PYFR(1)

NAME
pyfr - PyFR Documentation

Contents:

HOME

  Overview

  What is PyFR?

PyFR is an open-source Python based framework for solving advection-diffusion type problems on streaming architectures using the Flux Reconstruction approach of Huynh. The framework is designed to solve a range of governing systems on mixed unstructured grids containing various element types. It is also designed to target a range of hardware platforms via use of an in-built domain specific language derived from the Mako templating engine. The current release (PyFR 1.5.0) has the following capabilities:

    •   Governing Equations - Euler, Navier Stokes

    •   Dimensionality - 2D, 3D

    •   Element Types - Triangles, Quadrilaterals, Hexahedra, Prisms, Tetrahedra, Pyramids

    •   Platforms - CPU Clusters, Nvidia GPU Clusters, AMD GPU Clusters, Intel Xeon Phi Clusters

    •   Spatial Discretisation - High-Order Flux Reconstruction

    •   Temporal Discretisation - Explicit and Implicit (via Dual Time-Stepping)

    •   Precision - Single, Double

    •   Mesh Files Imported - Gmsh (.msh), CGNS (.cgns)

    •   Solution Files Exported - Unstructured VTK (.vtu, .pvtu)

  How do I Cite PyFR?

To cite PyFR, please reference the following paper:

    •   PyFR: An Open Source Framework for Solving Advection-Diffusion Type Problems on Streaming Architectures using the Flux Reconstruction Approach. F. D. Witherden, A. M. Farrington, P. E. Vincent. Computer Physics Communications, Volume 185, Pages 3028-3040, 2014.

  Who is Funding PyFR?

Development of PyFR is supported by the Engineering and Physical Sciences Research Council, Innovate UK, the European Commission, BAE Systems, Airbus, and the Air Force Office of Scientific Research. We are also grateful for hardware donations from Nvidia, Intel, and AMD.

THEORY

  Flux Reconstruction

  Overview

High-order numerical methods for unstructured grids combine the superior accuracy of high-order spectral or finite difference methods with the geometrical flexibility of low-order finite volume or finite element schemes. The Flux Reconstruction (FR) approach unifies various high-order schemes for unstructured grids within a single framework. Additionally, the FR approach exhibits a significant degree of element locality, and is thus able to run efficiently on modern streaming architectures, such as Graphical Processing Units (GPUs). The aforementioned properties of FR mean it offers a promising route to performing affordable, and hence industrially relevant, scale-resolving simulations of hitherto intractable unsteady flows (involving separation, acoustics etc.) within the vicinity of real-world engineering geometries. An detailed overview of the FR approach is given in:

    •   A Flux Reconstruction Approach to High-Order Schemes Including Discontinuous Galerkin Methods. H. T. Huynh. AIAA Paper 2007-4079

  Linear Stability

The linear stability of an FR schemes depends on the form of the correction function. Linear stability issues are discussed in:

    •   A New Class of High-Order Energy Stable Flux Reconstruction Schemes. P. E. Vincent, P. Castonguay, A. Jameson. Journal of Scientific Computing, Volume 47, Number 1, Pages 50-72, 2011

    •   Insights from von Neumann Analysis of High-Order Flux Reconstruction Schemes. P. E. Vincent, P. Castonguay, A. Jameson. Journal of Computational Physics, Volume 230, Issue 22, Pages 8134-8154, 2011

    •   A New Class of High-Order Energy Stable Flux Reconstruction Schemes for Triangular Elements. P. Castonguay, P. E. Vincent, A. Jameson. Journal of Scientific Computing, Volume 51, Number 1, Pages 224-256, 2012

    •   Energy Stable Flux Reconstruction Schemes for Advection-Diffusion Problems. P. Castonguay, D. M. Williams, P. E. Vincent, A. Jameson. Computer Methods in Applied Mechanics and Engineering, Volume 267, Pages 400-417, 2013

    •   Energy Stable Flux Reconstruction Schemes for Advection-Diffusion Problems on Triangles. D. M. Williams, P. Castonguay, P. E. Vincent, A. Jameson. Journal of Computational Physics, Volume 250, Pages 53-76, 2013

    •   Energy Stable Flux Reconstruction Schemes for Advection-Diffusion Problems on Tetrahedra. D. M. Williams, A. Jameson. Journal of Scientific Computing, Volume 59, Pages 721-759, 2014

    •   An Extended Range of Stable-Symmetric-Conservative Flux Reconstruction Correction Functions. P. E. Vincent, A. M. Farrington, F. D. Witherden, A. Jameson. Computer Methods in Applied Mechanics and Engineering, Volume 296, Pages 248-272, 2015

  Non-Linear Stability

The non-linear stability of an FR schemes depends on the location of the solution points. Non-linear stability issues are discussed in:

    •   On the Non-Linear Stability of Flux Reconstruction Schemes. A. Jameson, P. E. Vincent, P. Castonguay. Journal of Scientific Computing, Volume 50, Number 2, Pages 434-445, 2012

    •   An Analysis of Solution Point Coordinates for Flux Reconstruction Schemes on Triangular Elements. F. D. Witherden, P. E. Vincent. Journal of Scientific Computing, Volume 61, Pages 398-423, 2014

USER GUIDE

  Getting Started

  Downloading the Source

PyFR can be obtained here.

  Dependencies

  Overview

PyFR 1.5.0 has a hard dependency on Python 3.3+ and the following Python packages:

    1.  gimmik >= 2.0

    2.  h5py >= 2.6

    3.  mako >= 1.0.0

    4.  mpi4py >= 2.0

    5.  numpy >= 1.8

    6.  pytools >= 2016.2.1

Note that due to a bug in numpy PyFR is not compatible with 32-bit Python distributions.

  CUDA Backend

The CUDA backend targets NVIDIA GPUs with a compute capability of 2.0 or greater. The backend requires:

    1.  CUDA >= 4.2

    2.  pycuda >= 2015.1

  MIC Backend

The MIC backend targets Intel Xeon Phi co-processors. The backend requires:

    1.  ICC >= 14.0

    2.  Intel MKL >= 11.1

    3.  Intel MPSS >= 3.3

    4.  pymic >= 0.7 (post commit 4d8a2da)

  OpenCL Backend

The OpenCL backend targets a range of accelerators including GPUs from AMD and NVIDIA. The backend requires:

    1.  OpenCL

    2.  pyopencl >= 2015.2.4

    3.  clBLAS

  OpenMP Backend

The OpenMP backend targets multi-core CPUs. The backend requires:

    1.  GCC >= 4.9

    2.  A BLAS library compiled as a shared library (e.g. OpenBLAS)

  Running in Parallel

To partition meshes for running in parallel it is also necessary to have one of the following partitioners installed:

    1.  metis >= 5.0

    2.  scotch >= 6.0

  Importing CGNS Meshes

To import CGNS meshes it is necessary to have the following installed:

    1.  CGNS >= 3.3 (develop branch post commit e0faea6)

  Installation

Before running PyFR 1.5.0 it is first necessary to either install the software using the provided setup.py installer or add the root PyFR directory to PYTHONPATH using:

        user@computer ~/PyFR$ export PYTHONPATH=.:$PYTHONPATH

To manage installation of Python dependencies we strongly recommend using pip and virtualenv.

