. The Pool class exposed here is implemented as a thin wrapper around MPIPoolExecutor <#mpi4py.futures.MPIPoolExecutor>.

Note:
        The mpi4py.futures <#module-mpi4py.futures> package offers a higher level interface for asynchronously pushing tasks to MPI worker process, allowing for a clear separation between submitting tasks and waiting for the results.

    class mpi4py.util.pool.Pool
        Pool using MPI processes as workers.

        __init__(processes=None, initializer=None, initargs=(), **kwargs)
            Initialize a new Pool instance.

            Parameters

                •   processes (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>) – Number of worker processes.

                •   initializer (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], object <https://docs.python.org/3/library/functions.html#object>] | None <https://docs.python.org/3/library/constants.html#None>) – An callable used to initialize workers processes.

                •   initargs (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]) – A tuple of arguments to pass to the initializer.

                •   kwargs (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Note:
                Additional keyword arguments are passed down to the MPIPoolExecutor <#mpi4py.futures.MPIPoolExecutor> constructor.

        Warning:
                The maxtasksperchild and context arguments of multiprocessing.pool.Pool <https://docs.python.org/3/library/multiprocessing.html#multiprocessing.pool.Pool> are not supported. Specifying maxtasksperchild or context with a value other than None <https://docs.python.org/3/library/constants.html#None> will issue a warning of category UserWarning <https://docs.python.org/3/library/exceptions.html#UserWarning>.

        apply(func, args=(), kwds={})
            Call func with arguments args and keyword arguments kwds.

            Equivalent to func(*args, **kwds).

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], T <#mpi4py.typing.T>])

                •   args (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Any <https://docs.python.org/3/library/typing.html#typing.Any>])

                •   kwds (Mapping <https://docs.python.org/3/library/typing.html#typing.Mapping>[str <https://docs.python.org/3/library/stdtypes.html#str>, Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                T <#mpi4py.typing.T>

        apply_async(func, args=(), kwds={}, callback=None, error_callback=None)
            Asynchronous version of apply() returning ApplyResult.

            Parameters

                •   func (Callable[..., T <#mpi4py.typing.T>])

                •   args (Iterable[Any])

                •   kwds (Mapping[str <https://docs.python.org/3/library/stdtypes.html#str>, Any])

                •   callback (Callable[[T <#mpi4py.typing.T>], object <https://docs.python.org/3/library/functions.html#object>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   error_callback (Callable[[BaseException <https://docs.python.org/3/library/exceptions.html#BaseException>], object <https://docs.python.org/3/library/functions.html#object>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                AsyncResult <#mpi4py.util.pool.AsyncResult>[T <#mpi4py.typing.T>]

        map(func, iterable, chunksize=None)
            Apply func to each element in iterable.

            Equivalent to list(map(func, iterable)).

            Block until all results are ready and return them in a list <https://docs.python.org/3/library/stdtypes.html#list>.

            The iterable is choped into a number of chunks which are submitted as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer.

            Consider using imap() or imap_unordered() with explicit chunksize for better efficiency.

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[S <#mpi4py.typing.S>], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[S <#mpi4py.typing.S>])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[T <#mpi4py.typing.T>]

        map_async(func, iterable, chunksize=None, callback=None, error_callback=None)
            Asynchronous version of map() returning MapResult.

            Parameters

                •   func (Callable[[S <#mpi4py.typing.S>], T <#mpi4py.typing.T>])

                •   iterable (Iterable[S <#mpi4py.typing.S>])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>)

                •   callback (Callable[[T <#mpi4py.typing.T>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   error_callback (Callable[[BaseException <https://docs.python.org/3/library/exceptions.html#BaseException>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                MapResult <#mpi4py.util.pool.MapResult>[T <#mpi4py.typing.T>]

        imap(func, iterable, chunksize=1)
            Like map() but return an iterator <https://docs.python.org/3/glossary.html#term-iterator>.

            Equivalent to map(func, iterable).

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[S <#mpi4py.typing.S>], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[S <#mpi4py.typing.S>])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Iterator <https://docs.python.org/3/library/typing.html#typing.Iterator>[T <#mpi4py.typing.T>]

        imap_unordered(func, iterable, chunksize=1)
            Like imap() but ordering of results is arbitrary.

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[S <#mpi4py.typing.S>], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[S <#mpi4py.typing.S>])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Iterator <https://docs.python.org/3/library/typing.html#typing.Iterator>[T <#mpi4py.typing.T>]

        starmap(func, iterable, chunksize=None)
            Apply func to each argument tuple in iterable.

            Equivalent to list(itertools.starmap(func, iterable)).

            Block until all results are ready and return them in a list <https://docs.python.org/3/library/stdtypes.html#list>.

            The iterable is choped into a number of chunks which are submitted as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer.

            Consider using istarmap() or istarmap_unordered() with explicit chunksize for better efficiency.

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[T <#mpi4py.typing.T>]

        starmap_async(func, iterable, chunksize=None, callback=None, error_callback=None)
            Asynchronous version of starmap() returning MapResult.

            Parameters

                •   func (Callable[..., T <#mpi4py.typing.T>])

                •   iterable (Iterable[Iterable[Any]])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>)

                •   callback (Callable[[T <#mpi4py.typing.T>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   error_callback (Callable[[BaseException <https://docs.python.org/3/library/exceptions.html#BaseException>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                MapResult <#mpi4py.util.pool.MapResult>[T <#mpi4py.typing.T>]

        istarmap(func, iterable, chunksize=1)
            Like starmap() but return an iterator <https://docs.python.org/3/glossary.html#term-iterator>.

            Equivalent to itertools.starmap(func, iterable).

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Iterator <https://docs.python.org/3/library/typing.html#typing.Iterator>[T <#mpi4py.typing.T>]

        istarmap_unordered(func, iterable, chunksize=1)
            Like istarmap() but ordering of results is arbitrary.

            Parameters

                •   func (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], T <#mpi4py.typing.T>])

                •   iterable (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]])

                •   chunksize (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Iterator <https://docs.python.org/3/library/typing.html#typing.Iterator>[T <#mpi4py.typing.T>]

        close()
            Prevent any more tasks from being submitted to the pool.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        terminate()
            Stop the worker processes without completing pending tasks.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        join()
            Wait for the worker processes to exit.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

    class mpi4py.util.pool.ThreadPool
        Bases: Pool

        Pool using threads as workers.

    class mpi4py.util.pool.AsyncResult
        Asynchronous result.

        get(timeout=None)
            Return the result when it arrives.

            If timeout is not None <https://docs.python.org/3/library/constants.html#None> and the result does not arrive within timeout seconds then raise TimeoutError <https://docs.python.org/3/library/exceptions.html#TimeoutError>.

            If the remote call raised an exception then that exception will be reraised.

            Parameters
                timeout (float <https://docs.python.org/3/library/functions.html#float> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                T <#mpi4py.typing.T>

        wait(timeout=None)
            Wait until the result is available or timeout seconds pass.

            Parameters
                timeout (float <https://docs.python.org/3/library/functions.html#float> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        ready()
            Return whether the call has completed.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        successful()
            Return whether the call completed without raising an exception.

            If the result is not ready then raise ValueError <https://docs.python.org/3/library/exceptions.html#ValueError>.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

    class mpi4py.util.pool.ApplyResult
        Bases: AsyncResult

        Result type of apply_async().

    class mpi4py.util.pool.MapResult
        Bases: AsyncResult

        Result type of map_async() and starmap_async().

  mpi4py.util.sync

Added in version 4.0.0.

The mpi4py.util.sync module provides parallel synchronization utilities.

  Sequential execution

    class mpi4py.util.sync.Sequential
        Sequential execution.

        Context manager for sequential execution within a group of MPI processes.

        The implementation is based in MPI-1 point-to-point communication. A process with rank i waits in a blocking receive until the previous process rank i-1 finish executing and signals the next rank i with a send.

        __init__(comm, tag=0)
            Initialize sequential execution.

            Parameters

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>) – Intracommunicator context.

                •   tag (int <https://docs.python.org/3/library/functions.html#int>) – Tag for point-to-point communication.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        __enter__()
            Enter sequential execution.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        __exit__(*exc)
            Exit sequential execution.

            Parameters
                exc (object <https://docs.python.org/3/library/functions.html#object>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        begin()
            Begin sequential execution.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        end()
            End sequential execution.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  Global counter

    class mpi4py.util.sync.Counter
        Global counter.

        Produce consecutive values within a group of MPI processes. The counter interface is close to that of itertools.count <https://docs.python.org/3/library/itertools.html#itertools.count>.

        The implementation is based in MPI-3 one-sided operations. A root process (typically rank 0) holds the counter, and its value is queried and incremented with an atomic RMA fetch-and-add operation.

        __init__(start=0, step=1, *, typecode='i', comm=COMM_SELF, info=INFO_NULL, root=0)
            Initialize global counter.

            Parameters

                •   start (int <https://docs.python.org/3/library/functions.html#int>) – Start value.

                •   step (int <https://docs.python.org/3/library/functions.html#int>) – Increment value.

                •   typecode (str <https://docs.python.org/3/library/stdtypes.html#str>) – Type code as defined in the array <https://docs.python.org/3/library/array.html#module-array> module.

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>) – Intracommunicator context.

                •   info (Info <#mpi4py.MPI.Info>) – Info object for RMA context creation.

                •   root (int <https://docs.python.org/3/library/functions.html#int>) – Process rank holding the counter memory.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        __iter__()
            Implement iter(self).

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        __next__()
            Implement next(self).

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        next(incr=None)
            Return current value and increment.

            Parameters
                incr (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>) – Increment value.

            Returns
                The counter value before incrementing.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        free()
            Free counter resources.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  Mutual exclusion

    class mpi4py.util.sync.Mutex
        Mutual exclusion.

        Establish a critical section or mutual exclusion among MPI processes.

        The mutex interface is close to that of threading.Lock <https://docs.python.org/3/library/threading.html#threading.Lock> and threading.RLock <https://docs.python.org/3/library/threading.html#threading.RLock>, allowing the use of either recursive or non-recursive mutual exclusion. However, a mutex should be used within a group of MPI processes, not threads.

        In non-recursive mode, the semantics of Mutex are somewhat different than these of threading.Lock <https://docs.python.org/3/library/threading.html#threading.Lock>:

        •   Once acquired, a mutex is held and owned by a process until released.

        •   Trying to acquire a mutex already held raises RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>.

        •   Trying to release a mutex not yet held raises RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>.

    This mutex implementation uses the scalable and fair spinlock algorithm from [mcs-paper] <#mcs-paper> and took inspiration from the MPI-3 RMA implementation of [uam-book] <#uam-book>.

        __init__(*, recursive=False, comm=COMM_SELF, info=INFO_NULL)
            Initialize mutex object.

            Parameters

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>) – Intracommunicator context.

                •   recursive (bool <https://docs.python.org/3/library/functions.html#bool>) – Whether to allow recursive acquisition.

                •   info (Info <#mpi4py.MPI.Info>) – Info object for RMA context creation.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        __enter__()
            Acquire mutex.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        __exit__(*exc)
            Release mutex.

            Parameters
                exc (object <https://docs.python.org/3/library/functions.html#object>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        acquire(blocking=True)
            Acquire mutex, blocking or non-blocking.

            Parameters
                blocking (bool <https://docs.python.org/3/library/functions.html#bool>) – If True <https://docs.python.org/3/library/constants.html#True>, block until the mutex is held.

            Returns
                True <https://docs.python.org/3/library/constants.html#True> if the mutex is held, False <https://docs.python.org/3/library/constants.html#False> otherwise.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        release()
            Release mutex.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        locked()
            Return whether the mutex is held.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        count()
            Return the recursion count.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        free()
            Free mutex resources.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

[mcs-paper]
    John M. Mellor-Crummey and Michael L. Scott. Algorithms for scalable synchronization on shared-memory multiprocessors. ACM Transactions on Computer Systems, 9(1):21-65, February 1991. <https://doi.org/10.1145/103727.103729>

[uam-book]
    William Gropp, Torsten Hoefler, Rajeev Thakur, Ewing Lusk. Using Advanced MPI - Modern Features of the Message-Passing Interface. Chapter 4, Section 4.7, Pages 130-131. The MIT Press, November 2014. <https://mitpress.mit.edu/9780262527637/using-advanced-mpi/>

  Condition variable

    class mpi4py.util.sync.Condition
        Condition variable.

        A condition variable allows one or more MPI processes to wait until they are notified by another processes.

        The condition variable interface is close to that of threading.Condition <https://docs.python.org/3/library/threading.html#threading.Condition>, allowing the use of either recursive or non-recursive mutual exclusion. However, the condition variable should be used within a group of MPI processes, not threads.

        This condition variable implementation uses a MPI-3 RMA-based scalable and fair circular queue algorithm to track the set of waiting processes.

        __init__(mutex=None, *, recursive=True, comm=COMM_SELF, info=INFO_NULL)
            Initialize condition variable.

            Parameters

                •   mutex (Mutex <#mpi4py.util.sync.Mutex> | None <https://docs.python.org/3/library/constants.html#None>) – Mutual exclusion object.

                •   recursive (bool <https://docs.python.org/3/library/functions.html#bool>) – Whether to allow recursive acquisition.

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>) – Intracommunicator context.

                •   info (Info <#mpi4py.MPI.Info>) – Info object for RMA context creation.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        __enter__()
            Acquire the underlying mutex.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        __exit__(*exc)
            Release the underlying mutex.

            Parameters
                exc (object <https://docs.python.org/3/library/functions.html#object>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        acquire(blocking=True)
            Acquire the underlying mutex.

            Parameters
                blocking (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        release()
            Release the underlying mutex.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        locked()
            Return whether the underlying mutex is held.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        wait()
            Wait until notified by another process.

            Returns
                Always True <https://docs.python.org/3/library/constants.html#True>.

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        wait_for(predicate)
            Wait until a predicate evaluates to True <https://docs.python.org/3/library/constants.html#True>.

            Parameters
                predicate (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[], T <#mpi4py.typing.T>]) – callable returning a boolean.

            Returns
                The result of predicate once it evaluates to True <https://docs.python.org/3/library/constants.html#True>.

            Return type
                T <#mpi4py.typing.T>

        notify(n=1)
            Wake up one or more processes waiting on this condition.

            Parameters
                n (int <https://docs.python.org/3/library/functions.html#int>) – Maximum number of processes to wake up.

            Returns
                The actual number of processes woken up.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        notify_all()
            Wake up all processes waiting on this condition.

            Returns
                The actual number of processes woken up.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        free()
            Free condition resources.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  Semaphore object

    class mpi4py.util.sync.Semaphore
        Semaphore object.

        A semaphore object manages an internal counter which is decremented by each acquire() call and incremented by each release() call. The internal counter never reaches a value below zero; when acquire() finds that it is zero, it blocks and waits until some other process calls release().

        The semaphore interface is close to that of threading.Semaphore <https://docs.python.org/3/library/threading.html#threading.Semaphore> and threading.BoundedSemaphore <https://docs.python.org/3/library/threading.html#threading.BoundedSemaphore>, allowing the use of either bounded (default) or unbounded semaphores. With a bounded semaphore, the internal counter never exceeds its initial value; otherwise release() raises ValueError <https://docs.python.org/3/library/exceptions.html#ValueError>.

        This semaphore implementation uses a global Counter and a Condition variable to handle waiting and and notification.

        __init__(value=1, *, bounded=True, comm=COMM_SELF, info=INFO_NULL)
            Initialize semaphore object.

            Parameters

                •   value (int <https://docs.python.org/3/library/functions.html#int>) – Initial value for internal counter.

                •   bounded (bool <https://docs.python.org/3/library/functions.html#bool>) – Bound internal counter to initial value.

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>) – Intracommunicator context.

                •   info (Info <#mpi4py.MPI.Info>) – Info object for RMA context creation.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        __enter__()
            Acquire semaphore.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        __exit__(*exc)
            Release semaphore.

            Parameters
                exc (object <https://docs.python.org/3/library/functions.html#object>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        acquire(blocking=True)
            Acquire semaphore, decrementing the internal counter by one.

            Parameters
                blocking (bool <https://docs.python.org/3/library/functions.html#bool>) – If True <https://docs.python.org/3/library/constants.html#True>, block until the semaphore is acquired.

            Returns
                True <https://docs.python.org/3/library/constants.html#True> if the semaphore is acquired, False <https://docs.python.org/3/library/constants.html#False> otherwise.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        release(n=1)
            Release semaphore, incrementing the internal counter by one or more.

            Parameters
                n (int <https://docs.python.org/3/library/functions.html#int>) – Increment for the internal counter.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        free()
            Free semaphore resources.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  Examples

test-sync-1.py

            from mpi4py import MPI
            from mpi4py.util.sync import Counter, Sequential

            comm = MPI.COMM_WORLD

            counter = Counter(comm)
            with Sequential(comm):
               value = next(counter)
            counter.free()

            assert comm.rank == value

test-sync-2.py

            from mpi4py import MPI
            from mpi4py.util.sync import Counter, Mutex

            comm = MPI.COMM_WORLD

            mutex = Mutex(comm)
            counter = Counter(comm)
            with mutex:
               value = next(counter)
            counter.free()
            mutex.free()

            assert (
               list(range(comm.size)) ==
               sorted(comm.allgather(value))
            )

MPI4PY.RUN

Added in version 3.0.0.

At import time, mpi4py <#module-mpi4py> initializes the MPI execution environment calling MPI_Init_thread() and installs an exit hook to automatically call MPI_Finalize() just before the Python process terminates. Additionally, mpi4py <#module-mpi4py> overrides the default ERRORS_ARE_FATAL <#mpi4py.MPI.ERRORS_ARE_FATAL> error handler in favor of ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN>, which allows translating MPI errors in Python exceptions. These departures from standard MPI behavior may be controversial, but are quite convenient within the highly dynamic Python programming environment. Third-party code using mpi4py <#module-mpi4py> can just from mpi4py import MPI and perform MPI calls without the tedious initialization/finalization handling. MPI errors, once translated automatically to Python exceptions, can be dealt with the common try <https://docs.python.org/3/reference/compound_stmts.html#try>…except <https://docs.python.org/3/reference/compound_stmts.html#except>…finally <https://docs.python.org/3/reference/compound_stmts.html#finally> clauses; unhandled MPI exceptions will print a traceback which helps in locating problems in source code.

Unfortunately, the interplay of automatic MPI finalization and unhandled exceptions may lead to deadlocks. In unattended runs, these deadlocks will drain the battery of your laptop, or burn precious allocation hours in your supercomputing facility.

  Exceptions and deadlocks

Consider the following snippet of Python code. Assume this code is stored in a standard Python script file and run with mpiexec in two or more processes.

deadlock.py

            from mpi4py import MPI
            assert MPI.COMM_WORLD.Get_size() > 1
            rank = MPI.COMM_WORLD.Get_rank()
            if rank == 0:
                1/0
                MPI.COMM_WORLD.send(None, dest=1, tag=42)
            elif rank == 1:
                MPI.COMM_WORLD.recv(source=0, tag=42)

Process 0 raises ZeroDivisionError <https://docs.python.org/3/library/exceptions.html#ZeroDivisionError> exception before performing a send call to process 1. As the exception is not handled, the Python interpreter running in process 0 will proceed to exit with non-zero status. However, as mpi4py <#module-mpi4py> installed a finalizer hook to call MPI_Finalize() before exit, process 0 will block waiting for other processes to also enter the MPI_Finalize() call. Meanwhile, process 1 will block waiting for a message to arrive from process 0, thus never reaching to MPI_Finalize(). The whole MPI execution environment is irremediably in a deadlock state.

To alleviate this issue, mpi4py <#module-mpi4py> offers a simple, alternative command line execution mechanism based on using the -m <https://docs.python.org/3/using/cmdline.html#using-on-cmdline> flag and implemented with the runpy <https://docs.python.org/3/library/runpy.html#module-runpy> module. To use this features, Python code should be run passing -m mpi4py in the command line invoking the Python interpreter. In case of unhandled exceptions, the finalizer hook will call MPI_Abort() on the MPI_COMM_WORLD communicator, thus effectively aborting the MPI execution environment.

Warning:
        When a process is forced to abort, resources (e.g. open files) are not cleaned-up and any registered finalizers (either with the atexit <https://docs.python.org/3/library/atexit.html#module-atexit> module, the Python C/API function Py_AtExit() <https://docs.python.org/3/c-api/sys.html#c.Py_AtExit>, or even the C standard library function atexit()) will not be executed. Thus, aborting execution is an extremely impolite way of ensuring process termination. However, MPI provides no other mechanism to recover from a deadlock state.

  Command line

The use of -m mpi4py to execute Python code on the command line resembles that of the Python interpreter.

    •   mpiexec -n numprocs python -m mpi4py pyfile [arg] ...

    •   mpiexec -n numprocs python -m mpi4py -m mod [arg] ...

    •   mpiexec -n numprocs python -m mpi4py -c cmd [arg] ...

    •   mpiexec -n numprocs python -m mpi4py - [arg] ...

    <pyfile>
        Execute the Python code contained in pyfile, which must be a filesystem path referring to either a Python file, a directory containing a __main__.py file, or a zipfile containing a __main__.py file.

    -m <mod>
        Search sys.path <https://docs.python.org/3/library/sys.html#sys.path> for the named module mod and execute its contents.

    -c <cmd>
        Execute the Python code in the cmd string command.

    -   Read commands from standard input (sys.stdin <https://docs.python.org/3/library/sys.html#sys.stdin>).

See also:

            Command line <https://docs.python.org/3/using/cmdline.html#using-on-cmdline>
                Documentation on Python command line interface.

MPI4PY.BENCH

Added in version 3.0.0.

REFERENCE
mpi4py.MPI <#module-mpi4py.MPI> | Message Passing Interface.

  mpi4py.MPI

Message Passing Interface.

Classes
BottomType <#mpi4py.MPI.BottomType> | Type of BOTTOM <#mpi4py.MPI.BOTTOM>.
BufferAutomaticType <#mpi4py.MPI.BufferAutomaticType> | Type of BUFFER_AUTOMATIC <#mpi4py.MPI.BUFFER_AUTOMATIC>.
Cartcomm <#mpi4py.MPI.Cartcomm> | Cartesian topology intracommunicator.
Comm <#mpi4py.MPI.Comm> | Communication context.
Datatype <#mpi4py.MPI.Datatype> | Datatype object.
Distgraphcomm <#mpi4py.MPI.Distgraphcomm> | Distributed graph topology intracommunicator.
Errhandler <#mpi4py.MPI.Errhandler> | Error handler.
File <#mpi4py.MPI.File> | File I/O context.
Graphcomm <#mpi4py.MPI.Graphcomm> | General graph topology intracommunicator.
Grequest <#mpi4py.MPI.Grequest> | Generalized request handler.
Group <#mpi4py.MPI.Group> | Group of processes.
InPlaceType <#mpi4py.MPI.InPlaceType> | Type of IN_PLACE <#mpi4py.MPI.IN_PLACE>.
Info <#mpi4py.MPI.Info> | Info object.
Intercomm <#mpi4py.MPI.Intercomm> | Intercommunicator.
Intracomm <#mpi4py.MPI.Intracomm> | Intracommunicator.
Message <#mpi4py.MPI.Message> | Matched message.
Op <#mpi4py.MPI.Op> | Reduction operation.
Pickle <#mpi4py.MPI.Pickle> | Pickle/unpickle Python objects.
Prequest <#mpi4py.MPI.Prequest> | Persistent request handler.
Request <#mpi4py.MPI.Request> | Request handler.
Session <#mpi4py.MPI.Session> | Session context.
Status <#mpi4py.MPI.Status> | Status object.
Topocomm <#mpi4py.MPI.Topocomm> | Topology intracommunicator.
Win <#mpi4py.MPI.Win> | Remote memory access context.
buffer <#mpi4py.MPI.buffer> | Buffer.
memory <#mpi4py.MPI.memory> | alias of buffer <#mpi4py.MPI.buffer>

  mpi4py.MPI.BottomType

    class mpi4py.MPI.BottomType
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Type of BOTTOM <#mpi4py.MPI.BOTTOM>.

        static __new__(cls)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

  mpi4py.MPI.BufferAutomaticType

    class mpi4py.MPI.BufferAutomaticType
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Type of BUFFER_AUTOMATIC <#mpi4py.MPI.BUFFER_AUTOMATIC>.

        static __new__(cls)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

  mpi4py.MPI.Cartcomm

    class mpi4py.MPI.Cartcomm
        Bases: Topocomm <#mpi4py.MPI.Topocomm>

        Cartesian topology intracommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Cartcomm <#mpi4py.MPI.Cartcomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Get_cart_rank(coords) | Translate logical coordinates to ranks.
    Get_coords(rank) | Translate ranks to logical coordinates.
    Get_dim() | Return number of dimensions.
    Get_topo() | Return information on the cartesian topology.
    Shift(direction, disp) | Return a process ranks for data shifting with Sendrecv <#mpi4py.MPI.Comm.Sendrecv>.
    Sub(remain_dims) | Return a lower-dimensional Cartesian topology.

    Attributes Summary
    coords | Coordinates.
    dim | Number of dimensions.
    dims | Dimensions.
    ndim | Number of dimensions.
    periods | Periodicity.
    topo | Topology information.

    Methods Documentation

        Get_cart_rank(coords)
            Translate logical coordinates to ranks.

            Parameters
                coords (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_coords(rank)
            Translate ranks to logical coordinates.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]

        Get_dim()
            Return number of dimensions.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_topo()
            Return information on the cartesian topology.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]]

        Shift(direction, disp)
            Return a process ranks for data shifting with Sendrecv <#mpi4py.MPI.Comm.Sendrecv>.

            Parameters

                •   direction (int <https://docs.python.org/3/library/functions.html#int>)

                •   disp (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

        Sub(remain_dims)
            Return a lower-dimensional Cartesian topology.

            Parameters
                remain_dims (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[bool <https://docs.python.org/3/library/functions.html#bool>])

            Return type
                Cartcomm <#mpi4py.MPI.Cartcomm>

    Attributes Documentation

        coords
            Coordinates.

        dim Number of dimensions.

        dims
            Dimensions.

        ndim
            Number of dimensions.

        periods
            Periodicity.

        topo
            Topology information.

  mpi4py.MPI.Comm

    class mpi4py.MPI.Comm
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Communication context.

        static __new__(cls, comm=None)

            Parameters
                comm (Comm <#mpi4py.MPI.Comm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Abort([errorcode]) | Terminate the MPI execution environment.
    Ack_failed([num_to_ack]) | Acknowledge failures on a communicator.
    Agree(flag) | Blocking agreement.
    Allgather(sendbuf, recvbuf) | Gather to All.
    Allgather_init(sendbuf, recvbuf[, info]) | Persistent Gather to All.
    Allgatherv(sendbuf, recvbuf) | Gather to All Vector.
    Allgatherv_init(sendbuf, recvbuf[, info]) | Persistent Gather to All Vector.
    Allreduce(sendbuf, recvbuf[, op]) | Reduce to All.
    Allreduce_init(sendbuf, recvbuf[, op, info]) | Persistent Reduce to All.
    Alltoall(sendbuf, recvbuf) | All to All Scatter/Gather.
    Alltoall_init(sendbuf, recvbuf[, info]) | Persistent All to All Scatter/Gather.
    Alltoallv(sendbuf, recvbuf) | All to All Scatter/Gather Vector.
    Alltoallv_init(sendbuf, recvbuf[, info]) | Persistent All to All Scatter/Gather Vector.
    Alltoallw(sendbuf, recvbuf) | All to All Scatter/Gather General.
    Alltoallw_init(sendbuf, recvbuf[, info]) | Persistent All to All Scatter/Gather General.
    Attach_buffer(buf) | Attach a user-provided buffer for sending in buffered mode.
    Barrier() | Barrier synchronization.
    Barrier_init([info]) | Persistent Barrier.
    Bcast(buf[, root]) | Broadcast data from one process to all other processes.
    Bcast_init(buf[, root, info]) | Persistent Broadcast.
    Bsend(buf, dest[, tag]) | Blocking send in buffered mode.
    Bsend_init(buf, dest[, tag]) | Persistent request for a send in buffered mode.
    Call_errhandler(errorcode) | Call the error handler installed on a communicator.
    Clone() | Clone an existing communicator.
    Compare(comm) | Compare two communicators.
    Create(group) | Create communicator from group.
    Create_errhandler(errhandler_fn) | Create a new error handler for communicators.
    Create_keyval([copy_fn, delete_fn, nopython]) | Create a new attribute key for communicators.
    Delete_attr(keyval) | Delete attribute value associated with a key.
    Detach_buffer() | Remove an existing attached buffer.
    Disconnect() | Disconnect from a communicator.
    Dup([info]) | Duplicate a communicator.
    Dup_with_info(info) | Duplicate a communicator with hints.
    Flush_buffer() | Block until all buffered messages have been transmitted.
    Free() | Free a communicator.
    Free_keyval(keyval) | Free an attribute key for communicators.
    Gather(sendbuf, recvbuf[, root]) | Gather data to one process from all other processes.
    Gather_init(sendbuf, recvbuf[, root, info]) | Persistent Gather.
    Gatherv(sendbuf, recvbuf[, root]) | Gather Vector.
    Gatherv_init(sendbuf, recvbuf[, root, info]) | Persistent Gather Vector.
    Get_attr(keyval) | Retrieve attribute value by key.
    Get_errhandler() | Get the error handler for a communicator.
    Get_failed() | Extract the group of failed processes.
    Get_group() | Access the group associated with a communicator.
    Get_info() | Return the current hints for a communicator.
    Get_name() | Get the print name for this communicator.
    Get_parent() | Return the parent intercommunicator for this process.
    Get_rank() | Return the rank of this process in a communicator.
    Get_size() | Return the number of processes in a communicator.
    Get_topology() | Return the type of topology (if any) associated with a communicator.
    Iagree(flag) | Nonblocking agreement.
    Iallgather(sendbuf, recvbuf) | Nonblocking Gather to All.
    Iallgatherv(sendbuf, recvbuf) | Nonblocking Gather to All Vector.
    Iallreduce(sendbuf, recvbuf[, op]) | Nonblocking Reduce to All.
    Ialltoall(sendbuf, recvbuf) | Nonblocking All to All Scatter/Gather.
    Ialltoallv(sendbuf, recvbuf) | Nonblocking All to All Scatter/Gather Vector.
    Ialltoallw(sendbuf, recvbuf) | Nonblocking All to All Scatter/Gather General.
    Ibarrier() | Nonblocking Barrier.
    Ibcast(buf[, root]) | Nonblocking Broadcast.
    Ibsend(buf, dest[, tag]) | Nonblocking send in buffered mode.
    Idup([info]) | Nonblocking duplicate a communicator.
    Idup_with_info(info) | Nonblocking duplicate a communicator with hints.
    Iflush_buffer() | Nonblocking flush for buffered messages.
    Igather(sendbuf, recvbuf[, root]) | Nonblocking Gather.
    Igatherv(sendbuf, recvbuf[, root]) | Nonblocking Gather Vector.
    Improbe([source, tag, status]) | Nonblocking test for a matched message.
    Iprobe([source, tag, status]) | Nonblocking test for a message.
    Irecv(buf[, source, tag]) | Nonblocking receive.
    Ireduce(sendbuf, recvbuf[, op, root]) | Nonblocking Reduce to Root.
    Ireduce_scatter(sendbuf, recvbuf[, ...]) | Nonblocking Reduce-Scatter (vector version).
    Ireduce_scatter_block(sendbuf, recvbuf[, op]) | Nonblocking Reduce-Scatter Block (regular, non-vector version).
    Irsend(buf, dest[, tag]) | Nonblocking send in ready mode.
    Is_inter() | Return whether the communicator is an intercommunicator.
    Is_intra() | Return whether the communicator is an intracommunicator.
    Is_revoked() | Indicate whether the communicator has been revoked.
    Iscatter(sendbuf, recvbuf[, root]) | Nonblocking Scatter.
    Iscatterv(sendbuf, recvbuf[, root]) | Nonblocking Scatter Vector.
    Isend(buf, dest[, tag]) | Nonblocking send.
    Isendrecv(sendbuf, dest[, sendtag, recvbuf, ...]) | Nonblocking send and receive.
    Isendrecv_replace(buf, dest[, sendtag, ...]) | Send and receive a message.
    Ishrink() | Nonblocking shrink a communicator to remove all failed processes.
    Issend(buf, dest[, tag]) | Nonblocking send in synchronous mode.
    Join(fd) | Interconnect two processes connected by a socket.
    Mprobe([source, tag, status]) | Blocking test for a matched message.
    Precv_init(buf, partitions[, source, tag, info]) | Create request for a partitioned recv operation.
    Probe([source, tag, status]) | Blocking test for a message.
    Psend_init(buf, partitions, dest[, tag, info]) | Create request for a partitioned send operation.
    Recv(buf[, source, tag, status]) | Blocking receive.
    Recv_init(buf[, source, tag]) | Create a persistent request for a receive.
    Reduce(sendbuf, recvbuf[, op, root]) | Reduce to Root.
    Reduce_init(sendbuf, recvbuf[, op, root, info]) | Persistent Reduce to Root.
    Reduce_scatter(sendbuf, recvbuf[, ...]) | Reduce-Scatter (vector version).
    Reduce_scatter_block(sendbuf, recvbuf[, op]) | Reduce-Scatter Block (regular, non-vector version).
    Reduce_scatter_block_init(sendbuf, recvbuf) | Persistent Reduce-Scatter Block (regular, non-vector version).
    Reduce_scatter_init(sendbuf, recvbuf[, ...]) | Persistent Reduce-Scatter (vector version).
    Revoke() | Revoke a communicator.
    Rsend(buf, dest[, tag]) | Blocking send in ready mode.
    Rsend_init(buf, dest[, tag]) | Persistent request for a send in ready mode.
    Scatter(sendbuf, recvbuf[, root]) | Scatter data from one process to all other processes.
    Scatter_init(sendbuf, recvbuf[, root, info]) | Persistent Scatter.
    Scatterv(sendbuf, recvbuf[, root]) | Scatter Vector.
    Scatterv_init(sendbuf, recvbuf[, root, info]) | Persistent Scatter Vector.
    Send(buf, dest[, tag]) | Blocking send.
    Send_init(buf, dest[, tag]) | Create a persistent request for a standard send.
    Sendrecv(sendbuf, dest[, sendtag, recvbuf, ...]) | Send and receive a message.
    Sendrecv_replace(buf, dest[, sendtag, ...]) | Send and receive a message.
    Set_attr(keyval, attrval) | Store attribute value associated with a key.
    Set_errhandler(errhandler) | Set the error handler for a communicator.
    Set_info(info) | Set new values for the hints associated with a communicator.
    Set_name(name) | Set the print name for this communicator.
    Shrink() | Shrink a communicator to remove all failed processes.
    Split([color, key]) | Split communicator by color and key.
    Split_type(split_type[, key, info]) | Split communicator by split type.
    Ssend(buf, dest[, tag]) | Blocking send in synchronous mode.
    Ssend_init(buf, dest[, tag]) | Persistent request for a send in synchronous mode.
    allgather(sendobj) | Gather to All.
    allreduce(sendobj[, op]) | Reduce to All.
    alltoall(sendobj) | All to All Scatter/Gather.
    barrier() | Barrier synchronization.
    bcast(obj[, root]) | Broadcast.
    bsend(obj, dest[, tag]) | Send in buffered mode.
    f2py(arg) |
    free() | Call Free if not null or predefined.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    gather(sendobj[, root]) | Gather.
    ibsend(obj, dest[, tag]) | Nonblocking send in buffered mode.
    improbe([source, tag, status]) | Nonblocking test for a matched message.
    iprobe([source, tag, status]) | Nonblocking test for a message.
    irecv([buf, source, tag]) | Nonblocking receive.
    isend(obj, dest[, tag]) | Nonblocking send.
    issend(obj, dest[, tag]) | Nonblocking send in synchronous mode.
    mprobe([source, tag, status]) | Blocking test for a matched message.
    probe([source, tag, status]) | Blocking test for a message.
    py2f() |
    recv([buf, source, tag, status]) | Receive.
    reduce(sendobj[, op, root]) | Reduce to Root.
    scatter(sendobj[, root]) | Scatter.
    send(obj, dest[, tag]) | Send in standard mode.
    sendrecv(sendobj, dest[, sendtag, recvbuf, ...]) | Send and Receive.
    ssend(obj, dest[, tag]) | Send in synchronous mode.
    toint() | Translate object to integer handle.

