# 2. Installation and Building for Linux

## 2.1. Prerequisites

- A ROCm enabled platform. More information in ROCm Documentation. To build ROCm from the source, follow the previous link and navigate to How to install ROCm. This page will provide steps to install ROCm for specific operating systems. After following these steps to download the installer amdgpu-install, use the below command to install ROCm.

    sudo amdgpu-install --usecase=rocm

- rocBLAS is supported on the same Linux versions that are supported by ROCm

## 2.2. Installing Prebuilt Packages

rocBLAS can be installed on Ubuntu(R) or Debian using:

    sudo apt-get update
    sudo apt-get install rocblas

rocBLAS can be installed on CentOS using:

    sudo yum update
    sudo yum install rocblas

rocBLAS can be installed on SLES using:

    sudo dnf upgrade
    sudo dnf install rocblas

Once installed, rocBLAS can be used just like any other library with a C API. The rocblas.h header file must be included in the user code to make calls into rocBLAS, and the rocBLAS shared library will become link-time and run-time dependent for the user application.

Once installed, find rocblas.h and rocblas_module.f90 in the /opt/rocm/include directory. Only use these two installed files when needed in user code. Find other rocBLAS files in /opt/rocm/include/internal, However, do not include these files directly.

## 2.3. Building and Installing rocBLAS

For most users, building from source is not necessary, as rocBLAS can be used after installing the prebuilt packages as described above. If desired, users can use following instructions to build rocBLAS from source. Note the change in the –usecase command argument below to install the base ROCm developer stack in-order to build rocBLAS from the source.

    sudo amdgpu-install --usecase=rocmdev

### 2.3.1. Requirements

As a rule, 64GB of system memory is required for a full rocBLAS build. This value can be lower if rocBLAS is built with a different Tensile logic target (see the –logic command for ./install.sh). This value may also increase in the future as more functions are added to rocBLAS and dependencies such as Tensile grow.

### 2.3.2. Download rocBLAS

The rocBLAS source code is available at the rocBLAS github page. Check the ROCm version on your system. For Ubuntu(R), use:

    apt show rocm-libs -a

For Centos, use:

    yum info rocm-libs

The ROCm version has major, minor, and patch fields, possibly followed by a build specific identifier. For example, ROCm version could be 4.0.0.40000-23; this corresponds to major = 4, minor = 0, patch = 0, build identifier 40000-23. There are GitHub branches at the rocBLAS site with names rocm-major.minor.x where major and minor are the same as in the ROCm version. For ROCm version 4.0.0.40000-23, you must use the following to download rocBLAS:

    git clone -b release/rocm-rel-x.y https://github.com/ROCmSoftwarePlatform/rocBLAS.git
    cd rocBLAS

Replace x.y in the above command with the version of ROCm installed on your machine. For example, if you have ROCm 5.0 installed, then replace release/rocm-rel-x.y with release/rocm-rel-5.0.

Below are steps to build using install.sh script. The user can build either:

- dependencies + library

- dependencies + library + client

You only need (dependencies + library) if you call rocBLAS from your code. The client contains the test and benchmark code.

### 2.3.3. Library Dependencies

Dependencies are listed in the script install.sh. The -d flag to install.sh installs dependencies.

CMake has a minimum version requirement listed in the file install.sh. See –cmake_install flag in install.sh to upgrade automatically.

### 2.3.4. Build Library dependencies + Library

Common uses of install.sh to build (library dependencies + library) are in the table below:

Command | Description
--- | ---
`./install.sh -h` | Help information.
`./install.sh -d` | Build library dependencies and library in your local directory. The -d flag only needs to be used once. For subsequent invocations of install.sh it is not necessary to rebuild the dependencies.
`./install.sh` | Build library in your local directory. It is assumed dependencies have been built.
`./install.sh -i` | Build library, then build and install rocBLAS package in /opt/rocm/rocblas. You will be prompted for sudo access. This will install for all users. If you want to keep rocBLAS in your local directory, you do not need the -i flag.

### 2.3.5. Build Library Dependencies + Client Dependencies + Library + Client

Some client executables are listed in the table below:

executable name | description
--- | ---
rocblas-test | runs Google Tests to test the library
rocblas-bench | executable to benchmark or test functions
rocblas-example-sscal | example C code calling rocblas_sscal function

Common uses of install.sh to build (dependencies + library + client) are in the table below:

Command | Description
--- | ---
`./install.sh -h` | Help information.
`./install.sh -dc` | Build library dependencies, client dependencies, library, and client in your local directory. The -d flag only needs to be used once. For subsequent invocations of install.sh it is not necessary to rebuild the dependencies.
`./install.sh -c` | Build library and client in your local directory. It is assumed the dependencies have been built.
`./install.sh -idc` | Build library dependencies, client dependencies, library, client, then build and install the rocBLAS package. You will be prompted for sudo access. It is expected that if you want to install for all users you use the -i flag. If you want to keep rocBLAS in your local directory, you do not need the -i flag.
`./install.sh -ic` | Build and install rocBLAS package, and build the client. You will be prompted for sudo access. This will install for all users. If you want to keep rocBLAS in your local directory, you do not need the -i flag.

### 2.3.6. Build Clients without Library

The rocBLAS clients can be built on their own using install.sh with a preexisting rocBLAS library.

Note that the version of the rocBLAS clients being built should match the version of the installed rocBLAS. Find the version of the installed rocBLAS in the installed rocBLAS directory in the file include/internal/rocblas-version.h. Find the version of rocBLAS being built by running `grep"VERSION_STRING" CMakeLists.txt` in the rocBLAS directory being built.

Command | Description
--- | ---
`./install.sh --clients-only` | Build rocBLAS clients and use an installed rocBLAS library at ROCM_PATH (/opt/rocm if not specified).
`./install.sh --clients-only` `--library-path /path/to/rocBLAS` | Build rocBLAS clients and use a rocBLAS library at the specified location.