  Running PyFR

  Overview

PyFR 1.5.0 uses three distinct file formats:

    1.  .ini --- configuration file

    2.  .pyfrm --- mesh file

    3.  .pyfrs --- solution file

The following commands are available from the pyfr program:

    1.  pyfr import --- convert a Gmsh .msh file or CGNS .cgns file into a PyFR .pyfrm file.

        Example:

            pyfr import mesh.msh mesh.pyfrm

    2.  pyfr partition --- partition an existing mesh and associated solution files.

        Example:

            pyfr partition 2 mesh.pyfrm solution.pyfrs .

    3.  pyfr run --- start a new PyFR simulation. Example:

            pyfr run mesh.pyfrm configuration.ini

    4.  pyfr restart --- restart a PyFR simulation from an existing solution file. Example:

            pyfr restart mesh.pyfrm solution.pyfrs

    5.  pyfr export --- convert a PyFR .pyfrs file into an unstructured VTK .vtu or .pvtu file. Example:

            pyfr export mesh.pyfrm solution.pyfrs solution.vtu

  Running in Parallel

pyfr can be run in parallel. To do so prefix pyfr with mpirun -n <cores/devices>. Note that the mesh must be pre-partitioned, and the number of cores or devices must be equal to the number of partitions.

  Configuration File (.ini)

  Overview

The .ini configuration file parameterises the simulation. It is written in the INI format. Parameters are grouped into sections. The roles of each section and their associated parameters are described below.

  [backend]

Parameterises the backend with

    1.  precision --- number precision:
            single | double

    2.  rank-allocator --- MPI rank allocator:
            linear | random

Example:

        [backend]
        precision = double
        rank-allocator = linear

  [backend-cuda]

Parameterises the CUDA backend with

    1.  device-id --- method for selecting which device(s) to run on:
            int | round-robin | local-rank

    2.  gimmik-max-nnz --- cutoff for GiMMiK in terms of the number of non-zero entires in a constant matrix:
            int

    3.  mpi-type --- type of MPI library that is being used:
            standard | cuda-aware

    4.  block-1d --- block size for one dimensional pointwise kernels:
            int

    5.  block-2d --- block size for two dimensional pointwise kernels:
            int, int

Example:

        [backend-cuda]
        device-id = round-robin
        gimmik-max-nnz = 512
        mpi-type = standard
        block-1d = 64
        block-2d = 128, 2

  [backend-mic]

Parameterises the MIC backend with

    1.  device-id --- for selecting which device(s) to run on:
            int | local-rank

    2.  mkl-root --- path to MKL root directory:
            string

  [backend-opencl]

Parameterises the OpenCL backend with

    1.  platform-id --- for selecting platform id:
            int | string

    2.  device-type --- for selecting what type of device(s) to run on:
            all | cpu | gpu | accelerator

    3.  device-id --- for selecting which device(s) to run on:
            int | string | local-rank

    4.  gimmik-max-nnz --- cutoff for GiMMiK in terms of the number of non-zero entires in a constant matrix:
            int

    5.  local-size-1d --- local work size for one dimensional pointwise kernels:
            int

    6.  local-size-2d --- local work size for two dimensional pointwise kernels:
            int, int

Example:

        [backend-opencl]
        platform-id = 0
        device-type = gpu
        device-id = local-rank
        gimmik-max-nnz = 512
        local-size-1d = 16
        local-size-2d = 128, 1

  [backend-openmp]

Parameterises the OpenMP backend with

    1.  cc --- C compiler:
            string

    2.  cflags --- additional C compiler flags:
            string

    3.  cblas --- path to shared C BLAS library:
            string

    4.  cblas-type --- type of BLAS library:
            serial | parallel

Example:

        [backend-openmp]
        cc = gcc
        cblas= example/path/libBLAS.dylib
        cblas-type = parallel

  [constants]

Sets constants used in the simulation with

    1.  gamma --- ratio of specific heats:
            float

    2.  mu --- dynamic viscosity:
            float

    3.  Pr --- Prandtl number:
            float

    4.  cpTref --- product of specific heat at constant pressure and reference temperature for Sutherland's Law:

        float

    5.  cpTs --- product of specific heat at constant pressure and Sutherland temperature for Sutherland's Law:

        float

Example:

        [constants]
        gamma = 1.4
        mu = 0.001
        Pr = 0.72

  [solver]

Parameterises the solver with

    1.  system --- governing system:
            euler | navier-stokes

    2.  order --- order of polynomial solution basis:
            int

    3.  anti-alias --- type of anti-aliasing:
            flux | surf-flux | div-flux | flux, surf-flux | flux, div-flux | surf-flux, div-flux | flux, surf-flux, div-flux

    4.  viscosity-correction --- viscosity correction:
            none | sutherland

    5.  shock-capturing --- shock capturing scheme:
            none | artificial-viscosity

Example:

        [solver]
        system = navier-stokes
        order = 3
        anti-alias = flux
        viscosity-correction = none
        shock-capturing = artificial-viscosity

  [solver-time-integrator]

Parameterises the time-integration scheme used by the solver with

    1.  formulation --- formulation:
            std | dual

            where

            std requires

                        •   scheme --- time-integration scheme
                                euler | rk34 | rk4 | rk45 | tvd-rk3

                        •   tstart --- initial time
                                float

                        •   tend --- final time
                                float

                        •   dt --- time-step
                                float

                        •   controller --- time-step controller
                                none | pi

                                where

                                pi only works with rk34 and rk45 and requires

                                            •   atol --- absolute error tolerance
                                                    float

                                            •   rtol --- relative error tolerance
                                                    float

                                            •   errest-norm --- norm to use for estimating the error
                                                    uniform | l2

                                            •   safety-fact --- safety factor for step size adjustment (suitable range 0.80-0.95)
                                                    float

                                            •   min-fact --- minimum factor that the time-step can change between iterations (suitable range 0.1-0.5)
                                                    float

                                            •   max-fact --- maximum factor that the time-step can change between iterations (suitable range 2.0-6.0)
                                                    float

            dual requires

                        •   scheme --- time-integration scheme
                                backward-euler | bdf2 | bdf3

                        •   pseudo-scheme --- pseudo-time-integration scheme
                                euler | tvd-rk3 | rk4

