FM / collectives

/usr/include/boost/mpi/collectives

Name	Size	Mode	Actions
all_gather.hpp	4509	0644	edit dl rm
all_gatherv.hpp	4878	0644	edit dl rm
all_reduce.hpp	4929	0644	edit dl rm
all_to_all.hpp	4975	0644	edit dl rm
broadcast.hpp	4733	0644	edit dl rm
gather.hpp	5674	0644	edit dl rm
gatherv.hpp	5192	0644	edit dl rm
reduce.hpp	12895	0644	edit dl rm
scan.hpp	5907	0644	edit dl rm
scatter.hpp	6788	0644	edit dl rm
scatterv.hpp	5651	0644	edit dl rm

Edit: /usr/include/boost/mpi/collectives/all_to_all.hpp (4975B)

// 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 4.8. All-to-all
#ifndef BOOST_MPI_ALL_TO_ALL_HPP
#define BOOST_MPI_ALL_TO_ALL_HPP

#include <boost/mpi/exception.hpp>
#include <boost/mpi/datatype.hpp>
#include <vector>
#include <boost/mpi/packed_oarchive.hpp>
#include <boost/mpi/packed_iarchive.hpp>
#include <boost/mpi/communicator.hpp>
#include <boost/mpi/environment.hpp>
#include <boost/assert.hpp>
#include <boost/mpi/collectives_fwd.hpp>
#include <boost/mpi/allocator.hpp>

namespace boost { namespace mpi {
          
namespace detail {
  // We're performing an all-to-all with a type that has an
  // associated MPI datatype, so we'll use MPI_Alltoall to do all of
  // the work.
  template<typename T>
  void
  all_to_all_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_Alltoall,
                           (const_cast<T*>(in_values), n, type,
                            out_values, n, type, comm));
  }

// We're performing an all-to-all with a type that does not have an
  // associated MPI datatype, so we'll need to serialize
  // it.
  template<typename T>
  void
  all_to_all_impl(const communicator& comm, const T* in_values, int n,
                  T* out_values, mpl::false_)
  {
    int size = comm.size();
    int rank = comm.rank();

// The amount of data to be sent to each process
    std::vector<int> send_sizes(size);

// The displacements for each outgoing value.
    std::vector<int> send_disps(size);

// The buffer that will store all of the outgoing values
    std::vector<char, allocator<char> > outgoing;

// Pack the buffer with all of the outgoing values.
    for (int dest = 0; dest < size; ++dest) {
      // Keep track of the displacements
      send_disps[dest] = outgoing.size();

// Our own value will never be transmitted, so don't pack it.
      if (dest != rank) {
        packed_oarchive oa(comm, outgoing);
        for (int i = 0; i < n; ++i)
          oa << in_values[dest * n + i];
      }

// Keep track of the sizes
      send_sizes[dest] = outgoing.size() - send_disps[dest];
    }

// Determine how much data each process will receive.
    std::vector<int> recv_sizes(size);
    all_to_all(comm, send_sizes, recv_sizes);

// Prepare a buffer to receive the incoming data.
    std::vector<int> recv_disps(size);
    int sum = 0;
    for (int src = 0; src < size; ++src) {
      recv_disps[src] = sum;
      sum += recv_sizes[src];
    }
    std::vector<char, allocator<char> > incoming(sum > 0? sum : 1);

// Make sure we don't try to reference an empty vector
    if (outgoing.empty())
      outgoing.push_back(0);

// Transmit the actual data
    BOOST_MPI_CHECK_RESULT(MPI_Alltoallv,
                           (detail::c_data(outgoing), detail::c_data(send_sizes),
                            detail::c_data(send_disps), MPI_PACKED,
                            detail::c_data(incoming), detail::c_data(recv_sizes),
                            detail::c_data(recv_disps), MPI_PACKED,
                            comm));

// Deserialize data from the iarchive
    for (int src = 0; src < size; ++src) {
      if (src == rank) 
        std::copy(in_values + src * n, in_values + (src + 1) * n, 
                  out_values + src * n);
      else {
        packed_iarchive ia(comm, incoming, boost::archive::no_header,
                           recv_disps[src]);
        for (int i = 0; i < n; ++i)
          ia >> out_values[src * n + i];
      }
    }
  }
} // end namespace detail

template<typename T>
inline void
all_to_all(const communicator& comm, const T* in_values, T* out_values)
{
  detail::all_to_all_impl(comm, in_values, 1, out_values, is_mpi_datatype<T>());
}

template<typename T>
void
all_to_all(const communicator& comm, const std::vector<T>& in_values,
           std::vector<T>& out_values)
{
  BOOST_ASSERT((int)in_values.size() == comm.size());
  out_values.resize(comm.size());
  ::boost::mpi::all_to_all(comm, detail::c_data(in_values), detail::c_data(out_values));
}

template<typename T>
inline void
all_to_all(const communicator& comm, const T* in_values, int n, T* out_values)
{
  detail::all_to_all_impl(comm, in_values, n, out_values, is_mpi_datatype<T>());
}

template<typename T>
void
all_to_all(const communicator& comm, const std::vector<T>& in_values, int n,
           std::vector<T>& out_values)
{
  BOOST_ASSERT((int)in_values.size() == comm.size() * n);
  out_values.resize(comm.size() * n);
  ::boost::mpi::all_to_all(comm, detail::c_data(in_values), n, detail::c_data(out_values));
}

} } // end namespace boost::mpi

#endif // BOOST_MPI_ALL_TO_ALL_HPP

cmd: