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openmpi/ompi/mpi/c/reduce_local.c

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2.6 KiB
C
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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
/*
* Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2005 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2006-2009 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2013 Los Alamos National Security, LLC. All rights
* reserved.
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "ompi_config.h"
#include <stdio.h>
#include "ompi/mpi/c/bindings.h"
#include "ompi/runtime/params.h"
#include "ompi/communicator/communicator.h"
#include "ompi/errhandler/errhandler.h"
- Split the datatype engine into two parts: an MPI specific part in OMPI and a language agnostic part in OPAL. The convertor is completely moved into OPAL. This offers several benefits as described in RFC http://www.open-mpi.org/community/lists/devel/2009/07/6387.php namely: - Fewer basic types (int* and float* types, boolean and wchar - Fixing naming scheme to ompi-nomenclature. - Usability outside of the ompi-layer. - Due to the fixed nature of simple opal types, their information is completely known at compile time and therefore constified - With fewer datatypes (22), the actual sizes of bit-field types may be reduced from 64 to 32 bits, allowing reorganizing the opal_datatype structure, eliminating holes and keeping data required in convertor (upon send/recv) in one cacheline... This has implications to the convertor-datastructure and other parts of the code. - Several performance tests have been run, the netpipe latency does not change with this patch on Linux/x86-64 on the smoky cluster. - Extensive tests have been done to verify correctness (no new regressions) using: 1. mpi_test_suite on linux/x86-64 using clean ompi-trunk and ompi-ddt: a. running both trunk and ompi-ddt resulted in no differences (except for MPI_SHORT_INT and MPI_TYPE_MIX_LB_UB do now run correctly). b. with --enable-memchecker and running under valgrind (one buglet when run with static found in test-suite, commited) 2. ibm testsuite on linux/x86-64 using clean ompi-trunk and ompi-ddt: all passed (except for the dynamic/ tests failed!! as trunk/MTT) 3. compilation and usage of HDF5 tests on Jaguar using PGI and PathScale compilers. 4. compilation and usage on Scicortex. - Please note, that for the heterogeneous case, (-m32 compiled binaries/ompi), neither ompi-trunk, nor ompi-ddt branch would successfully launch. This commit was SVN r21641.
2009-07-13 08:56:31 +04:00
#include "ompi/datatype/ompi_datatype.h"
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
#include "ompi/op/op.h"
#include "ompi/memchecker.h"
#if OPAL_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
#pragma weak MPI_Reduce_local = PMPI_Reduce_local
#endif
#if OMPI_PROFILING_DEFINES
#include "ompi/mpi/c/profile/defines.h"
#endif
static const char FUNC_NAME[] = "MPI_Reduce_local";
int MPI_Reduce_local(const void *inbuf, void *inoutbuf, int count,
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
MPI_Datatype datatype, MPI_Op op)
{
MEMCHECKER(
memchecker_datatype(datatype);
);
if (MPI_PARAM_CHECK) {
char *msg;
int err = MPI_SUCCESS;
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
OMPI_ERR_INIT_FINALIZE(FUNC_NAME);
if (MPI_OP_NULL == op || NULL == op) {
err = MPI_ERR_OP;
} else if (!ompi_op_is_valid(op, datatype, &msg, FUNC_NAME)) {
int ret = OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_OP, msg);
free(msg);
return ret;
} else {
OMPI_CHECK_DATATYPE_FOR_SEND(err, datatype, count);
}
OMPI_ERRHANDLER_CHECK(err, MPI_COMM_WORLD, err, FUNC_NAME);
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
}
/* If the count is 0, just return */
if (0 == count) {
return MPI_SUCCESS;
}
OPAL_CR_ENTER_LIBRARY();
/* Invoke the op component to perform the back-end operation */
OBJ_RETAIN(op);
/* XXX -- CONST -- do not cast away const -- update mca/coll */
ompi_op_reduce(op,(void *) inbuf, inoutbuf, count, datatype);
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
OBJ_RELEASE(op);
return MPI_SUCCESS;
Two major things in this commit: * New "op" MPI layer framework * Addition of the MPI_REDUCE_LOCAL proposed function (for MPI-2.2) = Op framework = Add new "op" framework in the ompi layer. This framework replaces the hard-coded MPI_Op back-end functions for (MPI_Op, MPI_Datatype) tuples for pre-defined MPI_Ops, allowing components and modules to provide the back-end functions. The intent is that components can be written to take advantage of hardware acceleration (GPU, FPGA, specialized CPU instructions, etc.). Similar to other frameworks, components are intended to be able to discover at run-time if they can be used, and if so, elect themselves to be selected (or disqualify themselves from selection if they cannot run). If specialized hardware is not available, there is a default set of functions that will automatically be used. This framework is ''not'' used for user-defined MPI_Ops. The new op framework is similar to the existing coll framework, in that the final set of function pointers that are used on any given intrinsic MPI_Op can be a mixed bag of function pointers, potentially coming from multiple different op modules. This allows for hardware that only supports some of the operations, not all of them (e.g., a GPU that only supports single-precision operations). All the hard-coded back-end MPI_Op functions for (MPI_Op, MPI_Datatype) tuples still exist, but unlike coll, they're in the framework base (vs. being in a separate "basic" component) and are automatically used if no component is found at runtime that provides a module with the necessary function pointers. There is an "example" op component that will hopefully be useful to those writing meaningful op components. It is currently .ompi_ignore'd so that it doesn't impinge on other developers (it's somewhat chatty in terms of opal_output() so that you can tell when its functions have been invoked). See the README file in the example op component directory. Developers of new op components are encouraged to look at the following wiki pages: https://svn.open-mpi.org/trac/ompi/wiki/devel/Autogen https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateComponent https://svn.open-mpi.org/trac/ompi/wiki/devel/CreateFramework = MPI_REDUCE_LOCAL = Part of the MPI-2.2 proposal listed here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/24 is to add a new function named MPI_REDUCE_LOCAL. It is very easy to implement, so I added it (also because it makes testing the op framework pretty easy -- you can do it in serial rather than via parallel reductions). There's even a man page! This commit was SVN r20280.
2009-01-15 02:44:31 +03:00
}