                        •   tstart --- initial time
                                float

                        •   tend --- final time
                                float

                        •   dt --- time-step
                                float

                        •   pseudo-dt --- pseudo-time-step
                                float

                        •   controller --- pseudo-time-step controller
                                none

                                where

                                none requires

                                            •   pseudo-niters-max --- minimum number of iterations
                                                    int

                                            •   pseudo-niters-min --- maximum number of iterations
                                                    int

                                            •   pseudo-aresid --- absolute residual tolerance
                                                    float

                                            •   pseudo-rresid --- relative residual tolerance
                                                    float

Example:

        [solver-time-integrator]
        formulation = std
        scheme = rk45
        controller = pi
        tstart = 0.0
        tend = 10.0
        dt = 0.001
        atol = 0.00001
        rtol = 0.00001
        errest-norm = l2
        safety-fact = 0.9
        min-fact = 0.3
        max-fact = 2.5

  [solver-interfaces]

Parameterises the interfaces with

    1.  riemann-solver --- type of Riemann solver:
            rusanov | hll | hllc | roe | roem

    2.  ldg-beta --- beta parameter used for LDG:
            float

    3.  ldg-tau --- tau parameter used for LDG:
            float

Example:

        [solver-interfaces]
        riemann-solver = rusanov
        ldg-beta = 0.5
        ldg-tau = 0.1

  [solver-interfaces-line]

Parameterises the line interfaces with

    1.  flux-pts --- location of the flux points on a line interface:
            gauss-legendre | gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing on a line interface:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing on a line interface:
            gauss-legendre | gauss-legendre-lobatto

Example:

        [solver-interfaces-line]
        flux-pts = gauss-legendre
        quad-deg = 10
        quad-pts = gauss-legendre

  [solver-interfaces-tri]

Parameterises the triangular interfaces with

    1.  flux-pts --- location of the flux points on a triangular interface:
            williams-shunn

    2.  quad-deg --- degree of quadrature rule for anti-aliasing on a triangular interface:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing on a triangular interface:
            williams-shunn | witherden-vincent

Example:

        [solver-interfaces-tri]
        flux-pts = williams-shunn
        quad-deg = 10
        quad-pts = williams-shunn

  [solver-interfaces-quad]

Parameterises the quadrilateral interfaces with

    1.  flux-pts --- location of the flux points on a quadrilateral interface:
            gauss-legendre | gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing on a quadrilateral interface:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing on a quadrilateral interface:
            gauss-legendre | gauss-legendre-lobatto | witherden-vincent

Example:

        [solver-interfaces-quad]
        flux-pts = gauss-legendre
        quad-deg = 10
        quad-pts = gauss-legendre

  [solver-elements-tri]

Parameterises the triangular elements with

    1.  soln-pts --- location of the solution points in a triangular element:
            williams-shunn

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a triangular element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a triangular element:
            williams-shunn | witherden-vincent

Example:

        [solver-elements-tri]
        soln-pts = williams-shunn
        quad-deg = 10
        quad-pts = williams-shunn

  [solver-elements-quad]

Parameterises the quadrilateral elements with

    1.  soln-pts --- location of the solution points in a quadrilateral element:
            gauss-legendre | gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a quadrilateral element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a quadrilateral element:
            gauss-legendre | gauss-legendre-lobatto | witherden-vincent

Example:

        [solver-elements-quad]
        soln-pts = gauss-legendre
        quad-deg = 10
        quad-pts = gauss-legendre

  [solver-elements-hex]

Parameterises the hexahedral elements with

    1.  soln-pts --- location of the solution points in a hexahedral element:
            gauss-legendre | gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a hexahedral element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a hexahedral element:
            gauss-legendre | gauss-legendre-lobatto | witherden-vincent

Example:

        [solver-elements-hex]
        soln-pts = gauss-legendre
        quad-deg = 10
        quad-pts = gauss-legendre

  [solver-elements-tet]

Parameterises the tetrahedral elements with

    1.  soln-pts --- location of the solution points in a tetrahedral element:
            shunn-ham

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a tetrahedral element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a tetrahedral element:
            shunn-ham | witherden-vincent

Example:

        [solver-elements-tet]
        soln-pts = shunn-ham
        quad-deg = 10
        quad-pts = shunn-ham

  [solver-elements-pri]

Parameterises the prismatic elements with

    1.  soln-pts --- location of the solution points in a prismatic element:
            williams-shunn~gauss-legendre | williams-shunn~gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a prismatic element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a prismatic element:
            williams-shunn~gauss-legendre | williams-shunn~gauss-legendre-lobatto | witherden-vincent

Example:

        [solver-elements-pri]
        soln-pts = williams-shunn~gauss-legendre
        quad-deg = 10
        quad-pts = williams-shunn~gauss-legendre

  [solver-elements-pyr]

Parameterises the pyramidal elements with

    1.  soln-pts --- location of the solution points in a pyramidal element:
            gauss-legendre | gauss-legendre-lobatto

    2.  quad-deg --- degree of quadrature rule for anti-aliasing in a pyramidal element:
            int

    3.  quad-pts --- name of quadrature rule for anti-aliasing in a pyramidal element:
            witherden-vincent

Example:

        [solver-elements-pyr]
        soln-pts = gauss-legendre
        quad-deg = 10
        quad-pts = witherden-vincent

  [solver-source-terms]

Parameterises solution, space (x, y, [z]), and time (t) dependent source terms with

    1.  rho --- density source term:
            string

    2.  rhou --- x-momentum source term:
            string

    3.  rhov --- y-momentum source term:
            string

    4.  rhow --- z-momentum source term:
            string

    5.  E --- energy source term:
            string

Example:

        [solver-source-terms]
        rho = t
        rhou = x*y*sin(y)
        rhov = z*rho
        rhow = 1.0
        E = 1.0/(1.0+x)

  [solver-artificial-viscosity]

Parameterises artificial viscosity for shock capturing with

    1.  max-artvisc --- maximum artificial viscosity:
            float

    2.  s0 --- sensor cut-off:
            float

    3.  kappa --- sensor range:
            float

Example:

        [solver-artificial-viscosity]
        max-artvisc = 0.01
        s0 = 0.01
        kappa = 5.0

  [soln-filter]

Parameterises an exponential solution filter with

    1.  nsteps --- apply filter every nsteps:
            int

    2.  alpha --- strength of filter:
            float

    3.  order --- order of filter:
            int

    4.  cutoff --- cutoff frequency below which no filtering is applied:
            int

Example:

        [soln-filter]
        nsteps = 10
        alpha = 36.0
        order = 16
        cutoff = 1

  [soln-plugin-writer]

Periodically write the solution to disk in the pyfrs format. Parameterised with

    1.  dt-out --- write to disk every dt-out time units:
            float

    2.  basedir --- relative path to directory where outputs will be written:
            string

