| // 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 |