CHANGES¶
+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
Sessionclass 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 formultiprocessing.pool.
+mpi4py.util.sync: New synchronization utilities.
+Add runtime check for mismatch between
mpiexecand MPI library.
+Support scikit-build-core as an alternative build backend.
+
-
+
Support meson-python 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 +attributesDatatype.typestr,Datatype.typecharto simplify +NumPy interoperability for simple cases.
+Add methods
Comm.Create_errhandler(),Win.Create_errhandler(), +andFile.Create_errhandler()to create custom error handlers.
+Add support for pickle serialization of instances of MPI types. +All instances of
Datatype,Info, andStatuscan be +serialized. Instances ofOpcan be serialized only if created +throughmpi4pyby callingOp.Create(). Instances of other MPI +types can be serialized only if they reference predefined handles.
+Add
handleattribute andfromhandle()class method to MPI +classes to ease interoperability with external code. The handle +value is a unsigned integer guaranteed to fit on the platform’s +uintptr_tC 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 +baseCommclass.
+Group.Compare()andComm.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
LBandUBdatatypes are no longer available, use +Datatype.Create_resized()instead.
+The
HOSTpredefined attribute key is no longer available.
+The
MPI.memoryclass has been renamed toMPI.buffer. The old +name is still available as an alias to the new name.
+The
mpi4py.dlmodule is no longer available.
+The
mpi4py.get_configfunction returns an empty dictionary.
+
+Miscellaneous:
+-
+
The project is now licenced 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
mpi4pyname 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.BOTTOMto 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_workersproperty toMPIPoolExecutor.
+mpi4py.util.dtlib: Fix computation of alignment for predefined datatypes.
+mpi4py.util.pkl5: Fix deadlock when usingssend()+mprobe().
+mpi4py.util.pkl5: Add environment variableMPI4PY_PICKLE_THRESHOLD.
+mpi4py.rc: Interpret"y"and"n"strings as boolean values.
+Fix/add typemap/typestr for
MPI.WCHAR/MPI.COUNTdatatypes.
+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()andRequest.testsome().
+Add lowercase methods
Request.get_status()andRequest.cancel().
+Support for passing Python GPU arrays compliant with the DLPack data +interchange mechanism (link) and the
__cuda_array_interface__+(CAI) standard (link) to uppercase methods. This support requires +that mpi4py is built against 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 patternMPI4PY_FUTURES_*, the +previousMPI4PY_*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) 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
WinRMA 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 onconcurrent.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
MPImodule now exposes amemorytype which is a +lightweight variant of the builtinmemoryviewtype, 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 usescount=1and +displ=0as defaults, assuming that messages are specified +through user-defined datatypes.
+The
Request.Wait[all]()methods now returnTrueto match +the interface ofRequest.Test[all]().
+The
Winclass now implements the Python buffer interface.
+
+Backward-incompatible changes:
+-
+
The
bufargument of theMPI.Comm.recv()method is +deprecated, passing anything butNoneemits a warning.
+The
MPI.Win.memoryproperty was removed, use the +MPI.Win.tomemory()method instead.
+Executing
python -m mpi4pyin the command line is now +equivalent topython -m mpi4py.run. For the former behavior, +usepython -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 thempi4pynamespace 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_RETURNerror handler inCOMM_SELF+andCOMM_WORLD, as well as any newComm,Win, or +Fileinstance 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, +
destis a required argument.
+Change signature of all receive and probe methods, +
sourcedefaults toANY_SOURCE, +tagdefaults toANY_TAG.
+Change signature of send lowercase-spelling methods, +
objarguments are not mandatory.
+Change signature of recv lowercase-spelling methods, +renamed ‘obj’ arguments to ‘buf’.
+Change
Request.Waitsome()andRequest.Testsome()+to returnNoneorlist.
+Change signature of all lowercase-spelling collectives, +
sendobjarguments are now mandatory, +recvobjarguments were removed.
+Reduction operations
MAXLOCandMINLOCare no longer +special-cased in lowercase-spelling methodsComm.[all]reduce()+andComm.[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)`.
+Wininstances 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()toIntracomm.Cart_map().
+Move
Graphcomm.Map()toIntracomm.Graph_map().
+Remove the
mpi4py.MPEmodule.
+Rename the Cython definition file for use with
cimport+statement frommpi_c.pxdtolibmpi.pxd.
+
+
Release 1.3.1 [2013-08-07]¶
+-
+
Regenerate C wrappers with Cython 0.19.1 to support Python 3.3.
+Install
*.pxdfiles in<site-packages>/mpi4pyto ease the +support for Cython’scimportstatement 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()andRequest.{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/Makefilevariables.
+Fix issues with Open MPI < 1.4.2 related to error checking and +
MPI_XXX_NULLhandles.
+
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.
+Requestinstances 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()andComm.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 isNoneifkeyis not in the +Infoobject, or a string otherwise. Previously, the call +redundantly returned(None, False)for missing key-value pairs; +Noneis 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 ofdataand the extent of the +MPI datatype to define thecount).
+
+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 passingMPI_THREAD_MULTIPLE). In case +you need to change this behavior, you can tweak the contents of the +mpi4py.rcmodule.
+In order to obtain the values of predefined attributes attached to +the world communicator, now you have to use the
+Get_attr()+method on theMPI.COMM_WORLDinstance:++tag_ub = MPI.COMM_WORLD.Get_attr(MPI.TAG_UB) +
+In the previous implementation,
MPI.COMM_WORLDand +MPI.COMM_SELFwere associated to duplicates of the (C-level) +MPI_COMM_WORLDandMPI_COMM_SELFpredefined communicator +handles. Now this is no longer the case,MPI.COMM_WORLDand +MPI.COMM_SELFproxies the actualMPI_COMM_WORLDand +MPI_COMM_SELFhandles.
+Convenience aliases
MPI.WORLDandMPI.SELFwere removed. Use +insteadMPI.COMM_WORLDandMPI.COMM_SELF.
+Convenience constants
MPI.WORLD_SIZEandMPI.WORLD_RANKwere +removed. Use insteadMPI.COMM_WORLD.Get_size()and +MPI.COMM_WORLD.Get_rank().
+
+ 
+