    3.  basename --- pattern of output names:
            string

    4.  post-action --- command to execute after writing the file:
            string

    5.  post-action-mode --- how the post-action command should be executed:
            blocking | non-blocking

Example:

        [soln-plugin-writer]
        dt-out = 0.01
        basedir = .
        basename = files-{t:.2f}
        post-action = echo "Wrote file {soln} at time {t} for mesh {mesh}."
        post-action-mode = blocking

  [soln-plugin-fluidforce-name]

Periodically integrates the pressure and viscous stress on the boundary labelled name and writes out the resulting force vectors to a CSV file. Parameterised with

    1.  nsteps --- integrate every nsteps:
            int

    2.  file --- output file path; should the file already exist it will be appended to:
            string

    3.  header --- if to output a header row or not:
            boolean

Example:

        [soln-plugin-fluidforce-wing]
        nsteps = 10
        file = wing-forces.csv
        header = true

  [soln-plugin-nancheck]

Periodically checks the solution for NaN values. Parameterised with

    1.  nsteps --- check every nsteps:
            int

Example:

        [soln-plugin-nancheck]
        nsteps = 10

  [soln-plugin-residual]

Periodically calculates the residual and writes it out to a CSV file. Parameterised with

    1.  nsteps --- calculate every nsteps:
            int

    2.  file --- output file path; should the file already exist it will be appended to:
            string

    3.  header --- if to output a header row or not:
            boolean

Example:

        [soln-plugin-residual]
        nsteps = 10
        file = residual.csv
        header = true

  [soln-plugin-dtstats]

Write time-step statistics out to a CSV file. Parameterised with

    1.  flushsteps --- flush to disk every flushsteps:
            int

    2.  file --- output file path; should the file already exist it will be appended to:
            string

    3.  header --- if to output a header row or not:
            boolean

Example:

        [soln-plugin-dtstats]
        flushsteps = 100
        file = dtstats.csv
        header = true

  [soln-plugin-sampler]

Periodically samples specific points in the volume and writes them out to a CSV file. The plugin actually samples the solution point closest to each sample point, hence a slight discrepancy in the output sampling locations is to be expected. A nearest-neighbour search is used to locate the closest solution point to the sample point. The location process automatically takes advantage of scipy.spatial.cKDTree where available. Parameterised with

    1.  nsteps --- sample every nsteps:
            int

    2.  samp-pts --- list of points to sample:
            [(x, y), (x, y), ...] | [(x, y, z), (x, y, z), ...]

    3.  format --- output variable format:
            primitive | conservative

    4.  file --- output file path; should the file already exist it will be appended to:
            string

    5.  header --- if to output a header row or not:
            boolean

Example:

        [soln-plugin-sampler]
        nsteps = 10
        samp-pts = [(1.0, 0.7, 0.0), (1.0, 0.8, 0.0)]
        format = primative
        file = point-data.csv
        header = true

  [soln-plugin-tavg]

Time average quantities. Parameterised with

    1.  nsteps --- accumulate the average every nsteps time steps:
            int

    2.  dt-out --- write to disk every dt-out time units:
            float

    3.  basedir --- relative path to directory where outputs will be written:
            string

    4.  basename --- pattern of output names:
            string

    5.  avg-name --- expression as a function of the primitive variables, time (t), and space (x, y, [z]) to time average; multiple expressions, each with their own name, may be specified:
            string

Example:

        [soln-plugin-tavg]
        nsteps = 10
        dt-out = 2.0
        basedir = .
        basename = files-{t:06.2f}

        avg-p = p
        avg-p2 = p*p
        avg-vel = sqrt(u*u + v*v)

  [soln-bcs-name]

Parameterises constant, or if available space (x, y, [z]) and time (t) dependent, boundary condition labelled name in the .pyfrm file with

    1.  type --- type of boundary condition:
            char-riem-inv | no-slp-adia-wall | no-slp-isot-wall | slp-adia-wall | sub-in-frv | sub-in-ftpttang | sub-out-fp | sup-in-fa | sup-out-fn

            where

            char-riem-inv requires

                        •   rho --- density
                                float | string

                        •   u --- x-velocity
                                float | string

                        •   v --- y-velocity
                                float | string

                        •   w --- z-velocity
                                float | string

                        •   p --- static pressure
                                float | string

            no-slp-isot-wall requires

                        •   u --- x-velocity of wall
                                float

                        •   v --- y-velocity of wall
                                float

                        •   w --- z-velocity of wall
                                float

                        •   cpTw --- product of specific heat capacity at constant pressure and temperature of wall
                                float

            sub-in-frv requires

                        •   rho --- density
                                float | string

                        •   u --- x-velocity
                                float | string

                        •   v --- y-velocity
                                float | string

                        •   w --- z-velocity
                                float | string

            sub-in-ftpttang requires

                        •   pt --- total pressure
                                float

                        •   cpTt --- product of specific heat capacity at constant pressure and total temperature
                                float

                        •   theta --- azimuth angle (in degrees) of inflow measured in the x-y plane relative to the positive x-axis
                                float

                        •   phi --- inclination angle (in degrees) of inflow measured relative to the positive z-axis
                                float

            sub-out-fp requires

                        •   p --- static pressure
                                float | string

            sup-in-fa requires

                        •   rho --- density
                                float | string

                        •   u --- x-velocity
                                float | string

                        •   v --- y-velocity
                                float | string

                        •   w --- z-velocity
                                float | string

                        •   p --- static pressure
                                float | string

Example:

        [soln-bcs-bcwallupper]
        type = no-slp-isot-wall
        cpTw = 10.0
        u = 1.0

  [soln-ics]

Parameterises space (x, y, [z]) dependent initial conditions with

    1.  rho --- initial density distribution:
            string

    2.  u --- initial x-velocity distribution:
            string

    3.  v --- initial y-velocity distribution:
            string

    4.  w --- initial z-velocity distribution:
            string

    5.  p --- initial static pressure distribution:
            string

Example:

        [soln-ics]
        rho = 1.0
        u = x*y*sin(y)
        v = z
        w = 1.0
        p = 1.0/(1.0+x)

  Example --- 2D Couette Flow

Proceed with the following steps to run a serial 2D Couette flow simulation on a mixed unstructured mesh:

    1.  Create a working directory called couette_flow_2d/

    2.  Copy the configuration file PyFR/examples/couette_flow_2d/couette_flow_2d.ini into couette_flow_2d/

    3.  Copy the Gmsh mesh file PyFR/examples/couette_flow_2d/couette_flow_2d.msh into couette_flow_2d/

    4.  Run pyfr to covert the Gmsh mesh file into a PyFR mesh file called couette_flow_2d.pyfrm:

            pyfr import couette_flow_2d.msh couette_flow_2d.pyfrm

    5.  Run pyfr to solve the Navier-Stokes equations on the mesh, generating a series of PyFR solution files called couette_flow_2d-*.pyfrs:

            pyfr run -b cuda -p couette_flow_2d.pyfrm couette_flow_2d.ini

    6.  Run pyfr on the solution file couette_flow_2d-040.pyfrs converting it into an unstructured VTK file called couette_flow_2d-040.vtu. Note that in order to visualise the high-order data, each high-order element is sub-divided into smaller linear elements. The level of sub-division is controlled by the integer at the end of the command:

            pyfr export couette_flow_2d.pyfrm couette_flow_2d-040.pyfrs couette_flow_2d-040.vtu -d 4

    7.  Visualise the unstructured VTK file in Paraview
        [image: couette flow] [image] Colour map of steady-state density distribution..UNINDENT

  Example --- 2D Euler Vortex

Proceed with the following steps to run a parallel 2D Euler vortex simulation on a structured mesh:

    1.  Create a working directory called euler_vortex_2d/

    2.  Copy the configuration file PyFR/examples/euler_vortex_2d/euler_vortex_2d.ini into euler_vortex_2d/

    3.  Copy the Gmsh file PyFR/examples/euler_vortex_2d/euler_vortex_2d.msh into euler_vortex_2d/

    4.  Run pyfr to convert the Gmsh mesh file into a PyFR mesh file called euler_vortex_2d.pyfrm:

            pyfr import euler_vortex_2d.msh euler_vortex_2d.pyfrm

    5.  Run pyfr to partition the PyFR mesh file into two pieces:

            pyfr partition 2 euler_vortex_2d.pyfrm .

    6.  Run pyfr to solve the Euler equations on the mesh, generating a series of PyFR solution files called euler_vortex_2d*.pyfrs:

            mpirun -n 2 pyfr run -b cuda -p euler_vortex_2d.pyfrm euler_vortex_2d.ini

    7.  Run pyfr on the solution file euler_vortex_2d-100.0.pyfrs converting it into an unstructured VTK file called euler_vortex_2d-100.0.vtu. Note that in order to visualise the high-order data, each high-order element is sub-divided into smaller linear elements. The level of sub-division is controlled by the integer at the end of the command:

            pyfr export euler_vortex_2d.pyfrm euler_vortex_2d-100.0.pyfrs euler_vortex_2d-100.0.vtu -d 4

    8.  Visualise the unstructured VTK file in Paraview
        [image: euler vortex] [image] Colour map of density distribution at 100 time units..UNINDENT

DEVELOPER GUIDE

  A Brief Overview of the PyFR Framework

  Where to Start

The symbolic link pyfr.scripts.pyfr points to the script pyfr.scripts.main, which is where it all starts! Specifically, the function process_run calls the function _process_common, which in turn calls the function get_solver, returning an Integrator -- a composite of a Controller and a Stepper. The Integrator has a method named run, which is then called to run the simulation.

  Controller

A Controller acts to advance the simulation in time. Specifically, a Controller has a method named advance_to which advances a System to a specified time. There are three types of Controller available in PyFR 1.5.0:

    class pyfr.integrators.std.controllers.StdNoneController(*args, **kwargs)

        _accept_step(dt, idxcurr, err=None)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _reject_step(dt, idxold, err=None)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        controller_name = 'none'

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

    class pyfr.integrators.std.controllers.StdPIController(*args, **kwargs)

        _accept_step(dt, idxcurr, err=None)

        _add(*args)

        _controller_needs_errest

        _errest(x, y, z)

        _get_axnpby_kerns(n, subdims=None)

        _get_errest_kerns()

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _reject_step(dt, idxold, err=None)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        controller_name = 'pi'

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

    class pyfr.integrators.dual.controllers.DualNoneController(*args, **kwargs)

        _accept_step(dt, idxcurr)

        _add(*args)

        _dual_time_source()

        _get_axnpby_kerns(n, subdims=None)

        _get_errest_kerns()

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _resid(x, y)

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        controller_name = 'none'

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        run()

        soln

        step(t, dt)

Types of Controller are related via the following inheritance diagram:

  Stepper

A Stepper acts to advance the simulation by a single time-step. Specifically, a Stepper has a method named step which advances a System by a single time-step. There are 11 types of Stepper available in PyFR 1.5.0:

    class pyfr.integrators.std.steppers.StdEulerStepper(*args, **kwargs)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'euler'

    class pyfr.integrators.std.steppers.StdRK4Stepper(*args, **kwargs)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'rk4'

    class pyfr.integrators.std.steppers.StdRK34Stepper(*args, **kwargs)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        a = [0.32416573882874605, 0.5570978645055429, -0.08605491431272755]

        advance_to(t)

        b = [0.10407986927510238, 0.6019391368822611, 2.9750900268840206, -2.681109033041384]

        bhat = [0.3406814840808433, 0.09091523008632837, 2.866496742725443, -2.298093456892615]

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'rk34'

    class pyfr.integrators.std.steppers.StdRK45Stepper(*args, **kwargs)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        a = [0.22502245872571303, 0.5440433129514047, 0.14456824349399464, 0.7866643421983568]

        advance_to(t)

        b = [0.05122930664033915, 0.3809548257264019, -0.3733525963923833, 0.5925012850263623, 0.34866717899927996]

        bhat = [0.13721732210321927, 0.19188076232938728, -0.2292067211595315, 0.6242946765438954, 0.27581396018302956]

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'rk45'

    class pyfr.integrators.std.steppers.StdTVDRK3Stepper(*args, **kwargs)

        _add(*args)

        _controller_needs_errest

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _stepper_has_errest

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        formulation = 'std'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'tvd-rk3'

    class pyfr.integrators.dual.steppers.DualBDF2Stepper(*args, **kwargs)

        _add(*args)

        _dual_time_source

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'bdf2'

    class pyfr.integrators.dual.steppers.DualBDF3Stepper(*args, **kwargs)

        _add(*args)

        _dual_time_source

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'bdf3'

    class pyfr.integrators.dual.steppers.DualBackwardEulerStepper(*args, **kwargs)

        _add(*args)

        _dual_time_source

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        run()

        soln

        step(t, dt)

        stepper_name = 'backward-euler'

    class pyfr.integrators.dual.pseudosteppers.DualPseudoRK4Stepper(*args, **kwargs)

        _add(*args)

        _add_with_dts(*args, *, c)

        _dual_time_source()

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _pseudo_stepper_nregs

        _pseudo_stepper_order

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        pseudo_stepper_name = 'rk4'

        run()

        soln

        step(t, dt, dtau)

    class pyfr.integrators.dual.pseudosteppers.DualPseudoTVDRK3Stepper(*args, **kwargs)

        _add(*args)

        _add_with_dts(*args, *, c)