    Attributes Summary
    group | Group.
    handle | MPI handle.
    info | Info hints.
    is_inter | Is intercommunicator.
    is_intra | Is intracommunicator.
    is_topo | Is a topology.
    name | Print name.
    rank | Rank of this process.
    size | Number of processes.
    topology | Topology type.

    Methods Documentation

        Abort(errorcode=0)
            Terminate the MPI execution environment.

            Warning:
                The invocation of this method prevents the execution of various Python exit and cleanup mechanisms. Use this method as a last resort to prevent parallel deadlocks in case of unrecoverable errors.

            Parameters
                errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                NoReturn <https://docs.python.org/3/library/typing.html#typing.NoReturn>

        Ack_failed(num_to_ack=None)
            Acknowledge failures on a communicator.

            Parameters
                num_to_ack (int <https://docs.python.org/3/library/functions.html#int> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Agree(flag)
            Blocking agreement.

            Parameters
                flag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Allgather(sendbuf, recvbuf)
            Gather to All.

            Gather data from all processes and broadcast the combined data to all other processes.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Allgather_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Gather to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Allgatherv(sendbuf, recvbuf)
            Gather to All Vector.

            Gather data from all processes and send it to all other processes providing different amounts of data and displacements.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Allgatherv_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Gather to All Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Allreduce(sendbuf, recvbuf, op=SUM)
            Reduce to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Allreduce_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)
            Persistent Reduce to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Alltoall(sendbuf, recvbuf)
            All to All Scatter/Gather.

            Send data to all processes and recv data from all processes.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Alltoall_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent All to All Scatter/Gather.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Alltoallv(sendbuf, recvbuf)
            All to All Scatter/Gather Vector.

            Send data to all processes and recv data from all processes providing different amounts of data and displacements.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Alltoallv_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent All to All Scatter/Gather Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Alltoallw(sendbuf, recvbuf)
            All to All Scatter/Gather General.

            Send/recv data to/from all processes allowing the specification of different counts, displacements, and datatypes for each dest/source.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Alltoallw_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent All to All Scatter/Gather General.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Attach_buffer(buf)
            Attach a user-provided buffer for sending in buffered mode.

            Parameters
                buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Barrier()
            Barrier synchronization.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Barrier_init(info=INFO_NULL)
            Persistent Barrier.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Bcast(buf, root=0)
            Broadcast data from one process to all other processes.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Bcast_init(buf, root=0, info=INFO_NULL)
            Persistent Broadcast.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Bsend(buf, dest, tag=0)
            Blocking send in buffered mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Bsend_init(buf, dest, tag=0)
            Persistent request for a send in buffered mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Call_errhandler(errorcode)
            Call the error handler installed on a communicator.

            Parameters
                errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Clone()
            Clone an existing communicator.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Compare(comm)
            Compare two communicators.

            Parameters
                comm (Comm <#mpi4py.MPI.Comm>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Create(group)
            Create communicator from group.

            Parameters
                group (Group <#mpi4py.MPI.Group>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        classmethod Create_errhandler(errhandler_fn)
            Create a new error handler for communicators.

            Parameters
                errhandler_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Comm <#mpi4py.MPI.Comm>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
            Create a new attribute key for communicators.

            Parameters

                •   copy_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Comm <#mpi4py.MPI.Comm>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   delete_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Comm <#mpi4py.MPI.Comm>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   nopython (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Delete_attr(keyval)
            Delete attribute value associated with a key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Detach_buffer()
            Remove an existing attached buffer.

            Return type
                Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>

        Disconnect()
            Disconnect from a communicator.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Dup(info=None)
            Duplicate a communicator.

            Parameters
                info (Info <#mpi4py.MPI.Info> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Dup_with_info(info)
            Duplicate a communicator with hints.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Flush_buffer()
            Block until all buffered messages have been transmitted.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Free()
            Free a communicator.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Free_keyval(keyval)
            Free an attribute key for communicators.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Gather(sendbuf, recvbuf, root=0)
            Gather data to one process from all other processes.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Gather_init(sendbuf, recvbuf, root=0, info=INFO_NULL)
            Persistent Gather.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Gatherv(sendbuf, recvbuf, root=0)
            Gather Vector.

            Gather data to one process from all other processes providing different amounts of data and displacements.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Gatherv_init(sendbuf, recvbuf, root=0, info=INFO_NULL)
            Persistent Gather Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Get_attr(keyval)
            Retrieve attribute value by key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int> | Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>

        Get_errhandler()
            Get the error handler for a communicator.

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        Get_failed()
            Extract the group of failed processes.

            Return type
                Group <#mpi4py.MPI.Group>

        Get_group()
            Access the group associated with a communicator.

            Return type
                Group <#mpi4py.MPI.Group>

        Get_info()
            Return the current hints for a communicator.

            Return type
                Info <#mpi4py.MPI.Info>

        Get_name()
            Get the print name for this communicator.

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        classmethod Get_parent()
            Return the parent intercommunicator for this process.

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Get_rank()
            Return the rank of this process in a communicator.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_size()
            Return the number of processes in a communicator.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_topology()
            Return the type of topology (if any) associated with a communicator.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Iagree(flag)
            Nonblocking agreement.

            Parameters
                flag (Buffer <#mpi4py.typing.Buffer>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iallgather(sendbuf, recvbuf)
            Nonblocking Gather to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iallgatherv(sendbuf, recvbuf)
            Nonblocking Gather to All Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iallreduce(sendbuf, recvbuf, op=SUM)
            Nonblocking Reduce to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ialltoall(sendbuf, recvbuf)
            Nonblocking All to All Scatter/Gather.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ialltoallv(sendbuf, recvbuf)
            Nonblocking All to All Scatter/Gather Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ialltoallw(sendbuf, recvbuf)
            Nonblocking All to All Scatter/Gather General.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ibarrier()
            Nonblocking Barrier.

            Return type
                Request <#mpi4py.MPI.Request>

        Ibcast(buf, root=0)
            Nonblocking Broadcast.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ibsend(buf, dest, tag=0)
            Nonblocking send in buffered mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Idup(info=None)
            Nonblocking duplicate a communicator.

            Parameters
                info (Info <#mpi4py.MPI.Info> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[Self <https://docs.python.org/3/library/typing.html#typing.Self>, Request <#mpi4py.MPI.Request>]

        Idup_with_info(info)
            Nonblocking duplicate a communicator with hints.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[Self <https://docs.python.org/3/library/typing.html#typing.Self>, Request <#mpi4py.MPI.Request>]

        Iflush_buffer()
            Nonblocking flush for buffered messages.

            Return type
                Request <#mpi4py.MPI.Request>

        Igather(sendbuf, recvbuf, root=0)
            Nonblocking Gather.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Igatherv(sendbuf, recvbuf, root=0)
            Nonblocking Gather Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.MPI.Message> | None <https://docs.python.org/3/library/constants.html#None>

        Iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Irecv(buf, source=ANY_SOURCE, tag=ANY_TAG)
            Nonblocking receive.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ireduce(sendbuf, recvbuf, op=SUM, root=0)
            Nonblocking Reduce to Root.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ireduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
            Nonblocking Reduce-Scatter (vector version).

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvcounts (Sequence[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ireduce_scatter_block(sendbuf, recvbuf, op=SUM)
            Nonblocking Reduce-Scatter Block (regular, non-vector version).

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | BufSpecB <#mpi4py.typing.BufSpecB>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Irsend(buf, dest, tag=0)
            Nonblocking send in ready mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Is_inter()
            Return whether the communicator is an intercommunicator.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Is_intra()
            Return whether the communicator is an intracommunicator.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Is_revoked()
            Indicate whether the communicator has been revoked.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Iscatter(sendbuf, recvbuf, root=0)
            Nonblocking Scatter.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iscatterv(sendbuf, recvbuf, root=0)
            Nonblocking Scatter Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Isend(buf, dest, tag=0)
            Nonblocking send.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Isendrecv(sendbuf, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG)
            Nonblocking send and receive.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Isendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recvtag=ANY_TAG)
            Send and receive a message.

            Note:
                This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

        Caution:
                A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ishrink()
            Nonblocking shrink a communicator to remove all failed processes.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[Comm <#mpi4py.MPI.Comm>, Request <#mpi4py.MPI.Request>]

        Issend(buf, dest, tag=0)
            Nonblocking send in synchronous mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod Join(fd)
            Interconnect two processes connected by a socket.

            Parameters
                fd (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.MPI.Message>

        Precv_init(buf, partitions, source=ANY_SOURCE, tag=ANY_TAG, info=INFO_NULL)
            Create request for a partitioned recv operation.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   partitions (int <https://docs.python.org/3/library/functions.html#int>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a message.

            Note:
                This function blocks until the message arrives.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        Psend_init(buf, partitions, dest, tag=0, info=INFO_NULL)
            Create request for a partitioned send operation.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   partitions (int <https://docs.python.org/3/library/functions.html#int>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Recv(buf, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking receive.

            Note:
                This function blocks until the message is received.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Recv_init(buf, source=ANY_SOURCE, tag=ANY_TAG)
            Create a persistent request for a receive.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Reduce(sendbuf, recvbuf, op=SUM, root=0)
            Reduce to Root.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Reduce_init(sendbuf, recvbuf, op=SUM, root=0, info=INFO_NULL)
            Persistent Reduce to Root.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Reduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
            Reduce-Scatter (vector version).

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvcounts (Sequence[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Reduce_scatter_block(sendbuf, recvbuf, op=SUM)
            Reduce-Scatter Block (regular, non-vector version).

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | BufSpecB <#mpi4py.typing.BufSpecB>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Reduce_scatter_block_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)
            Persistent Reduce-Scatter Block (regular, non-vector version).

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | BufSpecB <#mpi4py.typing.BufSpecB>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Reduce_scatter_init(sendbuf, recvbuf, recvcounts=None, op=SUM, info=INFO_NULL)
            Persistent Reduce-Scatter (vector version).

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvcounts (Sequence[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Revoke()
            Revoke a communicator.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Rsend(buf, dest, tag=0)
            Blocking send in ready mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Rsend_init(buf, dest, tag=0)
            Persistent request for a send in ready mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        Scatter(sendbuf, recvbuf, root=0)
            Scatter data from one process to all other processes.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Scatter_init(sendbuf, recvbuf, root=0, info=INFO_NULL)
            Persistent Scatter.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Scatterv(sendbuf, recvbuf, root=0)
            Scatter Vector.

            Scatter data from one process to all other processes providing different amounts of data and displacements.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Scatterv_init(sendbuf, recvbuf, root=0, info=INFO_NULL)
            Persistent Scatter Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV> | None <https://docs.python.org/3/library/constants.html#None>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Send(buf, dest, tag=0)
            Blocking send.

            Note:
                This function may block until the message is received. Whether Send blocks or not depends on several factors and is implementation dependent.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Send_init(buf, dest, tag=0)
            Create a persistent request for a standard send.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Sendrecv(sendbuf, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
            Send and receive a message.

            Note:
                This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

        Caution:
                A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Sendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
            Send and receive a message.

            Note:
                This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

        Caution:
                A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_attr(keyval, attrval)
            Store attribute value associated with a key.

            Parameters

                •   keyval (int <https://docs.python.org/3/library/functions.html#int>)

                •   attrval (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_errhandler(errhandler)
            Set the error handler for a communicator.

            Parameters
                errhandler (Errhandler <#mpi4py.MPI.Errhandler>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_info(info)
            Set new values for the hints associated with a communicator.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_name(name)
            Set the print name for this communicator.

            Parameters
                name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Shrink()
            Shrink a communicator to remove all failed processes.

            Return type
                Comm <#mpi4py.MPI.Comm>

        Split(color=0, key=0)
            Split communicator by color and key.

            Parameters

                •   color (int <https://docs.python.org/3/library/functions.html#int>)

                •   key (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        Split_type(split_type, key=0, info=INFO_NULL)
            Split communicator by split type.

            Parameters

                •   split_type (int <https://docs.python.org/3/library/functions.html#int>)

                •   key (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        Ssend(buf, dest, tag=0)
            Blocking send in synchronous mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Ssend_init(buf, dest, tag=0)
            Persistent request for a send in synchronous mode.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        allgather(sendobj)
            Gather to All.

            Parameters
                sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        allreduce(sendobj, op=SUM)
            Reduce to All.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   op (Op <#mpi4py.MPI.Op> | Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Any <https://docs.python.org/3/library/typing.html#typing.Any>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        alltoall(sendobj)
            All to All Scatter/Gather.

            Parameters
                sendobj (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        barrier()
            Barrier synchronization.

            Note:
                This method is equivalent to Barrier.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        bcast(obj, root=0)
            Broadcast.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        bsend(obj, dest, tag=0)
            Send in buffered mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        free()
            Call Free if not null or predefined.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Comm <#mpi4py.MPI.Comm>

        gather(sendobj, root=0)
            Gather.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>

        ibsend(obj, dest, tag=0)
            Nonblocking send in buffered mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.MPI.Message> | None <https://docs.python.org/3/library/constants.html#None>

        iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
            Nonblocking receive.

            Parameters

                •   buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        isend(obj, dest, tag=0)
            Nonblocking send.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        issend(obj, dest, tag=0)
            Nonblocking send in synchronous mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Message <#mpi4py.MPI.Message>

        probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a message.

            Parameters

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Receive.

            Parameters

                •   buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any

        reduce(sendobj, op=SUM, root=0)
            Reduce to Root.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   op (Op <#mpi4py.MPI.Op> | Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Any <https://docs.python.org/3/library/typing.html#typing.Any>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>])

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>

        scatter(sendobj, root=0)
            Scatter.

            Parameters

                •   sendobj (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        send(obj, dest, tag=0)
            Send in standard mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        sendrecv(sendobj, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
            Send and Receive.

            Parameters

                •   sendobj (Any)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   sendtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvbuf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   recvtag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any

        ssend(obj, dest, tag=0)
            Send in synchronous mode.

            Parameters

                •   obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   dest (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        group
            Group.

        handle
            MPI handle.

        info
            Info hints.

        is_inter
            Is intercommunicator.

        is_intra
            Is intracommunicator.

        is_topo
            Is a topology.

        name
            Print name.

        rank
            Rank of this process.

        size
            Number of processes.

        topology
            Topology type.

  mpi4py.MPI.Datatype

    class mpi4py.MPI.Datatype
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Datatype object.

        static __new__(cls, datatype=None)

            Parameters
                datatype (Datatype <#mpi4py.MPI.Datatype> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Commit() | Commit the datatype.
    Create_contiguous(count) | Create a contiguous datatype.
    Create_darray(size, rank, gsizes, distribs, ...) | Create a datatype for a distributed array on Cartesian process grids.
    Create_f90_complex(p, r) | Return a bounded complex datatype.
    Create_f90_integer(r) | Return a bounded integer datatype.
    Create_f90_real(p, r) | Return a bounded real datatype.
    Create_hindexed(blocklengths, displacements) | Create an indexed datatype.
    Create_hindexed_block(blocklength, displacements) | Create an indexed datatype with constant-sized blocks.
    Create_hvector(count, blocklength, stride) | Create a vector (strided) datatype with stride in bytes.
    Create_indexed(blocklengths, displacements) | Create an indexed datatype.
    Create_indexed_block(blocklength, displacements) | Create an indexed datatype with constant-sized blocks.
    Create_keyval([copy_fn, delete_fn, nopython]) | Create a new attribute key for datatypes.
    Create_resized(lb, extent) | Create a datatype with a new lower bound and extent.
    Create_struct(blocklengths, displacements, ...) | Create a general composite (struct) datatype.
    Create_subarray(sizes, subsizes, starts[, order]) | Create a datatype for a subarray of a multidimensional array.
    Create_vector(count, blocklength, stride) | Create a vector (strided) datatype.
    Delete_attr(keyval) | Delete attribute value associated with a key.
    Dup() | Duplicate a datatype.
    Free() | Free the datatype.
    Free_keyval(keyval) | Free an attribute key for datatypes.
    Get_attr(keyval) | Retrieve attribute value by key.
    Get_contents() | Return the input arguments used to create a datatype.
    Get_envelope() | Return the number of input arguments used to create a datatype.
    Get_extent() | Return lower bound and extent of datatype.
    Get_name() | Get the print name for this datatype.
    Get_size() | Return the number of bytes occupied by entries in the datatype.
    Get_true_extent() | Return the true lower bound and extent of a datatype.
    Get_value_index(value, index) | Return a predefined pair datatype.
    Match_size(typeclass, size) | Find a datatype matching a specified size in bytes.
    Pack(inbuf, outbuf, position, comm) | Pack into contiguous memory according to datatype.
    Pack_external(datarep, inbuf, outbuf, position) | Pack into contiguous memory according to datatype.
    Pack_external_size(datarep, count) | Determine the amount of space needed to pack a message.
    Pack_size(count, comm) | Determine the amount of space needed to pack a message.
    Set_attr(keyval, attrval) | Store attribute value associated with a key.
    Set_name(name) | Set the print name for this datatype.
    Unpack(inbuf, position, outbuf, comm) | Unpack from contiguous memory according to datatype.
    Unpack_external(datarep, inbuf, position, outbuf) | Unpack from contiguous memory according to datatype.
    decode() | Convenience method for decoding a datatype.
    f2py(arg) |
    free() | Call Free if not null or predefined.
    fromcode(code) | Get predefined MPI datatype from character code or type string.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    tocode() | Get character code or type string from predefined MPI datatype.
    toint() | Translate object to integer handle.

    Attributes Summary
    combiner | Combiner.
    contents | Contents.
    envelope | Envelope.
    extent | Extent.
    handle | MPI handle.
    is_named | Is a named datatype.
    is_predefined | Is a predefined datatype.
    lb | Lower bound.
    name | Print name.
    size | Size (in bytes).
    true_extent | True extent.
    true_lb | True lower bound.
    true_ub | True upper bound.
    typechar | Character code.
    typestr | Type string.
    ub | Upper bound.

    Methods Documentation

        Commit()
            Commit the datatype.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_contiguous(count)
            Create a contiguous datatype.

            Parameters
                count (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_darray(size, rank, gsizes, distribs, dargs, psizes, order=ORDER_C)
            Create a datatype for a distributed array on Cartesian process grids.

            Parameters

                •   size (int <https://docs.python.org/3/library/functions.html#int>)

                •   rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   gsizes (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   distribs (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   dargs (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   psizes (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   order (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_f90_complex(p, r)
            Return a bounded complex datatype.

            Parameters

                •   p (int <https://docs.python.org/3/library/functions.html#int>)

                •   r (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_f90_integer(r)
            Return a bounded integer datatype.

            Parameters
                r (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_f90_real(p, r)
            Return a bounded real datatype.

            Parameters

                •   p (int <https://docs.python.org/3/library/functions.html#int>)

                •   r (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_hindexed(blocklengths, displacements)
            Create an indexed datatype.

            Note:
                Displacements are measured in bytes.

            Parameters

                •   blocklengths (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   displacements (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_hindexed_block(blocklength, displacements)
            Create an indexed datatype with constant-sized blocks.

            Note:
                Displacements are measured in bytes.

            Parameters

                •   blocklength (int <https://docs.python.org/3/library/functions.html#int>)

                •   displacements (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_hvector(count, blocklength, stride)
            Create a vector (strided) datatype with stride in bytes.

            Parameters

                •   count (int <https://docs.python.org/3/library/functions.html#int>)

                •   blocklength (int <https://docs.python.org/3/library/functions.html#int>)

                •   stride (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_indexed(blocklengths, displacements)
            Create an indexed datatype.

            Parameters

                •   blocklengths (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   displacements (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_indexed_block(blocklength, displacements)
            Create an indexed datatype with constant-sized blocks.

            Parameters

                •   blocklength (int <https://docs.python.org/3/library/functions.html#int>)

                •   displacements (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
            Create a new attribute key for datatypes.

            Parameters

                •   copy_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Datatype <#mpi4py.MPI.Datatype>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   delete_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Datatype <#mpi4py.MPI.Datatype>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   nopython (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Create_resized(lb, extent)
            Create a datatype with a new lower bound and extent.

            Parameters

                •   lb (int <https://docs.python.org/3/library/functions.html#int>)

                •   extent (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_struct(blocklengths, displacements, datatypes)
            Create a general composite (struct) datatype.

            Note:
                Displacements are measured in bytes.

            Parameters

                •   blocklengths (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   displacements (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   datatypes (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Datatype <#mpi4py.MPI.Datatype>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_subarray(sizes, subsizes, starts, order=ORDER_C)
            Create a datatype for a subarray of a multidimensional array.

            Parameters

                •   sizes (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   subsizes (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   starts (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   order (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Create_vector(count, blocklength, stride)
            Create a vector (strided) datatype.

            Parameters

                •   count (int <https://docs.python.org/3/library/functions.html#int>)

                •   blocklength (int <https://docs.python.org/3/library/functions.html#int>)

                •   stride (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Delete_attr(keyval)
            Delete attribute value associated with a key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Dup()
            Duplicate a datatype.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Free()
            Free the datatype.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Free_keyval(keyval)
            Free an attribute key for datatypes.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_attr(keyval)
            Retrieve attribute value by key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int> | Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>

        Get_contents()
            Return the input arguments used to create a datatype.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[Datatype <#mpi4py.MPI.Datatype>]]

        Get_envelope()
            Return the number of input arguments used to create a datatype.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

        Get_extent()
            Return lower bound and extent of datatype.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

        Get_name()
            Get the print name for this datatype.

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        Get_size()
            Return the number of bytes occupied by entries in the datatype.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_true_extent()
            Return the true lower bound and extent of a datatype.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

        classmethod Get_value_index(value, index)
            Return a predefined pair datatype.

            Parameters

                •   value (Datatype <#mpi4py.MPI.Datatype>)

                •   index (Datatype <#mpi4py.MPI.Datatype>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Match_size(typeclass, size)
            Find a datatype matching a specified size in bytes.

            Parameters

                •   typeclass (int <https://docs.python.org/3/library/functions.html#int>)

                •   size (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Pack(inbuf, outbuf, position, comm)
            Pack into contiguous memory according to datatype.

            Parameters

                •   inbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   outbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   position (int <https://docs.python.org/3/library/functions.html#int>)

                •   comm (Comm <#mpi4py.MPI.Comm>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Pack_external(datarep, inbuf, outbuf, position)
            Pack into contiguous memory according to datatype.

            Uses the portable data representation external32.

            Parameters

                •   datarep (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   inbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   outbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   position (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Pack_external_size(datarep, count)
            Determine the amount of space needed to pack a message.

            Uses the portable data representation external32.

            Note:
                Returns an upper bound measured in bytes.

            Parameters

                •   datarep (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   count (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Pack_size(count, comm)
            Determine the amount of space needed to pack a message.

            Note:
                Returns an upper bound measured in bytes.

            Parameters

                •   count (int <https://docs.python.org/3/library/functions.html#int>)

                •   comm (Comm <#mpi4py.MPI.Comm>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Set_attr(keyval, attrval)
            Store attribute value associated with a key.

            Parameters

                •   keyval (int <https://docs.python.org/3/library/functions.html#int>)

                •   attrval (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_name(name)
            Set the print name for this datatype.

            Parameters
                name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Unpack(inbuf, position, outbuf, comm)
            Unpack from contiguous memory according to datatype.

            Parameters

                •   inbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   position (int <https://docs.python.org/3/library/functions.html#int>)

                •   outbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   comm (Comm <#mpi4py.MPI.Comm>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Unpack_external(datarep, inbuf, position, outbuf)
            Unpack from contiguous memory according to datatype.

            Uses the portable data representation external32.

            Parameters

                •   datarep (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   inbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   position (int <https://docs.python.org/3/library/functions.html#int>)

                •   outbuf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        decode()
            Convenience method for decoding a datatype.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[Datatype <#mpi4py.MPI.Datatype>, str <https://docs.python.org/3/library/stdtypes.html#str>, dict <https://docs.python.org/3/library/stdtypes.html#dict>[str <https://docs.python.org/3/library/stdtypes.html#str>, Any <https://docs.python.org/3/library/typing.html#typing.Any>]]

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Datatype <#mpi4py.MPI.Datatype>

        free()
            Call Free if not null or predefined.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromcode(code)
            Get predefined MPI datatype from character code or type string.

            Parameters
                code (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                Datatype <#mpi4py.MPI.Datatype>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Datatype <#mpi4py.MPI.Datatype>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Datatype <#mpi4py.MPI.Datatype>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        tocode()
            Get character code or type string from predefined MPI datatype.

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        combiner
            Combiner.

        contents
            Contents.

        envelope
            Envelope.

        extent
            Extent.

        handle
            MPI handle.

        is_named
            Is a named datatype.

        is_predefined
            Is a predefined datatype.

        lb  Lower bound.

        name
            Print name.

        size
            Size (in bytes).

        true_extent
            True extent.

        true_lb
            True lower bound.

        true_ub
            True upper bound.

        typechar
            Character code.

        typestr
            Type string.

        ub  Upper bound.

  mpi4py.MPI.Distgraphcomm

    class mpi4py.MPI.Distgraphcomm
        Bases: Topocomm <#mpi4py.MPI.Topocomm>

        Distributed graph topology intracommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Distgraphcomm <#mpi4py.MPI.Distgraphcomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Get_dist_neighbors() | Return adjacency information for a distributed graph topology.
    Get_dist_neighbors_count() | Return adjacency information for a distributed graph topology.

    Methods Documentation

        Get_dist_neighbors()
            Return adjacency information for a distributed graph topology.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]] | None <https://docs.python.org/3/library/constants.html#None>]

        Get_dist_neighbors_count()
            Return adjacency information for a distributed graph topology.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Errhandler

    class mpi4py.MPI.Errhandler
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Error handler.

        static __new__(cls, errhandler=None)

            Parameters
                errhandler (Errhandler <#mpi4py.MPI.Errhandler> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Free() | Free an error handler.
    f2py(arg) |
    free() | Call Free if not null.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.

    Attributes Summary
    handle | MPI handle.

    Methods Documentation

        Free()
            Free an error handler.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        free()
            Call Free if not null.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        handle
            MPI handle.

  mpi4py.MPI.File

    class mpi4py.MPI.File
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        File I/O context.

        static __new__(cls, file=None)

            Parameters
                file (File <#mpi4py.MPI.File> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Call_errhandler(errorcode) | Call the error handler installed on a file.
    Close() | Close a file.
    Create_errhandler(errhandler_fn) | Create a new error handler for files.
    Delete(filename[, info]) | Delete a file.
    Get_amode() | Return the file access mode.
    Get_atomicity() | Return the atomicity mode.
    Get_byte_offset(offset) | Return the absolute byte position in the file.
    Get_errhandler() | Get the error handler for a file.
    Get_group() | Access the group of processes that opened the file.
    Get_info() | Return the current hints for a file.
    Get_position() | Return the current position of the individual file pointer.
    Get_position_shared() | Return the current position of the shared file pointer.
    Get_size() | Return the file size.
    Get_type_extent(datatype) | Return the extent of datatype in the file.
    Get_view() | Return the file view.
    Iread(buf) | Nonblocking read using individual file pointer.
    Iread_all(buf) | Nonblocking collective read using individual file pointer.
    Iread_at(offset, buf) | Nonblocking read using explicit offset.
    Iread_at_all(offset, buf) | Nonblocking collective read using explicit offset.
    Iread_shared(buf) | Nonblocking read using shared file pointer.
    Iwrite(buf) | Nonblocking write using individual file pointer.
    Iwrite_all(buf) | Nonblocking collective write using individual file pointer.
    Iwrite_at(offset, buf) | Nonblocking write using explicit offset.
    Iwrite_at_all(offset, buf) | Nonblocking collective write using explicit offset.
    Iwrite_shared(buf) | Nonblocking write using shared file pointer.
    Open(comm, filename[, amode, info]) | Open a file.
    Preallocate(size) | Preallocate storage space for a file.
    Read(buf[, status]) | Read using individual file pointer.
    Read_all(buf[, status]) | Collective read using individual file pointer.
    Read_all_begin(buf) | Start a split collective read using individual file pointer.
    Read_all_end(buf[, status]) | Complete a split collective read using individual file pointer.
    Read_at(offset, buf[, status]) | Read using explicit offset.
    Read_at_all(offset, buf[, status]) | Collective read using explicit offset.
    Read_at_all_begin(offset, buf) | Start a split collective read using explicit offset.
    Read_at_all_end(buf[, status]) | Complete a split collective read using explicit offset.
    Read_ordered(buf[, status]) | Collective read using shared file pointer.
    Read_ordered_begin(buf) | Start a split collective read using shared file pointer.
    Read_ordered_end(buf[, status]) | Complete a split collective read using shared file pointer.
    Read_shared(buf[, status]) | Read using shared file pointer.
    Seek(offset[, whence]) | Update the individual file pointer.
    Seek_shared(offset[, whence]) | Update the shared file pointer.
    Set_atomicity(flag) | Set the atomicity mode.
    Set_errhandler(errhandler) | Set the error handler for a file.
    Set_info(info) | Set new values for the hints associated with a file.
    Set_size(size) | Set the file size.
    Set_view([disp, etype, filetype, datarep, info]) | Set the file view.
    Sync() | Causes all previous writes to be transferred to the storage device.
    Write(buf[, status]) | Write using individual file pointer.
    Write_all(buf[, status]) | Collective write using individual file pointer.
    Write_all_begin(buf) | Start a split collective write using individual file pointer.
    Write_all_end(buf[, status]) | Complete a split collective write using individual file pointer.
    Write_at(offset, buf[, status]) | Write using explicit offset.
    Write_at_all(offset, buf[, status]) | Collective write using explicit offset.
    Write_at_all_begin(offset, buf) | Start a split collective write using explicit offset.
    Write_at_all_end(buf[, status]) | Complete a split collective write using explicit offset.
    Write_ordered(buf[, status]) | Collective write using shared file pointer.
    Write_ordered_begin(buf) | Start a split collective write using shared file pointer.
    Write_ordered_end(buf[, status]) | Complete a split collective write using shared file pointer.
    Write_shared(buf[, status]) | Write using shared file pointer.
    f2py(arg) |
    free() | Call Close if not null.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.

    Attributes Summary
    amode | Access mode.
    atomicity | Atomicity mode.
    group | Group.
    group_rank | Group rank.
    group_size | Group size.
    handle | MPI handle.
    info | Info hints.
    size | Size (in bytes).

    Methods Documentation

        Call_errhandler(errorcode)
            Call the error handler installed on a file.

            Parameters
                errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Close()
            Close a file.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Create_errhandler(errhandler_fn)
            Create a new error handler for files.

            Parameters
                errhandler_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[File <#mpi4py.MPI.File>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        classmethod Delete(filename, info=INFO_NULL)
            Delete a file.

            Parameters

                •   filename (PathLike <https://docs.python.org/3/library/os.html#os.PathLike> | str <https://docs.python.org/3/library/stdtypes.html#str> | bytes <https://docs.python.org/3/library/stdtypes.html#bytes>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_amode()
            Return the file access mode.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_atomicity()
            Return the atomicity mode.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Get_byte_offset(offset)
            Return the absolute byte position in the file.

            Note:
                Input offset is measured in etype units relative to the current file view.

            Parameters
                offset (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_errhandler()
            Get the error handler for a file.

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        Get_group()
            Access the group of processes that opened the file.

            Return type
                Group <#mpi4py.MPI.Group>

        Get_info()
            Return the current hints for a file.

            Return type
                Info <#mpi4py.MPI.Info>

        Get_position()
            Return the current position of the individual file pointer.

            Note:
                Position is measured in etype units relative to the current file view.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_position_shared()
            Return the current position of the shared file pointer.

            Note:
                Position is measured in etype units relative to the current view.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_size()
            Return the file size.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_type_extent(datatype)
            Return the extent of datatype in the file.

            Parameters
                datatype (Datatype <#mpi4py.MPI.Datatype>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_view()
            Return the file view.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, Datatype <#mpi4py.MPI.Datatype>, Datatype <#mpi4py.MPI.Datatype>, str <https://docs.python.org/3/library/stdtypes.html#str>]

        Iread(buf)
            Nonblocking read using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iread_all(buf)
            Nonblocking collective read using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iread_at(offset, buf)
            Nonblocking read using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iread_at_all(offset, buf)
            Nonblocking collective read using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iread_shared(buf)
            Nonblocking read using shared file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iwrite(buf)
            Nonblocking write using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iwrite_all(buf)
            Nonblocking collective write using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iwrite_at(offset, buf)
            Nonblocking write using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iwrite_at_all(offset, buf)
            Nonblocking collective write using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iwrite_shared(buf)
            Nonblocking write using shared file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod Open(comm, filename, amode=MODE_RDONLY, info=INFO_NULL)
            Open a file.

            Parameters

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>)

                •   filename (PathLike <https://docs.python.org/3/library/os.html#os.PathLike> | str <https://docs.python.org/3/library/stdtypes.html#str> | bytes <https://docs.python.org/3/library/stdtypes.html#bytes>)

                •   amode (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Preallocate(size)
            Preallocate storage space for a file.

            Parameters
                size (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read(buf, status=None)
            Read using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_all(buf, status=None)
            Collective read using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_all_begin(buf)
            Start a split collective read using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_all_end(buf, status=None)
            Complete a split collective read using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_at(offset, buf, status=None)
            Read using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_at_all(offset, buf, status=None)
            Collective read using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_at_all_begin(offset, buf)
            Start a split collective read using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_at_all_end(buf, status=None)
            Complete a split collective read using explicit offset.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_ordered(buf, status=None)
            Collective read using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_ordered_begin(buf)
            Start a split collective read using shared file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_ordered_end(buf, status=None)
            Complete a split collective read using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Read_shared(buf, status=None)
            Read using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Seek(offset, whence=SEEK_SET)
            Update the individual file pointer.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   whence (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Seek_shared(offset, whence=SEEK_SET)
            Update the shared file pointer.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   whence (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_atomicity(flag)
            Set the atomicity mode.

            Parameters
                flag (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_errhandler(errhandler)
            Set the error handler for a file.

            Parameters
                errhandler (Errhandler <#mpi4py.MPI.Errhandler>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_info(info)
            Set new values for the hints associated with a file.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_size(size)
            Set the file size.

            Parameters
                size (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_view(disp=0, etype=BYTE, filetype=None, datarep='native', info=INFO_NULL)
            Set the file view.

            Parameters

                •   disp (int <https://docs.python.org/3/library/functions.html#int>)

                •   etype (Datatype <#mpi4py.MPI.Datatype>)

                •   filetype (Datatype <#mpi4py.MPI.Datatype> | None <https://docs.python.org/3/library/constants.html#None>)

                •   datarep (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Sync()
            Causes all previous writes to be transferred to the storage device.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write(buf, status=None)
            Write using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_all(buf, status=None)
            Collective write using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_all_begin(buf)
            Start a split collective write using individual file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_all_end(buf, status=None)
            Complete a split collective write using individual file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_at(offset, buf, status=None)
            Write using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_at_all(offset, buf, status=None)
            Collective write using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_at_all_begin(offset, buf)
            Start a split collective write using explicit offset.

