// Copyright (C) 2005-2006 Douglas Gregor <doug.gregor -at- gmail.com>. | |
// 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 | |
#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> | |
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 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); | |
} | |
} // end namespace detail | |
template<typename T> | |
inline 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>()); | |
} | |
template<typename T> | |
void | |
all_gather(const communicator& comm, const T& in_value, | |
std::vector<T>& out_values) | |
{ | |
out_values.resize(comm.size()); | |
::boost::mpi::all_gather(comm, &in_value, 1, &out_values[0]); | |
} | |
template<typename T> | |
inline 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>()); | |
} | |
template<typename T> | |
void | |
all_gather(const communicator& comm, const T* in_values, int n, | |
std::vector<T>& out_values) | |
{ | |
out_values.resize(comm.size() * n); | |
::boost::mpi::all_gather(comm, in_values, n, &out_values[0]); | |
} | |
} } // end namespace boost::mpi | |
#endif // BOOST_MPI_ALL_GATHER_HPP |