        _dual_time_source()

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _pseudo_stepper_nregs

        _pseudo_stepper_order

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        pseudo_stepper_name = 'tvd-rk3'

        run()

        soln

        step(t, dt, dtau)

    class pyfr.integrators.dual.pseudosteppers.DualPseudoEulerStepper(*args, **kwargs)

        _add(*args)

        _add_with_dts(*args, *, c)

        _dual_time_source()

        _get_axnpby_kerns(n, subdims=None)

        _get_gndofs()

        _get_kernels(name, nargs, **kwargs)

        _get_plugins()

        _get_reg_banks(nreg)

        _prepare_reg_banks(*bidxes)

        _pseudo_stepper_nregs

        _pseudo_stepper_order

        _source_regidx

        _stepper_nfevals

        _stepper_nregs

        _stepper_order

        _stepper_regidx

        advance_to(t)

        call_plugin_dt(dt)

        cfgmeta

        collect_stats(stats)

        finalise_step(currsoln)

        formulation = 'dual'

        nsteps

        pseudo_stepper_name = 'euler'

        run()

        soln

        step(t, dt, dtau)

Types of Stepper are related via the following inheritance diagram:

  System

A System holds information/data for the system, including Elements, Interfaces, and the Backend with which the simulation is to run. A System has a method named rhs, which obtains the divergence of the flux (the 'right-hand-side') at each solution point. The method rhs invokes various kernels which have been pre-generated and loaded into queues. A System also has a method named _gen_kernels which acts to generate all the kernels required by a particular System. A kernel is an instance of a 'one-off' class with a method named run that implements the required kernel functionality. Individual kernels are produced by a kernel provider. PyFR 1.5.0 has various types of kernel provider. A Pointwise Kernel Provider produces point-wise kernels such as Riemann solvers and flux functions etc. These point-wise kernels are specified using an in-built platform-independent templating language derived from Mako, henceforth referred to as PyFR-Mako. There are two types of System available in PyFR 1.5.0:

    class pyfr.solvers.euler.system.EulerSystem(backend, rallocs, mesh, initsoln, nreg, cfg)

        _gen_kernels(eles, iint, mpiint, bcint)

        _gen_queues()

        _load_bc_inters(rallocs, mesh, elemap)

        _load_eles(rallocs, mesh, initsoln, nreg, nonce)

        _load_int_inters(rallocs, mesh, elemap)

        _load_mpi_inters(rallocs, mesh, elemap)

        _nonce_seq = count(0)

        _nqueues = 2

        bbcinterscls
            alias of EulerBaseBCInters

        ele_scal_upts(idx)

        elementscls
            alias of EulerElements

        filt(uinoutbank)

        intinterscls
            alias of EulerIntInters

        mpiinterscls
            alias of EulerMPIInters

        name = 'euler'

        rhs(t, uinbank, foutbank)

    class pyfr.solvers.navstokes.system.NavierStokesSystem(backend, rallocs, mesh, initsoln, nreg, cfg)

        _gen_kernels(eles, iint, mpiint, bcint)

        _gen_queues()

        _load_bc_inters(rallocs, mesh, elemap)

        _load_eles(rallocs, mesh, initsoln, nreg, nonce)

        _load_int_inters(rallocs, mesh, elemap)

        _load_mpi_inters(rallocs, mesh, elemap)

        _nonce_seq = count(0)

        _nqueues = 2

        bbcinterscls
            alias of NavierStokesBaseBCInters

        ele_scal_upts(idx)

        elementscls
            alias of NavierStokesElements

        filt(uinoutbank)

        intinterscls
            alias of NavierStokesIntInters

        mpiinterscls
            alias of NavierStokesMPIInters

        name = 'navier-stokes'

        rhs(t, uinbank, foutbank)

Types of System are related via the following inheritance diagram:

  Elements

An Elements holds information/data for a group of elements. There are two types of Elements available in PyFR 1.5.0:

    class pyfr.solvers.euler.elements.EulerElements(basiscls, eles, cfg)

        _gen_pnorm_fpts()

        _mag_pnorm_fpts = None

        _norm_pnorm_fpts = None

        _ploc_in_src_exprs = None

        _scratch_bufs

        _smats_djacs_mpts = None

        _soln_in_src_exprs = None

        _src_exprs = None

        _srtd_face_fpts = None

        con_to_pri(cons, cfg)

        convarmap = {2: ['rho', 'rhou', 'rhov', 'E'], 3: ['rho', 'rhou', 'rhov', 'rhow', 'E']}

        dualcoeffs = {2: ['rho', 'rhou', 'rhov', 'E'], 3: ['rho', 'rhou', 'rhov', 'rhow', 'E']}

        formulations = ['std', 'dual']

        get_mag_pnorms(eidx, fidx)

        get_mag_pnorms_for_inter(eidx, fidx)

        get_norm_pnorms(eidx, fidx)

        get_norm_pnorms_for_inter(eidx, fidx)

        get_ploc_for_inter(eidx, fidx)

        get_scal_fpts_for_inter(eidx, fidx)

        get_vect_fpts_for_inter(eidx, fidx)

        opmat(expr)

        ploc_at(name)

        ploc_at_np(name)

        plocfpts = None

        pri_to_con(pris, cfg)

        privarmap = {2: ['rho', 'u', 'v', 'p'], 3: ['rho', 'u', 'v', 'w', 'p']}

        rcpdjac_at(name)

        rcpdjac_at_np(name)

        set_backend(backend, nscalupts, nonce)

        set_ics_from_cfg()

        set_ics_from_soln(solnmat, solncfg)

        smat_at(name)

        smat_at_np(name)

        visvarmap = {2: {'velocity': ['u', 'v'], 'pressure': ['p'], 'density': ['rho']}, 3: {'velocity': ['u', 'v', 'w'], 'pressure': ['p'], 'density': ['rho']}}

    class pyfr.solvers.navstokes.elements.NavierStokesElements(basiscls, eles, cfg)

        _gen_pnorm_fpts()

