You need to have the following software properly installed in order to build MPI for Python:
A working MPI implementation, preferably supporting MPI-3 and built with shared/dynamic libraries.
If you want to build some MPI implementation from sources, check the instructions at Building MPI from sources in the appendix.
Python 2.7, 3.5 or above.
Some MPI-1 implementations do require the actual command line arguments to be passed in
MPI_Init(). In this case, you will need to use a rebuilt, MPI-enabled, Python interpreter executable. MPI for Python has some support for alleviating you from this task. Check the instructions at MPI-enabled Python interpreter in the appendix.
If you already have a working MPI (either if you installed it from sources or by using a pre-built package from your favourite GNU/Linux distribution) and the mpicc compiler wrapper is on your search path, you can use pip:
$ python -m pip install mpi4py
If the mpicc compiler wrapper is not on your
search path (or if it has a different name) you can use
env to pass the environment variable
providing the full path to the MPI compiler wrapper executable:
$ env MPICC=/path/to/mpicc python -m pip install mpi4py
pip keeps previouly built wheel files on its cache for
future reuse. If you want to reinstall the
using a different or updated MPI implementation, you have to either
first remove the cached wheel file with:
$ python -m pip cache remove mpi4py
or ask pip to disable the cache:
$ python -m pip install --no-cache-dir mpi4py
The MPI for Python package is available for download at the project website generously hosted by GitHub. You can use curl or wget to get a release tarball.
$ curl -O https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
$ wget https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
After unpacking the release tarball:
$ tar -zxf mpi4py-X.Y.Z.tar.gz $ cd mpi4py-X.Y.Z
the package is ready for building.
MPI for Python uses a standard distutils-based build system. However, some distutils commands (like build) have additional options:
Lets you specify a special location or name for the mpicc compiler wrapper.
Lets you pass a section with MPI configuration within a special configuration file.
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 or MPI-2 implementations, possibly providing a subset of MPI-3.
If you use a MPI implementation providing a mpicc compiler wrapper (e.g., MPICH, Open MPI), it will be used for compilation and linking. This is the preferred and easiest way of building MPI for Python.
If mpicc is located somewhere in your search path, 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:
$ python setup.py build --mpicc=/where/you/have/mpicc
Alternatively, you can provide all the relevant information about your
MPI implementation by editing the file called
mpi.cfg. You can
use the default section
[mpi] or add a new, custom section, for
[other_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 [other_mpi] include_dirs = /opt/mpi/include ... libraries = mpi ... library_dirs = /opt/mpi/lib ... runtime_library_dirs = /op/mpi/lib ... ...
and then run the build command, perhaps specifying you custom configuration section:
$ python setup.py build --mpi=other_mpi
After building, the package is ready for install.
If you have root privileges (either by log-in as the root user of by using sudo) and you want to install MPI for Python in your system for all users, just do:
$ python setup.py install
The previous steps will install the
mpi4py package at standard
If you do not have root privileges or you want to install MPI for Python for your private use, just do:
$ python setup.py install --user
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.
If you installed from source, issuing at the command line:
$ mpiexec -n 5 python demo/helloworld.py
or (in the case of ancient MPI-1 implementations):
$ mpirun -np 5 python `pwd`/demo/helloworld.py
will launch a five-process run of the Python interpreter and run the
demo/helloworld.py from the source distribution.
You can also run all the unittest scripts:
$ mpiexec -n 5 python test/runtests.py
or, if you have nose unit testing framework installed:
$ mpiexec -n 5 nosetests -w test
or, if you have py.test unit testing framework installed:
$ mpiexec -n 5 py.test test/