mpi4py 4.0.0

on Python PyPI

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 Session class 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 for multiprocessing.pool.

• mpi4py.util.sync: New synchronization utilities.

• Add runtime check for mismatch between mpiexec and 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
  attributes Datatype.typestr, Datatype.typechar to simplify
  NumPy interoperability for simple cases.

• Add methods Comm.Create_errhandler(), Win.Create_errhandler(),
  and File.Create_errhandler() to create custom error handlers.

• Add support for pickle serialization of instances of MPI types.
  All instances of Datatype, Info, and Status can be
  serialized. Instances of Op can be serialized only if created
  through mpi4py by calling Op.Create(). Instances of other MPI
  types can be serialized only if they reference predefined handles.

• Add handle attribute and fromhandle() class method to MPI
  classes to ease interoperability with external code. The handle
  value is an unsigned integer guaranteed to fit on the platform's
  uintptr_t C 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
  base Comm class.

• Group.Compare() and Comm.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 LB and UB datatypes are no longer available, use
  Datatype.Create_resized() instead.

• The HOST predefined attribute key is no longer available.

• The MPI.memory class has been renamed to MPI.buffer. The old
  name is still available as an alias to the new name.

• The mpi4py.dl module is no longer available.

• The mpi4py.get_config function returns an empty dictionary.

Miscellaneous:

• The project is now licensed 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 mpi4py name 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.