        _mag_pnorm_fpts = None

        _norm_pnorm_fpts = None

        _ploc_in_src_exprs = None

        _scratch_bufs

        _smats_djacs_mpts = None

        _soln_in_src_exprs = None

        _src_exprs = None

        _srtd_face_fpts = None

        con_to_pri(cons, cfg)

        convarmap = {2: ['rho', 'rhou', 'rhov', 'E'], 3: ['rho', 'rhou', 'rhov', 'rhow', 'E']}

        dualcoeffs = {2: ['rho', 'rhou', 'rhov', 'E'], 3: ['rho', 'rhou', 'rhov', 'rhow', 'E']}

        formulations = ['std', 'dual']

        get_artvisc_fpts_for_inter(eidx, fidx)

        get_mag_pnorms(eidx, fidx)

        get_mag_pnorms_for_inter(eidx, fidx)

        get_norm_pnorms(eidx, fidx)

        get_norm_pnorms_for_inter(eidx, fidx)

        get_ploc_for_inter(eidx, fidx)

        get_scal_fpts_for_inter(eidx, fidx)

        get_vect_fpts_for_inter(eidx, fidx)

        opmat(expr)

        ploc_at(name)

        ploc_at_np(name)

        plocfpts = None

        pri_to_con(pris, cfg)

        privarmap = {2: ['rho', 'u', 'v', 'p'], 3: ['rho', 'u', 'v', 'w', 'p']}

        rcpdjac_at(name)

        rcpdjac_at_np(name)

        set_backend(backend, nscalupts, nonce)

        set_ics_from_cfg()

        set_ics_from_soln(solnmat, solncfg)

        shockvar = 'rho'

        smat_at(name)

        smat_at_np(name)

        visvarmap = {2: {'velocity': ['u', 'v'], 'pressure': ['p'], 'density': ['rho']}, 3: {'velocity': ['u', 'v', 'w'], 'pressure': ['p'], 'density': ['rho']}}

Types of Elements are related via the following inheritance diagram:

  Interfaces

An Interfaces holds information/data for a group of interfaces. There are four types of (non-boundary) Interfaces available in PyFR 1.5.0:

    class pyfr.solvers.euler.inters.EulerIntInters(*args, **kwargs)

        _const_mat(inter, meth)

        _gen_perm(lhs, rhs)

        _scal_view(inter, meth)

        _scal_xchg_view(inter, meth)

        _vect_view(inter, meth)

        _vect_xchg_view(inter, meth)

        _view(inter, meth, vshape=())

        _xchg_view(inter, meth, vshape=())

    class pyfr.solvers.euler.inters.EulerMPIInters(*args, **kwargs)

        MPI_TAG = 2314

        _const_mat(inter, meth)

        _scal_view(inter, meth)

        _scal_xchg_view(inter, meth)

        _vect_view(inter, meth)

        _vect_xchg_view(inter, meth)

        _view(inter, meth, vshape=())

        _xchg_view(inter, meth, vshape=())

    class pyfr.solvers.navstokes.inters.NavierStokesIntInters(be, lhs, rhs, elemap, cfg)

        _const_mat(inter, meth)

        _gen_perm(lhs, rhs)

        _scal_view(inter, meth)

        _scal_xchg_view(inter, meth)

        _vect_view(inter, meth)

        _vect_xchg_view(inter, meth)

        _view(inter, meth, vshape=())

        _xchg_view(inter, meth, vshape=())

    class pyfr.solvers.navstokes.inters.NavierStokesMPIInters(be, lhs, rhsrank, rallocs, elemap, cfg)

        MPI_TAG = 2314

        _const_mat(inter, meth)

        _scal_view(inter, meth)

        _scal_xchg_view(inter, meth)

        _vect_view(inter, meth)

        _vect_xchg_view(inter, meth)

        _view(inter, meth, vshape=())

        _xchg_view(inter, meth, vshape=())

Types of (non-boundary) Interfaces are related via the following inheritance diagram:

  Backend

A Backend holds information/data for a backend. There are four types of Backend available in PyFR 1.5.0:

    class pyfr.backends.cuda.base.CUDABackend(cfg)

        _malloc_impl(nbytes)

        alias(obj, aobj)

        commit()

        const_matrix(initval, extent=None, tags=set())

        kernel(name, *args, **kwargs)

        lookup = None

        malloc(obj, extent)

        matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        matrix_bank(mats, initbank=0, tags=set())

        matrix_rslice(mat, p, q)

        name = 'cuda'

        queue()

        runall(sequence)

        view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

        xchg_matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        xchg_matrix_for_view(view, tags=set())

        xchg_view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

    class pyfr.backends.mic.base.MICBackend(cfg)

        _malloc_impl(nbytes)

        alias(obj, aobj)

        commit()

        const_matrix(initval, extent=None, tags=set())

        kernel(name, *args, **kwargs)

        lookup = None

        malloc(obj, extent)

        matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        matrix_bank(mats, initbank=0, tags=set())

        matrix_rslice(mat, p, q)

        name = 'mic'

        queue()

        runall(sequence)

        view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

        xchg_matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        xchg_matrix_for_view(view, tags=set())

        xchg_view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

    class pyfr.backends.opencl.base.OpenCLBackend(cfg)

        _malloc_impl(nbytes)

        alias(obj, aobj)

        commit()

        const_matrix(initval, extent=None, tags=set())

        kernel(name, *args, **kwargs)

        lookup = None

        malloc(obj, extent)

        matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        matrix_bank(mats, initbank=0, tags=set())

        matrix_rslice(mat, p, q)

        name = 'opencl'

        queue()

        runall(sequence)

        view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

        xchg_matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        xchg_matrix_for_view(view, tags=set())

        xchg_view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

    class pyfr.backends.openmp.base.OpenMPBackend(cfg)

        _malloc_impl(nbytes)

        alias(obj, aobj)

        commit()

        const_matrix(initval, extent=None, tags=set())

        kernel(name, *args, **kwargs)

        lookup = None

        malloc(obj, extent)

        matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        matrix_bank(mats, initbank=0, tags=set())

        matrix_rslice(mat, p, q)

        name = 'openmp'

        queue()

        runall(sequence)

        view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

        xchg_matrix(ioshape, initval=None, extent=None, aliases=None, tags=set())

        xchg_matrix_for_view(view, tags=set())

        xchg_view(matmap, rmap, cmap, rstridemap=None, vshape=(), tags=set())

Types of Backend are related via the following inheritance diagram:

  Pointwise Kernel Provider

A Pointwise Kernel Provider produces point-wise kernels. Specifically, a Pointwise Kernel Provider has a method named register, which adds a new method to an instance of a Pointwise Kernel Provider. This new method, when called, returns a kernel. A kernel is an instance of a 'one-off' class with a method named run that implements the required kernel functionality. The kernel functionality itself is specified using PyFR-Mako. Hence, a Pointwise Kernel Provider also has a method named _render_kernel, which renders PyFR-Mako into low-level platform-specific code. The _render_kernel method first sets the context for Mako (i.e. details about the Backend etc.) and then uses Mako to begin rendering the PyFR-Mako specification. When Mako encounters a pyfr:kernel an instance of a Kernel Generator is created, which is used to render the body of the pyfr:kernel. There are four types of Pointwise Kernel Provider available in PyFR 1.5.0:

    class pyfr.backends.cuda.provider.CUDAPointwiseKernelProvider(backend)

        _build_arglst(dims, argn, argt, argdict)

        _build_kernel(name, src, argtypes)

        _instantiate_kernel(dims, fun, arglst)

