// mpi_spawn.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpi.h"

#define NHOST 2

int main(int argc, char* argv[]) {

    int supported;
    int rank, size;
    MPI_Comm parent, intercomm; 
    
    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &supported);

    if(supported != MPI_THREAD_MULTIPLE){
        printf("The library does not support MPI_THREAD_MULTIPLE\n");
        exit(-1);
    }

    MPI_Comm_get_parent(&parent);

    if (parent == MPI_COMM_NULL){
        int i;
        int nproc[NHOST] = {1, 1};
        //char* progs[NHOST] = {"c:\\mpi_spawn",  "c:\\tm\\mpi_spawn"};
		char* progs[NHOST] = {"c:\\mpi_spawn", "c:\\mpi_spawn"};

        MPI_Info infos[NHOST];
        
        for (i=0; i < NHOST; i++) {
            MPI_Info_create(&infos[i]);
            MPI_Info_set(infos[i], "host", "localhost");
        }
        MPI_Comm_spawn_multiple(NHOST,
            progs, MPI_ARGVS_NULL, nproc, infos,
            0, MPI_COMM_WORLD, &intercomm, MPI_ERRCODES_IGNORE);
        for (i=0; i < NHOST; i++) {
            MPI_Info_free(&infos[i]);
        }
    }
    else{
        intercomm = parent;
    }
    MPI_Comm_rank(intercomm, &rank);
    MPI_Comm_size(intercomm, &size);
    printf("[%d/%d] Hello world\n", rank, size); fflush(stdout);

    MPI_Comm_free(&intercomm);
    MPI_Finalize();
    return 0;
}