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 releated 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. 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().