        _render_kernel(name, mod, tplargs)

        kernel_generator_cls
            alias of CUDAKernelGenerator

        register(mod)

    class pyfr.backends.mic.provider.MICPointwiseKernelProvider(backend)

        _build_arglst(dims, argn, argt, argdict)

        _build_kernel(name, src, argtypes, restype=None)

        _instantiate_kernel(dims, fun, arglst)

        _render_kernel(name, mod, tplargs)

        kernel_generator_cls
            alias of MICKernelGenerator

        register(mod)

    class pyfr.backends.opencl.provider.OpenCLPointwiseKernelProvider(backend)

        _build_arglst(dims, argn, argt, argdict)

        _build_kernel(name, src, argtypes)

        _instantiate_kernel(dims, fun, arglst)

        _render_kernel(name, mod, tplargs)

        kernel_generator_cls
            alias of OpenCLKernelGenerator

        register(mod)

    class pyfr.backends.openmp.provider.OpenMPPointwiseKernelProvider(backend)

        _build_arglst(dims, argn, argt, argdict)

        _build_kernel(name, src, argtypes, restype=None)

        _instantiate_kernel(dims, fun, arglst)

        _render_kernel(name, mod, tplargs)

        kernel_generator_cls
            alias of OpenMPKernelGenerator

        register(mod)

Types of Pointwise Kernel Provider are related via the following inheritance diagram:

  Kernel Generator

A Kernel Generator renders the PyFR-Mako in a pyfr:kernel into low-level platform-specific code. Specifically, a Kernel Generator has a method named render, which applies Backend specific regex and adds Backend specific 'boiler plate' code to produce the low-level platform-specific source -- which is compiled, linked, and loaded. There are four types of Kernel Generator available in PyFR 1.5.0:

    class pyfr.backends.cuda.generator.CUDAKernelGenerator(*args, **kwargs)

        _deref_arg_array_1d(arg)

        _deref_arg_array_2d(arg)

        _deref_arg_view(arg)

        _render_body(body)

        _render_spec()

        argspec()

        needs_ldim(arg)

        render()

    class pyfr.backends.mic.generator.MICKernelGenerator(name, ndim, args, body, fpdtype)

        _deref_arg_array_1d(arg)

        _deref_arg_array_2d(arg)

        _deref_arg_view(arg)

        _render_body(body)

        _render_spec_unpack()

        argspec()

        needs_ldim(arg)

        render()

    class pyfr.backends.opencl.generator.OpenCLKernelGenerator(*args, **kwargs)

        _deref_arg_array_1d(arg)

        _deref_arg_array_2d(arg)

        _deref_arg_view(arg)

        _render_body(body)

        _render_spec()

        argspec()

        needs_ldim(arg)

        render()

    class pyfr.backends.openmp.generator.OpenMPKernelGenerator(name, ndim, args, body, fpdtype)

        _deref_arg_array_1d(arg)

        _deref_arg_array_2d(arg)

        _deref_arg_view(arg)

        _render_body(body)

        _render_spec()

        argspec()

        needs_ldim(arg)

        render()

Types of Kernel Generator are related via the following inheritance diagram:

  PyFR-Mako

  PyFR-Mako Kernels

PyFR-Mako kernels are specifications of point-wise functionality that can be invoked directly from within PyFR. They are opened with a header of the form:

        <%pyfr:kernel name='kernel-name' ndim='data-dimensionality' [argument-name='argument-intent argument-attribute argument-data-type' ...]>

where

    1.  kernel-name --- name of kernel
            string

    2.  data-dimensionality --- dimensionality of data
            int

    3.  argument-name --- name of argument
            string

    4.  argument-intent --- intent of argument
            in | out | inout

    5.  argument-attribute --- attribute of argument
            mpi | scalar | view

    6.  argument-data-type --- data type of argument
            string

and are closed with a footer of the form:

        </%pyfr:kernel>

  PyFR-Mako Macros

PyFR-Mako macros are specifications of point-wise functionality that cannot be invoked directly from within PyFR, but can be embedded into PyFR-Mako kernels. PyFR-Mako macros can be viewed as building blocks for PyFR-mako kernels. They are opened with a header of the form:

        <%pyfr:macro name='macro-name' params='[parameter-name, ...]'>

where

    1.  macro-name --- name of macro
            string

    2.  parameter-name --- name of parameter
            string

and are closed with a footer of the form:

        </%pyfr:macro>

PyFR-Mako macros are embedded within a kernel using an expression of the following form:

        ${pyfr.expand('macro-name', ['parameter-name', ...])};

where

    1.  macro-name --- name of the macro
            string

    2.  parameter-name --- name of parameter
            string

  Syntax

  Basic Functionality

Basic functionality can be expressed using a restricted subset of the C programming language. Specifically, use of the following is allowed:

    1.  +,-,*,/ --- basic arithmetic

    2.  sin, cos, tan --- basic trigonometric functions

    3.  exp --- exponential

    4.  pow --- power

    5.  fabs --- absolute value

    6.  output = ( condition ? satisfied : unsatisfied ) --- ternary if

    7.  min --- minimum

    8.  max --- maximum

However, conditional if statements, as well as for/while loops, are not allowed.

  Expression Substitution

Mako expression substitution can be used to facilitate PyFR-Mako kernel specification. A Python expression expression prescribed thus ${expression} is substituted for the result when the PyFR-Mako kernel specification is interpreted at runtime.

Example:

        E = s[${ndims - 1}]

  Conditionals

Mako conditionals can be used to facilitate PyFR-Mako kernel specification. Conditionals are opened with % if condition: and closed with % endif. Note that such conditionals are evaluated when the PyFR-Mako kernel specification is interpreted at runtime, they are not embedded into the low-level kernel.

Example:

        % if ndims == 2:
            fout[0][1] += t_xx;     fout[1][1] += t_xy;
            fout[0][2] += t_xy;     fout[1][2] += t_yy;
            fout[0][3] += u*t_xx + v*t_xy + ${-c['mu']*c['gamma']/c['Pr']}*T_x;
            fout[1][3] += u*t_xy + v*t_yy + ${-c['mu']*c['gamma']/c['Pr']}*T_y;
        % endif

  Loops

Mako loops can be used to facilitate PyFR-Mako kernel specification. Loops are opened with % for condition: and closed with % endfor. Note that such loops are unrolled when the PyFR-Mako kernel specification is interpreted at runtime, they are not embedded into the low-level kernel.

Example:

        % for i in range(ndims):
            rhov[${i}] = s[${i + 1}];
            v[${i}] = invrho*rhov[${i}];
        % endfor

INDICES AND TABLES

    •   genindex

    •   modindex

    •   search

AUTHOR
Imperial College London

COPYRIGHT
2013-2016, Imperial College London