            Parameters

                •   offset (int <https://docs.python.org/3/library/functions.html#int>)

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_at_all_end(buf, status=None)
            Complete a split collective write using explicit offset.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_ordered(buf, status=None)
            Collective write using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_ordered_begin(buf)
            Start a split collective write using shared file pointer.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_ordered_end(buf, status=None)
            Complete a split collective write using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Write_shared(buf, status=None)
            Write using shared file pointer.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                File <#mpi4py.MPI.File>

        free()
            Call Close if not null.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                File <#mpi4py.MPI.File>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                File <#mpi4py.MPI.File>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        amode
            Access mode.

        atomicity
            Atomicity mode.

        group
            Group.

        group_rank
            Group rank.

        group_size
            Group size.

        handle
            MPI handle.

        info
            Info hints.

        size
            Size (in bytes).

  mpi4py.MPI.Graphcomm

    class mpi4py.MPI.Graphcomm
        Bases: Topocomm <#mpi4py.MPI.Topocomm>

        General graph topology intracommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Graphcomm <#mpi4py.MPI.Graphcomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Get_dims() | Return the number of nodes and edges.
    Get_neighbors(rank) | Return list of neighbors of a process.
    Get_neighbors_count(rank) | Return number of neighbors of a process.
    Get_topo() | Return index and edges.

    Attributes Summary
    dims | Number of nodes and edges.
    edges | Edges.
    index | Index.
    nedges | Number of edges.
    neighbors | Neighbors.
    nneighbors | Number of neighbors.
    nnodes | Number of nodes.
    topo | Topology information.

    Methods Documentation

        Get_dims()
            Return the number of nodes and edges.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

        Get_neighbors(rank)
            Return list of neighbors of a process.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]

        Get_neighbors_count(rank)
            Return number of neighbors of a process.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_topo()
            Return index and edges.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>], list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]]

    Attributes Documentation

        dims
            Number of nodes and edges.

        edges
            Edges.

        index
            Index.

        nedges
            Number of edges.

        neighbors
            Neighbors.

        nneighbors
            Number of neighbors.

        nnodes
            Number of nodes.

        topo
            Topology information.

  mpi4py.MPI.Grequest

    class mpi4py.MPI.Grequest
        Bases: Request <#mpi4py.MPI.Request>

        Generalized request handler.

        static __new__(cls, request=None)

            Parameters
                request (Grequest <#mpi4py.MPI.Grequest> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Complete() | Notify that a user-defined request is complete.
    Start([query_fn, free_fn, cancel_fn, args, ...]) | Create and return a user-defined request.
    complete([obj]) | Notify that a user-defined request is complete.

    Methods Documentation

        Complete()
            Notify that a user-defined request is complete.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Start(query_fn=None, free_fn=None, cancel_fn=None, args=None, kwargs=None)
            Create and return a user-defined request.

            Parameters

                •   query_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   free_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   cancel_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[...], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   args (tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   kwargs (dict <https://docs.python.org/3/library/stdtypes.html#dict>[str <https://docs.python.org/3/library/stdtypes.html#str>, Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Grequest <#mpi4py.MPI.Grequest>

        complete(obj=None)
            Notify that a user-defined request is complete.

            Parameters
                obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Group

    class mpi4py.MPI.Group
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Group of processes.

        static __new__(cls, group=None)

            Parameters
                group (Group <#mpi4py.MPI.Group> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Compare(group) | Compare two groups.
    Create_from_session_pset(session, pset_name) | Create a new group from session and process set.
    Difference(group1, group2) | Create a new group from the difference of two existing groups.
    Dup() | Duplicate a group.
    Excl(ranks) | Create a new group by excluding listed members.
    Free() | Free a group.
    Get_rank() | Return the rank of this process in a group.
    Get_size() | Return the number of processes in a group.
    Incl(ranks) | Create a new group by including listed members.
    Intersection(group1, group2) | Create a new group from the intersection of two existing groups.
    Range_excl(ranks) | Create a new group by excluding ranges of members.
    Range_incl(ranks) | Create a new group by including ranges of members.
    Translate_ranks([ranks, group]) | Translate ranks in a group to those in another group.
    Union(group1, group2) | Create a new group from the union of two existing groups.
    f2py(arg) |
    free() | Call Free if not null or predefined.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.

    Attributes Summary
    handle | MPI handle.
    rank | Rank of this process.
    size | Number of processes.

    Methods Documentation

        Compare(group)
            Compare two groups.

            Parameters
                group (Group <#mpi4py.MPI.Group>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        classmethod Create_from_session_pset(session, pset_name)
            Create a new group from session and process set.

            Parameters

                •   session (Session <#mpi4py.MPI.Session>)

                •   pset_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Difference(group1, group2)
            Create a new group from the difference of two existing groups.

            Parameters

                •   group1 (Group <#mpi4py.MPI.Group>)

                •   group2 (Group <#mpi4py.MPI.Group>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Dup()
            Duplicate a group.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Excl(ranks)
            Create a new group by excluding listed members.

            Parameters
                ranks (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Free()
            Free a group.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_rank()
            Return the rank of this process in a group.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_size()
            Return the number of processes in a group.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Incl(ranks)
            Create a new group by including listed members.

            Parameters
                ranks (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Intersection(group1, group2)
            Create a new group from the intersection of two existing groups.

            Parameters

                •   group1 (Group <#mpi4py.MPI.Group>)

                •   group2 (Group <#mpi4py.MPI.Group>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Range_excl(ranks)
            Create a new group by excluding ranges of members.

            Parameters
                ranks (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Range_incl(ranks)
            Create a new group by including ranges of members.

            Parameters
                ranks (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Translate_ranks(ranks=None, group=None)
            Translate ranks in a group to those in another group.

            Parameters

                •   ranks (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   group (Group <#mpi4py.MPI.Group> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]

        classmethod Union(group1, group2)
            Create a new group from the union of two existing groups.

            Parameters

                •   group1 (Group <#mpi4py.MPI.Group>)

                •   group2 (Group <#mpi4py.MPI.Group>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Group <#mpi4py.MPI.Group>

        free()
            Call Free if not null or predefined.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Group <#mpi4py.MPI.Group>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Group <#mpi4py.MPI.Group>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        handle
            MPI handle.

        rank
            Rank of this process.

        size
            Number of processes.

  mpi4py.MPI.InPlaceType

    class mpi4py.MPI.InPlaceType
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Type of IN_PLACE <#mpi4py.MPI.IN_PLACE>.

        static __new__(cls)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

  mpi4py.MPI.Info

    class mpi4py.MPI.Info
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Info object.

        static __new__(cls, info=None)

            Parameters
                info (Info <#mpi4py.MPI.Info> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Create([items]) | Create a new info object.
    Create_env([args]) | Create a new environment info object.
    Delete(key) | Remove a (key, value) pair from info.
    Dup() | Duplicate an existing info object.
    Free() | Free an info object.
    Get(key) | Retrieve the value associated with a key.
    Get_nkeys() | Return the number of currently defined keys in info.
    Get_nthkey(n) | Return the n-th defined key in info.
    Set(key, value) | Store a value associated with a key.
    clear() | Clear contents.
    copy() | Copy contents.
    f2py(arg) |
    free() | Call Free if not null or predefined.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    get(key[, default]) | Retrieve value by key.
    items() | Return list of items.
    keys() | Return list of keys.
    pop(key, *default) | Pop value by key.
    popitem() | Pop first item.
    py2f() |
    toint() | Translate object to integer handle.
    update([items]) | Update contents.
    values() | Return list of values.

    Attributes Summary
    handle | MPI handle.

    Methods Documentation

        classmethod Create(items=None)
            Create a new info object.

            Parameters
                items (Info <#mpi4py.MPI.Info> | Mapping <https://docs.python.org/3/library/typing.html#typing.Mapping>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>] | Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>]] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_env(args=None)
            Create a new environment info object.

            Parameters
                args (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[str <https://docs.python.org/3/library/stdtypes.html#str>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Delete(key)
            Remove a (key, value) pair from info.

            Parameters
                key (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Dup()
            Duplicate an existing info object.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Free()
            Free an info object.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get(key)
            Retrieve the value associated with a key.

            Parameters
                key (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str> | None <https://docs.python.org/3/library/constants.html#None>

        Get_nkeys()
            Return the number of currently defined keys in info.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_nthkey(n)
            Return the n-th defined key in info.

            Parameters
                n (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        Set(key, value)
            Store a value associated with a key.

            Parameters

                •   key (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   value (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        clear()
            Clear contents.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        copy()
            Copy contents.

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Info <#mpi4py.MPI.Info>

        free()
            Call Free if not null or predefined.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Info <#mpi4py.MPI.Info>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Info <#mpi4py.MPI.Info>

        get(key, default=None)
            Retrieve value by key.

            Parameters

                •   key (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   default (str <https://docs.python.org/3/library/stdtypes.html#str> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str> | None <https://docs.python.org/3/library/constants.html#None>

        items()
            Return list of items.

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>]]

        keys()
            Return list of keys.

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[str <https://docs.python.org/3/library/stdtypes.html#str>]

        pop(key, *default)
            Pop value by key.

            Parameters

                •   key (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   default (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        popitem()
            Pop first item.

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>]

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        update(items=(), **kwds)
            Update contents.

            Parameters

                •   items (Info <#mpi4py.MPI.Info> | Mapping <https://docs.python.org/3/library/typing.html#typing.Mapping>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>] | Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[str <https://docs.python.org/3/library/stdtypes.html#str>, str <https://docs.python.org/3/library/stdtypes.html#str>]])

                •   kwds (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        values()
            Return list of values.

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[str <https://docs.python.org/3/library/stdtypes.html#str>]

    Attributes Documentation

        handle
            MPI handle.

  mpi4py.MPI.Intercomm

    class mpi4py.MPI.Intercomm
        Bases: Comm <#mpi4py.MPI.Comm>

        Intercommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Intercomm <#mpi4py.MPI.Intercomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Create_from_groups(local_group, ...[, ...]) | Create communicator from group.
    Get_remote_group() | Access the remote group associated with the inter-communicator.
    Get_remote_size() | Intercommunicator remote size.
    Merge([high]) | Merge intercommunicator into an intracommunicator.

    Attributes Summary
    remote_group | Remote group.
    remote_size | Number of remote processes.

    Methods Documentation

        classmethod Create_from_groups(local_group, local_leader, remote_group, remote_leader, stringtag='org.mpi4py', info=INFO_NULL, errhandler=None)
            Create communicator from group.

            Parameters

                •   local_group (Group <#mpi4py.MPI.Group>)

                •   local_leader (int <https://docs.python.org/3/library/functions.html#int>)

                •   remote_group (Group <#mpi4py.MPI.Group>)

                •   remote_leader (int <https://docs.python.org/3/library/functions.html#int>)

                •   stringtag (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   errhandler (Errhandler <#mpi4py.MPI.Errhandler> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Intracomm <#mpi4py.MPI.Intracomm>

        Get_remote_group()
            Access the remote group associated with the inter-communicator.

            Return type
                Group <#mpi4py.MPI.Group>

        Get_remote_size()
            Intercommunicator remote size.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Merge(high=False)
            Merge intercommunicator into an intracommunicator.

            Parameters
                high (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Intracomm <#mpi4py.MPI.Intracomm>

    Attributes Documentation

        remote_group
            Remote group.

        remote_size
            Number of remote processes.

  mpi4py.MPI.Intracomm

    class mpi4py.MPI.Intracomm
        Bases: Comm <#mpi4py.MPI.Comm>

        Intracommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Intracomm <#mpi4py.MPI.Intracomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Accept(port_name[, info, root]) | Accept a request to form a new intercommunicator.
    Cart_map(dims[, periods]) | Determine optimal process placement on a Cartesian topology.
    Connect(port_name[, info, root]) | Make a request to form a new intercommunicator.
    Create_cart(dims[, periods, reorder]) | Create cartesian communicator.
    Create_dist_graph(sources, degrees, destinations) | Create distributed graph communicator.
    Create_dist_graph_adjacent(sources, destinations) | Create distributed graph communicator.
    Create_from_group(group[, stringtag, info, ...]) | Create communicator from group.
    Create_graph(index, edges[, reorder]) | Create graph communicator.
    Create_group(group[, tag]) | Create communicator from group.
    Create_intercomm(local_leader, peer_comm, ...) | Create intercommunicator.
    Exscan(sendbuf, recvbuf[, op]) | Exclusive Scan.
    Exscan_init(sendbuf, recvbuf[, op, info]) | Persistent Exclusive Scan.
    Graph_map(index, edges) | Determine optimal process placement on a graph topology.
    Iexscan(sendbuf, recvbuf[, op]) | Inclusive Scan.
    Iscan(sendbuf, recvbuf[, op]) | Inclusive Scan.
    Scan(sendbuf, recvbuf[, op]) | Inclusive Scan.
    Scan_init(sendbuf, recvbuf[, op, info]) | Persistent Inclusive Scan.
    Spawn(command[, args, maxprocs, info, root, ...]) | Spawn instances of a single MPI application.
    Spawn_multiple(command[, args, maxprocs, ...]) | Spawn instances of multiple MPI applications.
    exscan(sendobj[, op]) | Exclusive Scan.
    scan(sendobj[, op]) | Inclusive Scan.

    Methods Documentation

        Accept(port_name, info=INFO_NULL, root=0)
            Accept a request to form a new intercommunicator.

            Parameters

                •   port_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Cart_map(dims, periods=None)
            Determine optimal process placement on a Cartesian topology.

            Parameters

                •   dims (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   periods (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[bool <https://docs.python.org/3/library/functions.html#bool>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Connect(port_name, info=INFO_NULL, root=0)
            Make a request to form a new intercommunicator.

            Parameters

                •   port_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Create_cart(dims, periods=None, reorder=False)
            Create cartesian communicator.

            Parameters

                •   dims (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   periods (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[bool <https://docs.python.org/3/library/functions.html#bool>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   reorder (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Cartcomm <#mpi4py.MPI.Cartcomm>

        Create_dist_graph(sources, degrees, destinations, weights=None, info=INFO_NULL, reorder=False)
            Create distributed graph communicator.

            Parameters

                •   sources (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   degrees (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   destinations (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   weights (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   reorder (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Distgraphcomm <#mpi4py.MPI.Distgraphcomm>

        Create_dist_graph_adjacent(sources, destinations, sourceweights=None, destweights=None, info=INFO_NULL, reorder=False)
            Create distributed graph communicator.

            Parameters

                •   sources (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   destinations (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   sourceweights (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   destweights (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   reorder (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Distgraphcomm <#mpi4py.MPI.Distgraphcomm>

        classmethod Create_from_group(group, stringtag='org.mpi4py', info=INFO_NULL, errhandler=None)
            Create communicator from group.

            Parameters

                •   group (Group <#mpi4py.MPI.Group>)

                •   stringtag (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   errhandler (Errhandler <#mpi4py.MPI.Errhandler> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Intracomm <#mpi4py.MPI.Intracomm>

        Create_graph(index, edges, reorder=False)
            Create graph communicator.

            Parameters

                •   index (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   edges (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   reorder (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Graphcomm <#mpi4py.MPI.Graphcomm>

        Create_group(group, tag=0)
            Create communicator from group.

            Parameters

                •   group (Group <#mpi4py.MPI.Group>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Intracomm <#mpi4py.MPI.Intracomm>

        Create_intercomm(local_leader, peer_comm, remote_leader, tag=0)
            Create intercommunicator.

            Parameters

                •   local_leader (int <https://docs.python.org/3/library/functions.html#int>)

                •   peer_comm (Intracomm <#mpi4py.MPI.Intracomm>)

                •   remote_leader (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Exscan(sendbuf, recvbuf, op=SUM)
            Exclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Exscan_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)
            Persistent Exclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Graph_map(index, edges)
            Determine optimal process placement on a graph topology.

            Parameters

                •   index (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

                •   edges (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Iexscan(sendbuf, recvbuf, op=SUM)
            Inclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Iscan(sendbuf, recvbuf, op=SUM)
            Inclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Scan(sendbuf, recvbuf, op=SUM)
            Inclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Scan_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)
            Persistent Inclusive Scan.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec> | InPlace <#mpi4py.typing.InPlace>)

                •   recvbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   op (Op <#mpi4py.MPI.Op>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Spawn(command, args=None, maxprocs=1, info=INFO_NULL, root=0, errcodes=None)
            Spawn instances of a single MPI application.

            Parameters

                •   command (PathLike <https://docs.python.org/3/library/os.html#os.PathLike> | str <https://docs.python.org/3/library/stdtypes.html#str> | bytes <https://docs.python.org/3/library/stdtypes.html#bytes>)

                •   args (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[str <https://docs.python.org/3/library/stdtypes.html#str>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   maxprocs (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   errcodes (list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        Spawn_multiple(command, args=None, maxprocs=None, info=INFO_NULL, root=0, errcodes=None)
            Spawn instances of multiple MPI applications.

            Parameters

                •   command (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[PathLike <https://docs.python.org/3/library/os.html#os.PathLike> | str <https://docs.python.org/3/library/stdtypes.html#str> | bytes <https://docs.python.org/3/library/stdtypes.html#bytes>])

                •   args (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[str <https://docs.python.org/3/library/stdtypes.html#str>]] | None <https://docs.python.org/3/library/constants.html#None>)

                •   maxprocs (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   info (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Info <#mpi4py.MPI.Info>] | Info <#mpi4py.MPI.Info>)

                •   root (int <https://docs.python.org/3/library/functions.html#int>)

                •   errcodes (list <https://docs.python.org/3/library/stdtypes.html#list>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Intercomm <#mpi4py.MPI.Intercomm>

        exscan(sendobj, op=SUM)
            Exclusive Scan.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   op (Op <#mpi4py.MPI.Op> | Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Any <https://docs.python.org/3/library/typing.html#typing.Any>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        scan(sendobj, op=SUM)
            Inclusive Scan.

            Parameters

                •   sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

                •   op (Op <#mpi4py.MPI.Op> | Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Any <https://docs.python.org/3/library/typing.html#typing.Any>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

  mpi4py.MPI.Message

    class mpi4py.MPI.Message
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Matched message.

        static __new__(cls, message=None)

            Parameters
                message (Message <#mpi4py.MPI.Message> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Iprobe(comm[, source, tag, status]) | Nonblocking test for a matched message.
    Irecv(buf) | Nonblocking receive of matched message.
    Probe(comm[, source, tag, status]) | Blocking test for a matched message.
    Recv(buf[, status]) | Blocking receive of matched message.
    f2py(arg) |
    free() | Do nothing.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    iprobe(comm[, source, tag, status]) | Nonblocking test for a matched message.
    irecv() | Nonblocking receive of matched message.
    probe(comm[, source, tag, status]) | Blocking test for a matched message.
    py2f() |
    recv([status]) | Blocking receive of matched message.
    toint() | Translate object to integer handle.

    Attributes Summary
    handle | MPI handle.

    Methods Documentation

        classmethod Iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Parameters

                •   comm (Comm <#mpi4py.MPI.Comm>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self> | None <https://docs.python.org/3/library/constants.html#None>

        Irecv(buf)
            Nonblocking receive of matched message.

            Parameters
                buf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod Probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Parameters

                •   comm (Comm <#mpi4py.MPI.Comm>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Recv(buf, status=None)
            Blocking receive of matched message.

            Parameters

                •   buf (BufSpec <#mpi4py.typing.BufSpec>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Message <#mpi4py.MPI.Message>

        free()
            Do nothing.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Message <#mpi4py.MPI.Message>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Message <#mpi4py.MPI.Message>

        classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Nonblocking test for a matched message.

            Parameters

                •   comm (Comm <#mpi4py.MPI.Comm>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self> | None <https://docs.python.org/3/library/constants.html#None>

        irecv()
            Nonblocking receive of matched message.

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, status=None)
            Blocking test for a matched message.

            Parameters

                •   comm (Comm <#mpi4py.MPI.Comm>)

                •   source (int <https://docs.python.org/3/library/functions.html#int>)

                •   tag (int <https://docs.python.org/3/library/functions.html#int>)

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        recv(status=None)
            Blocking receive of matched message.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        handle
            MPI handle.

  mpi4py.MPI.Op

    class mpi4py.MPI.Op
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Reduction operation.

        static __new__(cls, op=None)

            Parameters
                op (Op <#mpi4py.MPI.Op> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Create(function[, commute]) | Create a user-defined reduction operation.
    Free() | Free a user-defined reduction operation.
    Is_commutative() | Query reduction operations for their commutativity.
    Reduce_local(inbuf, inoutbuf) | Apply a reduction operation to local data.
    f2py(arg) |
    free() | Call Free if not null or predefined.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.

    Attributes Summary
    handle | MPI handle.
    is_commutative | Is a commutative operation.
    is_predefined | Is a predefined operation.

    Methods Documentation

        classmethod Create(function, commute=False)
            Create a user-defined reduction operation.

            Parameters

                •   function (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Buffer <#mpi4py.typing.Buffer>, Buffer <#mpi4py.typing.Buffer>, Datatype <#mpi4py.MPI.Datatype>], None <https://docs.python.org/3/library/constants.html#None>])

                •   commute (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Free()
            Free a user-defined reduction operation.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Is_commutative()
            Query reduction operations for their commutativity.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Reduce_local(inbuf, inoutbuf)
            Apply a reduction operation to local data.

            Parameters

                •   inbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   inoutbuf (BufSpec <#mpi4py.typing.BufSpec>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Op <#mpi4py.MPI.Op>

        free()
            Call Free if not null or predefined.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Op <#mpi4py.MPI.Op>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Op <#mpi4py.MPI.Op>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        handle
            MPI handle.

        is_commutative
            Is a commutative operation.

        is_predefined
            Is a predefined operation.

  mpi4py.MPI.Pickle

    class mpi4py.MPI.Pickle
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Pickle/unpickle Python objects.

        static __new__(cls, pickle=None)

            Parameters
                pickle (Pickle <#mpi4py.MPI.Pickle> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    dumps(obj) | Serialize object to pickle data stream.
    dumps_oob(obj) | Serialize object to pickle data stream and out-of-band buffers.
    loads(data) | Deserialize object from pickle data stream.
    loads_oob(data, buffers) | Deserialize object from pickle data stream and out-of-band buffers.

    Attributes Summary
    PROTOCOL | Protocol version.
    THRESHOLD | Out-of-band threshold.

    Methods Documentation

        dumps(obj)
            Serialize object to pickle data stream.

            Parameters
                obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                bytes <https://docs.python.org/3/library/stdtypes.html#bytes>

        dumps_oob(obj)
            Serialize object to pickle data stream and out-of-band buffers.

            Parameters
                obj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[bytes <https://docs.python.org/3/library/stdtypes.html#bytes>, list <https://docs.python.org/3/library/stdtypes.html#list>[buffer <#mpi4py.MPI.buffer>]]

        loads(data)
            Deserialize object from pickle data stream.

            Parameters
                data (Buffer <#mpi4py.typing.Buffer>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        loads_oob(data, buffers)
            Deserialize object from pickle data stream and out-of-band buffers.

            Parameters

                •   data (Buffer <#mpi4py.typing.Buffer>)

                •   buffers (Iterable <https://docs.python.org/3/library/typing.html#typing.Iterable>[Buffer <#mpi4py.typing.Buffer>])

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

    Attributes Documentation

        PROTOCOL
            Protocol version.

        THRESHOLD
            Out-of-band threshold.

  mpi4py.MPI.Prequest

    class mpi4py.MPI.Prequest
        Bases: Request <#mpi4py.MPI.Request>

        Persistent request handler.

        static __new__(cls, request=None)

            Parameters
                request (Prequest <#mpi4py.MPI.Prequest> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Parrived(partition) | Test partial completion of a partitioned receive operation.
    Pready(partition) | Mark a given partition as ready.
    Pready_list(partitions) | Mark a sequence of partitions as ready.
    Pready_range(partition_low, partition_high) | Mark a range of partitions as ready.
    Start() | Initiate a communication with a persistent request.
    Startall(requests) | Start a collection of persistent requests.

    Methods Documentation

        Parrived(partition)
            Test partial completion of a partitioned receive operation.

            Parameters
                partition (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Pready(partition)
            Mark a given partition as ready.

            Parameters
                partition (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Pready_list(partitions)
            Mark a sequence of partitions as ready.

            Parameters
                partitions (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Pready_range(partition_low, partition_high)
            Mark a range of partitions as ready.

            Parameters

                •   partition_low (int <https://docs.python.org/3/library/functions.html#int>)

                •   partition_high (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Start()
            Initiate a communication with a persistent request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Startall(requests)
            Start a collection of persistent requests.

            Parameters
                requests (list <https://docs.python.org/3/library/stdtypes.html#list>[Prequest <#mpi4py.MPI.Prequest>])

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Request

    class mpi4py.MPI.Request
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Request handler.

        static __new__(cls, request=None)

            Parameters
                request (Request <#mpi4py.MPI.Request> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Cancel() | Cancel a request.
    Free() | Free a communication request.
    Get_status([status]) | Non-destructive test for the completion of a request.
    Get_status_all(requests[, statuses]) | Non-destructive test for the completion of all requests.
    Get_status_any(requests[, status]) | Non-destructive test for the completion of any requests.
    Get_status_some(requests[, statuses]) | Non-destructive test for completion of some requests.
    Test([status]) | Test for the completion of a non-blocking operation.
    Testall(requests[, statuses]) | Test for completion of all previously initiated requests.
    Testany(requests[, status]) | Test for completion of any previously initiated request.
    Testsome(requests[, statuses]) | Test for completion of some previously initiated requests.
    Wait([status]) | Wait for a non-blocking operation to complete.
    Waitall(requests[, statuses]) | Wait for all previously initiated requests to complete.
    Waitany(requests[, status]) | Wait for any previously initiated request to complete.
    Waitsome(requests[, statuses]) | Wait for some previously initiated requests to complete.
    cancel() | Cancel a request.
    f2py(arg) |
    free() | Call Free if not null.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    get_status([status]) | Non-destructive test for the completion of a request.
    get_status_all(requests[, statuses]) | Non-destructive test for the completion of all requests.
    get_status_any(requests[, status]) | Non-destructive test for the completion of any requests.
    get_status_some(requests[, statuses]) | Non-destructive test for completion of some requests.
    py2f() |
    test([status]) | Test for the completion of a non-blocking operation.
    testall(requests[, statuses]) | Test for completion of all previously initiated requests.
    testany(requests[, status]) | Test for completion of any previously initiated request.
    testsome(requests[, statuses]) | Test for completion of some previously initiated requests.
    toint() | Translate object to integer handle.
    wait([status]) | Wait for a non-blocking operation to complete.
    waitall(requests[, statuses]) | Wait for all previously initiated requests to complete.
    waitany(requests[, status]) | Wait for any previously initiated request to complete.
    waitsome(requests[, statuses]) | Wait for some previously initiated requests to complete.

    Attributes Summary
    handle | MPI handle.

    Methods Documentation

        Cancel()
            Cancel a request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Free()
            Free a communication request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_status(status=None)
            Non-destructive test for the completion of a request.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod Get_status_all(requests, statuses=None)
            Non-destructive test for the completion of all requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod Get_status_any(requests, status=None)
            Non-destructive test for the completion of any requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, bool <https://docs.python.org/3/library/functions.html#bool>]

        classmethod Get_status_some(requests, statuses=None)
            Non-destructive test for completion of some requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>

        Test(status=None)
            Test for the completion of a non-blocking operation.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod Testall(requests, statuses=None)
            Test for completion of all previously initiated requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod Testany(requests, status=None)
            Test for completion of any previously initiated request.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, bool <https://docs.python.org/3/library/functions.html#bool>]

        classmethod Testsome(requests, statuses=None)
            Test for completion of some previously initiated requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>

        Wait(status=None)
            Wait for a non-blocking operation to complete.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        classmethod Waitall(requests, statuses=None)
            Wait for all previously initiated requests to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        classmethod Waitany(requests, status=None)
            Wait for any previously initiated request to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        classmethod Waitsome(requests, statuses=None)
            Wait for some previously initiated requests to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>

        cancel()
            Cancel a request.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        free()
            Call Free if not null.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Request <#mpi4py.MPI.Request>

        get_status(status=None)
            Non-destructive test for the completion of a request.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod get_status_all(requests, statuses=None)
            Non-destructive test for the completion of all requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        classmethod get_status_any(requests, status=None)
            Non-destructive test for the completion of any requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, bool <https://docs.python.org/3/library/functions.html#bool>]

        classmethod get_status_some(requests, statuses=None)
            Non-destructive test for completion of some requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        test(status=None)
            Test for the completion of a non-blocking operation.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[bool <https://docs.python.org/3/library/functions.html#bool>, Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>]

        classmethod testall(requests, statuses=None)
            Test for completion of all previously initiated requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[bool <https://docs.python.org/3/library/functions.html#bool>, list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>]

        classmethod testany(requests, status=None)
            Test for completion of any previously initiated request.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, bool <https://docs.python.org/3/library/functions.html#bool>, Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>]

        classmethod testsome(requests, statuses=None)
            Test for completion of some previously initiated requests.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>, list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>]

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        wait(status=None)
            Wait for a non-blocking operation to complete.

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Any <https://docs.python.org/3/library/typing.html#typing.Any>

        classmethod waitall(requests, statuses=None)
            Wait for all previously initiated requests to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        classmethod waitany(requests, status=None)
            Wait for any previously initiated request to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        classmethod waitsome(requests, statuses=None)
            Wait for some previously initiated requests to complete.

            Parameters

                •   requests (Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[Request <#mpi4py.MPI.Request>])

                •   statuses (list <https://docs.python.org/3/library/stdtypes.html#list>[Status <#mpi4py.MPI.Status>] | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | None <https://docs.python.org/3/library/constants.html#None>, list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>]

    Attributes Documentation

        handle
            MPI handle.

  mpi4py.MPI.Session

    class mpi4py.MPI.Session
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Session context.

        static __new__(cls, session=None)

            Parameters
                session (Session <#mpi4py.MPI.Session> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Attach_buffer(buf) | Attach a user-provided buffer for sending in buffered mode.
    Call_errhandler(errorcode) | Call the error handler installed on a session.
    Create_errhandler(errhandler_fn) | Create a new error handler for sessions.
    Create_group(pset_name) | Create a new group from session and process set.
    Detach_buffer() | Remove an existing attached buffer.
    Finalize() | Finalize a session.
    Flush_buffer() | Block until all buffered messages have been transmitted.
    Get_errhandler() | Get the error handler for a session.
    Get_info() | Return the current hints for a session.
    Get_nth_pset(n[, info]) | Name of the n-th process set.
    Get_num_psets([info]) | Number of available process sets.
    Get_pset_info(pset_name) | Return the current hints for a session and process set.
    Iflush_buffer() | Nonblocking flush for buffered messages.
    Init([info, errhandler]) | Create a new session.
    Set_errhandler(errhandler) | Set the error handler for a session.
    f2py(arg) |
    free() | Call Finalize if not null.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.

    Attributes Summary
    handle | MPI handle.

    Methods Documentation

        Attach_buffer(buf)
            Attach a user-provided buffer for sending in buffered mode.

            Parameters
                buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Call_errhandler(errorcode)
            Call the error handler installed on a session.

            Parameters
                errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Create_errhandler(errhandler_fn)
            Create a new error handler for sessions.

            Parameters
                errhandler_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Session <#mpi4py.MPI.Session>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        Create_group(pset_name)
            Create a new group from session and process set.

            Parameters
                pset_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                Group <#mpi4py.MPI.Group>

        Detach_buffer()
            Remove an existing attached buffer.

            Return type
                Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>

        Finalize()
            Finalize a session.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Flush_buffer()
            Block until all buffered messages have been transmitted.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_errhandler()
            Get the error handler for a session.

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        Get_info()
            Return the current hints for a session.

            Return type
                Info <#mpi4py.MPI.Info>

        Get_nth_pset(n, info=INFO_NULL)
            Name of the n-th process set.

            Parameters

                •   n (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        Get_num_psets(info=INFO_NULL)
            Number of available process sets.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_pset_info(pset_name)
            Return the current hints for a session and process set.

            Parameters
                pset_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                Info <#mpi4py.MPI.Info>

        Iflush_buffer()
            Nonblocking flush for buffered messages.

            Return type
                Request <#mpi4py.MPI.Request>

        classmethod Init(info=INFO_NULL, errhandler=None)
            Create a new session.

            Parameters

                •   info (Info <#mpi4py.MPI.Info>)

                •   errhandler (Errhandler <#mpi4py.MPI.Errhandler> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Set_errhandler(errhandler)
            Set the error handler for a session.

            Parameters
                errhandler (Errhandler <#mpi4py.MPI.Errhandler>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Session <#mpi4py.MPI.Session>

        free()
            Call Finalize if not null.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Session <#mpi4py.MPI.Session>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Session <#mpi4py.MPI.Session>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

    Attributes Documentation

        handle
            MPI handle.

  mpi4py.MPI.Status

    class mpi4py.MPI.Status
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Status object.

        static __new__(cls, status=None)

            Parameters
                status (Status <#mpi4py.MPI.Status> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Get_count([datatype]) | Get the number of top level elements.
    Get_elements(datatype) | Get the number of basic elements in a datatype.
    Get_error() | Get message error.
    Get_source() | Get message source.
    Get_tag() | Get message tag.
    Is_cancelled() | Test to see if a request was cancelled.
    Set_cancelled(flag) | Set the cancelled state associated with a status.
    Set_elements(datatype, count) | Set the number of elements in a status.
    Set_error(error) | Set message error.
    Set_source(source) | Set message source.
    Set_tag(tag) | Set message tag.
    f2py(arg) |
    py2f() |
    tomemory() | Return status memory view.

    Attributes Summary
    cancelled | Cancelled state.
    count | Byte count.
    error | Message error.
    source | Message source.
    tag | Message tag.

    Methods Documentation

        Get_count(datatype=BYTE)
            Get the number of top level elements.

            Parameters
                datatype (Datatype <#mpi4py.MPI.Datatype>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_elements(datatype)
            Get the number of basic elements in a datatype.

            Parameters
                datatype (Datatype <#mpi4py.MPI.Datatype>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_error()
            Get message error.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_source()
            Get message source.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_tag()
            Get message tag.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Is_cancelled()
            Test to see if a request was cancelled.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Set_cancelled(flag)
            Set the cancelled state associated with a status.

            Note:
                This method should be used only when implementing query callback functions for generalized requests.

            Parameters
                flag (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_elements(datatype, count)
            Set the number of elements in a status.

            Note:
                This method should be only used when implementing query callback functions for generalized requests.

            Parameters

                •   datatype (Datatype <#mpi4py.MPI.Datatype>)

                •   count (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_error(error)
            Set message error.

            Parameters
                error (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_source(source)
            Set message source.

            Parameters
                source (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_tag(tag)
            Set message tag.

            Parameters
                tag (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod f2py(arg)

            Parameters
                arg (list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>])

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        py2f()

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]

        tomemory()
            Return status memory view.

