diff options
Diffstat (limited to 'boost/mpi/collectives/all_gather.hpp')
| -rw-r--r-- | boost/mpi/collectives/all_gather.hpp | 131 |
1 files changed, 93 insertions, 38 deletions
diff --git a/boost/mpi/collectives/all_gather.hpp b/boost/mpi/collectives/all_gather.hpp index da73186c64..4adaeb9c87 100644 --- a/boost/mpi/collectives/all_gather.hpp +++ b/boost/mpi/collectives/all_gather.hpp @@ -1,52 +1,107 @@ -// Copyright (C) 2005-2006 Douglas Gregor <doug.gregor -at- gmail.com>. +// Copyright (C) 2005, 2006 Douglas Gregor. // Use, modification and distribution is subject to the Boost Software // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) -// Message Passing Interface 1.1 -- Section 4.7. Gather-to-all -#ifndef BOOST_MPI_ALL_GATHER_HPP -#define BOOST_MPI_ALL_GATHER_HPP +// Message Passing Interface 1.1 -- Section 4.5. Gather +#ifndef BOOST_MPI_ALLGATHER_HPP +#define BOOST_MPI_ALLGATHER_HPP +#include <cassert> +#include <cstddef> +#include <numeric> #include <boost/mpi/exception.hpp> #include <boost/mpi/datatype.hpp> #include <vector> -#include <boost/serialization/vector.hpp> - -// all_gather falls back to gather+broadcast in some cases -#include <boost/mpi/collectives/broadcast.hpp> -#include <boost/mpi/collectives/gather.hpp> +#include <boost/mpi/packed_oarchive.hpp> +#include <boost/mpi/packed_iarchive.hpp> +#include <boost/mpi/detail/point_to_point.hpp> +#include <boost/mpi/communicator.hpp> +#include <boost/mpi/environment.hpp> +#include <boost/mpi/detail/offsets.hpp> +#include <boost/mpi/detail/antiques.hpp> +#include <boost/assert.hpp> namespace boost { namespace mpi { namespace detail { - // We're all-gathering for a type that has an associated MPI - // datatype, so we'll use MPI_Gather to do all of the work. - template<typename T> - void - all_gather_impl(const communicator& comm, const T* in_values, int n, - T* out_values, mpl::true_) - { - MPI_Datatype type = boost::mpi::get_mpi_datatype<T>(*in_values); - BOOST_MPI_CHECK_RESULT(MPI_Allgather, - (const_cast<T*>(in_values), n, type, - out_values, n, type, comm)); - } +// We're all-gathering for a type that has an associated MPI +// datatype, so we'll use MPI_Gather to do all of the work. +template<typename T> +void +all_gather_impl(const communicator& comm, const T* in_values, int n, + T* out_values, mpl::true_) +{ + MPI_Datatype type = get_mpi_datatype<T>(*in_values); + BOOST_MPI_CHECK_RESULT(MPI_Allgather, + (const_cast<T*>(in_values), n, type, + out_values, n, type, comm)); +} - // We're all-gathering for a type that has no associated MPI - // type. So, we'll do a manual gather followed by a broadcast. - template<typename T> - void - all_gather_impl(const communicator& comm, const T* in_values, int n, - T* out_values, mpl::false_) - { - gather(comm, in_values, n, out_values, 0); - broadcast(comm, out_values, comm.size() * n, 0); +// We're all-gathering for a type that does not have an +// associated MPI datatype, so we'll need to serialize +// it. +template<typename T> +void +all_gather_impl(const communicator& comm, const T* in_values, int n, + T* out_values, int const* sizes, int const* skips, mpl::false_) +{ + int nproc = comm.size(); + // first, gather all size, these size can be different for + // each process + packed_oarchive oa(comm); + for (int i = 0; i < n; ++i) { + oa << in_values[i]; } + std::vector<int> oasizes(nproc); + int oasize = oa.size(); + BOOST_MPI_CHECK_RESULT(MPI_Allgather, + (&oasize, 1, MPI_INTEGER, + c_data(oasizes), 1, MPI_INTEGER, + MPI_Comm(comm))); + // Gather the archives, which can be of different sizes, so + // we need to use allgatherv. + // Every thing is contiguous, so the offsets can be + // deduced from the collected sizes. + std::vector<int> offsets(nproc); + sizes2offsets(oasizes, offsets); + packed_iarchive::buffer_type recv_buffer(std::accumulate(oasizes.begin(), oasizes.end(), 0)); + BOOST_MPI_CHECK_RESULT(MPI_Allgatherv, + (const_cast<void*>(oa.address()), int(oa.size()), MPI_BYTE, + c_data(recv_buffer), c_data(oasizes), c_data(offsets), MPI_BYTE, + MPI_Comm(comm))); + for (int src = 0; src < nproc; ++src) { + int nb = sizes ? sizes[src] : n; + int skip = skips ? skips[src] : 0; + std::advance(out_values, skip); + if (src == comm.rank()) { // this is our local data + for (int i = 0; i < nb; ++i) { + *out_values++ = *in_values++; + } + } else { + packed_iarchive ia(comm, recv_buffer, boost::archive::no_header, offsets[src]); + for (int i = 0; i < nb; ++i) { + ia >> *out_values++; + } + } + } +} + +// We're all-gathering for a type that does not have an +// associated MPI datatype, so we'll need to serialize +// it. +template<typename T> +void +all_gather_impl(const communicator& comm, const T* in_values, int n, + T* out_values, mpl::false_ isnt_mpi_type) +{ + all_gather_impl(comm, in_values, n, out_values, (int const*)0, (int const*)0, isnt_mpi_type); +} } // end namespace detail template<typename T> -inline void +void all_gather(const communicator& comm, const T& in_value, T* out_values) { detail::all_gather_impl(comm, &in_value, 1, out_values, is_mpi_datatype<T>()); @@ -54,15 +109,15 @@ all_gather(const communicator& comm, const T& in_value, T* out_values) template<typename T> void -all_gather(const communicator& comm, const T& in_value, - std::vector<T>& out_values) +all_gather(const communicator& comm, const T& in_value, std::vector<T>& out_values) { + using detail::c_data; out_values.resize(comm.size()); - ::boost::mpi::all_gather(comm, &in_value, 1, &out_values[0]); + ::boost::mpi::all_gather(comm, in_value, c_data(out_values)); } template<typename T> -inline void +void all_gather(const communicator& comm, const T* in_values, int n, T* out_values) { detail::all_gather_impl(comm, in_values, n, out_values, is_mpi_datatype<T>()); @@ -70,11 +125,11 @@ all_gather(const communicator& comm, const T* in_values, int n, T* out_values) template<typename T> void -all_gather(const communicator& comm, const T* in_values, int n, - std::vector<T>& out_values) +all_gather(const communicator& comm, const T* in_values, int n, std::vector<T>& out_values) { + using detail::c_data; out_values.resize(comm.size() * n); - ::boost::mpi::all_gather(comm, in_values, n, &out_values[0]); + ::boost::mpi::all_gather(comm, in_values, n, c_data(out_values)); } } } // end namespace boost::mpi |