=======================
HISTORY: MPI for Python
=======================
:Author: Lisandro Dalcin
:Organization: CIMEC_
:Address: PTLC, 3000 Santa Fe, Argentina
:Contact: dalcinl@gmail.com
:Web Site: http://mpi4py.scipy.org/
.. contents::
Release 0.6.0 (200X-XX-XX)
==========================
* Point to point communications with pickled data were
reimplemented. Now a single message (for the data) is needed, the
message length is obtained using MPI routines ``MPI_Probe()`` and
``MPI_Get_count()``. Because of this, ``MPI.Comm.Sendrecv()`` for
pickled data is no longer implemented in terms of the canonical
``MPI_Sendrecv()``
* Collective communications with pickled data are now safer in 64 bits
architectures when the available memory is more than 2GB. In short:
now pickled data is concatenated in a single contiguous buffer. This
necessarily introduces some CPU and memory overhead at the sending
processes.
* Added initial support for vector variants of collectives.
* Added initial support for generalized requests. However, this is not
expected to work yet on the Python side.
* Solved some import-time warnings/errors for Open MPI with shared
libraries. In short: ``sys.setdlopenflags()`` is passed
``RTLD_GLOBAL`` for importing MPI extension modules.
* Pushed some fixes for building on SGI ALTIX machines.
Release 0.5.0 (2007-07-31)
==========================
* some nasty globals (size, rank, zero, last, even, odd) in MPI module
are no longer available. Convenience functions ``distribute()``,
``pprint()``, and ``rprint()`` are now prefixed with an
underscore. Now it is safe to do wildcard import ``from mpi4py.MPI
import *``, ``MPI.Exception`` will then be available as
``ExceptionMPI``.
* fixed and improved support for spawning new MPI processes with
``Intracomm.Spawn()``. Arguments are now only required at the
specified root. Added support for getting the error codes: just pass
a (perhaps empty) list at the root, and the results will go there
(and previous list items go away).
* improved way to pass arguments to windows for *RMA* calls
``Win.Put()``, ``Win.Get()``, and ``Win.Accumulate()``. This is
backward-incompatible, but far better and simpler than previous
approach. Window attributes (base, size, disp_unit) are now
accesible trough a property ``attrs``; a new property ``memory`` was
added to access the memory buffer (you could use it to build a NumPy
array with ``numpy.frombuffer()``).
* compile time support for selecting MPI thread level with option
``--thread-level=xxx`` where ``xxx`` should be one of ``single``,
``funneled``, ``serialized``, or ``multiple``. In the near future
this will be selectable at runtime.
* compile time support for detecting (possibly) leaked MPI handles
with option ``--enable-leak-warning``. Then, a warning will be
issued if any handle (other than MPI_Status) is not ``MPI_XXX_NULL``
at destruction time. This feature helps to discover unfreed handles,
as ``mpi4py`` currently does not automatically free them for
you.
* compile time support for faster (and fewer) MPI calls with option
``--enable-fast-errcheck``. This mode avoids calls for
getting/setting/restoring error handlers in order to be able to
raise Python exceptions instead of the default MPI action (aborting
processes) . This assumes that all MPI handles (``Comm``, ``Win``,
``File``) have a ``MPI_ERRORS_RETURN`` error handler. Additionally,
``MPI_ERRORS_RETURN`` is set at import time in ``MPI_COMM_SELF``,
``MPI_COMM_WORLD``, and ``MPI_FILE_NULL``, and at creation time for
new MPI handles created through ``mpi4py``. Unfortunately, this
mode can interact badly with external modules/libraries making MPI
calls, so it should be used with care.
* introduced many changes at the C and Python level for better support
the upcoming Python 3.0 following the ``py3k-struni`` branch.
Release 0.4.0 (2007-06-01)
==========================
* support for direct communication of objects exporting single-segment
buffer interface, should work with numpy/numarray/Numeric.
* support for non-blocking communications. Request/Prequest classes
are now fully implemented and functional.
* full support for parallel I/O and one-sided communications.
* almost full support for parallel process management.
* support for using many MPI-2 features availables in some MPI-1
implementations. Added option '--try-mpi-2' to 'build' command. Use
it to test for MPI-2 features available in a MPI-1 implementations,
or a incomplete/broken MPI-2 implementation.
Release 0.3.1 (2002-08-02)
==========================
* setup.py:
- Simplified build process, now based in 'mpicc' compiler,
by request and suggestions from Brian Granger.
* mpi/MPI.py:
- Removed '@staticmethod' decorators in order to support Py2.3,
by request from Brian Granger.
* mpi/ext/libmpi.c:
- Removed call to MPI_Init().
* mpi/ext/pickle.c:
- Added faster pickling support.
* mpi/ext/macros.h:
- Updated to support Open MPI implementation.
* mpi/ext/mpi_cobj.c:
- Removed support for CObject.
Release 0.2.0 (2005-05-25)
==========================
* mpi/MPI.py:
- file mpi/mpi.py renamed to mpi/MPI.py
- Corrected a bug in Op.__init__ method, moved initialization code
of some private attributes to Op.__new__ method.
- Added SWIG and CObject support to all MPI types using an improved
mechanism.
* mpi/MPU.py:
- file mpi/mpu.py renamed to mpi/MPU.py
* mpi/ext/libmpi.[c,h]:
- Added files libmpi.[c,h]. They contains all code previously
located in files mpi/ext/*object.[c,h].
- Added new extension module ``libmpi`` wich exports API pointers
using the approach suggested in
http://www.python.org/doc/2.3.5/ext/using-cobjects.html
- Added number methods to all MPI types (except ``Status``) in order
to support truth value testing. All predefined objects
``MPI_<OBJ>_NULL`` now have a truth value of ``False``.
* mpi/ext/mpi.c:
- Implemented cart_map() and graph_map().
- Corrected a bug in errhandler_free(), format string for
PyArg_ParseTuple() changed from "O" to "O&".
- Renamed file mpi/ext/mpi4py.c to mpi/ext/mpi.c; removed file
mpi/ext/mpi4py.h.
- Extension module ``_mpi`` use the new ``libmpi`` module to get the
C API.
* mpi/ext/mpi_swig.i:
- Changed typemaps for MPI objects. Now accepting PySwigObject and
PySwigPacked indistinctly.
- Extension module ``_mpi_swig`` uses the new ``libmpi`` module to
get the C API. Converter functions renamed to
``as_<Type>`` and ``from_<Type>``.
* mpi/ext/mpi_cobj.c:
- Extension module ``_mpi_cobj`` containing CObject support uses
uses the new ``libmpi`` module to get the C API. Converter
functions named ``as_<Type>`` and ``from_<Type>``.
Release 0.1.0 (2005-01-09)
==========================
This is the first release of *MPI for Python*.
.. _CIMEC: http://www.cimec.org.ar/