            Return type
                memoryview <https://docs.python.org/3/library/stdtypes.html#memoryview>

    Attributes Documentation

        cancelled
            Cancelled state.

        count
            Byte count.

        error
            Message error.

        source
            Message source.

        tag Message tag.

  mpi4py.MPI.Topocomm

    class mpi4py.MPI.Topocomm
        Bases: Intracomm <#mpi4py.MPI.Intracomm>

        Topology intracommunicator.

        static __new__(cls, comm=None)

            Parameters
                comm (Topocomm <#mpi4py.MPI.Topocomm> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Ineighbor_allgather(sendbuf, recvbuf) | Nonblocking Neighbor Gather to All.
    Ineighbor_allgatherv(sendbuf, recvbuf) | Nonblocking Neighbor Gather to All Vector.
    Ineighbor_alltoall(sendbuf, recvbuf) | Nonblocking Neighbor All to All.
    Ineighbor_alltoallv(sendbuf, recvbuf) | Nonblocking Neighbor All to All Vector.
    Ineighbor_alltoallw(sendbuf, recvbuf) | Nonblocking Neighbor All to All General.
    Neighbor_allgather(sendbuf, recvbuf) | Neighbor Gather to All.
    Neighbor_allgather_init(sendbuf, recvbuf[, info]) | Persistent Neighbor Gather to All.
    Neighbor_allgatherv(sendbuf, recvbuf) | Neighbor Gather to All Vector.
    Neighbor_allgatherv_init(sendbuf, recvbuf[, ...]) | Persistent Neighbor Gather to All Vector.
    Neighbor_alltoall(sendbuf, recvbuf) | Neighbor All to All.
    Neighbor_alltoall_init(sendbuf, recvbuf[, info]) | Persistent Neighbor All to All.
    Neighbor_alltoallv(sendbuf, recvbuf) | Neighbor All to All Vector.
    Neighbor_alltoallv_init(sendbuf, recvbuf[, info]) | Persistent Neighbor All to All Vector.
    Neighbor_alltoallw(sendbuf, recvbuf) | Neighbor All to All General.
    Neighbor_alltoallw_init(sendbuf, recvbuf[, info]) | Persistent Neighbor All to All General.
    neighbor_allgather(sendobj) | Neighbor Gather to All.
    neighbor_alltoall(sendobj) | Neighbor All to All.

    Attributes Summary
    degrees | Number of incoming and outgoing neighbors.
    indegree | Number of incoming neighbors.
    inedges | Incoming neighbors.
    inoutedges | Incoming and outgoing neighbors.
    outdegree | Number of outgoing neighbors.
    outedges | Outgoing neighbors.

    Methods Documentation

        Ineighbor_allgather(sendbuf, recvbuf)
            Nonblocking Neighbor Gather to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ineighbor_allgatherv(sendbuf, recvbuf)
            Nonblocking Neighbor Gather to All Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ineighbor_alltoall(sendbuf, recvbuf)
            Nonblocking Neighbor All to All.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ineighbor_alltoallv(sendbuf, recvbuf)
            Nonblocking Neighbor All to All Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                Request <#mpi4py.MPI.Request>

        Ineighbor_alltoallw(sendbuf, recvbuf)
            Nonblocking Neighbor All to All General.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

            Return type
                Request <#mpi4py.MPI.Request>

        Neighbor_allgather(sendbuf, recvbuf)
            Neighbor Gather to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Neighbor_allgather_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Neighbor Gather to All.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Neighbor_allgatherv(sendbuf, recvbuf)
            Neighbor Gather to All Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Neighbor_allgatherv_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Neighbor Gather to All Vector.

            Parameters

                •   sendbuf (BufSpec <#mpi4py.typing.BufSpec>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Neighbor_alltoall(sendbuf, recvbuf)
            Neighbor All to All.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Neighbor_alltoall_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Neighbor All to All.

            Parameters

                •   sendbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   recvbuf (BufSpecB <#mpi4py.typing.BufSpecB>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Neighbor_alltoallv(sendbuf, recvbuf)
            Neighbor All to All Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Neighbor_alltoallv_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Neighbor All to All Vector.

            Parameters

                •   sendbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   recvbuf (BufSpecV <#mpi4py.typing.BufSpecV>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        Neighbor_alltoallw(sendbuf, recvbuf)
            Neighbor All to All General.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Neighbor_alltoallw_init(sendbuf, recvbuf, info=INFO_NULL)
            Persistent Neighbor All to All General.

            Parameters

                •   sendbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

                •   recvbuf (BufSpecW <#mpi4py.typing.BufSpecW>)

                •   info (Info <#mpi4py.MPI.Info>)

            Return type
                Prequest <#mpi4py.MPI.Prequest>

        neighbor_allgather(sendobj)
            Neighbor Gather to All.

            Parameters
                sendobj (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

        neighbor_alltoall(sendobj)
            Neighbor All to All.

            Parameters
                sendobj (list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>])

            Return type
                list <https://docs.python.org/3/library/stdtypes.html#list>[Any <https://docs.python.org/3/library/typing.html#typing.Any>]

    Attributes Documentation

        degrees
            Number of incoming and outgoing neighbors.

        indegree
            Number of incoming neighbors.

        inedges
            Incoming neighbors.

        inoutedges
            Incoming and outgoing neighbors.

        outdegree
            Number of outgoing neighbors.

        outedges
            Outgoing neighbors.

  mpi4py.MPI.Win

    class mpi4py.MPI.Win
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Remote memory access context.

        static __new__(cls, win=None)

            Parameters
                win (Win <#mpi4py.MPI.Win> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    Accumulate(origin, target_rank[, target, op]) | Accumulate data into the target process.
    Allocate(size[, disp_unit, info, comm]) | Create an window object for one-sided communication.
    Allocate_shared(size[, disp_unit, info, comm]) | Create an window object for one-sided communication.
    Attach(memory) | Attach a local memory region.
    Call_errhandler(errorcode) | Call the error handler installed on a window.
    Compare_and_swap(origin, compare, result, ...) | Perform one-sided atomic compare-and-swap.
    Complete() | Complete an RMA operation begun after an Start.
    Create(memory[, disp_unit, info, comm]) | Create an window object for one-sided communication.
    Create_dynamic([info, comm]) | Create an window object for one-sided communication.
    Create_errhandler(errhandler_fn) | Create a new error handler for windows.
    Create_keyval([copy_fn, delete_fn, nopython]) | Create a new attribute key for windows.
    Delete_attr(keyval) | Delete attribute value associated with a key.
    Detach(memory) | Detach a local memory region.
    Fence([assertion]) | Perform an MPI fence synchronization on a window.
    Fetch_and_op(origin, result, target_rank[, ...]) | Perform one-sided read-modify-write.
    Flush(rank) | Complete all outstanding RMA operations at a target.
    Flush_all() | Complete all outstanding RMA operations at all targets.
    Flush_local(rank) | Complete locally all outstanding RMA operations at a target.
    Flush_local_all() | Complete locally all outstanding RMA operations at all targets.
    Free() | Free a window.
    Free_keyval(keyval) | Free an attribute key for windows.
    Get(origin, target_rank[, target]) | Get data from a memory window on a remote process.
    Get_accumulate(origin, result, target_rank) | Fetch-and-accumulate data into the target process.
    Get_attr(keyval) | Retrieve attribute value by key.
    Get_errhandler() | Get the error handler for a window.
    Get_group() | Access the group of processes that created the window.
    Get_info() | Return the current hints for a window.
    Get_name() | Get the print name for this window.
    Lock(rank[, lock_type, assertion]) | Begin an RMA access epoch at the target process.
    Lock_all([assertion]) | Begin an RMA access epoch at all processes.
    Post(group[, assertion]) | Start an RMA exposure epoch.
    Put(origin, target_rank[, target]) | Put data into a memory window on a remote process.
    Raccumulate(origin, target_rank[, target, op]) | Fetch-and-accumulate data into the target process.
    Rget(origin, target_rank[, target]) | Get data from a memory window on a remote process.
    Rget_accumulate(origin, result, target_rank) | Accumulate data into the target process using remote memory access.
    Rput(origin, target_rank[, target]) | Put data into a memory window on a remote process.
    Set_attr(keyval, attrval) | Store attribute value associated with a key.
    Set_errhandler(errhandler) | Set the error handler for a window.
    Set_info(info) | Set new values for the hints associated with a window.
    Set_name(name) | Set the print name for this window.
    Shared_query(rank) | Query the process-local address for remote memory segments.
    Start(group[, assertion]) | Start an RMA access epoch for MPI.
    Sync() | Synchronize public and private copies of the window.
    Test() | Test whether an RMA exposure epoch has completed.
    Unlock(rank) | Complete an RMA access epoch at the target process.
    Unlock_all() | Complete an RMA access epoch at all processes.
    Wait() | Complete an RMA exposure epoch begun with Post.
    f2py(arg) |
    free() | Call Free if not null.
    fromhandle(handle) | Create object from MPI handle.
    fromint(arg, /) | Translate integer handle to object.
    py2f() |
    toint() | Translate object to integer handle.
    tomemory() | Return window memory buffer.

    Attributes Summary
    attrs | Attributes.
    flavor | Create flavor.
    group | Group.
    group_rank | Group rank.
    group_size | Group size.
    handle | MPI handle.
    info | Info hints.
    model | Memory model.
    name | Print name.

    Methods Documentation

        Accumulate(origin, target_rank, target=None, op=SUM)
            Accumulate data into the target process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Allocate(size, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
            Create an window object for one-sided communication.

            Parameters

                •   size (int <https://docs.python.org/3/library/functions.html#int>)

                •   disp_unit (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Allocate_shared(size, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
            Create an window object for one-sided communication.

            Parameters

                •   size (int <https://docs.python.org/3/library/functions.html#int>)

                •   disp_unit (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        Attach(memory)
            Attach a local memory region.

            Parameters
                memory (Buffer <#mpi4py.typing.Buffer>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Call_errhandler(errorcode)
            Call the error handler installed on a window.

            Parameters
                errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Compare_and_swap(origin, compare, result, target_rank, target_disp=0)
            Perform one-sided atomic compare-and-swap.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   compare (BufSpec <#mpi4py.typing.BufSpec>)

                •   result (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target_disp (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Complete()
            Complete an RMA operation begun after an Start.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Create(memory, disp_unit=1, info=INFO_NULL, comm=COMM_SELF)
            Create an window object for one-sided communication.

            Parameters

                •   memory (Buffer <#mpi4py.typing.Buffer> | Bottom <#mpi4py.typing.Bottom>)

                •   disp_unit (int <https://docs.python.org/3/library/functions.html#int>)

                •   info (Info <#mpi4py.MPI.Info>)

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>)

            Return type
                Self

        classmethod Create_dynamic(info=INFO_NULL, comm=COMM_SELF)
            Create an window object for one-sided communication.

            Parameters

                •   info (Info <#mpi4py.MPI.Info>)

                •   comm (Intracomm <#mpi4py.MPI.Intracomm>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

        classmethod Create_errhandler(errhandler_fn)
            Create a new error handler for windows.

            Parameters
                errhandler_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Win <#mpi4py.MPI.Win>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)
            Create a new attribute key for windows.

            Parameters

                •   copy_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Win <#mpi4py.MPI.Win>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], Any <https://docs.python.org/3/library/typing.html#typing.Any>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   delete_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Win <#mpi4py.MPI.Win>, int <https://docs.python.org/3/library/functions.html#int>, Any <https://docs.python.org/3/library/typing.html#typing.Any>], None <https://docs.python.org/3/library/constants.html#None>] | None <https://docs.python.org/3/library/constants.html#None>)

                •   nopython (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Delete_attr(keyval)
            Delete attribute value associated with a key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Detach(memory)
            Detach a local memory region.

            Parameters
                memory (Buffer <#mpi4py.typing.Buffer>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Fence(assertion=0)
            Perform an MPI fence synchronization on a window.

            Parameters
                assertion (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Fetch_and_op(origin, result, target_rank, target_disp=0, op=SUM)
            Perform one-sided read-modify-write.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   result (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target_disp (int <https://docs.python.org/3/library/functions.html#int>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Flush(rank)
            Complete all outstanding RMA operations at a target.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Flush_all()
            Complete all outstanding RMA operations at all targets.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Flush_local(rank)
            Complete locally all outstanding RMA operations at a target.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Flush_local_all()
            Complete locally all outstanding RMA operations at all targets.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Free()
            Free a window.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod Free_keyval(keyval)
            Free an attribute key for windows.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get(origin, target_rank, target=None)
            Get data from a memory window on a remote process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_accumulate(origin, result, target_rank, target=None, op=SUM)
            Fetch-and-accumulate data into the target process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   result (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Get_attr(keyval)
            Retrieve attribute value by key.

            Parameters
                keyval (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                int <https://docs.python.org/3/library/functions.html#int> | Any <https://docs.python.org/3/library/typing.html#typing.Any> | None <https://docs.python.org/3/library/constants.html#None>

        Get_errhandler()
            Get the error handler for a window.

            Return type
                Errhandler <#mpi4py.MPI.Errhandler>

        Get_group()
            Access the group of processes that created the window.

            Return type
                Group <#mpi4py.MPI.Group>

        Get_info()
            Return the current hints for a window.

            Return type
                Info <#mpi4py.MPI.Info>

        Get_name()
            Get the print name for this window.

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

        Lock(rank, lock_type=LOCK_EXCLUSIVE, assertion=0)
            Begin an RMA access epoch at the target process.

            Parameters

                •   rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   lock_type (int <https://docs.python.org/3/library/functions.html#int>)

                •   assertion (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Lock_all(assertion=0)
            Begin an RMA access epoch at all processes.

            Parameters
                assertion (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Post(group, assertion=0)
            Start an RMA exposure epoch.

            Parameters

                •   group (Group <#mpi4py.MPI.Group>)

                •   assertion (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Put(origin, target_rank, target=None)
            Put data into a memory window on a remote process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Raccumulate(origin, target_rank, target=None, op=SUM)
            Fetch-and-accumulate data into the target process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Rget(origin, target_rank, target=None)
            Get data from a memory window on a remote process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Request <#mpi4py.MPI.Request>

        Rget_accumulate(origin, result, target_rank, target=None, op=SUM)
            Accumulate data into the target process using remote memory access.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   result (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

                •   op (Op <#mpi4py.MPI.Op>)

            Return type
                Request <#mpi4py.MPI.Request>

        Rput(origin, target_rank, target=None)
            Put data into a memory window on a remote process.

            Parameters

                •   origin (BufSpec <#mpi4py.typing.BufSpec>)

                •   target_rank (int <https://docs.python.org/3/library/functions.html#int>)

                •   target (TargetSpec <#mpi4py.typing.TargetSpec> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                Request <#mpi4py.MPI.Request>

        Set_attr(keyval, attrval)
            Store attribute value associated with a key.

            Parameters

                •   keyval (int <https://docs.python.org/3/library/functions.html#int>)

                •   attrval (Any <https://docs.python.org/3/library/typing.html#typing.Any>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_errhandler(errhandler)
            Set the error handler for a window.

            Parameters
                errhandler (Errhandler <#mpi4py.MPI.Errhandler>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_info(info)
            Set new values for the hints associated with a window.

            Parameters
                info (Info <#mpi4py.MPI.Info>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Set_name(name)
            Set the print name for this window.

            Parameters
                name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Shared_query(rank)
            Query the process-local address for remote memory segments.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[buffer <#mpi4py.MPI.buffer>, int <https://docs.python.org/3/library/functions.html#int>]

        Start(group, assertion=0)
            Start an RMA access epoch for MPI.

            Parameters

                •   group (Group <#mpi4py.MPI.Group>)

                •   assertion (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Sync()
            Synchronize public and private copies of the window.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Test()
            Test whether an RMA exposure epoch has completed.

            Return type
                bool <https://docs.python.org/3/library/functions.html#bool>

        Unlock(rank)
            Complete an RMA access epoch at the target process.

            Parameters
                rank (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Unlock_all()
            Complete an RMA access epoch at all processes.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        Wait()
            Complete an RMA exposure epoch begun with Post.

            Return type
                Literal <https://docs.python.org/3/library/typing.html#typing.Literal>[True]

        classmethod f2py(arg)

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Win <#mpi4py.MPI.Win>

        free()
            Call Free if not null.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        classmethod fromhandle(handle)
            Create object from MPI handle.

            Parameters
                handle (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Win <#mpi4py.MPI.Win>

        classmethod fromint(arg, /)
            Translate integer handle to object.

            Parameters
                arg (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                Win <#mpi4py.MPI.Win>

        py2f()

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        toint()
            Translate object to integer handle.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        tomemory()
            Return window memory buffer.

            Return type
                buffer <#mpi4py.MPI.buffer>

    Attributes Documentation

        attrs
            Attributes.

        flavor
            Create flavor.

        group
            Group.

        group_rank
            Group rank.

        group_size
            Group size.

        handle
            MPI handle.

        info
            Info hints.

        model
            Memory model.

        name
            Print name.

  mpi4py.MPI.buffer

    class mpi4py.MPI.buffer
        Bases: object <https://docs.python.org/3/library/functions.html#object>

        Buffer.

        static __new__(cls, buf, /)

            Parameters
                buf (Buffer <#mpi4py.typing.Buffer>)

            Return type
                Self <https://docs.python.org/3/library/typing.html#typing.Self>

    Methods Summary
    allocate(nbytes[, clear]) | Buffer allocation.
    cast(format[, shape]) | Cast to a memoryview <https://docs.python.org/3/library/stdtypes.html#memoryview> with new format or shape.
    fromaddress(address, nbytes[, readonly]) | Buffer from address and size in bytes.
    frombuffer(obj[, readonly]) | Buffer from buffer-like object.
    release() | Release the underlying buffer exposed by the buffer object.
    tobytes([order]) | Return the data in the buffer as a byte string.
    toreadonly() | Return a readonly version of the buffer object.

    Attributes Summary
    address | Buffer address.
    format | Format of each element.
    itemsize | Size (in bytes) of each element.
    nbytes | Buffer size (in bytes).
    obj | Object exposing buffer.
    readonly | Buffer is read-only.

    Methods Documentation

        static allocate(nbytes, clear=False)
            Buffer allocation.

            Parameters

                •   nbytes (int <https://docs.python.org/3/library/functions.html#int>)

                •   clear (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                buffer <#mpi4py.MPI.buffer>

        cast(format, shape=Ellipsis)
            Cast to a memoryview <https://docs.python.org/3/library/stdtypes.html#memoryview> with new format or shape.

            Parameters

                •   format (str <https://docs.python.org/3/library/stdtypes.html#str>)

                •   shape (list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>] | tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, ...])

            Return type
                memoryview <https://docs.python.org/3/library/stdtypes.html#memoryview>

        static fromaddress(address, nbytes, readonly=False)
            Buffer from address and size in bytes.

            Parameters

                •   address (int <https://docs.python.org/3/library/functions.html#int>)

                •   nbytes (int <https://docs.python.org/3/library/functions.html#int>)

                •   readonly (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                buffer <#mpi4py.MPI.buffer>

        static frombuffer(obj, readonly=False)
            Buffer from buffer-like object.

            Parameters

                •   obj (Buffer <#mpi4py.typing.Buffer>)

                •   readonly (bool <https://docs.python.org/3/library/functions.html#bool>)

            Return type
                buffer <#mpi4py.MPI.buffer>

        release()
            Release the underlying buffer exposed by the buffer object.

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

        tobytes(order=None)
            Return the data in the buffer as a byte string.

            Parameters
                order (str <https://docs.python.org/3/library/stdtypes.html#str> | None <https://docs.python.org/3/library/constants.html#None>)

            Return type
                bytes <https://docs.python.org/3/library/stdtypes.html#bytes>

        toreadonly()
            Return a readonly version of the buffer object.

            Return type
                buffer <#mpi4py.MPI.buffer>

    Attributes Documentation

        address
            Buffer address.

        format
            Format of each element.

        itemsize
            Size (in bytes) of each element.

        nbytes
            Buffer size (in bytes).

        obj Object exposing buffer.

        readonly
            Buffer is read-only.

  mpi4py.MPI.memory

    mpi4py.MPI.memory
        alias of buffer <#mpi4py.MPI.buffer>

Exceptions
Exception <#mpi4py.MPI.Exception> | Exception class.

  mpi4py.MPI.Exception

    exception mpi4py.MPI.Exception
        Bases: RuntimeError <https://docs.python.org/3/library/exceptions.html#RuntimeError>

        Exception class.

        __init__(ierr=SUCCESS, /)

            Parameters
                ierr (int <https://docs.python.org/3/library/functions.html#int>)

            Return type
                None <https://docs.python.org/3/library/constants.html#None>

    Methods Summary
    Get_error_class() | Error class.
    Get_error_code() | Error code.
    Get_error_string() | Error string.

    Attributes Summary
    error_class | Error class.
    error_code | Error code.
    error_string | Error string.

    Methods Documentation

        Get_error_class()
            Error class.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_error_code()
            Error code.

            Return type
                int <https://docs.python.org/3/library/functions.html#int>

        Get_error_string()
            Error string.

            Return type
                str <https://docs.python.org/3/library/stdtypes.html#str>

    Attributes Documentation

        error_class
            Error class.

        error_code
            Error code.

        error_string
            Error string.

Functions
Add_error_class <#mpi4py.MPI.Add_error_class>() | Add an error class to the known error classes.
Add_error_code <#mpi4py.MPI.Add_error_code>(errorclass) | Add an error code to an error class.
Add_error_string <#mpi4py.MPI.Add_error_string>(errorcode, string) | Associate an error string with an error class or error code.
Aint_add <#mpi4py.MPI.Aint_add>(base, disp) | Return the sum of base address and displacement.
Aint_diff <#mpi4py.MPI.Aint_diff>(addr1, addr2) | Return the difference between absolute addresses.
Alloc_mem <#mpi4py.MPI.Alloc_mem>(size[, info]) | Allocate memory for message passing and remote memory access.
Attach_buffer <#mpi4py.MPI.Attach_buffer>(buf) | Attach a user-provided buffer for sending in buffered mode.
Close_port <#mpi4py.MPI.Close_port>(port_name) | Close a port.
Compute_dims <#mpi4py.MPI.Compute_dims>(nnodes, dims) | Return a balanced distribution of processes per coordinate direction.
Detach_buffer <#mpi4py.MPI.Detach_buffer>() | Remove an existing attached buffer.
Finalize <#mpi4py.MPI.Finalize>() | Terminate the MPI execution environment.
Flush_buffer <#mpi4py.MPI.Flush_buffer>() | Block until all buffered messages have been transmitted.
Free_mem <#mpi4py.MPI.Free_mem>(mem) | Free memory allocated with Alloc_mem <#mpi4py.MPI.Alloc_mem>.
Get_abi_fortran_info <#mpi4py.MPI.Get_abi_fortran_info>() | Obtain information about the Fortran MPI ABI.
Get_abi_info <#mpi4py.MPI.Get_abi_info>() | Obtain information about the MPI ABI.
Get_abi_version <#mpi4py.MPI.Get_abi_version>() | Obtain the MPI ABI version number.
Get_address <#mpi4py.MPI.Get_address>(location) | Get the address of a location in memory.
Get_error_class <#mpi4py.MPI.Get_error_class>(errorcode) | Convert an error code into an error class.
Get_error_string <#mpi4py.MPI.Get_error_string>(errorcode) | Return the error string for a given error class or error code.
Get_hw_resource_info <#mpi4py.MPI.Get_hw_resource_info>() | Obtain information about the hardware platform of the calling processor.
Get_library_version <#mpi4py.MPI.Get_library_version>() | Obtain the version string of the MPI library.
Get_processor_name <#mpi4py.MPI.Get_processor_name>() | Obtain the name of the calling processor.
Get_version <#mpi4py.MPI.Get_version>() | Obtain the version number of the MPI standard.
Iflush_buffer <#mpi4py.MPI.Iflush_buffer>() | Nonblocking flush for buffered messages.
Init <#mpi4py.MPI.Init>() | Initialize the MPI execution environment.
Init_thread <#mpi4py.MPI.Init_thread>([required]) | Initialize the MPI execution environment.
Is_finalized <#mpi4py.MPI.Is_finalized>() | Indicate whether Finalize <#mpi4py.MPI.Finalize> has completed.
Is_initialized <#mpi4py.MPI.Is_initialized>() | Indicate whether Init <#mpi4py.MPI.Init> has been called.
Is_thread_main <#mpi4py.MPI.Is_thread_main>() | Indicate whether this thread called Init <#mpi4py.MPI.Init> or Init_thread <#mpi4py.MPI.Init_thread>.
Lookup_name <#mpi4py.MPI.Lookup_name>(service_name[, info]) | Lookup a port name given a service name.
Open_port <#mpi4py.MPI.Open_port>([info]) | Return an address used to connect group of processes.
Pcontrol <#mpi4py.MPI.Pcontrol>(level) | Control profiling.
Publish_name <#mpi4py.MPI.Publish_name>(service_name, port_name[, info]) | Publish a service name.
Query_thread <#mpi4py.MPI.Query_thread>() | Return the level of thread support provided by the MPI library.
Register_datarep <#mpi4py.MPI.Register_datarep>(datarep, read_fn, write_fn, ...) | Register user-defined data representations.
Remove_error_class <#mpi4py.MPI.Remove_error_class>(errorclass) | Remove an error class from the known error classes.
Remove_error_code <#mpi4py.MPI.Remove_error_code>(errorcode) | Remove an error code from the known error codes.
Remove_error_string <#mpi4py.MPI.Remove_error_string>(errorcode) | Remove error string association from error class or error code.
Unpublish_name <#mpi4py.MPI.Unpublish_name>(service_name, port_name[, info]) | Unpublish a service name.
Wtick <#mpi4py.MPI.Wtick>() | Return the resolution of Wtime <#mpi4py.MPI.Wtime>.
Wtime <#mpi4py.MPI.Wtime>() | Return an elapsed time on the calling processor.
get_vendor <#mpi4py.MPI.get_vendor>() | Information about the underlying MPI implementation.

  mpi4py.MPI.Add_error_class

    mpi4py.MPI.Add_error_class()
        Add an error class to the known error classes.

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Add_error_code

    mpi4py.MPI.Add_error_code(errorclass)
        Add an error code to an error class.

        Parameters
            errorclass (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Add_error_string

    mpi4py.MPI.Add_error_string(errorcode, string)
        Associate an error string with an error class or error code.

        Parameters

            •   errorcode (int <https://docs.python.org/3/library/functions.html#int>)

            •   string (str <https://docs.python.org/3/library/stdtypes.html#str>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Aint_add

    mpi4py.MPI.Aint_add(base, disp)
        Return the sum of base address and displacement.

        Parameters

            •   base (int <https://docs.python.org/3/library/functions.html#int>)

            •   disp (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Aint_diff

    mpi4py.MPI.Aint_diff(addr1, addr2)
        Return the difference between absolute addresses.

        Parameters

            •   addr1 (int <https://docs.python.org/3/library/functions.html#int>)

            •   addr2 (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Alloc_mem

    mpi4py.MPI.Alloc_mem(size, info=INFO_NULL)
        Allocate memory for message passing and remote memory access.

        Parameters

            •   size (int <https://docs.python.org/3/library/functions.html#int>)

            •   info (Info <#mpi4py.MPI.Info>)

        Return type
            buffer <#mpi4py.MPI.buffer>

  mpi4py.MPI.Attach_buffer

    mpi4py.MPI.Attach_buffer(buf)
        Attach a user-provided buffer for sending in buffered mode.

        Parameters
            buf (Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Close_port

    mpi4py.MPI.Close_port(port_name)
        Close a port.

        Parameters
            port_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Compute_dims

    mpi4py.MPI.Compute_dims(nnodes, dims)
        Return a balanced distribution of processes per coordinate direction.

        Parameters

            •   nnodes (int <https://docs.python.org/3/library/functions.html#int>)

            •   dims (int <https://docs.python.org/3/library/functions.html#int> | Sequence <https://docs.python.org/3/library/typing.html#typing.Sequence>[int <https://docs.python.org/3/library/functions.html#int>])

        Return type
            list <https://docs.python.org/3/library/stdtypes.html#list>[int <https://docs.python.org/3/library/functions.html#int>]

  mpi4py.MPI.Detach_buffer

    mpi4py.MPI.Detach_buffer()
        Remove an existing attached buffer.

        Return type
            Buffer <#mpi4py.typing.Buffer> | None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Finalize

    mpi4py.MPI.Finalize()
        Terminate the MPI execution environment.

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Flush_buffer

    mpi4py.MPI.Flush_buffer()
        Block until all buffered messages have been transmitted.

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Free_mem

    mpi4py.MPI.Free_mem(mem)
        Free memory allocated with Alloc_mem <#mpi4py.MPI.Alloc_mem>.

        Parameters
            mem (buffer <#mpi4py.MPI.buffer>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Get_abi_fortran_info

    mpi4py.MPI.Get_abi_fortran_info()
        Obtain information about the Fortran MPI ABI.

        Return type
            Info <#mpi4py.MPI.Info>

  mpi4py.MPI.Get_abi_info

    mpi4py.MPI.Get_abi_info()
        Obtain information about the MPI ABI.

        Return type
            Info <#mpi4py.MPI.Info>

  mpi4py.MPI.Get_abi_version

    mpi4py.MPI.Get_abi_version()
        Obtain the MPI ABI version number.

        Return type
            tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

  mpi4py.MPI.Get_address

    mpi4py.MPI.Get_address(location)
        Get the address of a location in memory.

        Parameters
            location (Buffer <#mpi4py.typing.Buffer> | Bottom <#mpi4py.typing.Bottom>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Get_error_class

    mpi4py.MPI.Get_error_class(errorcode)
        Convert an error code into an error class.

        Parameters
            errorcode (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Get_error_string

    mpi4py.MPI.Get_error_string(errorcode)
        Return the error string for a given error class or error code.

        Parameters
            errorcode (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

  mpi4py.MPI.Get_hw_resource_info

    mpi4py.MPI.Get_hw_resource_info()
        Obtain information about the hardware platform of the calling processor.

        Return type
            Info <#mpi4py.MPI.Info>

  mpi4py.MPI.Get_library_version

    mpi4py.MPI.Get_library_version()
        Obtain the version string of the MPI library.

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

  mpi4py.MPI.Get_processor_name

    mpi4py.MPI.Get_processor_name()
        Obtain the name of the calling processor.

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

  mpi4py.MPI.Get_version

    mpi4py.MPI.Get_version()
        Obtain the version number of the MPI standard.

        Return type
            tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]

  mpi4py.MPI.Iflush_buffer

    mpi4py.MPI.Iflush_buffer()
        Nonblocking flush for buffered messages.

        Return type
            Request <#mpi4py.MPI.Request>

  mpi4py.MPI.Init

    mpi4py.MPI.Init()
        Initialize the MPI execution environment.

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Init_thread

    mpi4py.MPI.Init_thread(required=THREAD_MULTIPLE)
        Initialize the MPI execution environment.

        Parameters
            required (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Is_finalized

    mpi4py.MPI.Is_finalized()
        Indicate whether Finalize <#mpi4py.MPI.Finalize> has completed.

        Return type
            bool <https://docs.python.org/3/library/functions.html#bool>

  mpi4py.MPI.Is_initialized

    mpi4py.MPI.Is_initialized()
        Indicate whether Init <#mpi4py.MPI.Init> has been called.

        Return type
            bool <https://docs.python.org/3/library/functions.html#bool>

  mpi4py.MPI.Is_thread_main

    mpi4py.MPI.Is_thread_main()
        Indicate whether this thread called Init <#mpi4py.MPI.Init> or Init_thread <#mpi4py.MPI.Init_thread>.

        Return type
            bool <https://docs.python.org/3/library/functions.html#bool>

  mpi4py.MPI.Lookup_name

    mpi4py.MPI.Lookup_name(service_name, info=INFO_NULL)
        Lookup a port name given a service name.

        Parameters

            •   service_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   info (Info <#mpi4py.MPI.Info>)

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

  mpi4py.MPI.Open_port

    mpi4py.MPI.Open_port(info=INFO_NULL)
        Return an address used to connect group of processes.

        Parameters
            info (Info <#mpi4py.MPI.Info>)

        Return type
            str <https://docs.python.org/3/library/stdtypes.html#str>

  mpi4py.MPI.Pcontrol

    mpi4py.MPI.Pcontrol(level)
        Control profiling.

        Parameters
            level (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Publish_name

    mpi4py.MPI.Publish_name(service_name, port_name, info=INFO_NULL)
        Publish a service name.

        Parameters

            •   service_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   port_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   info (Info <#mpi4py.MPI.Info>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Query_thread

    mpi4py.MPI.Query_thread()
        Return the level of thread support provided by the MPI library.

        Return type
            int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.Register_datarep

    mpi4py.MPI.Register_datarep(datarep, read_fn, write_fn, extent_fn)
        Register user-defined data representations.

        Parameters

            •   datarep (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   read_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Buffer <#mpi4py.typing.Buffer>, Datatype <#mpi4py.MPI.Datatype>, int <https://docs.python.org/3/library/functions.html#int>, Buffer <#mpi4py.typing.Buffer>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            •   write_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Buffer <#mpi4py.typing.Buffer>, Datatype <#mpi4py.MPI.Datatype>, int <https://docs.python.org/3/library/functions.html#int>, Buffer <#mpi4py.typing.Buffer>, int <https://docs.python.org/3/library/functions.html#int>], None <https://docs.python.org/3/library/constants.html#None>])

            •   extent_fn (Callable <https://docs.python.org/3/library/typing.html#typing.Callable>[[Datatype <#mpi4py.MPI.Datatype>], int <https://docs.python.org/3/library/functions.html#int>])

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Remove_error_class

    mpi4py.MPI.Remove_error_class(errorclass)
        Remove an error class from the known error classes.

        Parameters
            errorclass (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Remove_error_code

    mpi4py.MPI.Remove_error_code(errorcode)
        Remove an error code from the known error codes.

        Parameters
            errorcode (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Remove_error_string

    mpi4py.MPI.Remove_error_string(errorcode)
        Remove error string association from error class or error code.

        Parameters
            errorcode (int <https://docs.python.org/3/library/functions.html#int>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Unpublish_name

    mpi4py.MPI.Unpublish_name(service_name, port_name, info=INFO_NULL)
        Unpublish a service name.

        Parameters

            •   service_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   port_name (str <https://docs.python.org/3/library/stdtypes.html#str>)

            •   info (Info <#mpi4py.MPI.Info>)

        Return type
            None <https://docs.python.org/3/library/constants.html#None>

  mpi4py.MPI.Wtick

    mpi4py.MPI.Wtick()
        Return the resolution of Wtime <#mpi4py.MPI.Wtime>.

        Return type
            float <https://docs.python.org/3/library/functions.html#float>

  mpi4py.MPI.Wtime

    mpi4py.MPI.Wtime()
        Return an elapsed time on the calling processor.

        Return type
            float <https://docs.python.org/3/library/functions.html#float>

  mpi4py.MPI.get_vendor

    mpi4py.MPI.get_vendor()
        Information about the underlying MPI implementation.

        Returns

            •   string with the name of the MPI implementation.

            •   integer 3-tuple version number (major, minor, micro).

