// Copyright 2005 The Trustees of Indiana University. | |
// 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) | |
// Authors: Douglas Gregor | |
// Andrew Lumsdaine | |
#ifndef BOOST_GRAPH_PARALLEL_INPLACE_ALL_TO_ALL_HPP | |
#define BOOST_GRAPH_PARALLEL_INPLACE_ALL_TO_ALL_HPP | |
#ifndef BOOST_GRAPH_USE_MPI | |
#error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included" | |
#endif | |
// | |
// Implements the inplace all-to-all communication algorithm. | |
// | |
#include <vector> | |
#include <iterator> | |
namespace boost { namespace parallel { | |
template<typename ProcessGroup, typename T> | |
// where {LinearProcessGroup<ProcessGroup>, MessagingProcessGroup<ProcessGroup>} | |
void | |
inplace_all_to_all(ProcessGroup pg, | |
const std::vector<std::vector<T> >& outgoing, | |
std::vector<std::vector<T> >& incoming) | |
{ | |
typedef typename std::vector<T>::size_type size_type; | |
typedef typename ProcessGroup::process_size_type process_size_type; | |
typedef typename ProcessGroup::process_id_type process_id_type; | |
process_size_type p = num_processes(pg); | |
// Make sure there are no straggling messages | |
synchronize(pg); | |
// Send along the count (always) and the data (if count > 0) | |
for (process_id_type dest = 0; dest < p; ++dest) { | |
if (dest != process_id(pg)) { | |
send(pg, dest, 0, outgoing[dest].size()); | |
if (!outgoing[dest].empty()) | |
send(pg, dest, 1, &outgoing[dest].front(), outgoing[dest].size()); | |
} | |
} | |
// Make sure all of the data gets transferred | |
synchronize(pg); | |
// Receive the sizes and data | |
for (process_id_type source = 0; source < p; ++source) { | |
if (source != process_id(pg)) { | |
size_type size; | |
receive(pg, source, 0, size); | |
incoming[source].resize(size); | |
if (size > 0) | |
receive(pg, source, 1, &incoming[source].front(), size); | |
} else if (&incoming != &outgoing) { | |
incoming[source] = outgoing[source]; | |
} | |
} | |
} | |
template<typename ProcessGroup, typename T> | |
// where {LinearProcessGroup<ProcessGroup>, MessagingProcessGroup<ProcessGroup>} | |
void | |
inplace_all_to_all(ProcessGroup pg, std::vector<std::vector<T> >& data) | |
{ | |
inplace_all_to_all(pg, data, data); | |
} | |
} } // end namespace boost::parallel | |
#endif // BOOST_GRAPH_PARALLEL_INPLACE_ALL_TO_ALL_HPP |