mpi_environment.h

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 *   Copyright (C) 2004-2015 The PaGMO development team,                     *
 *   Advanced Concepts Team (ACT), European Space Agency (ESA)               *
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 *   https://github.com/esa/pagmo                                            *
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 *   act@esa.int                                                             *
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#ifndef PAGMO_MPI_ENVIRONMENT_H
#define PAGMO_MPI_ENVIRONMENT_H

#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/numeric/conversion/cast.hpp>
#include <boost/utility.hpp>
#include <mpi.h>
#include <sstream>
#include <string>
#include <vector>

#include "config.h"

namespace pagmo
{


class __PAGMO_VISIBLE mpi_environment: private boost::noncopyable
{
        public:
                mpi_environment();
                ~mpi_environment();
                static bool is_multithread();
                static int get_size();
                static int get_rank();

                template <class T>
                static void recv(T &retval, int source)
                {
                        check_init();
                        MPI_Status status;
                        // First receive the size.
                        int size;
                        MPI_Recv(static_cast<void *>(&size),1,MPI_INT,source,0,MPI_COMM_WORLD,&status);
                        // Prepare the vector of chars.
                        std::vector<char> buffer_char(boost::numeric_cast<std::vector<char>::size_type>(size),0);
                        // Receive the payload.
                        MPI_Recv(static_cast<void *>(&buffer_char[0]),size,MPI_CHAR,source,1,MPI_COMM_WORLD,&status);
                        // Build the string from the vector.
                        const std::string buffer_str(buffer_char.begin(),buffer_char.end());
                        // Unpickle the payload.
                        std::stringstream ss(buffer_str);
                        boost::archive::text_iarchive ia(ss);
                        ia >> retval;
                }

                template <class T>
                static void send(const T &payload, int destination)
                {
                        check_init();
                        std::stringstream ss;
                        boost::archive::text_oarchive oa(ss);
                        oa << payload;
                        const std::string buffer_str(ss.str());
                        std::vector<char> buffer_char(buffer_str.begin(),buffer_str.end());
                        // Send the size.
                        int size = boost::numeric_cast<int>(buffer_char.size());
                        MPI_Send(static_cast<void *>(&size),1,MPI_INT,destination,0,MPI_COMM_WORLD);
                        // Send the string.
                        MPI_Send(static_cast<void *>(&buffer_char[0]),size,MPI_CHAR,destination,1,MPI_COMM_WORLD);
                }
                static bool iprobe(int);
        private:
                static void listen();
                static void check_init();
                static bool     m_initialised;
                static bool     m_multithread;
};

}

#endif