        Return type
            tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[str <https://docs.python.org/3/library/stdtypes.html#str>, tuple <https://docs.python.org/3/library/stdtypes.html#tuple>[int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>, int <https://docs.python.org/3/library/functions.html#int>]]

Attributes
UNDEFINED <#mpi4py.MPI.UNDEFINED> | Constant UNDEFINED of type int <https://docs.python.org/3/library/functions.html#int>
ANY_SOURCE <#mpi4py.MPI.ANY_SOURCE> | Constant ANY_SOURCE of type int <https://docs.python.org/3/library/functions.html#int>
ANY_TAG <#mpi4py.MPI.ANY_TAG> | Constant ANY_TAG of type int <https://docs.python.org/3/library/functions.html#int>
PROC_NULL <#mpi4py.MPI.PROC_NULL> | Constant PROC_NULL of type int <https://docs.python.org/3/library/functions.html#int>
ROOT <#mpi4py.MPI.ROOT> | Constant ROOT of type int <https://docs.python.org/3/library/functions.html#int>
KEYVAL_INVALID <#mpi4py.MPI.KEYVAL_INVALID> | Constant KEYVAL_INVALID of type int <https://docs.python.org/3/library/functions.html#int>
TAG_UB <#mpi4py.MPI.TAG_UB> | Constant TAG_UB of type int <https://docs.python.org/3/library/functions.html#int>
IO <#mpi4py.MPI.IO> | Constant IO of type int <https://docs.python.org/3/library/functions.html#int>
WTIME_IS_GLOBAL <#mpi4py.MPI.WTIME_IS_GLOBAL> | Constant WTIME_IS_GLOBAL of type int <https://docs.python.org/3/library/functions.html#int>
UNIVERSE_SIZE <#mpi4py.MPI.UNIVERSE_SIZE> | Constant UNIVERSE_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
APPNUM <#mpi4py.MPI.APPNUM> | Constant APPNUM of type int <https://docs.python.org/3/library/functions.html#int>
LASTUSEDCODE <#mpi4py.MPI.LASTUSEDCODE> | Constant LASTUSEDCODE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_BASE <#mpi4py.MPI.WIN_BASE> | Constant WIN_BASE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_SIZE <#mpi4py.MPI.WIN_SIZE> | Constant WIN_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_DISP_UNIT <#mpi4py.MPI.WIN_DISP_UNIT> | Constant WIN_DISP_UNIT of type int <https://docs.python.org/3/library/functions.html#int>
WIN_CREATE_FLAVOR <#mpi4py.MPI.WIN_CREATE_FLAVOR> | Constant WIN_CREATE_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR <#mpi4py.MPI.WIN_FLAVOR> | Constant WIN_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
WIN_MODEL <#mpi4py.MPI.WIN_MODEL> | Constant WIN_MODEL of type int <https://docs.python.org/3/library/functions.html#int>
SUCCESS <#mpi4py.MPI.SUCCESS> | Constant SUCCESS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_LASTCODE <#mpi4py.MPI.ERR_LASTCODE> | Constant ERR_LASTCODE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ABI <#mpi4py.MPI.ERR_ABI> | Constant ERR_ABI of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TYPE <#mpi4py.MPI.ERR_TYPE> | Constant ERR_TYPE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_REQUEST <#mpi4py.MPI.ERR_REQUEST> | Constant ERR_REQUEST of type int <https://docs.python.org/3/library/functions.html#int>
ERR_OP <#mpi4py.MPI.ERR_OP> | Constant ERR_OP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_GROUP <#mpi4py.MPI.ERR_GROUP> | Constant ERR_GROUP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO <#mpi4py.MPI.ERR_INFO> | Constant ERR_INFO of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ERRHANDLER <#mpi4py.MPI.ERR_ERRHANDLER> | Constant ERR_ERRHANDLER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SESSION <#mpi4py.MPI.ERR_SESSION> | Constant ERR_SESSION of type int <https://docs.python.org/3/library/functions.html#int>
ERR_COMM <#mpi4py.MPI.ERR_COMM> | Constant ERR_COMM of type int <https://docs.python.org/3/library/functions.html#int>
ERR_WIN <#mpi4py.MPI.ERR_WIN> | Constant ERR_WIN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE <#mpi4py.MPI.ERR_FILE> | Constant ERR_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BUFFER <#mpi4py.MPI.ERR_BUFFER> | Constant ERR_BUFFER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_COUNT <#mpi4py.MPI.ERR_COUNT> | Constant ERR_COUNT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TAG <#mpi4py.MPI.ERR_TAG> | Constant ERR_TAG of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RANK <#mpi4py.MPI.ERR_RANK> | Constant ERR_RANK of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ROOT <#mpi4py.MPI.ERR_ROOT> | Constant ERR_ROOT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TRUNCATE <#mpi4py.MPI.ERR_TRUNCATE> | Constant ERR_TRUNCATE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_IN_STATUS <#mpi4py.MPI.ERR_IN_STATUS> | Constant ERR_IN_STATUS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PENDING <#mpi4py.MPI.ERR_PENDING> | Constant ERR_PENDING of type int <https://docs.python.org/3/library/functions.html#int>
ERR_TOPOLOGY <#mpi4py.MPI.ERR_TOPOLOGY> | Constant ERR_TOPOLOGY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DIMS <#mpi4py.MPI.ERR_DIMS> | Constant ERR_DIMS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ARG <#mpi4py.MPI.ERR_ARG> | Constant ERR_ARG of type int <https://docs.python.org/3/library/functions.html#int>
ERR_OTHER <#mpi4py.MPI.ERR_OTHER> | Constant ERR_OTHER of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNKNOWN <#mpi4py.MPI.ERR_UNKNOWN> | Constant ERR_UNKNOWN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INTERN <#mpi4py.MPI.ERR_INTERN> | Constant ERR_INTERN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_KEYVAL <#mpi4py.MPI.ERR_KEYVAL> | Constant ERR_KEYVAL of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_MEM <#mpi4py.MPI.ERR_NO_MEM> | Constant ERR_NO_MEM of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_KEY <#mpi4py.MPI.ERR_INFO_KEY> | Constant ERR_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_VALUE <#mpi4py.MPI.ERR_INFO_VALUE> | Constant ERR_INFO_VALUE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_INFO_NOKEY <#mpi4py.MPI.ERR_INFO_NOKEY> | Constant ERR_INFO_NOKEY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SPAWN <#mpi4py.MPI.ERR_SPAWN> | Constant ERR_SPAWN of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PORT <#mpi4py.MPI.ERR_PORT> | Constant ERR_PORT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SERVICE <#mpi4py.MPI.ERR_SERVICE> | Constant ERR_SERVICE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NAME <#mpi4py.MPI.ERR_NAME> | Constant ERR_NAME of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PROC_ABORTED <#mpi4py.MPI.ERR_PROC_ABORTED> | Constant ERR_PROC_ABORTED of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BASE <#mpi4py.MPI.ERR_BASE> | Constant ERR_BASE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_SIZE <#mpi4py.MPI.ERR_SIZE> | Constant ERR_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DISP <#mpi4py.MPI.ERR_DISP> | Constant ERR_DISP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ASSERT <#mpi4py.MPI.ERR_ASSERT> | Constant ERR_ASSERT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_LOCKTYPE <#mpi4py.MPI.ERR_LOCKTYPE> | Constant ERR_LOCKTYPE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_CONFLICT <#mpi4py.MPI.ERR_RMA_CONFLICT> | Constant ERR_RMA_CONFLICT of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_SYNC <#mpi4py.MPI.ERR_RMA_SYNC> | Constant ERR_RMA_SYNC of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_RANGE <#mpi4py.MPI.ERR_RMA_RANGE> | Constant ERR_RMA_RANGE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_ATTACH <#mpi4py.MPI.ERR_RMA_ATTACH> | Constant ERR_RMA_ATTACH of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_SHARED <#mpi4py.MPI.ERR_RMA_SHARED> | Constant ERR_RMA_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
ERR_RMA_FLAVOR <#mpi4py.MPI.ERR_RMA_FLAVOR> | Constant ERR_RMA_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>
ERR_BAD_FILE <#mpi4py.MPI.ERR_BAD_FILE> | Constant ERR_BAD_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_SUCH_FILE <#mpi4py.MPI.ERR_NO_SUCH_FILE> | Constant ERR_NO_SUCH_FILE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE_EXISTS <#mpi4py.MPI.ERR_FILE_EXISTS> | Constant ERR_FILE_EXISTS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_FILE_IN_USE <#mpi4py.MPI.ERR_FILE_IN_USE> | Constant ERR_FILE_IN_USE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_AMODE <#mpi4py.MPI.ERR_AMODE> | Constant ERR_AMODE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_ACCESS <#mpi4py.MPI.ERR_ACCESS> | Constant ERR_ACCESS of type int <https://docs.python.org/3/library/functions.html#int>
ERR_READ_ONLY <#mpi4py.MPI.ERR_READ_ONLY> | Constant ERR_READ_ONLY of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NO_SPACE <#mpi4py.MPI.ERR_NO_SPACE> | Constant ERR_NO_SPACE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_QUOTA <#mpi4py.MPI.ERR_QUOTA> | Constant ERR_QUOTA of type int <https://docs.python.org/3/library/functions.html#int>
ERR_NOT_SAME <#mpi4py.MPI.ERR_NOT_SAME> | Constant ERR_NOT_SAME of type int <https://docs.python.org/3/library/functions.html#int>
ERR_IO <#mpi4py.MPI.ERR_IO> | Constant ERR_IO of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNSUPPORTED_OPERATION <#mpi4py.MPI.ERR_UNSUPPORTED_OPERATION> | Constant ERR_UNSUPPORTED_OPERATION of type int <https://docs.python.org/3/library/functions.html#int>
ERR_UNSUPPORTED_DATAREP <#mpi4py.MPI.ERR_UNSUPPORTED_DATAREP> | Constant ERR_UNSUPPORTED_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_CONVERSION <#mpi4py.MPI.ERR_CONVERSION> | Constant ERR_CONVERSION of type int <https://docs.python.org/3/library/functions.html#int>
ERR_DUP_DATAREP <#mpi4py.MPI.ERR_DUP_DATAREP> | Constant ERR_DUP_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>
ERR_VALUE_TOO_LARGE <#mpi4py.MPI.ERR_VALUE_TOO_LARGE> | Constant ERR_VALUE_TOO_LARGE of type int <https://docs.python.org/3/library/functions.html#int>
ERR_REVOKED <#mpi4py.MPI.ERR_REVOKED> | Constant ERR_REVOKED of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PROC_FAILED <#mpi4py.MPI.ERR_PROC_FAILED> | Constant ERR_PROC_FAILED of type int <https://docs.python.org/3/library/functions.html#int>
ERR_PROC_FAILED_PENDING <#mpi4py.MPI.ERR_PROC_FAILED_PENDING> | Constant ERR_PROC_FAILED_PENDING of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_C <#mpi4py.MPI.ORDER_C> | Constant ORDER_C of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_FORTRAN <#mpi4py.MPI.ORDER_FORTRAN> | Constant ORDER_FORTRAN of type int <https://docs.python.org/3/library/functions.html#int>
ORDER_F <#mpi4py.MPI.ORDER_F> | Constant ORDER_F of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_LOGICAL <#mpi4py.MPI.TYPECLASS_LOGICAL> | Constant TYPECLASS_LOGICAL of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_INTEGER <#mpi4py.MPI.TYPECLASS_INTEGER> | Constant TYPECLASS_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_REAL <#mpi4py.MPI.TYPECLASS_REAL> | Constant TYPECLASS_REAL of type int <https://docs.python.org/3/library/functions.html#int>
TYPECLASS_COMPLEX <#mpi4py.MPI.TYPECLASS_COMPLEX> | Constant TYPECLASS_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_NONE <#mpi4py.MPI.DISTRIBUTE_NONE> | Constant DISTRIBUTE_NONE of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_BLOCK <#mpi4py.MPI.DISTRIBUTE_BLOCK> | Constant DISTRIBUTE_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_CYCLIC <#mpi4py.MPI.DISTRIBUTE_CYCLIC> | Constant DISTRIBUTE_CYCLIC of type int <https://docs.python.org/3/library/functions.html#int>
DISTRIBUTE_DFLT_DARG <#mpi4py.MPI.DISTRIBUTE_DFLT_DARG> | Constant DISTRIBUTE_DFLT_DARG of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_NAMED <#mpi4py.MPI.COMBINER_NAMED> | Constant COMBINER_NAMED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_DUP <#mpi4py.MPI.COMBINER_DUP> | Constant COMBINER_DUP of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_CONTIGUOUS <#mpi4py.MPI.COMBINER_CONTIGUOUS> | Constant COMBINER_CONTIGUOUS of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_VECTOR <#mpi4py.MPI.COMBINER_VECTOR> | Constant COMBINER_VECTOR of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HVECTOR <#mpi4py.MPI.COMBINER_HVECTOR> | Constant COMBINER_HVECTOR of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_INDEXED <#mpi4py.MPI.COMBINER_INDEXED> | Constant COMBINER_INDEXED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HINDEXED <#mpi4py.MPI.COMBINER_HINDEXED> | Constant COMBINER_HINDEXED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_INDEXED_BLOCK <#mpi4py.MPI.COMBINER_INDEXED_BLOCK> | Constant COMBINER_INDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_HINDEXED_BLOCK <#mpi4py.MPI.COMBINER_HINDEXED_BLOCK> | Constant COMBINER_HINDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_STRUCT <#mpi4py.MPI.COMBINER_STRUCT> | Constant COMBINER_STRUCT of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_SUBARRAY <#mpi4py.MPI.COMBINER_SUBARRAY> | Constant COMBINER_SUBARRAY of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_DARRAY <#mpi4py.MPI.COMBINER_DARRAY> | Constant COMBINER_DARRAY of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_RESIZED <#mpi4py.MPI.COMBINER_RESIZED> | Constant COMBINER_RESIZED of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_VALUE_INDEX <#mpi4py.MPI.COMBINER_VALUE_INDEX> | Constant COMBINER_VALUE_INDEX of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_INTEGER <#mpi4py.MPI.COMBINER_F90_INTEGER> | Constant COMBINER_F90_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_REAL <#mpi4py.MPI.COMBINER_F90_REAL> | Constant COMBINER_F90_REAL of type int <https://docs.python.org/3/library/functions.html#int>
COMBINER_F90_COMPLEX <#mpi4py.MPI.COMBINER_F90_COMPLEX> | Constant COMBINER_F90_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>
F_SOURCE <#mpi4py.MPI.F_SOURCE> | Constant F_SOURCE of type int <https://docs.python.org/3/library/functions.html#int>
F_TAG <#mpi4py.MPI.F_TAG> | Constant F_TAG of type int <https://docs.python.org/3/library/functions.html#int>
F_ERROR <#mpi4py.MPI.F_ERROR> | Constant F_ERROR of type int <https://docs.python.org/3/library/functions.html#int>
F_STATUS_SIZE <#mpi4py.MPI.F_STATUS_SIZE> | Constant F_STATUS_SIZE of type int <https://docs.python.org/3/library/functions.html#int>
IDENT <#mpi4py.MPI.IDENT> | Constant IDENT of type int <https://docs.python.org/3/library/functions.html#int>
CONGRUENT <#mpi4py.MPI.CONGRUENT> | Constant CONGRUENT of type int <https://docs.python.org/3/library/functions.html#int>
SIMILAR <#mpi4py.MPI.SIMILAR> | Constant SIMILAR of type int <https://docs.python.org/3/library/functions.html#int>
UNEQUAL <#mpi4py.MPI.UNEQUAL> | Constant UNEQUAL of type int <https://docs.python.org/3/library/functions.html#int>
CART <#mpi4py.MPI.CART> | Constant CART of type int <https://docs.python.org/3/library/functions.html#int>
GRAPH <#mpi4py.MPI.GRAPH> | Constant GRAPH of type int <https://docs.python.org/3/library/functions.html#int>
DIST_GRAPH <#mpi4py.MPI.DIST_GRAPH> | Constant DIST_GRAPH of type int <https://docs.python.org/3/library/functions.html#int>
UNWEIGHTED <#mpi4py.MPI.UNWEIGHTED> | Constant UNWEIGHTED of type int <https://docs.python.org/3/library/functions.html#int>
WEIGHTS_EMPTY <#mpi4py.MPI.WEIGHTS_EMPTY> | Constant WEIGHTS_EMPTY of type int <https://docs.python.org/3/library/functions.html#int>
COMM_TYPE_SHARED <#mpi4py.MPI.COMM_TYPE_SHARED> | Constant COMM_TYPE_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
COMM_TYPE_HW_GUIDED <#mpi4py.MPI.COMM_TYPE_HW_GUIDED> | Constant COMM_TYPE_HW_GUIDED of type int <https://docs.python.org/3/library/functions.html#int>
COMM_TYPE_HW_UNGUIDED <#mpi4py.MPI.COMM_TYPE_HW_UNGUIDED> | Constant COMM_TYPE_HW_UNGUIDED of type int <https://docs.python.org/3/library/functions.html#int>
COMM_TYPE_RESOURCE_GUIDED <#mpi4py.MPI.COMM_TYPE_RESOURCE_GUIDED> | Constant COMM_TYPE_RESOURCE_GUIDED of type int <https://docs.python.org/3/library/functions.html#int>
BSEND_OVERHEAD <#mpi4py.MPI.BSEND_OVERHEAD> | Constant BSEND_OVERHEAD of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_CREATE <#mpi4py.MPI.WIN_FLAVOR_CREATE> | Constant WIN_FLAVOR_CREATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_ALLOCATE <#mpi4py.MPI.WIN_FLAVOR_ALLOCATE> | Constant WIN_FLAVOR_ALLOCATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_DYNAMIC <#mpi4py.MPI.WIN_FLAVOR_DYNAMIC> | Constant WIN_FLAVOR_DYNAMIC of type int <https://docs.python.org/3/library/functions.html#int>
WIN_FLAVOR_SHARED <#mpi4py.MPI.WIN_FLAVOR_SHARED> | Constant WIN_FLAVOR_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
WIN_SEPARATE <#mpi4py.MPI.WIN_SEPARATE> | Constant WIN_SEPARATE of type int <https://docs.python.org/3/library/functions.html#int>
WIN_UNIFIED <#mpi4py.MPI.WIN_UNIFIED> | Constant WIN_UNIFIED of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOCHECK <#mpi4py.MPI.MODE_NOCHECK> | Constant MODE_NOCHECK of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOSTORE <#mpi4py.MPI.MODE_NOSTORE> | Constant MODE_NOSTORE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOPUT <#mpi4py.MPI.MODE_NOPUT> | Constant MODE_NOPUT of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOPRECEDE <#mpi4py.MPI.MODE_NOPRECEDE> | Constant MODE_NOPRECEDE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_NOSUCCEED <#mpi4py.MPI.MODE_NOSUCCEED> | Constant MODE_NOSUCCEED of type int <https://docs.python.org/3/library/functions.html#int>
LOCK_EXCLUSIVE <#mpi4py.MPI.LOCK_EXCLUSIVE> | Constant LOCK_EXCLUSIVE of type int <https://docs.python.org/3/library/functions.html#int>
LOCK_SHARED <#mpi4py.MPI.LOCK_SHARED> | Constant LOCK_SHARED of type int <https://docs.python.org/3/library/functions.html#int>
MODE_RDONLY <#mpi4py.MPI.MODE_RDONLY> | Constant MODE_RDONLY of type int <https://docs.python.org/3/library/functions.html#int>
MODE_WRONLY <#mpi4py.MPI.MODE_WRONLY> | Constant MODE_WRONLY of type int <https://docs.python.org/3/library/functions.html#int>
MODE_RDWR <#mpi4py.MPI.MODE_RDWR> | Constant MODE_RDWR of type int <https://docs.python.org/3/library/functions.html#int>
MODE_CREATE <#mpi4py.MPI.MODE_CREATE> | Constant MODE_CREATE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_EXCL <#mpi4py.MPI.MODE_EXCL> | Constant MODE_EXCL of type int <https://docs.python.org/3/library/functions.html#int>
MODE_DELETE_ON_CLOSE <#mpi4py.MPI.MODE_DELETE_ON_CLOSE> | Constant MODE_DELETE_ON_CLOSE of type int <https://docs.python.org/3/library/functions.html#int>
MODE_UNIQUE_OPEN <#mpi4py.MPI.MODE_UNIQUE_OPEN> | Constant MODE_UNIQUE_OPEN of type int <https://docs.python.org/3/library/functions.html#int>
MODE_SEQUENTIAL <#mpi4py.MPI.MODE_SEQUENTIAL> | Constant MODE_SEQUENTIAL of type int <https://docs.python.org/3/library/functions.html#int>
MODE_APPEND <#mpi4py.MPI.MODE_APPEND> | Constant MODE_APPEND of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_SET <#mpi4py.MPI.SEEK_SET> | Constant SEEK_SET of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_CUR <#mpi4py.MPI.SEEK_CUR> | Constant SEEK_CUR of type int <https://docs.python.org/3/library/functions.html#int>
SEEK_END <#mpi4py.MPI.SEEK_END> | Constant SEEK_END of type int <https://docs.python.org/3/library/functions.html#int>
DISPLACEMENT_CURRENT <#mpi4py.MPI.DISPLACEMENT_CURRENT> | Constant DISPLACEMENT_CURRENT of type int <https://docs.python.org/3/library/functions.html#int>
DISP_CUR <#mpi4py.MPI.DISP_CUR> | Constant DISP_CUR of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_SINGLE <#mpi4py.MPI.THREAD_SINGLE> | Constant THREAD_SINGLE of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_FUNNELED <#mpi4py.MPI.THREAD_FUNNELED> | Constant THREAD_FUNNELED of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_SERIALIZED <#mpi4py.MPI.THREAD_SERIALIZED> | Constant THREAD_SERIALIZED of type int <https://docs.python.org/3/library/functions.html#int>
THREAD_MULTIPLE <#mpi4py.MPI.THREAD_MULTIPLE> | Constant THREAD_MULTIPLE of type int <https://docs.python.org/3/library/functions.html#int>
VERSION <#mpi4py.MPI.VERSION> | Constant VERSION of type int <https://docs.python.org/3/library/functions.html#int>
SUBVERSION <#mpi4py.MPI.SUBVERSION> | Constant SUBVERSION of type int <https://docs.python.org/3/library/functions.html#int>
MAX_PROCESSOR_NAME <#mpi4py.MPI.MAX_PROCESSOR_NAME> | Constant MAX_PROCESSOR_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_ERROR_STRING <#mpi4py.MPI.MAX_ERROR_STRING> | Constant MAX_ERROR_STRING of type int <https://docs.python.org/3/library/functions.html#int>
MAX_PORT_NAME <#mpi4py.MPI.MAX_PORT_NAME> | Constant MAX_PORT_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_INFO_KEY <#mpi4py.MPI.MAX_INFO_KEY> | Constant MAX_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>
MAX_INFO_VAL <#mpi4py.MPI.MAX_INFO_VAL> | Constant MAX_INFO_VAL of type int <https://docs.python.org/3/library/functions.html#int>
MAX_OBJECT_NAME <#mpi4py.MPI.MAX_OBJECT_NAME> | Constant MAX_OBJECT_NAME of type int <https://docs.python.org/3/library/functions.html#int>
MAX_DATAREP_STRING <#mpi4py.MPI.MAX_DATAREP_STRING> | Constant MAX_DATAREP_STRING of type int <https://docs.python.org/3/library/functions.html#int>
MAX_LIBRARY_VERSION_STRING <#mpi4py.MPI.MAX_LIBRARY_VERSION_STRING> | Constant MAX_LIBRARY_VERSION_STRING of type int <https://docs.python.org/3/library/functions.html#int>
MAX_PSET_NAME_LEN <#mpi4py.MPI.MAX_PSET_NAME_LEN> | Constant MAX_PSET_NAME_LEN of type int <https://docs.python.org/3/library/functions.html#int>
MAX_STRINGTAG_LEN <#mpi4py.MPI.MAX_STRINGTAG_LEN> | Constant MAX_STRINGTAG_LEN of type int <https://docs.python.org/3/library/functions.html#int>
DATATYPE_NULL <#mpi4py.MPI.DATATYPE_NULL> | Object DATATYPE_NULL of type Datatype <#mpi4py.MPI.Datatype>
PACKED <#mpi4py.MPI.PACKED> | Object PACKED of type Datatype <#mpi4py.MPI.Datatype>
BYTE <#mpi4py.MPI.BYTE> | Object BYTE of type Datatype <#mpi4py.MPI.Datatype>
AINT <#mpi4py.MPI.AINT> | Object AINT of type Datatype <#mpi4py.MPI.Datatype>
OFFSET <#mpi4py.MPI.OFFSET> | Object OFFSET of type Datatype <#mpi4py.MPI.Datatype>
COUNT <#mpi4py.MPI.COUNT> | Object COUNT of type Datatype <#mpi4py.MPI.Datatype>
CHAR <#mpi4py.MPI.CHAR> | Object CHAR of type Datatype <#mpi4py.MPI.Datatype>
WCHAR <#mpi4py.MPI.WCHAR> | Object WCHAR of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_CHAR <#mpi4py.MPI.SIGNED_CHAR> | Object SIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>
SHORT <#mpi4py.MPI.SHORT> | Object SHORT of type Datatype <#mpi4py.MPI.Datatype>
INT <#mpi4py.MPI.INT> | Object INT of type Datatype <#mpi4py.MPI.Datatype>
LONG <#mpi4py.MPI.LONG> | Object LONG of type Datatype <#mpi4py.MPI.Datatype>
LONG_LONG <#mpi4py.MPI.LONG_LONG> | Object LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_CHAR <#mpi4py.MPI.UNSIGNED_CHAR> | Object UNSIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_SHORT <#mpi4py.MPI.UNSIGNED_SHORT> | Object UNSIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED <#mpi4py.MPI.UNSIGNED> | Object UNSIGNED of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_LONG <#mpi4py.MPI.UNSIGNED_LONG> | Object UNSIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_LONG_LONG <#mpi4py.MPI.UNSIGNED_LONG_LONG> | Object UNSIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
FLOAT <#mpi4py.MPI.FLOAT> | Object FLOAT of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE <#mpi4py.MPI.DOUBLE> | Object DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
LONG_DOUBLE <#mpi4py.MPI.LONG_DOUBLE> | Object LONG_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
C_BOOL <#mpi4py.MPI.C_BOOL> | Object C_BOOL of type Datatype <#mpi4py.MPI.Datatype>
INT8_T <#mpi4py.MPI.INT8_T> | Object INT8_T of type Datatype <#mpi4py.MPI.Datatype>
INT16_T <#mpi4py.MPI.INT16_T> | Object INT16_T of type Datatype <#mpi4py.MPI.Datatype>
INT32_T <#mpi4py.MPI.INT32_T> | Object INT32_T of type Datatype <#mpi4py.MPI.Datatype>
INT64_T <#mpi4py.MPI.INT64_T> | Object INT64_T of type Datatype <#mpi4py.MPI.Datatype>
UINT8_T <#mpi4py.MPI.UINT8_T> | Object UINT8_T of type Datatype <#mpi4py.MPI.Datatype>
UINT16_T <#mpi4py.MPI.UINT16_T> | Object UINT16_T of type Datatype <#mpi4py.MPI.Datatype>
UINT32_T <#mpi4py.MPI.UINT32_T> | Object UINT32_T of type Datatype <#mpi4py.MPI.Datatype>
UINT64_T <#mpi4py.MPI.UINT64_T> | Object UINT64_T of type Datatype <#mpi4py.MPI.Datatype>
FLOAT16_T <#mpi4py.MPI.FLOAT16_T> | Object FLOAT16_T of type Datatype <#mpi4py.MPI.Datatype>
FLOAT32_T <#mpi4py.MPI.FLOAT32_T> | Object FLOAT32_T of type Datatype <#mpi4py.MPI.Datatype>
FLOAT64_T <#mpi4py.MPI.FLOAT64_T> | Object FLOAT64_T of type Datatype <#mpi4py.MPI.Datatype>
BFLOAT16_T <#mpi4py.MPI.BFLOAT16_T> | Object BFLOAT16_T of type Datatype <#mpi4py.MPI.Datatype>
C_COMPLEX <#mpi4py.MPI.C_COMPLEX> | Object C_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_FLOAT_COMPLEX <#mpi4py.MPI.C_FLOAT_COMPLEX> | Object C_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_DOUBLE_COMPLEX <#mpi4py.MPI.C_DOUBLE_COMPLEX> | Object C_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
C_LONG_DOUBLE_COMPLEX <#mpi4py.MPI.C_LONG_DOUBLE_COMPLEX> | Object C_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_BOOL <#mpi4py.MPI.CXX_BOOL> | Object CXX_BOOL of type Datatype <#mpi4py.MPI.Datatype>
CXX_FLOAT_COMPLEX <#mpi4py.MPI.CXX_FLOAT_COMPLEX> | Object CXX_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_DOUBLE_COMPLEX <#mpi4py.MPI.CXX_DOUBLE_COMPLEX> | Object CXX_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
CXX_LONG_DOUBLE_COMPLEX <#mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX> | Object CXX_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
SHORT_INT <#mpi4py.MPI.SHORT_INT> | Object SHORT_INT of type Datatype <#mpi4py.MPI.Datatype>
INT_INT <#mpi4py.MPI.INT_INT> | Object INT_INT of type Datatype <#mpi4py.MPI.Datatype>
TWOINT <#mpi4py.MPI.TWOINT> | Object TWOINT of type Datatype <#mpi4py.MPI.Datatype>
LONG_INT <#mpi4py.MPI.LONG_INT> | Object LONG_INT of type Datatype <#mpi4py.MPI.Datatype>
FLOAT_INT <#mpi4py.MPI.FLOAT_INT> | Object FLOAT_INT of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_INT <#mpi4py.MPI.DOUBLE_INT> | Object DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>
LONG_DOUBLE_INT <#mpi4py.MPI.LONG_DOUBLE_INT> | Object LONG_DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>
CHARACTER <#mpi4py.MPI.CHARACTER> | Object CHARACTER of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL <#mpi4py.MPI.LOGICAL> | Object LOGICAL of type Datatype <#mpi4py.MPI.Datatype>
INTEGER <#mpi4py.MPI.INTEGER> | Object INTEGER of type Datatype <#mpi4py.MPI.Datatype>
REAL <#mpi4py.MPI.REAL> | Object REAL of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_PRECISION <#mpi4py.MPI.DOUBLE_PRECISION> | Object DOUBLE_PRECISION of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX <#mpi4py.MPI.COMPLEX> | Object COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
DOUBLE_COMPLEX <#mpi4py.MPI.DOUBLE_COMPLEX> | Object DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL1 <#mpi4py.MPI.LOGICAL1> | Object LOGICAL1 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL2 <#mpi4py.MPI.LOGICAL2> | Object LOGICAL2 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL4 <#mpi4py.MPI.LOGICAL4> | Object LOGICAL4 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL8 <#mpi4py.MPI.LOGICAL8> | Object LOGICAL8 of type Datatype <#mpi4py.MPI.Datatype>
LOGICAL16 <#mpi4py.MPI.LOGICAL16> | Object LOGICAL16 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER1 <#mpi4py.MPI.INTEGER1> | Object INTEGER1 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER2 <#mpi4py.MPI.INTEGER2> | Object INTEGER2 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER4 <#mpi4py.MPI.INTEGER4> | Object INTEGER4 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER8 <#mpi4py.MPI.INTEGER8> | Object INTEGER8 of type Datatype <#mpi4py.MPI.Datatype>
INTEGER16 <#mpi4py.MPI.INTEGER16> | Object INTEGER16 of type Datatype <#mpi4py.MPI.Datatype>
REAL2 <#mpi4py.MPI.REAL2> | Object REAL2 of type Datatype <#mpi4py.MPI.Datatype>
REAL4 <#mpi4py.MPI.REAL4> | Object REAL4 of type Datatype <#mpi4py.MPI.Datatype>
REAL8 <#mpi4py.MPI.REAL8> | Object REAL8 of type Datatype <#mpi4py.MPI.Datatype>
REAL16 <#mpi4py.MPI.REAL16> | Object REAL16 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX4 <#mpi4py.MPI.COMPLEX4> | Object COMPLEX4 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX8 <#mpi4py.MPI.COMPLEX8> | Object COMPLEX8 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX16 <#mpi4py.MPI.COMPLEX16> | Object COMPLEX16 of type Datatype <#mpi4py.MPI.Datatype>
COMPLEX32 <#mpi4py.MPI.COMPLEX32> | Object COMPLEX32 of type Datatype <#mpi4py.MPI.Datatype>
UNSIGNED_INT <#mpi4py.MPI.UNSIGNED_INT> | Object UNSIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_SHORT <#mpi4py.MPI.SIGNED_SHORT> | Object SIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_INT <#mpi4py.MPI.SIGNED_INT> | Object SIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_LONG <#mpi4py.MPI.SIGNED_LONG> | Object SIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>
SIGNED_LONG_LONG <#mpi4py.MPI.SIGNED_LONG_LONG> | Object SIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>
BOOL <#mpi4py.MPI.BOOL> | Object BOOL of type Datatype <#mpi4py.MPI.Datatype>
SINT8_T <#mpi4py.MPI.SINT8_T> | Object SINT8_T of type Datatype <#mpi4py.MPI.Datatype>
SINT16_T <#mpi4py.MPI.SINT16_T> | Object SINT16_T of type Datatype <#mpi4py.MPI.Datatype>
SINT32_T <#mpi4py.MPI.SINT32_T> | Object SINT32_T of type Datatype <#mpi4py.MPI.Datatype>
SINT64_T <#mpi4py.MPI.SINT64_T> | Object SINT64_T of type Datatype <#mpi4py.MPI.Datatype>
F_BOOL <#mpi4py.MPI.F_BOOL> | Object F_BOOL of type Datatype <#mpi4py.MPI.Datatype>
F_INT <#mpi4py.MPI.F_INT> | Object F_INT of type Datatype <#mpi4py.MPI.Datatype>
F_FLOAT <#mpi4py.MPI.F_FLOAT> | Object F_FLOAT of type Datatype <#mpi4py.MPI.Datatype>
F_DOUBLE <#mpi4py.MPI.F_DOUBLE> | Object F_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>
F_COMPLEX <#mpi4py.MPI.F_COMPLEX> | Object F_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
F_FLOAT_COMPLEX <#mpi4py.MPI.F_FLOAT_COMPLEX> | Object F_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
F_DOUBLE_COMPLEX <#mpi4py.MPI.F_DOUBLE_COMPLEX> | Object F_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>
REQUEST_NULL <#mpi4py.MPI.REQUEST_NULL> | Object REQUEST_NULL of type Request <#mpi4py.MPI.Request>
MESSAGE_NULL <#mpi4py.MPI.MESSAGE_NULL> | Object MESSAGE_NULL of type Message <#mpi4py.MPI.Message>
MESSAGE_NO_PROC <#mpi4py.MPI.MESSAGE_NO_PROC> | Object MESSAGE_NO_PROC of type Message <#mpi4py.MPI.Message>
OP_NULL <#mpi4py.MPI.OP_NULL> | Object OP_NULL of type Op <#mpi4py.MPI.Op>
MAX <#mpi4py.MPI.MAX> | Object MAX of type Op <#mpi4py.MPI.Op>
MIN <#mpi4py.MPI.MIN> | Object MIN of type Op <#mpi4py.MPI.Op>
SUM <#mpi4py.MPI.SUM> | Object SUM of type Op <#mpi4py.MPI.Op>
PROD <#mpi4py.MPI.PROD> | Object PROD of type Op <#mpi4py.MPI.Op>
LAND <#mpi4py.MPI.LAND> | Object LAND of type Op <#mpi4py.MPI.Op>
BAND <#mpi4py.MPI.BAND> | Object BAND of type Op <#mpi4py.MPI.Op>
LOR <#mpi4py.MPI.LOR> | Object LOR of type Op <#mpi4py.MPI.Op>
BOR <#mpi4py.MPI.BOR> | Object BOR of type Op <#mpi4py.MPI.Op>
LXOR <#mpi4py.MPI.LXOR> | Object LXOR of type Op <#mpi4py.MPI.Op>
BXOR <#mpi4py.MPI.BXOR> | Object BXOR of type Op <#mpi4py.MPI.Op>
MAXLOC <#mpi4py.MPI.MAXLOC> | Object MAXLOC of type Op <#mpi4py.MPI.Op>
MINLOC <#mpi4py.MPI.MINLOC> | Object MINLOC of type Op <#mpi4py.MPI.Op>
REPLACE <#mpi4py.MPI.REPLACE> | Object REPLACE of type Op <#mpi4py.MPI.Op>
NO_OP <#mpi4py.MPI.NO_OP> | Object NO_OP of type Op <#mpi4py.MPI.Op>
GROUP_NULL <#mpi4py.MPI.GROUP_NULL> | Object GROUP_NULL of type Group <#mpi4py.MPI.Group>
GROUP_EMPTY <#mpi4py.MPI.GROUP_EMPTY> | Object GROUP_EMPTY of type Group <#mpi4py.MPI.Group>
INFO_NULL <#mpi4py.MPI.INFO_NULL> | Object INFO_NULL of type Info <#mpi4py.MPI.Info>
INFO_ENV <#mpi4py.MPI.INFO_ENV> | Object INFO_ENV of type Info <#mpi4py.MPI.Info>
ERRHANDLER_NULL <#mpi4py.MPI.ERRHANDLER_NULL> | Object ERRHANDLER_NULL of type Errhandler <#mpi4py.MPI.Errhandler>
ERRORS_RETURN <#mpi4py.MPI.ERRORS_RETURN> | Object ERRORS_RETURN of type Errhandler <#mpi4py.MPI.Errhandler>
ERRORS_ABORT <#mpi4py.MPI.ERRORS_ABORT> | Object ERRORS_ABORT of type Errhandler <#mpi4py.MPI.Errhandler>
ERRORS_ARE_FATAL <#mpi4py.MPI.ERRORS_ARE_FATAL> | Object ERRORS_ARE_FATAL of type Errhandler <#mpi4py.MPI.Errhandler>
SESSION_NULL <#mpi4py.MPI.SESSION_NULL> | Object SESSION_NULL of type Session <#mpi4py.MPI.Session>
COMM_NULL <#mpi4py.MPI.COMM_NULL> | Object COMM_NULL of type Comm <#mpi4py.MPI.Comm>
COMM_SELF <#mpi4py.MPI.COMM_SELF> | Object COMM_SELF of type Intracomm <#mpi4py.MPI.Intracomm>
COMM_WORLD <#mpi4py.MPI.COMM_WORLD> | Object COMM_WORLD of type Intracomm <#mpi4py.MPI.Intracomm>
WIN_NULL <#mpi4py.MPI.WIN_NULL> | Object WIN_NULL of type Win <#mpi4py.MPI.Win>
FILE_NULL <#mpi4py.MPI.FILE_NULL> | Object FILE_NULL of type File <#mpi4py.MPI.File>
BOTTOM <#mpi4py.MPI.BOTTOM> | Object BOTTOM of type BottomType <#mpi4py.MPI.BottomType>
IN_PLACE <#mpi4py.MPI.IN_PLACE> | Object IN_PLACE of type InPlaceType <#mpi4py.MPI.InPlaceType>
BUFFER_AUTOMATIC <#mpi4py.MPI.BUFFER_AUTOMATIC> | Object BUFFER_AUTOMATIC of type BufferAutomaticType <#mpi4py.MPI.BufferAutomaticType>
pickle <#mpi4py.MPI.pickle> | Object pickle of type Pickle <#mpi4py.MPI.Pickle>

