/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include <stdlib.h>

#include <stdio.h>

#include <mpi.h>

int main(int argc, char **argv)

{

    int size;

    int rank;

    int *msg = NULL;

    int msg_sz = 0;

    int niter = 1;

    int iter;

    int i;

    if (MPI_Init(&argc, &argv) != MPI_SUCCESS) {

        printf("ERROR: problem with MPI_Init\n");

        fflush(stdout);

    }

    if (MPI_Comm_size(MPI_COMM_WORLD, &size) != MPI_SUCCESS) {

        printf("ERROR: problem with MPI_Comm_size\n");

        fflush(stdout);

    }

    if (MPI_Comm_rank(MPI_COMM_WORLD, &rank) != MPI_SUCCESS) {

        printf("ERROR: problem with MPI_Comm_rank\n");

        fflush(stdout);

    }

    printf("sr: size %d rank %d\n", size, rank);

    fflush(stdout);

    if (size < 2) {

        printf("ERROR: needs to be run with at least 2 procs\n");

        fflush(stdout);

    }

    if (argc > 1) {

        sscanf(argv[1], "%d", &msg_sz);

    }

    if (argc > 2) {

        sscanf(argv[2], "%d", &niter);

    }

    if (rank == 0) {

        printf("msg_sz=%d, niter=%d\n", msg_sz, niter);

        fflush(stdout);

    }

    if (msg_sz > 0) {

        msg = (int *) malloc(msg_sz * sizeof(int));

    }

    if (rank == 0) {

        /* usleep(10000); */

        for (iter = 0; iter < niter; iter++) {

            for (i = 0; i < msg_sz; i++) {

                msg[i] = iter * msg_sz + i;

            }

            if (MPI_Send(msg, msg_sz, MPI_INT, 1, iter, MPI_COMM_WORLD)

                != MPI_SUCCESS) {

                printf("ERROR: problem with MPI_Send\n");

                fflush(stdout);

            }

        }

    } else if (rank == 1) {

        MPI_Status status;

        for (iter = 0; iter < niter; iter++) {

            if (MPI_Recv(msg, msg_sz, MPI_INT, 0, iter, MPI_COMM_WORLD, &status) != MPI_SUCCESS) {

                printf("ERROR: problem with MPI_Recv\n");

                fflush(stdout);

            }

            for (i = 0; i < msg_sz; i++) {

                if (msg[i] != iter * msg_sz + i) {

                    printf("ERROR: %d != %d, i=%d iter=%d\n", msg[i], iter * msg_sz + i, i, iter);

                    fflush(stdout);

                    abort();

                }

            }

        }

        printf("All messages successfully received!\n");

        fflush(stdout);

    }

    printf("sr: process %d finished\n", rank);

    fflush(stdout);

    if (MPI_Finalize() != MPI_SUCCESS) {

        printf("ERROR: problem with MPI_Finalize\n");

        fflush(stdout);

    }

    return 0;

}