lib_mpi_multidomain.h

/*
Multiscale Universal Interface Code Coupling Library

Copyright (C) 2017 Y. H. Tang, S. Kudo, X. Bian, Z. Li, G. E. Karniadakis

This software is jointly licensed under the Apache License, Version 2.0
and the GNU General Public License version 3, you may use it according
to either.

** Apache License, version 2.0 **

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

** GNU General Public License, version 3 **

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

** File Details **

Filename: lib_mpi_multidomain.h
Created: Jun 1, 2015
Author: Y. H. Tang
Description:
*/

#ifndef LIB_MPI_MULTIDOMAIN_H_
#define LIB_MPI_MULTIDOMAIN_H_

#include "lib_uri.h"
#include "comm_mpi.h"
#include "lib_mpi_helper.h"
#include "uniface.h"

namespace mui
{

using namespace mpi;

template<class CONFIG>
inline std::vector<uniface<CONFIG> *> create_uniface( std::string domain, std::vector<std::string> interfaces, MPI_Comm world = MPI_COMM_WORLD )
{
    // gather total number of interfaces (edges of the graph)
    int global_size, global_rank;
    MPI_Comm_size( world, &global_size );
    MPI_Comm_rank( world, &global_rank );

    std::map<int, std::string> map;
    std::vector<int> my_hashes;
    for( auto &i : interfaces ) {
        auto h = std::hash<std::string>()( i );
        my_hashes.push_back( h );
        map[h] = i;
    }
    for( int i = 0; i < global_size; i++ ) {
        if( global_rank == i ) {
            for( auto &e : map ) {
                printf( "> rank %d \"%s\" registered interface %s as %08X\n", global_rank, domain.c_str(), e.second.c_str(), e.first );
            }
        }
        MPI_Barrier( world );
    }

    int n_unique;
    std::set<int> unique_ifs;
    if( global_rank == 0 ) {
        std::vector<int> nifs = gather( ( int )interfaces.size(), world );
        std::vector<int> displs( global_size + 1, 0 );
        std::partial_sum( nifs.begin(), nifs.end(), displs.begin() + 1 );

        std::vector<int> all_hashes( displs.back() );
        MPI_Gatherv( my_hashes.data(), my_hashes.size(), MPI_INT, all_hashes.data(), nifs.data(), displs.data(), MPI_INT, 0, world );

        for( auto &i : all_hashes ) unique_ifs.insert( i );
        n_unique = unique_ifs.size();
        printf( "> %d distinct interfaces found\n", n_unique );
    } else {
        gather( ( int )interfaces.size(), world );
        MPI_Gatherv( my_hashes.data(), my_hashes.size(), MPI_INT, NULL, NULL, NULL, MPI_INT, 0, world );
    }
    MPI_Barrier( world );
    MPI_Bcast( &n_unique, 1, MPI_INT, 0, world );
    std::vector<int> uniq_hashes( n_unique );
    if( global_rank == 0 ) uniq_hashes.assign( unique_ifs.begin(), unique_ifs.end() );
    MPI_Bcast( uniq_hashes.data(), n_unique, MPI_INT, 0, world );

    std::vector<uniface<CONFIG> *> unifaces;
    for( auto &i : uniq_hashes ) {
        MPI_Comm comm_ifs;
        if( map.find( i ) != map.end() ) {
            MPI_Comm_split( world, 1, global_rank, &comm_ifs );
            int comm_rank;
            MPI_Comm_rank( comm_ifs, &comm_rank );
            if( comm_rank == 0 ) printf( "> setting up interface %s [%08X] (rank ids are local to each interface)\n", map[i].c_str(), i );
            std::string full_uri( "mpi://" );
            full_uri = full_uri + domain + "/" + map[i];
            unifaces.push_back( new uniface<CONFIG>( new comm_mpi_smart( full_uri.c_str(), comm_ifs ) ) );
        } else {
            MPI_Comm_split( world, 0, global_rank, &comm_ifs );
        }

        MPI_Barrier( world );
    }

    return unifaces;
}

}

#endif /* LIB_MPI_MULTIDOMAIN_H_ */