  mpi4py.MPI.UNDEFINED

    mpi4py.MPI.UNDEFINED: int <https://docs.python.org/3/library/functions.html#int> = UNDEFINED
        Constant UNDEFINED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ANY_SOURCE

    mpi4py.MPI.ANY_SOURCE: int <https://docs.python.org/3/library/functions.html#int> = ANY_SOURCE
        Constant ANY_SOURCE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ANY_TAG

    mpi4py.MPI.ANY_TAG: int <https://docs.python.org/3/library/functions.html#int> = ANY_TAG
        Constant ANY_TAG of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.PROC_NULL

    mpi4py.MPI.PROC_NULL: int <https://docs.python.org/3/library/functions.html#int> = PROC_NULL
        Constant PROC_NULL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ROOT

    mpi4py.MPI.ROOT: int <https://docs.python.org/3/library/functions.html#int> = ROOT
        Constant ROOT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.KEYVAL_INVALID

    mpi4py.MPI.KEYVAL_INVALID: int <https://docs.python.org/3/library/functions.html#int> = KEYVAL_INVALID
        Constant KEYVAL_INVALID of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.TAG_UB

    mpi4py.MPI.TAG_UB: int <https://docs.python.org/3/library/functions.html#int> = TAG_UB
        Constant TAG_UB of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.IO

    mpi4py.MPI.IO: int <https://docs.python.org/3/library/functions.html#int> = IO
        Constant IO of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WTIME_IS_GLOBAL

    mpi4py.MPI.WTIME_IS_GLOBAL: int <https://docs.python.org/3/library/functions.html#int> = WTIME_IS_GLOBAL
        Constant WTIME_IS_GLOBAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.UNIVERSE_SIZE

    mpi4py.MPI.UNIVERSE_SIZE: int <https://docs.python.org/3/library/functions.html#int> = UNIVERSE_SIZE
        Constant UNIVERSE_SIZE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.APPNUM

    mpi4py.MPI.APPNUM: int <https://docs.python.org/3/library/functions.html#int> = APPNUM
        Constant APPNUM of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.LASTUSEDCODE

    mpi4py.MPI.LASTUSEDCODE: int <https://docs.python.org/3/library/functions.html#int> = LASTUSEDCODE
        Constant LASTUSEDCODE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_BASE

    mpi4py.MPI.WIN_BASE: int <https://docs.python.org/3/library/functions.html#int> = WIN_BASE
        Constant WIN_BASE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_SIZE

    mpi4py.MPI.WIN_SIZE: int <https://docs.python.org/3/library/functions.html#int> = WIN_SIZE
        Constant WIN_SIZE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_DISP_UNIT

    mpi4py.MPI.WIN_DISP_UNIT: int <https://docs.python.org/3/library/functions.html#int> = WIN_DISP_UNIT
        Constant WIN_DISP_UNIT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_CREATE_FLAVOR

    mpi4py.MPI.WIN_CREATE_FLAVOR: int <https://docs.python.org/3/library/functions.html#int> = WIN_CREATE_FLAVOR
        Constant WIN_CREATE_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_FLAVOR

    mpi4py.MPI.WIN_FLAVOR: int <https://docs.python.org/3/library/functions.html#int> = WIN_FLAVOR
        Constant WIN_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_MODEL

    mpi4py.MPI.WIN_MODEL: int <https://docs.python.org/3/library/functions.html#int> = WIN_MODEL
        Constant WIN_MODEL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SUCCESS

    mpi4py.MPI.SUCCESS: int <https://docs.python.org/3/library/functions.html#int> = SUCCESS
        Constant SUCCESS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_LASTCODE

    mpi4py.MPI.ERR_LASTCODE: int <https://docs.python.org/3/library/functions.html#int> = ERR_LASTCODE
        Constant ERR_LASTCODE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ABI

    mpi4py.MPI.ERR_ABI: int <https://docs.python.org/3/library/functions.html#int> = ERR_ABI
        Constant ERR_ABI of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_TYPE

    mpi4py.MPI.ERR_TYPE: int <https://docs.python.org/3/library/functions.html#int> = ERR_TYPE
        Constant ERR_TYPE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_REQUEST

    mpi4py.MPI.ERR_REQUEST: int <https://docs.python.org/3/library/functions.html#int> = ERR_REQUEST
        Constant ERR_REQUEST of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_OP

    mpi4py.MPI.ERR_OP: int <https://docs.python.org/3/library/functions.html#int> = ERR_OP
        Constant ERR_OP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_GROUP

    mpi4py.MPI.ERR_GROUP: int <https://docs.python.org/3/library/functions.html#int> = ERR_GROUP
        Constant ERR_GROUP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_INFO

    mpi4py.MPI.ERR_INFO: int <https://docs.python.org/3/library/functions.html#int> = ERR_INFO
        Constant ERR_INFO of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ERRHANDLER

    mpi4py.MPI.ERR_ERRHANDLER: int <https://docs.python.org/3/library/functions.html#int> = ERR_ERRHANDLER
        Constant ERR_ERRHANDLER of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_SESSION

    mpi4py.MPI.ERR_SESSION: int <https://docs.python.org/3/library/functions.html#int> = ERR_SESSION
        Constant ERR_SESSION of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_COMM

    mpi4py.MPI.ERR_COMM: int <https://docs.python.org/3/library/functions.html#int> = ERR_COMM
        Constant ERR_COMM of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_WIN

    mpi4py.MPI.ERR_WIN: int <https://docs.python.org/3/library/functions.html#int> = ERR_WIN
        Constant ERR_WIN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_FILE

    mpi4py.MPI.ERR_FILE: int <https://docs.python.org/3/library/functions.html#int> = ERR_FILE
        Constant ERR_FILE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_BUFFER

    mpi4py.MPI.ERR_BUFFER: int <https://docs.python.org/3/library/functions.html#int> = ERR_BUFFER
        Constant ERR_BUFFER of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_COUNT

    mpi4py.MPI.ERR_COUNT: int <https://docs.python.org/3/library/functions.html#int> = ERR_COUNT
        Constant ERR_COUNT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_TAG

    mpi4py.MPI.ERR_TAG: int <https://docs.python.org/3/library/functions.html#int> = ERR_TAG
        Constant ERR_TAG of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RANK

    mpi4py.MPI.ERR_RANK: int <https://docs.python.org/3/library/functions.html#int> = ERR_RANK
        Constant ERR_RANK of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ROOT

    mpi4py.MPI.ERR_ROOT: int <https://docs.python.org/3/library/functions.html#int> = ERR_ROOT
        Constant ERR_ROOT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_TRUNCATE

    mpi4py.MPI.ERR_TRUNCATE: int <https://docs.python.org/3/library/functions.html#int> = ERR_TRUNCATE
        Constant ERR_TRUNCATE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_IN_STATUS

    mpi4py.MPI.ERR_IN_STATUS: int <https://docs.python.org/3/library/functions.html#int> = ERR_IN_STATUS
        Constant ERR_IN_STATUS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_PENDING

    mpi4py.MPI.ERR_PENDING: int <https://docs.python.org/3/library/functions.html#int> = ERR_PENDING
        Constant ERR_PENDING of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_TOPOLOGY

    mpi4py.MPI.ERR_TOPOLOGY: int <https://docs.python.org/3/library/functions.html#int> = ERR_TOPOLOGY
        Constant ERR_TOPOLOGY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_DIMS

    mpi4py.MPI.ERR_DIMS: int <https://docs.python.org/3/library/functions.html#int> = ERR_DIMS
        Constant ERR_DIMS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ARG

    mpi4py.MPI.ERR_ARG: int <https://docs.python.org/3/library/functions.html#int> = ERR_ARG
        Constant ERR_ARG of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_OTHER

    mpi4py.MPI.ERR_OTHER: int <https://docs.python.org/3/library/functions.html#int> = ERR_OTHER
        Constant ERR_OTHER of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_UNKNOWN

    mpi4py.MPI.ERR_UNKNOWN: int <https://docs.python.org/3/library/functions.html#int> = ERR_UNKNOWN
        Constant ERR_UNKNOWN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_INTERN

    mpi4py.MPI.ERR_INTERN: int <https://docs.python.org/3/library/functions.html#int> = ERR_INTERN
        Constant ERR_INTERN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_KEYVAL

    mpi4py.MPI.ERR_KEYVAL: int <https://docs.python.org/3/library/functions.html#int> = ERR_KEYVAL
        Constant ERR_KEYVAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_NO_MEM

    mpi4py.MPI.ERR_NO_MEM: int <https://docs.python.org/3/library/functions.html#int> = ERR_NO_MEM
        Constant ERR_NO_MEM of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_INFO_KEY

    mpi4py.MPI.ERR_INFO_KEY: int <https://docs.python.org/3/library/functions.html#int> = ERR_INFO_KEY
        Constant ERR_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_INFO_VALUE

    mpi4py.MPI.ERR_INFO_VALUE: int <https://docs.python.org/3/library/functions.html#int> = ERR_INFO_VALUE
        Constant ERR_INFO_VALUE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_INFO_NOKEY

    mpi4py.MPI.ERR_INFO_NOKEY: int <https://docs.python.org/3/library/functions.html#int> = ERR_INFO_NOKEY
        Constant ERR_INFO_NOKEY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_SPAWN

    mpi4py.MPI.ERR_SPAWN: int <https://docs.python.org/3/library/functions.html#int> = ERR_SPAWN
        Constant ERR_SPAWN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_PORT

    mpi4py.MPI.ERR_PORT: int <https://docs.python.org/3/library/functions.html#int> = ERR_PORT
        Constant ERR_PORT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_SERVICE

    mpi4py.MPI.ERR_SERVICE: int <https://docs.python.org/3/library/functions.html#int> = ERR_SERVICE
        Constant ERR_SERVICE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_NAME

    mpi4py.MPI.ERR_NAME: int <https://docs.python.org/3/library/functions.html#int> = ERR_NAME
        Constant ERR_NAME of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_PROC_ABORTED

    mpi4py.MPI.ERR_PROC_ABORTED: int <https://docs.python.org/3/library/functions.html#int> = ERR_PROC_ABORTED
        Constant ERR_PROC_ABORTED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_BASE

    mpi4py.MPI.ERR_BASE: int <https://docs.python.org/3/library/functions.html#int> = ERR_BASE
        Constant ERR_BASE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_SIZE

    mpi4py.MPI.ERR_SIZE: int <https://docs.python.org/3/library/functions.html#int> = ERR_SIZE
        Constant ERR_SIZE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_DISP

    mpi4py.MPI.ERR_DISP: int <https://docs.python.org/3/library/functions.html#int> = ERR_DISP
        Constant ERR_DISP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ASSERT

    mpi4py.MPI.ERR_ASSERT: int <https://docs.python.org/3/library/functions.html#int> = ERR_ASSERT
        Constant ERR_ASSERT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_LOCKTYPE

    mpi4py.MPI.ERR_LOCKTYPE: int <https://docs.python.org/3/library/functions.html#int> = ERR_LOCKTYPE
        Constant ERR_LOCKTYPE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_CONFLICT

    mpi4py.MPI.ERR_RMA_CONFLICT: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_CONFLICT
        Constant ERR_RMA_CONFLICT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_SYNC

    mpi4py.MPI.ERR_RMA_SYNC: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_SYNC
        Constant ERR_RMA_SYNC of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_RANGE

    mpi4py.MPI.ERR_RMA_RANGE: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_RANGE
        Constant ERR_RMA_RANGE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_ATTACH

    mpi4py.MPI.ERR_RMA_ATTACH: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_ATTACH
        Constant ERR_RMA_ATTACH of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_SHARED

    mpi4py.MPI.ERR_RMA_SHARED: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_SHARED
        Constant ERR_RMA_SHARED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_RMA_FLAVOR

    mpi4py.MPI.ERR_RMA_FLAVOR: int <https://docs.python.org/3/library/functions.html#int> = ERR_RMA_FLAVOR
        Constant ERR_RMA_FLAVOR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_BAD_FILE

    mpi4py.MPI.ERR_BAD_FILE: int <https://docs.python.org/3/library/functions.html#int> = ERR_BAD_FILE
        Constant ERR_BAD_FILE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_NO_SUCH_FILE

    mpi4py.MPI.ERR_NO_SUCH_FILE: int <https://docs.python.org/3/library/functions.html#int> = ERR_NO_SUCH_FILE
        Constant ERR_NO_SUCH_FILE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_FILE_EXISTS

    mpi4py.MPI.ERR_FILE_EXISTS: int <https://docs.python.org/3/library/functions.html#int> = ERR_FILE_EXISTS
        Constant ERR_FILE_EXISTS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_FILE_IN_USE

    mpi4py.MPI.ERR_FILE_IN_USE: int <https://docs.python.org/3/library/functions.html#int> = ERR_FILE_IN_USE
        Constant ERR_FILE_IN_USE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_AMODE

    mpi4py.MPI.ERR_AMODE: int <https://docs.python.org/3/library/functions.html#int> = ERR_AMODE
        Constant ERR_AMODE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_ACCESS

    mpi4py.MPI.ERR_ACCESS: int <https://docs.python.org/3/library/functions.html#int> = ERR_ACCESS
        Constant ERR_ACCESS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_READ_ONLY

    mpi4py.MPI.ERR_READ_ONLY: int <https://docs.python.org/3/library/functions.html#int> = ERR_READ_ONLY
        Constant ERR_READ_ONLY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_NO_SPACE

    mpi4py.MPI.ERR_NO_SPACE: int <https://docs.python.org/3/library/functions.html#int> = ERR_NO_SPACE
        Constant ERR_NO_SPACE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_QUOTA

    mpi4py.MPI.ERR_QUOTA: int <https://docs.python.org/3/library/functions.html#int> = ERR_QUOTA
        Constant ERR_QUOTA of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_NOT_SAME

    mpi4py.MPI.ERR_NOT_SAME: int <https://docs.python.org/3/library/functions.html#int> = ERR_NOT_SAME
        Constant ERR_NOT_SAME of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_IO

    mpi4py.MPI.ERR_IO: int <https://docs.python.org/3/library/functions.html#int> = ERR_IO
        Constant ERR_IO of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_UNSUPPORTED_OPERATION

    mpi4py.MPI.ERR_UNSUPPORTED_OPERATION: int <https://docs.python.org/3/library/functions.html#int> = ERR_UNSUPPORTED_OPERATION
        Constant ERR_UNSUPPORTED_OPERATION of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_UNSUPPORTED_DATAREP

    mpi4py.MPI.ERR_UNSUPPORTED_DATAREP: int <https://docs.python.org/3/library/functions.html#int> = ERR_UNSUPPORTED_DATAREP
        Constant ERR_UNSUPPORTED_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_CONVERSION

    mpi4py.MPI.ERR_CONVERSION: int <https://docs.python.org/3/library/functions.html#int> = ERR_CONVERSION
        Constant ERR_CONVERSION of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_DUP_DATAREP

    mpi4py.MPI.ERR_DUP_DATAREP: int <https://docs.python.org/3/library/functions.html#int> = ERR_DUP_DATAREP
        Constant ERR_DUP_DATAREP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_VALUE_TOO_LARGE

    mpi4py.MPI.ERR_VALUE_TOO_LARGE: int <https://docs.python.org/3/library/functions.html#int> = ERR_VALUE_TOO_LARGE
        Constant ERR_VALUE_TOO_LARGE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_REVOKED

    mpi4py.MPI.ERR_REVOKED: int <https://docs.python.org/3/library/functions.html#int> = ERR_REVOKED
        Constant ERR_REVOKED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_PROC_FAILED

    mpi4py.MPI.ERR_PROC_FAILED: int <https://docs.python.org/3/library/functions.html#int> = ERR_PROC_FAILED
        Constant ERR_PROC_FAILED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ERR_PROC_FAILED_PENDING

    mpi4py.MPI.ERR_PROC_FAILED_PENDING: int <https://docs.python.org/3/library/functions.html#int> = ERR_PROC_FAILED_PENDING
        Constant ERR_PROC_FAILED_PENDING of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ORDER_C

    mpi4py.MPI.ORDER_C: int <https://docs.python.org/3/library/functions.html#int> = ORDER_C
        Constant ORDER_C of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ORDER_FORTRAN

    mpi4py.MPI.ORDER_FORTRAN: int <https://docs.python.org/3/library/functions.html#int> = ORDER_FORTRAN
        Constant ORDER_FORTRAN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.ORDER_F

    mpi4py.MPI.ORDER_F: int <https://docs.python.org/3/library/functions.html#int> = ORDER_F
        Constant ORDER_F of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.TYPECLASS_LOGICAL

    mpi4py.MPI.TYPECLASS_LOGICAL: int <https://docs.python.org/3/library/functions.html#int> = TYPECLASS_LOGICAL
        Constant TYPECLASS_LOGICAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.TYPECLASS_INTEGER

    mpi4py.MPI.TYPECLASS_INTEGER: int <https://docs.python.org/3/library/functions.html#int> = TYPECLASS_INTEGER
        Constant TYPECLASS_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.TYPECLASS_REAL

    mpi4py.MPI.TYPECLASS_REAL: int <https://docs.python.org/3/library/functions.html#int> = TYPECLASS_REAL
        Constant TYPECLASS_REAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.TYPECLASS_COMPLEX

    mpi4py.MPI.TYPECLASS_COMPLEX: int <https://docs.python.org/3/library/functions.html#int> = TYPECLASS_COMPLEX
        Constant TYPECLASS_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISTRIBUTE_NONE

    mpi4py.MPI.DISTRIBUTE_NONE: int <https://docs.python.org/3/library/functions.html#int> = DISTRIBUTE_NONE
        Constant DISTRIBUTE_NONE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISTRIBUTE_BLOCK

    mpi4py.MPI.DISTRIBUTE_BLOCK: int <https://docs.python.org/3/library/functions.html#int> = DISTRIBUTE_BLOCK
        Constant DISTRIBUTE_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISTRIBUTE_CYCLIC

    mpi4py.MPI.DISTRIBUTE_CYCLIC: int <https://docs.python.org/3/library/functions.html#int> = DISTRIBUTE_CYCLIC
        Constant DISTRIBUTE_CYCLIC of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISTRIBUTE_DFLT_DARG

    mpi4py.MPI.DISTRIBUTE_DFLT_DARG: int <https://docs.python.org/3/library/functions.html#int> = DISTRIBUTE_DFLT_DARG
        Constant DISTRIBUTE_DFLT_DARG of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_NAMED

    mpi4py.MPI.COMBINER_NAMED: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_NAMED
        Constant COMBINER_NAMED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_DUP

    mpi4py.MPI.COMBINER_DUP: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_DUP
        Constant COMBINER_DUP of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_CONTIGUOUS

    mpi4py.MPI.COMBINER_CONTIGUOUS: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_CONTIGUOUS
        Constant COMBINER_CONTIGUOUS of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_VECTOR

    mpi4py.MPI.COMBINER_VECTOR: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_VECTOR
        Constant COMBINER_VECTOR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_HVECTOR

    mpi4py.MPI.COMBINER_HVECTOR: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_HVECTOR
        Constant COMBINER_HVECTOR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_INDEXED

    mpi4py.MPI.COMBINER_INDEXED: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_INDEXED
        Constant COMBINER_INDEXED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_HINDEXED

    mpi4py.MPI.COMBINER_HINDEXED: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_HINDEXED
        Constant COMBINER_HINDEXED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_INDEXED_BLOCK

    mpi4py.MPI.COMBINER_INDEXED_BLOCK: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_INDEXED_BLOCK
        Constant COMBINER_INDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_HINDEXED_BLOCK

    mpi4py.MPI.COMBINER_HINDEXED_BLOCK: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_HINDEXED_BLOCK
        Constant COMBINER_HINDEXED_BLOCK of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_STRUCT

    mpi4py.MPI.COMBINER_STRUCT: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_STRUCT
        Constant COMBINER_STRUCT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_SUBARRAY

    mpi4py.MPI.COMBINER_SUBARRAY: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_SUBARRAY
        Constant COMBINER_SUBARRAY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_DARRAY

    mpi4py.MPI.COMBINER_DARRAY: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_DARRAY
        Constant COMBINER_DARRAY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_RESIZED

    mpi4py.MPI.COMBINER_RESIZED: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_RESIZED
        Constant COMBINER_RESIZED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_VALUE_INDEX

    mpi4py.MPI.COMBINER_VALUE_INDEX: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_VALUE_INDEX
        Constant COMBINER_VALUE_INDEX of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_F90_INTEGER

    mpi4py.MPI.COMBINER_F90_INTEGER: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_F90_INTEGER
        Constant COMBINER_F90_INTEGER of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_F90_REAL

    mpi4py.MPI.COMBINER_F90_REAL: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_F90_REAL
        Constant COMBINER_F90_REAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMBINER_F90_COMPLEX

    mpi4py.MPI.COMBINER_F90_COMPLEX: int <https://docs.python.org/3/library/functions.html#int> = COMBINER_F90_COMPLEX
        Constant COMBINER_F90_COMPLEX of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.F_SOURCE

    mpi4py.MPI.F_SOURCE: int <https://docs.python.org/3/library/functions.html#int> = F_SOURCE
        Constant F_SOURCE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.F_TAG

    mpi4py.MPI.F_TAG: int <https://docs.python.org/3/library/functions.html#int> = F_TAG
        Constant F_TAG of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.F_ERROR

    mpi4py.MPI.F_ERROR: int <https://docs.python.org/3/library/functions.html#int> = F_ERROR
        Constant F_ERROR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.F_STATUS_SIZE

    mpi4py.MPI.F_STATUS_SIZE: int <https://docs.python.org/3/library/functions.html#int> = F_STATUS_SIZE
        Constant F_STATUS_SIZE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.IDENT

    mpi4py.MPI.IDENT: int <https://docs.python.org/3/library/functions.html#int> = IDENT
        Constant IDENT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.CONGRUENT

    mpi4py.MPI.CONGRUENT: int <https://docs.python.org/3/library/functions.html#int> = CONGRUENT
        Constant CONGRUENT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SIMILAR

    mpi4py.MPI.SIMILAR: int <https://docs.python.org/3/library/functions.html#int> = SIMILAR
        Constant SIMILAR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.UNEQUAL

    mpi4py.MPI.UNEQUAL: int <https://docs.python.org/3/library/functions.html#int> = UNEQUAL
        Constant UNEQUAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.CART

    mpi4py.MPI.CART: int <https://docs.python.org/3/library/functions.html#int> = CART
        Constant CART of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.GRAPH

    mpi4py.MPI.GRAPH: int <https://docs.python.org/3/library/functions.html#int> = GRAPH
        Constant GRAPH of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DIST_GRAPH

    mpi4py.MPI.DIST_GRAPH: int <https://docs.python.org/3/library/functions.html#int> = DIST_GRAPH
        Constant DIST_GRAPH of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.UNWEIGHTED

    mpi4py.MPI.UNWEIGHTED: int <https://docs.python.org/3/library/functions.html#int> = UNWEIGHTED
        Constant UNWEIGHTED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WEIGHTS_EMPTY

    mpi4py.MPI.WEIGHTS_EMPTY: int <https://docs.python.org/3/library/functions.html#int> = WEIGHTS_EMPTY
        Constant WEIGHTS_EMPTY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMM_TYPE_SHARED

    mpi4py.MPI.COMM_TYPE_SHARED: int <https://docs.python.org/3/library/functions.html#int> = COMM_TYPE_SHARED
        Constant COMM_TYPE_SHARED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMM_TYPE_HW_GUIDED

    mpi4py.MPI.COMM_TYPE_HW_GUIDED: int <https://docs.python.org/3/library/functions.html#int> = COMM_TYPE_HW_GUIDED
        Constant COMM_TYPE_HW_GUIDED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMM_TYPE_HW_UNGUIDED

    mpi4py.MPI.COMM_TYPE_HW_UNGUIDED: int <https://docs.python.org/3/library/functions.html#int> = COMM_TYPE_HW_UNGUIDED
        Constant COMM_TYPE_HW_UNGUIDED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.COMM_TYPE_RESOURCE_GUIDED

    mpi4py.MPI.COMM_TYPE_RESOURCE_GUIDED: int <https://docs.python.org/3/library/functions.html#int> = COMM_TYPE_RESOURCE_GUIDED
        Constant COMM_TYPE_RESOURCE_GUIDED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.BSEND_OVERHEAD

    mpi4py.MPI.BSEND_OVERHEAD: int <https://docs.python.org/3/library/functions.html#int> = BSEND_OVERHEAD
        Constant BSEND_OVERHEAD of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_FLAVOR_CREATE

    mpi4py.MPI.WIN_FLAVOR_CREATE: int <https://docs.python.org/3/library/functions.html#int> = WIN_FLAVOR_CREATE
        Constant WIN_FLAVOR_CREATE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_FLAVOR_ALLOCATE

    mpi4py.MPI.WIN_FLAVOR_ALLOCATE: int <https://docs.python.org/3/library/functions.html#int> = WIN_FLAVOR_ALLOCATE
        Constant WIN_FLAVOR_ALLOCATE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_FLAVOR_DYNAMIC

    mpi4py.MPI.WIN_FLAVOR_DYNAMIC: int <https://docs.python.org/3/library/functions.html#int> = WIN_FLAVOR_DYNAMIC
        Constant WIN_FLAVOR_DYNAMIC of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_FLAVOR_SHARED

    mpi4py.MPI.WIN_FLAVOR_SHARED: int <https://docs.python.org/3/library/functions.html#int> = WIN_FLAVOR_SHARED
        Constant WIN_FLAVOR_SHARED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_SEPARATE

    mpi4py.MPI.WIN_SEPARATE: int <https://docs.python.org/3/library/functions.html#int> = WIN_SEPARATE
        Constant WIN_SEPARATE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.WIN_UNIFIED

    mpi4py.MPI.WIN_UNIFIED: int <https://docs.python.org/3/library/functions.html#int> = WIN_UNIFIED
        Constant WIN_UNIFIED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_NOCHECK

    mpi4py.MPI.MODE_NOCHECK: int <https://docs.python.org/3/library/functions.html#int> = MODE_NOCHECK
        Constant MODE_NOCHECK of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_NOSTORE

    mpi4py.MPI.MODE_NOSTORE: int <https://docs.python.org/3/library/functions.html#int> = MODE_NOSTORE
        Constant MODE_NOSTORE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_NOPUT

    mpi4py.MPI.MODE_NOPUT: int <https://docs.python.org/3/library/functions.html#int> = MODE_NOPUT
        Constant MODE_NOPUT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_NOPRECEDE

    mpi4py.MPI.MODE_NOPRECEDE: int <https://docs.python.org/3/library/functions.html#int> = MODE_NOPRECEDE
        Constant MODE_NOPRECEDE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_NOSUCCEED

    mpi4py.MPI.MODE_NOSUCCEED: int <https://docs.python.org/3/library/functions.html#int> = MODE_NOSUCCEED
        Constant MODE_NOSUCCEED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.LOCK_EXCLUSIVE

    mpi4py.MPI.LOCK_EXCLUSIVE: int <https://docs.python.org/3/library/functions.html#int> = LOCK_EXCLUSIVE
        Constant LOCK_EXCLUSIVE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.LOCK_SHARED

    mpi4py.MPI.LOCK_SHARED: int <https://docs.python.org/3/library/functions.html#int> = LOCK_SHARED
        Constant LOCK_SHARED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_RDONLY

    mpi4py.MPI.MODE_RDONLY: int <https://docs.python.org/3/library/functions.html#int> = MODE_RDONLY
        Constant MODE_RDONLY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_WRONLY

    mpi4py.MPI.MODE_WRONLY: int <https://docs.python.org/3/library/functions.html#int> = MODE_WRONLY
        Constant MODE_WRONLY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_RDWR

    mpi4py.MPI.MODE_RDWR: int <https://docs.python.org/3/library/functions.html#int> = MODE_RDWR
        Constant MODE_RDWR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_CREATE

    mpi4py.MPI.MODE_CREATE: int <https://docs.python.org/3/library/functions.html#int> = MODE_CREATE
        Constant MODE_CREATE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_EXCL

    mpi4py.MPI.MODE_EXCL: int <https://docs.python.org/3/library/functions.html#int> = MODE_EXCL
        Constant MODE_EXCL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_DELETE_ON_CLOSE

    mpi4py.MPI.MODE_DELETE_ON_CLOSE: int <https://docs.python.org/3/library/functions.html#int> = MODE_DELETE_ON_CLOSE
        Constant MODE_DELETE_ON_CLOSE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_UNIQUE_OPEN

    mpi4py.MPI.MODE_UNIQUE_OPEN: int <https://docs.python.org/3/library/functions.html#int> = MODE_UNIQUE_OPEN
        Constant MODE_UNIQUE_OPEN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_SEQUENTIAL

    mpi4py.MPI.MODE_SEQUENTIAL: int <https://docs.python.org/3/library/functions.html#int> = MODE_SEQUENTIAL
        Constant MODE_SEQUENTIAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MODE_APPEND

    mpi4py.MPI.MODE_APPEND: int <https://docs.python.org/3/library/functions.html#int> = MODE_APPEND
        Constant MODE_APPEND of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SEEK_SET

    mpi4py.MPI.SEEK_SET: int <https://docs.python.org/3/library/functions.html#int> = SEEK_SET
        Constant SEEK_SET of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SEEK_CUR

    mpi4py.MPI.SEEK_CUR: int <https://docs.python.org/3/library/functions.html#int> = SEEK_CUR
        Constant SEEK_CUR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SEEK_END

    mpi4py.MPI.SEEK_END: int <https://docs.python.org/3/library/functions.html#int> = SEEK_END
        Constant SEEK_END of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISPLACEMENT_CURRENT

    mpi4py.MPI.DISPLACEMENT_CURRENT: int <https://docs.python.org/3/library/functions.html#int> = DISPLACEMENT_CURRENT
        Constant DISPLACEMENT_CURRENT of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DISP_CUR

    mpi4py.MPI.DISP_CUR: int <https://docs.python.org/3/library/functions.html#int> = DISP_CUR
        Constant DISP_CUR of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.THREAD_SINGLE

    mpi4py.MPI.THREAD_SINGLE: int <https://docs.python.org/3/library/functions.html#int> = THREAD_SINGLE
        Constant THREAD_SINGLE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.THREAD_FUNNELED

    mpi4py.MPI.THREAD_FUNNELED: int <https://docs.python.org/3/library/functions.html#int> = THREAD_FUNNELED
        Constant THREAD_FUNNELED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.THREAD_SERIALIZED

    mpi4py.MPI.THREAD_SERIALIZED: int <https://docs.python.org/3/library/functions.html#int> = THREAD_SERIALIZED
        Constant THREAD_SERIALIZED of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.THREAD_MULTIPLE

    mpi4py.MPI.THREAD_MULTIPLE: int <https://docs.python.org/3/library/functions.html#int> = THREAD_MULTIPLE
        Constant THREAD_MULTIPLE of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.VERSION

    mpi4py.MPI.VERSION: int <https://docs.python.org/3/library/functions.html#int> = VERSION
        Constant VERSION of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.SUBVERSION

    mpi4py.MPI.SUBVERSION: int <https://docs.python.org/3/library/functions.html#int> = SUBVERSION
        Constant SUBVERSION of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_PROCESSOR_NAME

    mpi4py.MPI.MAX_PROCESSOR_NAME: int <https://docs.python.org/3/library/functions.html#int> = MAX_PROCESSOR_NAME
        Constant MAX_PROCESSOR_NAME of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_ERROR_STRING

    mpi4py.MPI.MAX_ERROR_STRING: int <https://docs.python.org/3/library/functions.html#int> = MAX_ERROR_STRING
        Constant MAX_ERROR_STRING of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_PORT_NAME

    mpi4py.MPI.MAX_PORT_NAME: int <https://docs.python.org/3/library/functions.html#int> = MAX_PORT_NAME
        Constant MAX_PORT_NAME of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_INFO_KEY

    mpi4py.MPI.MAX_INFO_KEY: int <https://docs.python.org/3/library/functions.html#int> = MAX_INFO_KEY
        Constant MAX_INFO_KEY of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_INFO_VAL

    mpi4py.MPI.MAX_INFO_VAL: int <https://docs.python.org/3/library/functions.html#int> = MAX_INFO_VAL
        Constant MAX_INFO_VAL of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_OBJECT_NAME

    mpi4py.MPI.MAX_OBJECT_NAME: int <https://docs.python.org/3/library/functions.html#int> = MAX_OBJECT_NAME
        Constant MAX_OBJECT_NAME of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_DATAREP_STRING

    mpi4py.MPI.MAX_DATAREP_STRING: int <https://docs.python.org/3/library/functions.html#int> = MAX_DATAREP_STRING
        Constant MAX_DATAREP_STRING of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_LIBRARY_VERSION_STRING

