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mpi4py
======
.. automodule:: mpi4py
:synopsis: The MPI for Python package.
Runtime configuration options
-----------------------------
.. data:: mpi4py.rc
This object has attributes exposing runtime configuration options that
become effective at import time of the :mod:`~mpi4py.MPI` module.
.. rubric:: Attributes Summary
.. table::
:widths: grid
============== ========================================================
`initialize` Automatic MPI initialization at import
`threads` Request initialization with thread support
`thread_level` Level of thread support to request
`finalize` Automatic MPI finalization at exit
`fast_reduce` Use tree-based reductions for objects
`recv_mprobe` Use matched probes to receive objects
`irecv_bufsz` Default buffer size in bytes for :meth:`~MPI.Comm.irecv`
`errors` Error handling policy
============== ========================================================
.. rubric:: Attributes Documentation
.. attribute:: mpi4py.rc.initialize
Automatic MPI initialization at import.
:type: :class:`bool`
:default: :obj:`True`
.. seealso:: :envvar:`MPI4PY_RC_INITIALIZE`
.. attribute:: mpi4py.rc.threads
Request initialization with thread support.
:type: :class:`bool`
:default: :obj:`True`
.. seealso:: :envvar:`MPI4PY_RC_THREADS`
.. attribute:: mpi4py.rc.thread_level
Level of thread support to request.
:type: :class:`str`
:default: ``"multiple"``
:choices: ``"multiple"``, ``"serialized"``, ``"funneled"``, ``"single"``
.. seealso:: :envvar:`MPI4PY_RC_THREAD_LEVEL`
.. attribute:: mpi4py.rc.finalize
Automatic MPI finalization at exit.
:type: :obj:`None` or :class:`bool`
:default: :obj:`None`
.. seealso:: :envvar:`MPI4PY_RC_FINALIZE`
.. attribute:: mpi4py.rc.fast_reduce
Use tree-based reductions for objects.
:type: :class:`bool`
:default: :obj:`True`
.. seealso:: :envvar:`MPI4PY_RC_FAST_REDUCE`
.. attribute:: mpi4py.rc.recv_mprobe
Use matched probes to receive objects.
:type: :class:`bool`
:default: :obj:`True`
.. seealso:: :envvar:`MPI4PY_RC_RECV_MPROBE`
.. attribute:: mpi4py.rc.irecv_bufsz
Default buffer size in bytes for :meth:`~MPI.Comm.irecv`.
:type: :class:`int`
:default: ``32768``
.. seealso:: :envvar:`MPI4PY_RC_IRECV_BUFSZ`
.. versionadded:: 4.0.0
.. attribute:: mpi4py.rc.errors
Error handling policy.
:type: :class:`str`
:default: ``"exception"``
:choices: ``"exception"``, ``"default"``, ``"abort"``, ``"fatal"``
.. seealso:: :envvar:`MPI4PY_RC_ERRORS`
.. rubric:: Example
MPI for Python features automatic initialization and finalization of the MPI
execution environment. By using the `mpi4py.rc` object, MPI initialization and
finalization can be handled programmatically::
import mpi4py
mpi4py.rc.initialize = False # do not initialize MPI automatically
mpi4py.rc.finalize = False # do not finalize MPI automatically
from mpi4py import MPI # import the 'MPI' module
MPI.Init() # manual initialization of the MPI environment
... # your finest code here ...
MPI.Finalize() # manual finalization of the MPI environment
Environment variables
---------------------
The following environment variables override the corresponding attributes of
the :data:`mpi4py.rc` and :data:`MPI.pickle` objects at import time of the
:mod:`~mpi4py.MPI` module.
.. note::
For variables of boolean type, accepted values are ``0`` and ``1``
(interpreted as :obj:`False` and :obj:`True`, respectively), and strings
specifying a `YAML boolean`_ value (case-insensitive).
.. _YAML boolean: https://yaml.org/type/bool.html
.. envvar:: MPI4PY_RC_INITIALIZE
:type: :class:`bool`
:default: :obj:`True`
Whether to automatically initialize MPI at import time of the
:mod:`mpi4py.MPI` module.
.. seealso:: :attr:`mpi4py.rc.initialize`
.. versionadded:: 4.0.0
.. envvar:: MPI4PY_RC_FINALIZE
:type: :obj:`None` | :class:`bool`
:default: :obj:`None`
:choices: :obj:`None`, :obj:`True`, :obj:`False`
Whether to automatically finalize MPI at exit time of the Python process.
.. seealso:: :attr:`mpi4py.rc.finalize`
.. versionadded:: 4.0.0
.. envvar:: MPI4PY_RC_THREADS
:type: :class:`bool`
:default: :obj:`True`
Whether to initialize MPI with thread support.
.. seealso:: :attr:`mpi4py.rc.threads`
.. versionadded:: 3.1.0
.. envvar:: MPI4PY_RC_THREAD_LEVEL
:default: ``"multiple"``
:choices: ``"single"``, ``"funneled"``,
``"serialized"``, ``"multiple"``
The level of required thread support.
.. seealso:: :attr:`mpi4py.rc.thread_level`
.. versionadded:: 3.1.0
.. envvar:: MPI4PY_RC_FAST_REDUCE
:type: :class:`bool`
:default: :obj:`True`
Whether to use tree-based reductions for objects.
.. seealso:: :attr:`mpi4py.rc.fast_reduce`
.. versionadded:: 3.1.0
.. envvar:: MPI4PY_RC_RECV_MPROBE
:type: :class:`bool`
:default: :obj:`True`
Whether to use matched probes to receive objects.
.. seealso:: :attr:`mpi4py.rc.recv_mprobe`
.. envvar:: MPI4PY_RC_IRECV_BUFSZ
:type: :class:`int`
:default: ``32768``
Default buffer size in bytes for :meth:`~MPI.Comm.irecv`.
.. seealso:: :attr:`mpi4py.rc.irecv_bufsz`
.. versionadded:: 4.0.0
.. envvar:: MPI4PY_RC_ERRORS
:default: ``"exception"``
:choices: ``"exception"``, ``"default"``, ``"abort"``, ``"fatal"``
Controls default MPI error handling policy.
.. seealso:: :attr:`mpi4py.rc.errors`
.. versionadded:: 3.1.0
.. envvar:: MPI4PY_PICKLE_PROTOCOL
:type: :class:`int`
:default: :data:`pickle.HIGHEST_PROTOCOL`
Controls the default pickle protocol to use when communicating Python
objects.
.. seealso:: :attr:`~mpi4py.MPI.Pickle.PROTOCOL` attribute of the
:data:`MPI.pickle` object within the :mod:`~mpi4py.MPI` module.
.. versionadded:: 3.1.0
.. envvar:: MPI4PY_PICKLE_THRESHOLD
:type: :class:`int`
:default: ``262144``
Controls the default buffer size threshold for switching from in-band to
out-of-band buffer handling when using pickle protocol version 5 or higher.
.. seealso:: :attr:`~mpi4py.MPI.Pickle.THRESHOLD` attribute of the
:data:`MPI.pickle` object within the :mod:`~mpi4py.MPI` module.
.. versionadded:: 3.1.2
Miscellaneous functions
-----------------------
.. autofunction:: mpi4py.profile
.. autofunction:: mpi4py.get_include
.. autofunction:: mpi4py.get_config
.. Local variables:
.. fill-column: 79
.. End:
|
