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82 lines
2.5 KiB
82 lines
2.5 KiB
// Copyright (C) 2005-2006 Douglas Gregor <doug.gregor -at- gmail.com>. |
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// Use, modification and distribution is subject to the Boost Software |
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// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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// Message Passing Interface 1.1 -- Section 4.7. Gather-to-all |
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#ifndef BOOST_MPI_ALL_GATHER_HPP |
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#define BOOST_MPI_ALL_GATHER_HPP |
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#include <boost/mpi/exception.hpp> |
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#include <boost/mpi/datatype.hpp> |
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#include <vector> |
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#include <boost/serialization/vector.hpp> |
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// all_gather falls back to gather+broadcast in some cases |
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#include <boost/mpi/collectives/broadcast.hpp> |
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#include <boost/mpi/collectives/gather.hpp> |
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namespace boost { namespace mpi { |
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namespace detail { |
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// We're all-gathering for a type that has an associated MPI |
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// datatype, so we'll use MPI_Gather to do all of the work. |
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template<typename T> |
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void |
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all_gather_impl(const communicator& comm, const T* in_values, int n, |
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T* out_values, mpl::true_) |
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{ |
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MPI_Datatype type = boost::mpi::get_mpi_datatype<T>(*in_values); |
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BOOST_MPI_CHECK_RESULT(MPI_Allgather, |
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(const_cast<T*>(in_values), n, type, |
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out_values, n, type, comm)); |
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} |
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// We're all-gathering for a type that has no associated MPI |
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// type. So, we'll do a manual gather followed by a broadcast. |
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template<typename T> |
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void |
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all_gather_impl(const communicator& comm, const T* in_values, int n, |
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T* out_values, mpl::false_) |
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{ |
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gather(comm, in_values, n, out_values, 0); |
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broadcast(comm, out_values, comm.size() * n, 0); |
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} |
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} // end namespace detail |
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template<typename T> |
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inline void |
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all_gather(const communicator& comm, const T& in_value, T* out_values) |
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{ |
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detail::all_gather_impl(comm, &in_value, 1, out_values, is_mpi_datatype<T>()); |
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} |
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template<typename T> |
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void |
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all_gather(const communicator& comm, const T& in_value, |
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std::vector<T>& out_values) |
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{ |
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out_values.resize(comm.size()); |
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::boost::mpi::all_gather(comm, &in_value, 1, &out_values[0]); |
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} |
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template<typename T> |
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inline void |
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all_gather(const communicator& comm, const T* in_values, int n, T* out_values) |
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{ |
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detail::all_gather_impl(comm, in_values, n, out_values, is_mpi_datatype<T>()); |
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} |
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template<typename T> |
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void |
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all_gather(const communicator& comm, const T* in_values, int n, |
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std::vector<T>& out_values) |
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{ |
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out_values.resize(comm.size() * n); |
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::boost::mpi::all_gather(comm, in_values, n, &out_values[0]); |
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} |
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} } // end namespace boost::mpi |
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#endif // BOOST_MPI_ALL_GATHER_HPP
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