    mpi4py.MPI.MAX_LIBRARY_VERSION_STRING: int <https://docs.python.org/3/library/functions.html#int> = MAX_LIBRARY_VERSION_STRING
        Constant MAX_LIBRARY_VERSION_STRING of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_PSET_NAME_LEN

    mpi4py.MPI.MAX_PSET_NAME_LEN: int <https://docs.python.org/3/library/functions.html#int> = MAX_PSET_NAME_LEN
        Constant MAX_PSET_NAME_LEN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.MAX_STRINGTAG_LEN

    mpi4py.MPI.MAX_STRINGTAG_LEN: int <https://docs.python.org/3/library/functions.html#int> = MAX_STRINGTAG_LEN
        Constant MAX_STRINGTAG_LEN of type int <https://docs.python.org/3/library/functions.html#int>

  mpi4py.MPI.DATATYPE_NULL

    mpi4py.MPI.DATATYPE_NULL: Datatype <#mpi4py.MPI.Datatype> = DATATYPE_NULL
        Object DATATYPE_NULL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.PACKED

    mpi4py.MPI.PACKED: Datatype <#mpi4py.MPI.Datatype> = PACKED
        Object PACKED of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.BYTE

    mpi4py.MPI.BYTE: Datatype <#mpi4py.MPI.Datatype> = BYTE
        Object BYTE of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.AINT

    mpi4py.MPI.AINT: Datatype <#mpi4py.MPI.Datatype> = AINT
        Object AINT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.OFFSET

    mpi4py.MPI.OFFSET: Datatype <#mpi4py.MPI.Datatype> = OFFSET
        Object OFFSET of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COUNT

    mpi4py.MPI.COUNT: Datatype <#mpi4py.MPI.Datatype> = COUNT
        Object COUNT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CHAR

    mpi4py.MPI.CHAR: Datatype <#mpi4py.MPI.Datatype> = CHAR
        Object CHAR of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.WCHAR

    mpi4py.MPI.WCHAR: Datatype <#mpi4py.MPI.Datatype> = WCHAR
        Object WCHAR of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SIGNED_CHAR

    mpi4py.MPI.SIGNED_CHAR: Datatype <#mpi4py.MPI.Datatype> = SIGNED_CHAR
        Object SIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SHORT

    mpi4py.MPI.SHORT: Datatype <#mpi4py.MPI.Datatype> = SHORT
        Object SHORT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT

    mpi4py.MPI.INT: Datatype <#mpi4py.MPI.Datatype> = INT
        Object INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LONG

    mpi4py.MPI.LONG: Datatype <#mpi4py.MPI.Datatype> = LONG
        Object LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LONG_LONG

    mpi4py.MPI.LONG_LONG: Datatype <#mpi4py.MPI.Datatype> = LONG_LONG
        Object LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED_CHAR

    mpi4py.MPI.UNSIGNED_CHAR: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED_CHAR
        Object UNSIGNED_CHAR of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED_SHORT

    mpi4py.MPI.UNSIGNED_SHORT: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED_SHORT
        Object UNSIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED

    mpi4py.MPI.UNSIGNED: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED
        Object UNSIGNED of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED_LONG

    mpi4py.MPI.UNSIGNED_LONG: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED_LONG
        Object UNSIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED_LONG_LONG

    mpi4py.MPI.UNSIGNED_LONG_LONG: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED_LONG_LONG
        Object UNSIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.FLOAT

    mpi4py.MPI.FLOAT: Datatype <#mpi4py.MPI.Datatype> = FLOAT
        Object FLOAT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.DOUBLE

    mpi4py.MPI.DOUBLE: Datatype <#mpi4py.MPI.Datatype> = DOUBLE
        Object DOUBLE of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LONG_DOUBLE

    mpi4py.MPI.LONG_DOUBLE: Datatype <#mpi4py.MPI.Datatype> = LONG_DOUBLE
        Object LONG_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.C_BOOL

    mpi4py.MPI.C_BOOL: Datatype <#mpi4py.MPI.Datatype> = C_BOOL
        Object C_BOOL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT8_T

    mpi4py.MPI.INT8_T: Datatype <#mpi4py.MPI.Datatype> = INT8_T
        Object INT8_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT16_T

    mpi4py.MPI.INT16_T: Datatype <#mpi4py.MPI.Datatype> = INT16_T
        Object INT16_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT32_T

    mpi4py.MPI.INT32_T: Datatype <#mpi4py.MPI.Datatype> = INT32_T
        Object INT32_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT64_T

    mpi4py.MPI.INT64_T: Datatype <#mpi4py.MPI.Datatype> = INT64_T
        Object INT64_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UINT8_T

    mpi4py.MPI.UINT8_T: Datatype <#mpi4py.MPI.Datatype> = UINT8_T
        Object UINT8_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UINT16_T

    mpi4py.MPI.UINT16_T: Datatype <#mpi4py.MPI.Datatype> = UINT16_T
        Object UINT16_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UINT32_T

    mpi4py.MPI.UINT32_T: Datatype <#mpi4py.MPI.Datatype> = UINT32_T
        Object UINT32_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UINT64_T

    mpi4py.MPI.UINT64_T: Datatype <#mpi4py.MPI.Datatype> = UINT64_T
        Object UINT64_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.FLOAT16_T

    mpi4py.MPI.FLOAT16_T: Datatype <#mpi4py.MPI.Datatype> = FLOAT16_T
        Object FLOAT16_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.FLOAT32_T

    mpi4py.MPI.FLOAT32_T: Datatype <#mpi4py.MPI.Datatype> = FLOAT32_T
        Object FLOAT32_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.FLOAT64_T

    mpi4py.MPI.FLOAT64_T: Datatype <#mpi4py.MPI.Datatype> = FLOAT64_T
        Object FLOAT64_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.BFLOAT16_T

    mpi4py.MPI.BFLOAT16_T: Datatype <#mpi4py.MPI.Datatype> = BFLOAT16_T
        Object BFLOAT16_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.C_COMPLEX

    mpi4py.MPI.C_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = C_COMPLEX
        Object C_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.C_FLOAT_COMPLEX

    mpi4py.MPI.C_FLOAT_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = C_FLOAT_COMPLEX
        Object C_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.C_DOUBLE_COMPLEX

    mpi4py.MPI.C_DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = C_DOUBLE_COMPLEX
        Object C_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.C_LONG_DOUBLE_COMPLEX

    mpi4py.MPI.C_LONG_DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = C_LONG_DOUBLE_COMPLEX
        Object C_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CXX_BOOL

    mpi4py.MPI.CXX_BOOL: Datatype <#mpi4py.MPI.Datatype> = CXX_BOOL
        Object CXX_BOOL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CXX_FLOAT_COMPLEX

    mpi4py.MPI.CXX_FLOAT_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = CXX_FLOAT_COMPLEX
        Object CXX_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CXX_DOUBLE_COMPLEX

    mpi4py.MPI.CXX_DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = CXX_DOUBLE_COMPLEX
        Object CXX_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX

    mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = CXX_LONG_DOUBLE_COMPLEX
        Object CXX_LONG_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SHORT_INT

    mpi4py.MPI.SHORT_INT: Datatype <#mpi4py.MPI.Datatype> = SHORT_INT
        Object SHORT_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INT_INT

    mpi4py.MPI.INT_INT: Datatype <#mpi4py.MPI.Datatype> = INT_INT
        Object INT_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.TWOINT

    mpi4py.MPI.TWOINT: Datatype <#mpi4py.MPI.Datatype> = TWOINT
        Object TWOINT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LONG_INT

    mpi4py.MPI.LONG_INT: Datatype <#mpi4py.MPI.Datatype> = LONG_INT
        Object LONG_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.FLOAT_INT

    mpi4py.MPI.FLOAT_INT: Datatype <#mpi4py.MPI.Datatype> = FLOAT_INT
        Object FLOAT_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.DOUBLE_INT

    mpi4py.MPI.DOUBLE_INT: Datatype <#mpi4py.MPI.Datatype> = DOUBLE_INT
        Object DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LONG_DOUBLE_INT

    mpi4py.MPI.LONG_DOUBLE_INT: Datatype <#mpi4py.MPI.Datatype> = LONG_DOUBLE_INT
        Object LONG_DOUBLE_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.CHARACTER

    mpi4py.MPI.CHARACTER: Datatype <#mpi4py.MPI.Datatype> = CHARACTER
        Object CHARACTER of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL

    mpi4py.MPI.LOGICAL: Datatype <#mpi4py.MPI.Datatype> = LOGICAL
        Object LOGICAL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER

    mpi4py.MPI.INTEGER: Datatype <#mpi4py.MPI.Datatype> = INTEGER
        Object INTEGER of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REAL

    mpi4py.MPI.REAL: Datatype <#mpi4py.MPI.Datatype> = REAL
        Object REAL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.DOUBLE_PRECISION

    mpi4py.MPI.DOUBLE_PRECISION: Datatype <#mpi4py.MPI.Datatype> = DOUBLE_PRECISION
        Object DOUBLE_PRECISION of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COMPLEX

    mpi4py.MPI.COMPLEX: Datatype <#mpi4py.MPI.Datatype> = COMPLEX
        Object COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.DOUBLE_COMPLEX

    mpi4py.MPI.DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = DOUBLE_COMPLEX
        Object DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL1

    mpi4py.MPI.LOGICAL1: Datatype <#mpi4py.MPI.Datatype> = LOGICAL1
        Object LOGICAL1 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL2

    mpi4py.MPI.LOGICAL2: Datatype <#mpi4py.MPI.Datatype> = LOGICAL2
        Object LOGICAL2 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL4

    mpi4py.MPI.LOGICAL4: Datatype <#mpi4py.MPI.Datatype> = LOGICAL4
        Object LOGICAL4 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL8

    mpi4py.MPI.LOGICAL8: Datatype <#mpi4py.MPI.Datatype> = LOGICAL8
        Object LOGICAL8 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.LOGICAL16

    mpi4py.MPI.LOGICAL16: Datatype <#mpi4py.MPI.Datatype> = LOGICAL16
        Object LOGICAL16 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER1

    mpi4py.MPI.INTEGER1: Datatype <#mpi4py.MPI.Datatype> = INTEGER1
        Object INTEGER1 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER2

    mpi4py.MPI.INTEGER2: Datatype <#mpi4py.MPI.Datatype> = INTEGER2
        Object INTEGER2 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER4

    mpi4py.MPI.INTEGER4: Datatype <#mpi4py.MPI.Datatype> = INTEGER4
        Object INTEGER4 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER8

    mpi4py.MPI.INTEGER8: Datatype <#mpi4py.MPI.Datatype> = INTEGER8
        Object INTEGER8 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.INTEGER16

    mpi4py.MPI.INTEGER16: Datatype <#mpi4py.MPI.Datatype> = INTEGER16
        Object INTEGER16 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REAL2

    mpi4py.MPI.REAL2: Datatype <#mpi4py.MPI.Datatype> = REAL2
        Object REAL2 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REAL4

    mpi4py.MPI.REAL4: Datatype <#mpi4py.MPI.Datatype> = REAL4
        Object REAL4 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REAL8

    mpi4py.MPI.REAL8: Datatype <#mpi4py.MPI.Datatype> = REAL8
        Object REAL8 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REAL16

    mpi4py.MPI.REAL16: Datatype <#mpi4py.MPI.Datatype> = REAL16
        Object REAL16 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COMPLEX4

    mpi4py.MPI.COMPLEX4: Datatype <#mpi4py.MPI.Datatype> = COMPLEX4
        Object COMPLEX4 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COMPLEX8

    mpi4py.MPI.COMPLEX8: Datatype <#mpi4py.MPI.Datatype> = COMPLEX8
        Object COMPLEX8 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COMPLEX16

    mpi4py.MPI.COMPLEX16: Datatype <#mpi4py.MPI.Datatype> = COMPLEX16
        Object COMPLEX16 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.COMPLEX32

    mpi4py.MPI.COMPLEX32: Datatype <#mpi4py.MPI.Datatype> = COMPLEX32
        Object COMPLEX32 of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.UNSIGNED_INT

    mpi4py.MPI.UNSIGNED_INT: Datatype <#mpi4py.MPI.Datatype> = UNSIGNED_INT
        Object UNSIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SIGNED_SHORT

    mpi4py.MPI.SIGNED_SHORT: Datatype <#mpi4py.MPI.Datatype> = SIGNED_SHORT
        Object SIGNED_SHORT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SIGNED_INT

    mpi4py.MPI.SIGNED_INT: Datatype <#mpi4py.MPI.Datatype> = SIGNED_INT
        Object SIGNED_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SIGNED_LONG

    mpi4py.MPI.SIGNED_LONG: Datatype <#mpi4py.MPI.Datatype> = SIGNED_LONG
        Object SIGNED_LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SIGNED_LONG_LONG

    mpi4py.MPI.SIGNED_LONG_LONG: Datatype <#mpi4py.MPI.Datatype> = SIGNED_LONG_LONG
        Object SIGNED_LONG_LONG of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.BOOL

    mpi4py.MPI.BOOL: Datatype <#mpi4py.MPI.Datatype> = BOOL
        Object BOOL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SINT8_T

    mpi4py.MPI.SINT8_T: Datatype <#mpi4py.MPI.Datatype> = SINT8_T
        Object SINT8_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SINT16_T

    mpi4py.MPI.SINT16_T: Datatype <#mpi4py.MPI.Datatype> = SINT16_T
        Object SINT16_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SINT32_T

    mpi4py.MPI.SINT32_T: Datatype <#mpi4py.MPI.Datatype> = SINT32_T
        Object SINT32_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.SINT64_T

    mpi4py.MPI.SINT64_T: Datatype <#mpi4py.MPI.Datatype> = SINT64_T
        Object SINT64_T of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_BOOL

    mpi4py.MPI.F_BOOL: Datatype <#mpi4py.MPI.Datatype> = F_BOOL
        Object F_BOOL of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_INT

    mpi4py.MPI.F_INT: Datatype <#mpi4py.MPI.Datatype> = F_INT
        Object F_INT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_FLOAT

    mpi4py.MPI.F_FLOAT: Datatype <#mpi4py.MPI.Datatype> = F_FLOAT
        Object F_FLOAT of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_DOUBLE

    mpi4py.MPI.F_DOUBLE: Datatype <#mpi4py.MPI.Datatype> = F_DOUBLE
        Object F_DOUBLE of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_COMPLEX

    mpi4py.MPI.F_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = F_COMPLEX
        Object F_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_FLOAT_COMPLEX

    mpi4py.MPI.F_FLOAT_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = F_FLOAT_COMPLEX
        Object F_FLOAT_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.F_DOUBLE_COMPLEX

    mpi4py.MPI.F_DOUBLE_COMPLEX: Datatype <#mpi4py.MPI.Datatype> = F_DOUBLE_COMPLEX
        Object F_DOUBLE_COMPLEX of type Datatype <#mpi4py.MPI.Datatype>

  mpi4py.MPI.REQUEST_NULL

    mpi4py.MPI.REQUEST_NULL: Request <#mpi4py.MPI.Request> = REQUEST_NULL
        Object REQUEST_NULL of type Request <#mpi4py.MPI.Request>

  mpi4py.MPI.MESSAGE_NULL

    mpi4py.MPI.MESSAGE_NULL: Message <#mpi4py.MPI.Message> = MESSAGE_NULL
        Object MESSAGE_NULL of type Message <#mpi4py.MPI.Message>

  mpi4py.MPI.MESSAGE_NO_PROC

    mpi4py.MPI.MESSAGE_NO_PROC: Message <#mpi4py.MPI.Message> = MESSAGE_NO_PROC
        Object MESSAGE_NO_PROC of type Message <#mpi4py.MPI.Message>

  mpi4py.MPI.OP_NULL

    mpi4py.MPI.OP_NULL: Op <#mpi4py.MPI.Op> = OP_NULL
        Object OP_NULL of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.MAX

    mpi4py.MPI.MAX: Op <#mpi4py.MPI.Op> = MAX
        Object MAX of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.MIN

    mpi4py.MPI.MIN: Op <#mpi4py.MPI.Op> = MIN
        Object MIN of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.SUM

    mpi4py.MPI.SUM: Op <#mpi4py.MPI.Op> = SUM
        Object SUM of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.PROD

    mpi4py.MPI.PROD: Op <#mpi4py.MPI.Op> = PROD
        Object PROD of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.LAND

    mpi4py.MPI.LAND: Op <#mpi4py.MPI.Op> = LAND
        Object LAND of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.BAND

    mpi4py.MPI.BAND: Op <#mpi4py.MPI.Op> = BAND
        Object BAND of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.LOR

    mpi4py.MPI.LOR: Op <#mpi4py.MPI.Op> = LOR
        Object LOR of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.BOR

    mpi4py.MPI.BOR: Op <#mpi4py.MPI.Op> = BOR
        Object BOR of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.LXOR

    mpi4py.MPI.LXOR: Op <#mpi4py.MPI.Op> = LXOR
        Object LXOR of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.BXOR

    mpi4py.MPI.BXOR: Op <#mpi4py.MPI.Op> = BXOR
        Object BXOR of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.MAXLOC

    mpi4py.MPI.MAXLOC: Op <#mpi4py.MPI.Op> = MAXLOC
        Object MAXLOC of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.MINLOC

    mpi4py.MPI.MINLOC: Op <#mpi4py.MPI.Op> = MINLOC
        Object MINLOC of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.REPLACE

    mpi4py.MPI.REPLACE: Op <#mpi4py.MPI.Op> = REPLACE
        Object REPLACE of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.NO_OP

    mpi4py.MPI.NO_OP: Op <#mpi4py.MPI.Op> = NO_OP
        Object NO_OP of type Op <#mpi4py.MPI.Op>

        Parameters

            •   x (Any)

            •   y (Any)

        Return type
            Any

  mpi4py.MPI.GROUP_NULL

    mpi4py.MPI.GROUP_NULL: Group <#mpi4py.MPI.Group> = GROUP_NULL
        Object GROUP_NULL of type Group <#mpi4py.MPI.Group>

  mpi4py.MPI.GROUP_EMPTY

    mpi4py.MPI.GROUP_EMPTY: Group <#mpi4py.MPI.Group> = GROUP_EMPTY
        Object GROUP_EMPTY of type Group <#mpi4py.MPI.Group>

  mpi4py.MPI.INFO_NULL

    mpi4py.MPI.INFO_NULL: Info <#mpi4py.MPI.Info> = INFO_NULL
        Object INFO_NULL of type Info <#mpi4py.MPI.Info>

  mpi4py.MPI.INFO_ENV

    mpi4py.MPI.INFO_ENV: Info <#mpi4py.MPI.Info> = INFO_ENV
        Object INFO_ENV of type Info <#mpi4py.MPI.Info>

  mpi4py.MPI.ERRHANDLER_NULL

    mpi4py.MPI.ERRHANDLER_NULL: Errhandler <#mpi4py.MPI.Errhandler> = ERRHANDLER_NULL
        Object ERRHANDLER_NULL of type Errhandler <#mpi4py.MPI.Errhandler>

  mpi4py.MPI.ERRORS_RETURN

    mpi4py.MPI.ERRORS_RETURN: Errhandler <#mpi4py.MPI.Errhandler> = ERRORS_RETURN
        Object ERRORS_RETURN of type Errhandler <#mpi4py.MPI.Errhandler>

  mpi4py.MPI.ERRORS_ABORT

    mpi4py.MPI.ERRORS_ABORT: Errhandler <#mpi4py.MPI.Errhandler> = ERRORS_ABORT
        Object ERRORS_ABORT of type Errhandler <#mpi4py.MPI.Errhandler>

  mpi4py.MPI.ERRORS_ARE_FATAL

    mpi4py.MPI.ERRORS_ARE_FATAL: Errhandler <#mpi4py.MPI.Errhandler> = ERRORS_ARE_FATAL
        Object ERRORS_ARE_FATAL of type Errhandler <#mpi4py.MPI.Errhandler>

  mpi4py.MPI.SESSION_NULL

    mpi4py.MPI.SESSION_NULL: Session <#mpi4py.MPI.Session> = SESSION_NULL
        Object SESSION_NULL of type Session <#mpi4py.MPI.Session>

  mpi4py.MPI.COMM_NULL

    mpi4py.MPI.COMM_NULL: Comm <#mpi4py.MPI.Comm> = COMM_NULL
        Object COMM_NULL of type Comm <#mpi4py.MPI.Comm>

  mpi4py.MPI.COMM_SELF

    mpi4py.MPI.COMM_SELF: Intracomm <#mpi4py.MPI.Intracomm> = COMM_SELF
        Object COMM_SELF of type Intracomm <#mpi4py.MPI.Intracomm>

  mpi4py.MPI.COMM_WORLD

    mpi4py.MPI.COMM_WORLD: Intracomm <#mpi4py.MPI.Intracomm> = COMM_WORLD
        Object COMM_WORLD of type Intracomm <#mpi4py.MPI.Intracomm>

  mpi4py.MPI.WIN_NULL

    mpi4py.MPI.WIN_NULL: Win <#mpi4py.MPI.Win> = WIN_NULL
        Object WIN_NULL of type Win <#mpi4py.MPI.Win>

  mpi4py.MPI.FILE_NULL

    mpi4py.MPI.FILE_NULL: File <#mpi4py.MPI.File> = FILE_NULL
        Object FILE_NULL of type File <#mpi4py.MPI.File>

  mpi4py.MPI.BOTTOM

    mpi4py.MPI.BOTTOM: BottomType <#mpi4py.MPI.BottomType> = BOTTOM
        Object BOTTOM of type BottomType <#mpi4py.MPI.BottomType>

  mpi4py.MPI.IN_PLACE

    mpi4py.MPI.IN_PLACE: InPlaceType <#mpi4py.MPI.InPlaceType> = IN_PLACE
        Object IN_PLACE of type InPlaceType <#mpi4py.MPI.InPlaceType>

  mpi4py.MPI.BUFFER_AUTOMATIC

    mpi4py.MPI.BUFFER_AUTOMATIC: BufferAutomaticType <#mpi4py.MPI.BufferAutomaticType> = BUFFER_AUTOMATIC
        Object BUFFER_AUTOMATIC of type BufferAutomaticType <#mpi4py.MPI.BufferAutomaticType>

  mpi4py.MPI.pickle

    mpi4py.MPI.pickle: Pickle <#mpi4py.MPI.Pickle> = <mpi4py.MPI.Pickle object>
        Object pickle of type Pickle <#mpi4py.MPI.Pickle>

CITATION

If MPI for Python been significant to a project that leads to an academic publication, please acknowledge that fact by citing the project.

    •   M. Rogowski, S. Aseeri, D. Keyes, and L. Dalcin, mpi4py.futures: MPI-Based Asynchronous Task Execution for Python, IEEE Transactions on Parallel and Distributed Systems, 34(2):611-622, 2023. <https://doi.org/10.1109/TPDS.2022.3225481>

    •   L. Dalcin and Y.-L. L. Fang, mpi4py: Status Update After 12 Years of Development, Computing in Science & Engineering, 23(4):47-54, 2021. <https://doi.org/10.1109/MCSE.2021.3083216>

    •   L. Dalcin, P. Kler, R. Paz, and A. Cosimo, Parallel Distributed Computing using Python, Advances in Water Resources, 34(9):1124-1139, 2011. <https://doi.org/10.1016/j.advwatres.2011.04.013>

    •   L. Dalcin, R. Paz, M. Storti, and J. D’Elia, MPI for Python: performance improvements and MPI-2 extensions, Journal of Parallel and Distributed Computing, 68(5):655-662, 2008. <https://doi.org/10.1016/j.jpdc.2007.09.005>

    •   L. Dalcin, R. Paz, and M. Storti, MPI for Python, Journal of Parallel and Distributed Computing, 65(9):1108-1115, 2005. <https://doi.org/10.1016/j.jpdc.2005.03.010>

INSTALLATION

  Wheel packages

The mpi4py project builds and publishes binary wheels able to run in a variety of:

    •   operating systems: Linux, macOS, Windows;

    •   processor architectures: AMD64, ARM64;

    •   MPI implementations: MPICH, Open MPI, MVAPICH, Intel MPI, HPE Cray MPICH, Microsoft MPI;

    •   Python implementations: CPython, PyPy.

These mpi4py wheels are distributed via the Python Package Index (PyPI <https://pypi.org/project/mpi4py/>) and can be installed with Python package managers like pip <https://pip.pypa.io>:

            python -m pip install mpi4py

The mpi4py wheels can be installed in standard Python virtual environments. The MPI runtime can be provided by other wheels installed in the same virtual environment.

Tip:
        Intel publishes production-grade Intel MPI wheels <https://pypi.org/project/impi-rt/#files> for Linux (x86_64) and Windows (AMD64). mpi4py and MPI wheels can be installed side by side to get a ready-to-use Python+MPI environment:

                    python -m pip install mpi4py impi-rt

Tip:
        The mpi4py project publishes MPICH wheels <https://pypi.org/project/mpich/#files> and Open MPI wheels <https://pypi.org/project/openmpi/#files> for Linux (x86_64/aarch64) and macOS (arm64/x86_64). mpi4py and MPI wheels can be installed side by side to get a ready-to-use Python+MPI environment:

                    python -m pip install mpi4py mpich    # for MPICH
                    python -m pip install mpi4py openmpi  # for Open MPI

        Warning:
                The MPI wheels are distributed with special focus on ease of use, convenience, compatibility, and interoperability. The Linux wheels are built in somewhat constrained environments with relatively dated Linux distributions (manylinux <https://github.com/pypa/manylinux> container images). Therefore, they may lack support for features like GPU awareness (CUDA/ROCm) and C++/Fortran bindings. In production scenarios, it is recommended to use external (either custom-built or system-provided) MPI installations.

The mpi4py wheels can also be installed (with pip <https://pip.pypa.io>) in conda <https://docs.conda.io> environments and they should work out of the box, without any special tweak to environment variables, for any of the MPI packages provided by conda-forge <https://conda-forge.org/>.

Externally-provided MPI implementations may come from a system package manager, sysadmin-maintained builds accessible via module files, or customized user builds. Such usage is supported and encouraged. However, there are a few platform-specific considerations to take into account.

  Linux

The Linux (x86_64/aarch64) wheels require one of

    •   MPICH <https://mpich.org> or any other ABI-compatible derivative, like MVAPICH <https://mvapich.cse.ohio-state.edu>, Intel MPI <https://software.intel.com/intel-mpi-library>, HPE Cray MPICH <https://cpe.ext.hpe.com/docs/latest/mpt/mpich/>

    •   Open MPI <https://open-mpi.org> or any other ABI-compatible derivative, like NVIDIA HPC-X <https://developer.nvidia.com/networking/hpc-x>

Users may need to set the LD_LIBRARY_PATH environment variable such that the dynamic linker is able to find at runtime the MPI shared library file (libmpi.so.*).

  Fedora/RHEL

On Fedora/RHEL systems, both MPICH and Open MPI are available for installation. There is no default or preferred MPI implementation. Instead, users must select their favorite MPI implementation by loading the proper MPI module.

            module load mpi/mpich-$(arch)    # for MPICH
            module load mpi/openmpi-$(arch)  # for Open MPI

After loading the requested MPI module, the LD_LIBRARY_PATH environment variable should be properly setup.

  Debian/Ubuntu

On Debian/Ubuntu systems, Open MPI is the default MPI implementation and most of the MPI-based applications and libraries provided by the distribution depend on Open MPI. Nonetheless, MPICH is also available to users for installation.

In Ubuntu 22.04 and older, due to legacy reasons, the MPICH ABI is slightly broken: the MPI shared library file is named libmpich.so.12 instead of libmpi.so.12 as required by the MPICH ABI Compatibility Initiative <https://www.mpich.org/abi/>.

Users without sudo access can workaround this issue creating a symbolic link anywhere in their home directory and appending to LD_LIBRARY_PATH.

            mkdir -p ~/.local/lib
            libdir=/usr/lib/$(arch)-linux-gnu
            ln -s $libdir/libmpich.so.12 ~/.local/lib/libmpi.so.12
            export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:~/.local/lib

A system-wide fix for all users requires sudo access:

            libdir=/usr/lib/$(arch)-linux-gnu
            sudo ln -sr $libdir/libmpi{ch,}.so.12

  HPE Cray OS

On HPE Cray systems, users must load the cray-mpich-abi module. For further details, refer to man intro_mpi <https://cpe.ext.hpe.com/docs/latest/mpt/mpich/intro_mpi.html#using-mpich-abi-compatibility>.

  macOS

The macOS (arm64/x86_64) wheels require

    •   MPICH <https://mpich.org> or Open MPI <https://open-mpi.org> installed (either manually or via a package manager) in the standard system prefix /usr/local

    •   MPICH <https://mpich.org> or Open MPI <https://open-mpi.org> installed via Homebrew <https://brew.sh/> in the default prefix /opt/homebrew

    •   MPICH <https://mpich.org> or Open MPI <https://open-mpi.org> installed via MacPorts <https://www.macports.org/> in the default prefix /opt/local

  Windows

The Windows (AMD64) wheels require one of

    •   Intel MPI <https://software.intel.com/intel-mpi-library>

    •   Microsoft MPI <https://learn.microsoft.com/message-passing-interface/microsoft-mpi>

User may need to set the I_MPI_ROOT or MSMPI_BIN environment variables such that the MPI dynamic link library (DLL) (impi.dll or msmpi.dll) can be found at runtime.

Intel MPI is under active development and supports recent versions of the MPI standard. Intel MPI can be installed with pip (see the impi-rt <https://pypi.org/project/impi-rt/> package on PyPI), being therefore straightforward to get it up and running within a Python environment. Intel MPI can also be installed system-wide as part of the Intel oneAPI HPC Toolkit for Windows or via standalone online/offline installers.

  Conda packages

The conda-forge <https://conda-forge.org/> community provides ready-to-use binary packages from an ever growing collection of software libraries built around the multi-platform conda package manager. Four MPI implementations are available on conda-forge: Open MPI (Linux and macOS), MPICH (Linux and macOS), Intel MPI (Linux and Windows), and Microsoft MPI (Windows). You can install mpi4py and your preferred MPI implementation using the conda <https://docs.conda.io> package manager:

    •   to use MPICH do:

                conda install -c conda-forge mpi4py mpich

    •   to use Open MPI do:

                conda install -c conda-forge mpi4py openmpi

    •   to use Intel MPI do:

                conda install -c conda-forge mpi4py impi_rt

    •   to use Microsoft MPI do:

                conda install -c conda-forge mpi4py msmpi

MPICH and many of its derivatives are ABI-compatible. You can provide the package specification mpich=X.Y.*=external_* (where X and Y are the major and minor version numbers) to request the conda package manager to use system-provided MPICH (or derivative) libraries. Similarly, you can provide the package specification openmpi=X.Y.*=external_* to use system-provided Open MPI libraries.

The openmpi package on conda-forge has built-in CUDA support, but it is disabled by default. To enable it, follow the instruction outlined during conda install. Additionally, UCX support is also available once the ucx package is installed.

Warning:
        The MPI conda-forge packages are built with special focus on compatibility. The MPICH and Open MPI packages are built in a constrained environment with relatively dated OS images. Therefore, they may lack support for high-performance features like cross-memory attach (XPMEM/CMA). In production scenarios, it is recommended to use external (either custom-built or system-provided) MPI installations. See the relevant conda-forge documentation about using external MPI libraries <https://conda-forge.org/docs/user/tipsandtricks/#using-external-message-passing-interface-mpi-libraries> .

  System packages

mpi4py is readily available through system package managers of most Linux distributions and the most popular community package managers for macOS.

  Linux

On Fedora Linux systems (as well as RHEL and their derivatives using the EPEL software repository), you can install binary packages with the system package manager:

    •   using dnf and the mpich package:

                sudo dnf install python3-mpi4py-mpich

    •   using dnf and the openmpi package:

                sudo dnf install python3-mpi4py-openmpi

Please remember to load the correct MPI module for your chosen MPI implementation:

    •   for the mpich package do:

                module load mpi/mpich-$(arch)
                python -c "from mpi4py import MPI"

    •   for the openmpi package do:

                module load mpi/openmpi-$(arch)
                python -c "from mpi4py import MPI"

On Ubuntu Linux and Debian Linux systems, binary packages are available for installation using the system package manager:

            sudo apt install python3-mpi4py

On Arch Linux systems, binary packages are available for installation using the system package manager:

            sudo pacman -S python-mpi4py

  macOS

macOS users can install mpi4py using the Homebrew <https://brew.sh/> package manager:

            brew install mpi4py

Note that the Homebrew mpi4py package uses Open MPI. Alternatively, install the mpich package and next install mpi4py from sources using pip.

Alternatively, mpi4py can be installed from MacPorts <https://www.macports.org/>:

            sudo port install py-mpi4py

  Building from sources

Installing mpi4py from pre-built binary wheels, conda packages, or system packages is not always desired or appropriate. For example, the mpi4py wheels published on PyPI may not be interoperable with non-mainstream, vendor-specific MPI implementations; or a system mpi4py package may be built with a alternative, non-default MPI implementation. In such scenarios, mpi4py can still be installed from its source distribution (sdist) using pip:

            python -m pip install --no-binary=mpi4py mpi4py

You can also install the in-development version with:

            python -m pip install git+https://github.com/mpi4py/mpi4py

or:

            python -m pip install https://github.com/mpi4py/mpi4py/tarball/master

Note:
        Installing mpi4py from its source distribution (available on PyPI) or Git source code repository (available on GitHub) requires a C compiler and a working MPI implementation with development headers and libraries.

Warning:
        pip keeps previously built wheel files in its cache for future reuse. If you want to reinstall the mpi4py package from its source distribution using a different or updated MPI implementation, you have to either first remove the cached wheel file:

                    python -m pip cache remove mpi4py
                    python -m pip install --no-binary=mpi4py mpi4py

        or ask pip to disable the cache:

                    python -m pip install --no-cache-dir --no-binary=mpi4py mpi4py

  Build backends

mpi4py supports three different build backends: setuptools <https://setuptools.pypa.io/> (default), scikit-build-core <https://scikit-build-core.readthedocs.io/> (CMake <https://cmake.org/>-based), and meson-python <https://meson-python.readthedocs.io/> (Meson <https://mesonbuild.com/>-based). The build backend can be selected by setting the MPI4PY_BUILD_BACKEND environment variable.

    MPI4PY_BUILD_BACKEND

        Choices
            "setuptools", "scikit-build-core", "meson-python"

        Default
            "setuptools"

    Request a build backend for building mpi4py from sources.

  Using setuptools

Tip:
        Set the MPI4PY_BUILD_BACKEND environment variable to "setuptools" to use the setuptools <https://setuptools.pypa.io/> build backend.

When using the default setuptools <https://setuptools.pypa.io/> build backend, mpi4py relies on the legacy Python distutils framework to build C extension modules. The following environment variables affect the build configuration.

    MPI4PY_BUILD_MPICC
        The mpicc compiler wrapper command is searched for in the executable search path (PATH environment variable) and used to compile the mpi4py.MPI <#module-mpi4py.MPI> C extension module. Alternatively, use the MPI4PY_BUILD_MPICC environment variable to the full path or command corresponding to the MPI-aware C compiler.

    MPI4PY_BUILD_MPILD
        The mpicc compiler wrapper command is also used for linking the mpi4py.MPI <#module-mpi4py.MPI> C extension module. Alternatively, use the MPI4PY_BUILD_MPILD environment variable to specify the full path or command corresponding to the MPI-aware C linker.

    MPI4PY_BUILD_MPICFG
        If the MPI implementation does not provide a compiler wrapper, or it is not installed in a default system location, all relevant build information like include/library locations and library lists can be provided in an ini-style configuration file under a [mpi] section. mpi4py can then be asked to use the custom build information by setting the MPI4PY_BUILD_MPICFG environment variable to the full path of the configuration file. As an example, see the mpi.cfg file located in the top level mpi4py source directory.

    MPI4PY_BUILD_CONFIGURE
        Some vendor MPI implementations may not provide complete coverage of the MPI standard, or may provide partial features of newer MPI standard versions while advertising support for an older version. Setting the MPI4PY_BUILD_CONFIGURE environment variable to a non-empty string will trigger the run of exhaustive checks for the availability of all MPI constants, predefined handles, and routines.

    MPI4PY_BUILD_MPIABI
        Setting the MPI4PY_BUILD_MPIABI environment variable to "1" enables enhanced support for the MPI 5.0 standard ABI and the MPICH or Open MPI legacy ABIs. The mpi4py.MPI <#module-mpi4py.MPI> extension module is then able to dynamically link at runtime with older versions (down to the MPI 3.0 standard) of the corresponding MPI implementation used at compile time. This feature is only available on Linux, macOS, and Windows. POSIX-like systems other than Linux and macOS are not currently supported, although they could easily be: all what is needed is for the platform to either support weak symbols in shared modules/libraries, or support the standard POSIX dlopen()/dlsym() APIs.

    MPI4PY_BUILD_PYSABI
        Build with the CPython 3.10+ Stable ABI <https://docs.python.org/3/c-api/stable.html#stable-abi>. Setting the MPI4PY_BUILD_PYSABI environment variable to a string "{major}.{minor}" defines the Py_LIMITED_API <https://docs.python.org/3/c-api/stable.html#c.Py_LIMITED_API> value to use for building extension modules.

The following environment variables are aliases for the ones described above. Having shorter names, they are convenient for occasional use in the command line. Its usage is not recommended in automation scenarios like packaging recipes, deployment scripts, and container image creation.

    MPICC
        Convenience alias for MPI4PY_BUILD_MPICC.

    MPILD
        Convenience alias for MPI4PY_BUILD_MPILD.

    MPICFG
        Convenience alias for MPI4PY_BUILD_MPICFG.

  Using scikit-build-core

Tip:
        Set the MPI4PY_BUILD_BACKEND environment variable to "scikit-build-core" to use the scikit-build-core <https://scikit-build-core.readthedocs.io/> build backend.

When using the scikit-build-core <https://scikit-build-core.readthedocs.io/> build backend, mpi4py delegates all of MPI build configuration to CMake <https://cmake.org/>’s FindMPI <https://cmake.org/cmake/help/latest/module/FindMPI.html> module. Besides the obvious advantage of cross-platform support, this delegation to CMake may be convenient in build environments exposing vendor software stacks via intricate module systems. Note however that mpi4py will not be able to look for MPI routines available beyond the MPI standard version the MPI implementation advertises to support (via the MPI_VERSION and MPI_SUBVERSION macro constants in the mpi.h header file), any missing MPI constant or symbol will prevent a successful build.

  Using meson-python

Tip:
        Set the MPI4PY_BUILD_BACKEND environment variable to "meson-python" to use the meson-python <https://meson-python.readthedocs.io/> build backend.

When using the meson-python <https://meson-python.readthedocs.io/> build backend, mpi4py delegates build tasks to the Meson <https://mesonbuild.com/> build system.

Warning:
        mpi4py support for the meson-python <https://meson-python.readthedocs.io/> build backend is experimental. For the time being, users must set the CC <https://docs.python.org/3/using/configure.html#envvar-CC> environment variable to the command or path corresponding to the mpicc C compiler wrapper.

DEVELOPMENT

  Prerequisites

You need to have the following software properly installed to develop MPI for Python:

    •   Python <https://www.python.org/> 3.8 or above.

    •   The Cython <https://cython.org/> compiler.

    •   A working MPI <https://www.mpi-forum.org/> implementation like MPICH <https://www.mpich.org/> or Open MPI <https://www.open-mpi.org/>, preferably supporting MPI-4 and built with shared/dynamic libraries.

Optionally, consider installing the following packages:

    •   NumPy <https://numpy.org/> for enabling comprehensive testing of MPI communication.

    •   CuPy <https://cupy.dev/> for enabling comprehensive testing with a GPU-aware MPI.

    •   Sphinx <https://www.sphinx-doc.org/> to build the documentation.

Tip:
        Most routine development tasks like building, installing in editable mode, testing, and generating documentation can be performed with the spin <https://github.com/scientific-python/spin> developer tool. Run spin at the top level source directory for a list of available subcommands.

  Building

MPI for Python uses setuptools-based build system that relies on the setup.py file. Some setuptools commands (e.g., build) accept additional options:

    --mpi=
        Lets you pass a section with MPI configuration within a special configuration file. Alternatively, you can use the MPICFG <#envvar-MPICFG> environment variable.

    --mpicc=
        Specify the path or name of the mpicc C compiler wrapper. Alternatively, use the MPICC <#envvar-MPICC> environment variable.

    --mpild=
        Specify the full path or name for the MPI-aware C linker. Alternatively, use the MPILD <#envvar-MPILD> environment variable. If not set, the mpicc C compiler wrapper is used for linking.

    --configure
        Runs exhaustive tests for checking about missing MPI types, constants, and functions. This option should be passed in order to build MPI for Python against old MPI-1, MPI-2, or MPI-3 implementations, possibly providing a subset of MPI-4.

If you use a MPI implementation providing a mpicc C compiler wrapper (e.g., MPICH or Open MPI), it will be used for compilation and linking. This is the preferred and easiest way to build MPI for Python.

If mpicc is found in the executable search path (PATH environment variable), simply run the build command:

            $ python setup.py build

If mpicc is not in your search path or the compiler wrapper has a different name, you can run the build command specifying its location, either via the --mpicc command option or using the MPICC <#envvar-MPICC> environment variable:

            $ python setup.py build --mpicc=/path/to/mpicc
            $ env MPICC=/path/to/mpicc python setup.py build

Alternatively, you can provide all the relevant information about your MPI implementation by editing the mpi.cfg file located in the top level source directory. You can use the default section [mpi] or add a new custom section, for example [vendor_mpi] (see the examples provided in the mpi.cfg file as a starting point to write your own section):

            [mpi]
            include_dirs         = /usr/local/mpi/include
            libraries            = mpi
            library_dirs         = /usr/local/mpi/lib
            runtime_library_dirs = /usr/local/mpi/lib

            [vendor_mpi]
            include_dirs         = /opt/mpi/include ...
            libraries            = mpi ...
            library_dirs         = /opt/mpi/lib ...
            runtime_library_dirs = /opt/mpi/lib ...

            ...

and then run the build command specifying you custom configuration section:

            $ python setup.py build --mpi=vendor_mpi
            $ env MPICFG=vendor_mpi python setup.py build

  Installing

MPI for Python can be installed in editable mode:

            $ python -m pip install --editable .

After modifying Cython sources, an in-place rebuild is needed:

            $ python setup.py build --inplace

  Testing

To quickly test the installation:

            $ mpiexec -n 5 python -m mpi4py.bench helloworld
            Hello, World! I am process 0 of 5 on localhost.
            Hello, World! I am process 1 of 5 on localhost.
            Hello, World! I am process 2 of 5 on localhost.
            Hello, World! I am process 3 of 5 on localhost.
            Hello, World! I am process 4 of 5 on localhost.

            $ mpiexec -n 5 python -m mpi4py.bench ringtest -l 10 -n 1048576
            time for 10 loops = 0.00361614 seconds (5 processes, 1048576 bytes)

If you installed from a git clone or the source distribution, issuing at the command line:

            $ mpiexec -n 5 python demo/helloworld.py

will launch a five-process run of the Python interpreter and run the demo script demo/helloworld.py from the source distribution.

You can also run all the unittest scripts:

            $ mpiexec -n 5 python test/main.py

or, if you have the pytest <https://docs.pytest.org/> unit testing framework installed:

            $ mpiexec -n 5 pytest

GUIDELINES

  Fair play

  Summary

This section defines Rules of Play for companies and outside developers that engage with the mpi4py project. It covers:

    •   Restrictions on use of the mpi4py name.

    •   How and whether to publish a modified distribution.

    •   How to make us aware of patched versions.

After reading this section, companies and developers will know what kinds of behavior the mpi4py developers and contributors would like to see, and which we consider troublesome, bothersome, and unacceptable.

This document is a close adaptation of NumPy NEP 36 <https://numpy.org/neps/nep-0036-fair-play.html>.

  Motivation

Occasionally, we learn of modified mpi4py versions and binary distributions circulated by outsiders. These patched versions can cause problems to mpi4py users (see, e.g., mpi4py/mpi4py#508 <https://github.com/mpi4py/mpi4py/issues/508>). When issues like these arise, our developers waste time identifying the problematic release, locating alterations, and determining an appropriate course of action.

In addition, packages on the Python Packaging Index are sometimes named such that users assume they are sanctioned or maintained by the mpi4py developers. We wish to reduce the number of such incidents.

  Scope

This document aims to define a minimal set of rules that, when followed, will be considered good-faith efforts in line with the expectations of the mpi4py developers and contributors.

Our hope is that companies and outside developers who feel they need to modify mpi4py will first consider contributing to the project, or use alternative mechanisms for patching and extending mpi4py.

When in doubt, please talk to us first <https://github.com/mpi4py/mpi4py/discussions/>. We may suggest an alternative; at minimum, we’ll be informed and we may even grant an exception if deemed appropriate.

  Fair play rules

    1.  Do not reuse the mpi4py name for projects not affiliated with the mpi4py project.

        At time of writing, there are only a handful of mpi4py-named packages developed by the mpi4py project, including mpi4py and mpi4py-fft. We ask that outside packages not include the phrase mpi4py, i.e., avoid names such as mycompany-mpi4py or mpi4py-mycompany.

        To be clear, this rule only applies to modules (package names); it is perfectly acceptable to have a submodule of your own package named mycompany.mpi4py.

    2.  Do not publish binary mpi4py wheels on PyPI (<https://pypi.org/>).

        We ask companies and outside developers to not publish binary mpi4py wheels in the main Python Package Index (<https://pypi.org/>) under names such mpi4py-mpich, mpi4py-openmpi, or mpi4py-vendor_mpi.

        The usual approaches to build binary Python wheels involve the embedding of dependent shared libraries. While such an approach may seem convenient and often is, in the particular case of MPI and mpi4py it is ultimately harmful to end users. Embedding the MPI shared libraries would prevent the use of external, system-provided MPI installations with hardware-specific optimizations and site-specific tweaks.

        The MPI 5.0 standard features an Application Binary Interface (ABI) for MPI, see [mpi-abi-paper] <#mpi-abi-paper> and [mpi-abi-issue] <#mpi-abi-issue>. Such standardization allows for any binary dependent on the MPI library to be used with multiple MPI backends. Once MPI implementations provide support for the new MPI ABI, the mpi4py project will follow and add support to the binary wheels published on PyPI.

    [mpi-abi-paper]
        J. Hammond, L. Dalcin, E. Schnetter, M. Pérache, J. B. Besnard, J. Brown, G. Brito Gadeschi, S. Byrne, J. Schuchart, and H. Zhou. MPI Application Binary Interface Standardization. EuroMPI 2023, Bristol, UK, September 2023. <https://doi.org/10.1145/3615318.3615319>

    [mpi-abi-issue]
        MPI Forum GitHub Issue: MPI needs a standard ABI. <https://github.com/mpi-forum/mpi-issues/issues/751>

    3.  Do not republish modified versions of mpi4py.

        Modified versions of mpi4py make it very difficult for the developers to address bug reports, since we typically do not know which parts of mpi4py have been modified.

        If you have to break this rule (and we implore you not to!), then make it clear in the __version__ tag that you have modified mpi4py, e.g.:

                >>> print(mpi4py.__version__)
                '4.0.0+mycompany.13`

    We understand that minor patches are often required to make a library work inside of a package ecosystem. This is totally acceptable, but we ask that no substantive changes are made.

    4.  Do not extend or modify mpi4py’s API.

        If you absolutely have to break the previous rule, please do not add additional functions to the namespace, or modify the API of existing functions. Having additional functions exposed in distributed versions is confusing for users and developers alike.

LICENSE

Copyright (c) 2025, Lisandro Dalcin

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    1.  Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

    2.  Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

    3.  Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

CHANGES

  Release 4.1.1 [2025-10-10]

    •   Add MPIABI-aware import hook support.

    •   Support MPI.ERR_ERRHANDLER <#mpi4py.MPI.ERR_ERRHANDLER> with Open MPI.

    •   Fix Windows build issues with Intel MPI 2021.16.

    •   Minor fixes and improvements to typing stubs.

    •   Minor fixes to documentation.

    •   Publish Python 3.8-3.14 and PyPy 3.11 wheels.

    •   PyPy 3.10 (EOL) wheels are no longer published.

  Release 4.1.0 [2025-06-25]

    •   New features:

        •   Publish binary wheel packages on PyPI <https://pypi.org/project/mpi4py/#files> with support for multiple operating systems (Linux, macOS, Windows), processor architectures (AMD64, ARM64), MPI implementations (MPICH, Open MPI, and their ABI-compatible derivatives), and Python implementations (CPython, PyPy).

        •   Add support for the MPI 5.0 standard.

            •   MPI handle serialization with integral values.

            •   Fixed-size Fortran LOGICAL datatypes.

            •   Query ABI version/info and Fortran ABI info.

        •   MPI.Datatype.Create_contiguous <#mpi4py.MPI.Datatype.Create_contiguous> now uses BigMPI <https://doi.org/10.1109/ExaMPI.2014.5>’s approach when using MPI implementations that do not yet support the MPI 4.0 large-count APIs.

        •   Add support for MPI.FLOAT16_T <#mpi4py.MPI.FLOAT16_T> and MPI.BFLOAT16_T <#mpi4py.MPI.BFLOAT16_T> datatypes. These datatypes are not yet standard but available as extensions in MPI implementations.

        •   Add MPI.Status.tomemory <#mpi4py.MPI.Status.tomemory> to expose the status contents as a memoryview <https://docs.python.org/3/library/stdtypes.html#memoryview> object.

    •   Enhancements:

        •   Support (opt-in via MPI4PY_BUILD_PYSABI <#envvar-MPI4PY_BUILD_PYSABI>) for building with Py_LIMITED_API <https://docs.python.org/3/c-api/stable.html#c.Py_LIMITED_API> under Python 3.10+ (requires Cython 3.1+).

        •   Support (opt-in via MPI4PY_BUILD_MPIABI <#envvar-MPI4PY_BUILD_MPIABI>) for building with the MPI 5.0 standard ABI and the MPICH or Open MPI legacy ABIs. The MPI <#module-mpi4py.MPI> extension module will be able to dynamically link at runtime with older versions (down to the MPI 3.0 standard) of the MPI implementation used at compile time. Only available on Linux, macOS, and Windows.

        •   Support a buffersize parameter in the MPIPoolExecutor.map() <#mpi4py.futures.MPIPoolExecutor.map> and MPIPoolExecutor.starmap() <#mpi4py.futures.MPIPoolExecutor.starmap> methods to limit the number of pending tasks.

        •   Improve ownership management of DLPack capsules.

        •   Reimplement MPI DLL search path on Windows.

        •   Minor fixes to typing stubs and documentation.

    •   Backward-incompatible changes:

        •   Python 3.8+ is required.

        •   The MPI.Exception <#mpi4py.MPI.Exception> class is now a heap type.

        •   The types of the MPI.BOTTOM <#mpi4py.MPI.BOTTOM>, MPI.IN_PLACE <#mpi4py.MPI.IN_PLACE>, and MPI.BUFFER_AUTOMATIC <#mpi4py.MPI.BUFFER_AUTOMATIC> are no longer subclasses of int <https://docs.python.org/3/library/functions.html#int>.

  Release 4.0.3 [2025-02-13]

    •   Fix DLPack v1.0 support.

  Release 4.0.2 [2025-02-01]

    •   Support MPI-4 features within Intel MPI 2021.14.

    •   Various fixes and updates to tests.

    •   Minor fixes to typing support.

    •   Minor fix to documentation.

  Release 4.0.1 [2024-10-11]

    •   Update support for Python 3.13:

        •   Enable Cython 3.1 support for free-threaded CPython.

        •   Allow compiling Cython-generated C sources with the full Python C-API.

        •   Fix MPI DLL path workarounds on Windows after changes to locals().

    •   Enhancements to test suite:

        •   Support XML reports via unittest-xml-reporting.

        •   Add command line options to exclude tests by patterns and files.

        •   Refactor Python 2 code to use Python 3 constructs using pyupgrade.

    •   Miscellaneous:

        •   Minor and mostly inconsequential subclass fix in mpi4py.util.pkl5.

        •   Update compatibility workarounds for legacy MPICH 3.0 release.

  Release 4.0.0 [2024-07-28]

    •   New features:

        •   Add support for the MPI-4.0 standard.

            •   Use large count MPI-4 routines.

            •   Add persistent collective communication.

            •   Add partitioned point-to-point communication.

            •   Add new communicator constructors.

            •   Add the Session class and its methods.

        •   Add support for the MPI-4.1 standard.

            •   Add non-destructive completion test for multiple requests.

            •   Add value-index datatype constructor.

            •   Add communicator/session buffer attach/detach/flush.

            •   Support for removal of error classes/codes/strings.

            •   Support for querying hardware resource information.

        •   Add preliminary support for the upcoming MPI-5.0 standard.

            •   User-level failure mitigation (ULFM).

        •   mpi4py.util.pool: New drop-in replacement for multiprocessing.pool.

        •   mpi4py.util.sync: New synchronization utilities.

        •   Add runtime check for mismatch between mpiexec and MPI library.

        •   Support scikit-build-core <https://scikit-build.readthedocs.io/> as an alternative build backend.

        •   Support meson-python <https://meson-python.readthedocs.io/> as an alternative build backend.

    •   Enhancements:

        •   mpi4py.futures: Support for parallel tasks.

        •   mpi4py.futures: Report exception tracebacks in workers.

        •   mpi4py.util.pkl5: Add support for collective communication.

        •   Add methods Datatype.fromcode(), Datatype.tocode() and attributes Datatype.typestr, Datatype.typechar to simplify NumPy interoperability for simple cases.

        •   Add methods Comm.Create_errhandler(), Win.Create_errhandler(), and File.Create_errhandler() to create custom error handlers.

        •   Add support for pickle serialization of instances of MPI types. All instances of Datatype, Info, and Status can be serialized. Instances of Op can be serialized only if created through mpi4py by calling Op.Create(). Instances of other MPI types can be serialized only if they reference predefined handles.

        •   Add handle attribute and fromhandle() class method to MPI classes to ease interoperability with external code. The handle value is an unsigned integer guaranteed to fit on the platform’s uintptr_t C type.

        •   Add lowercase free() method to MPI classes to ease MPI object deallocation and cleanup. This method eventually attempts to call Free(), but only if the object’s MPI handle is not a null or predefined handle, and such call is allowed within the World Model init/finalize.

    •   Backward-incompatible changes:

        •   Python 2 is no longer supported, Python 3.6+ is required, but typing stubs are supported for Python 3.8+.

        •   The Intracomm.Create_group() method is no longer defined in the base Comm class.

        •   Group.Compare() and Comm.Compare() are no longer class methods but instance methods. Existing codes using the former class methods are expected to continue working.

        •   Group.Translate_ranks() is no longer a class method but an instance method. Existing codes using the former class method are expected to continue working.

        •   The LB and UB datatypes are no longer available, use Datatype.Create_resized() instead.

        •   The HOST predefined attribute key is no longer available.

        •   The MPI.memory class has been renamed to MPI.buffer. The old name is still available as an alias to the new name.

        •   The mpi4py.dl module is no longer available.

        •   The mpi4py.get_config function returns an empty dictionary.

    •   Miscellaneous:

        •   The project is now licensed under the BSD-3-Clause license. This change is fairly inconsequential for users and distributors. It simply adds an additional clause against using contributor names for promotional purposes without their consent.

        •   Add a new guidelines section to documentation laying out new fair play rules. These rules ask companies and outside developers to refrain from reusing the mpi4py name in unaffiliated projects, publishing binary mpi4py wheels on the main Python Package Index (PyPI), and distributing modified versions with incompatible or extended API changes. The primary motivation of these rules is to avoid fragmentation and end-user confusion.

  Release 3.1.6 [2024-04-14]

Warning:
        This is the last release supporting Python 2.

    •   Fix various build issues.

  Release 3.1.5 [2023-10-04]

Warning:
        This is the last release supporting Python 2.

    •   Rebuild C sources with Cython 0.29.36 to support Python 3.12.

  Release 3.1.4 [2022-11-02]

Warning:
        This is the last release supporting Python 2.

    •   Rebuild C sources with Cython 0.29.32 to support Python 3.11.

    •   Fix contiguity check for DLPack and CAI buffers.

    •   Workaround build failures with setuptools v60.

  Release 3.1.3 [2021-11-25]

Warning:
        This is the last release supporting Python 2.

    •   Add missing support for MPI.BOTTOM to generalized all-to-all collectives.

  Release 3.1.2 [2021-11-04]

Warning:
        This is the last release supporting Python 2.

    •   mpi4py.futures: Add _max_workers property to MPIPoolExecutor.

    •   mpi4py.util.dtlib: Fix computation of alignment for predefined datatypes.

    •   mpi4py.util.pkl5: Fix deadlock when using ssend() + mprobe().

    •   mpi4py.util.pkl5: Add environment variable MPI4PY_PICKLE_THRESHOLD.

    •   mpi4py.rc: Interpret "y" and "n" strings as boolean values.

    •   Fix/add typemap/typestr for MPI.WCHAR/MPI.COUNT datatypes.

    •   Minor fixes and additions to documentation.

    •   Minor fixes to typing support.

    •   Support for local version identifier (PEP-440).

  Release 3.1.1 [2021-08-14]

Warning:
        This is the last release supporting Python 2.

    •   Fix typo in Requires-Python package metadata.

    •   Regenerate C sources with Cython 0.29.24.

  Release 3.1.0 [2021-08-12]

Warning:
        This is the last release supporting Python 2.

    •   New features:

        •   mpi4py.util: New package collecting miscellaneous utilities.

    •   Enhancements:

        •   Add pickle-based Request.waitsome() and Request.testsome().

        •   Add lowercase methods Request.get_status() and Request.cancel().

        •   Support for passing Python GPU arrays compliant with the DLPack <https://github.com/dmlc/dlpack> data interchange mechanism (link <https://data-apis.org/array-api/latest/design_topics/data_interchange.html>) and the __cuda_array_interface__ (CAI) standard (link <https://numba.readthedocs.io/en/stable/cuda/cuda_array_interface.html>) to uppercase methods. This support requires that mpi4py is built against CUDA-aware MPI <https://developer.nvidia.com/blog/introduction-cuda-aware-mpi/> implementations. This feature is currently experimental and subject to future changes.

        •   mpi4py.futures: Add support for initializers and canceling futures at shutdown. Environment variables names now follow the pattern MPI4PY_FUTURES_*, the previous MPI4PY_* names are deprecated.

        •   Add type annotations to Cython code. The first line of the docstring of functions and methods displays a signature including type annotations.

        •   Add companion stub files to support type checkers.

        •   Support for weak references.

    •   Miscellaneous:

        •   Add a new mpi4py publication (link <https://doi.org/10.1109/MCSE.2021.3083216>) to the citation listing.

  Release 3.0.3 [2019-11-04]

    •   Regenerate Cython wrappers to support Python 3.8.

  Release 3.0.2 [2019-06-11]

    •   Bug fixes:

        •   Fix handling of readonly buffers in support for Python 2 legacy buffer interface. The issue triggers only when using a buffer-like object that is readonly and does not export the new Python 3 buffer interface.

        •   Fix build issues with Open MPI 4.0.x series related to removal of many MPI-1 symbols deprecated in MPI-2 and removed in MPI-3.

        •   Minor documentation fixes.

  Release 3.0.1 [2019-02-15]

    •   Bug fixes:

        •   Fix Comm.scatter() and other collectives corrupting input send list. Add safety measures to prevent related issues in global reduction operations.

        •   Fix error-checking code for counts in Op.Reduce_local().

    •   Enhancements:

        •   Map size-specific Python/NumPy typecodes to MPI datatypes.

        •   Allow partial specification of target list/tuple arguments in the various Win RMA methods.

        •   Workaround for removal of MPI_{LB|UB} in Open MPI 4.0.

        •   Support for Microsoft MPI v10.0.

  Release 3.0.0 [2017-11-08]

    •   New features:

        •   mpi4py.futures: Execute computations asynchronously using a pool of MPI processes. This package is based on concurrent.futures from the Python standard library.

        •   mpi4py.run: Run Python code and abort execution in case of unhandled exceptions to prevent deadlocks.

        •   mpi4py.bench: Run basic MPI benchmarks and tests.

    •   Enhancements:

        •   Lowercase, pickle-based collective communication calls are now thread-safe through the use of fine-grained locking.

        •   The MPI module now exposes a memory type which is a lightweight variant of the builtin memoryview type, but exposes both the legacy Python 2 and the modern Python 3 buffer interface under a Python 2 runtime.

        •   The MPI.Comm.Alltoallw() method now uses count=1 and displ=0 as defaults, assuming that messages are specified through user-defined datatypes.

        •   The Request.Wait[all]() methods now return True to match the interface of Request.Test[all]().

        •   The Win class now implements the Python buffer interface.

    •   Backward-incompatible changes:

        •   The buf argument of the MPI.Comm.recv() method is deprecated, passing anything but None emits a warning.

        •   The MPI.Win.memory property was removed, use the MPI.Win.tomemory() method instead.

        •   Executing python -m mpi4py in the command line is now equivalent to python -m mpi4py.run. For the former behavior, use python -m mpi4py.bench.

        •   Python 2.6 and 3.2 are no longer supported. The mpi4py.MPI module may still build and partially work, but other pure-Python modules under the mpi4py namespace will not.

        •   Windows: Remove support for legacy MPICH2, Open MPI, and DeinoMPI.

  Release 2.0.0 [2015-10-18]

    •   Support for MPI-3 features.

        •   Matched probes and receives.

        •   Nonblocking collectives.

        •   Neighborhood collectives.

        •   New communicator constructors.

        •   Request-based RMA operations.

        •   New RMA communication and synchronisation calls.

        •   New window constructors.

        •   New datatype constructor.

        •   New C++ boolean and floating complex datatypes.

    •   Support for MPI-2 features not included in previous releases.

        •   Generalized All-to-All collective (Comm.Alltoallw())

        •   User-defined data representations (Register_datarep())

    •   New scalable implementation of reduction operations for Python objects. This code is based on binomial tree algorithms using point-to-point communication and duplicated communicator contexts. To disable this feature, use mpi4py.rc.fast_reduce = False.

    •   Backward-incompatible changes:

        •   Python 2.4, 2.5, 3.0 and 3.1 are no longer supported.

        •   Default MPI error handling policies are overridden. After import, mpi4py sets the ERRORS_RETURN error handler in COMM_SELF and COMM_WORLD, as well as any new Comm, Win, or File instance created through mpi4py, thus effectively ignoring the MPI rules about error handler inheritance. This way, MPI errors translate to Python exceptions. To disable this behavior and use the standard MPI error handling rules, use mpi4py.rc.errors = 'default'.

        •   Change signature of all send methods, dest is a required argument.

        •   Change signature of all receive and probe methods, source defaults to ANY_SOURCE, tag defaults to ANY_TAG.

        •   Change signature of send lowercase-spelling methods, obj arguments are not mandatory.

        •   Change signature of recv lowercase-spelling methods, renamed ‘obj’ arguments to ‘buf’.

        •   Change Request.Waitsome() and Request.Testsome() to return None or list.

        •   Change signature of all lowercase-spelling collectives, sendobj arguments are now mandatory, recvobj arguments were removed.

        •   Reduction operations MAXLOC and MINLOC are no longer special-cased in lowercase-spelling methods Comm.[all]reduce() and Comm.[ex]scan(), the input object must be specified as a tuple (obj, location).

        •   Change signature of name publishing functions. The new signatures are Publish_name(service_name, port_name, info=INFO_NULL) and Unpublish_name(service_name, port_name, info=INFO_NULL)`.

        •   Win instances now cache Python objects exposing memory by keeping references instead of using MPI attribute caching.

        •   Change signature of Win.Lock(). The new signature is Win.Lock(rank, lock_type=LOCK_EXCLUSIVE, assertion=0).

        •   Move Cartcomm.Map() to Intracomm.Cart_map().

        •   Move Graphcomm.Map() to Intracomm.Graph_map().

        •   Remove the mpi4py.MPE module.

        •   Rename the Cython definition file for use with cimport statement from mpi_c.pxd to libmpi.pxd.

  Release 1.3.1 [2013-08-07]

    •   Regenerate C wrappers with Cython 0.19.1 to support Python 3.3.

    •   Install *.pxd files in <site-packages>/mpi4py to ease the support for Cython’s cimport statement in code requiring to access mpi4py internals.

    •   As a side-effect of using Cython 0.19.1, ancient Python 2.3 is no longer supported. If you really need it, you can install an older Cython and run python setup.py build_src --force.

  Release 1.3 [2012-01-20]

    •   Now Comm.recv() accept a buffer to receive the message.

    •   Add Comm.irecv() and Request.{wait|test}[any|all]().

    •   Add Intracomm.Spawn_multiple().

    •   Better buffer handling for PEP 3118 and legacy buffer interfaces.

    •   Add support for attribute attribute caching on communicators, datatypes and windows.

    •   Install MPI-enabled Python interpreter as <path>/mpi4py/bin/python-mpi.

    •   Windows: Support for building with Open MPI.

  Release 1.2.2 [2010-09-13]

    •   Add mpi4py.get_config() to retrieve information (compiler wrappers, includes, libraries, etc) about the MPI implementation employed to build mpi4py.

    •   Workaround Python libraries with missing GILState-related API calls in case of non-threaded Python builds.

    •   Windows: look for MPICH2, DeinoMPI, Microsoft HPC Pack at their default install locations under %ProgramFiles.

    •   MPE: fix hacks related to old API’s, these hacks are broken when MPE is built with a MPI implementations other than MPICH2.

    •   HP-MPI: fix for missing Fortran datatypes, use dlopen() to load the MPI shared library before MPI_Init()

    •   Many distutils-related fixes, cleanup, and enhancements, better logics to find MPI compiler wrappers.

    •   Support for pip install mpi4py.

  Release 1.2.1 [2010-02-26]

    •   Fix declaration in Cython include file. This declaration, while valid for Cython, broke the simple-minded parsing used in conf/mpidistutils.py to implement configure-tests for availability of MPI symbols.

    •   Update SWIG support and make it compatible with Python 3. Also generate an warning for SWIG < 1.3.28.

    •   Fix distutils-related issues in Mac OS X. Now ARCHFLAGS environment variable is honored of all Python’s config/Makefile variables.

    •   Fix issues with Open MPI < 1.4.2 related to error checking and MPI_XXX_NULL handles.

  Release 1.2 [2009-12-29]

    •   Automatic MPI datatype discovery for NumPy arrays and PEP-3118 buffers. Now buffer-like objects can be messaged directly, it is no longer required to explicitly pass a 2/3-list/tuple like [data, MPI.DOUBLE], or [data, count, MPI.DOUBLE]. Only basic types are supported, i.e., all C/C99-native signed/unsigned integral types and single/double precision real/complex floating types. Many thanks to Eilif Muller for the initial feedback.

    •   Nonblocking send of pickled Python objects. Many thanks to Andreas Kloeckner for the initial patch and enlightening discussion about this enhancement.

    •   Request instances now hold a reference to the Python object exposing the buffer involved in point-to-point communication or parallel I/O. Many thanks to Andreas Kloeckner for the initial feedback.

    •   Support for logging of user-defined states and events using MPE <https://www.mcs.anl.gov/research/projects/perfvis/>. Runtime (i.e., without requiring a recompile!) activation of logging of all MPI calls is supported in POSIX platforms implementing dlopen().

    •   Support for all the new features in MPI-2.2 (new C99 and F90 datatypes, distributed graph topology, local reduction operation, and other minor enhancements).

    •   Fix the annoying issues related to Open MPI and Python dynamic loading of extension modules in platforms supporting dlopen().

    •   Fix SLURM dynamic loading issues on SiCortex. Many thanks to Ian Langmore for providing me shell access.

  Release 1.1.0 [2009-06-06]

    •   Fix bug in Comm.Iprobe() that caused segfaults as Python C-API calls were issued with the GIL released (issue #2).

    •   Add Comm.bsend() and Comm.ssend() for buffered and synchronous send semantics when communicating general Python objects.

    •   Now the call Info.Get(key) return a single value (i.e, instead of a 2-tuple); this value is None if key is not in the Info object, or a string otherwise. Previously, the call redundantly returned (None, False) for missing key-value pairs; None is enough to signal a missing entry.

    •   Add support for parametrized Fortran datatypes.

    •   Add support for decoding user-defined datatypes.

    •   Add support for user-defined reduction operations on memory buffers. However, at most 16 user-defined reduction operations can be created. Ask the author for more room if you need it.

  Release 1.0.0 [2009-03-20]

This is the fist release of the all-new, Cython-based, implementation of MPI for Python. Unfortunately, this implementation is not backward-compatible with the previous one. The list below summarizes the more important changes that can impact user codes.

    •   Some communication calls had overloaded functionality. Now there is a clear distinction between communication of general Python object with pickle, and (fast, near C-speed) communication of buffer-like objects (e.g., NumPy arrays).

        •   for communicating general Python objects, you have to use all-lowercase methods, like send(), recv(), bcast(), etc.

        •   for communicating array data, you have to use Send(), Recv(), Bcast(), etc. methods. Buffer arguments to these calls must be explicitly specified by using a 2/3-list/tuple like [data, MPI.DOUBLE], or [data, count, MPI.DOUBLE] (the former one uses the byte-size of data and the extent of the MPI datatype to define the count).

    •   Indexing a communicator with an integer returned a special object associating the communication with a target rank, alleviating you from specifying source/destination/root arguments in point-to-point and collective communications. This functionality is no longer available, expressions like:

                MPI.COMM_WORLD[0].Send(...)
                MPI.COMM_WORLD[0].Recv(...)
                MPI.COMM_WORLD[0].Bcast(...)

    have to be replaced by:

                MPI.COMM_WORLD.Send(..., dest=0)
                MPI.COMM_WORLD.Recv(..., source=0)
                MPI.COMM_WORLD.Bcast(..., root=0)

    •   Automatic MPI initialization (i.e., at import time) requests the maximum level of MPI thread support (i.e., it is done by calling MPI_Init_thread() and passing MPI_THREAD_MULTIPLE). In case you need to change this behavior, you can tweak the contents of the mpi4py.rc module.

    •   In order to obtain the values of predefined attributes attached to the world communicator, now you have to use the Get_attr() method on the MPI.COMM_WORLD instance:

                tag_ub = MPI.COMM_WORLD.Get_attr(MPI.TAG_UB)

    •   In the previous implementation, MPI.COMM_WORLD and MPI.COMM_SELF were associated to duplicates of the (C-level) MPI_COMM_WORLD and MPI_COMM_SELF predefined communicator handles. Now this is no longer the case, MPI.COMM_WORLD and MPI.COMM_SELF proxies the actual MPI_COMM_WORLD and MPI_COMM_SELF handles.

    •   Convenience aliases MPI.WORLD and MPI.SELF were removed. Use instead MPI.COMM_WORLD and MPI.COMM_SELF.

    •   Convenience constants MPI.WORLD_SIZE and MPI.WORLD_RANK were removed. Use instead MPI.COMM_WORLD.Get_size() and MPI.COMM_WORLD.Get_rank().

Author
Lisandro Dalcin

Copyright
2026, Lisandro Dalcin