/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *
 *  (C) 2007 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include <stdio.h>
#include <stdlib.h>
#include "mpi.h"
#include "mpitest.h"

/*
 * This test makes sure that each process can send to each other process.
 * If there are bugs in the handling of request completions or in
 * queue operations, then this test may fail on them (it did with
 * early EagerShort handling).
 */

#define MAXPES 32
#define MYBUFSIZE 16*1024
static int buffer[MAXPES][MYBUFSIZE];

#define NUM_RUNS 10

int main(int argc, char *argv[])
{
    int i;
    int count, size;
    int self, npes;
    double secs;
    MPI_Request request[MAXPES];
    MPI_Status status;

    MTest_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &self);
    MPI_Comm_size(MPI_COMM_WORLD, &npes);

    if (npes > MAXPES) {
        fprintf(stderr, "This program requires a comm_world no larger than %d", MAXPES);
        MPI_Abort(MPI_COMM_WORLD, 1);
    }

    for (size = 1; size <= MYBUFSIZE; size += size) {
        secs = -MPI_Wtime();
        for (count = 0; count < NUM_RUNS; count++) {
            MPI_Barrier(MPI_COMM_WORLD);

            for (i = 0; i < npes; i++) {
                if (i != self)
                    MPI_Irecv(buffer[i], size, MPI_INT, i,
                              MPI_ANY_TAG, MPI_COMM_WORLD, &request[i]);
            }

            for (i = 0; i < npes; i++) {
                if (i != self)
                    MPI_Send(buffer[self], size, MPI_INT, i, 0, MPI_COMM_WORLD);
            }

            for (i = 0; i < npes; i++) {
                if (i != self)
                    MPI_Wait(&request[i], &status);
            }

        }
        MPI_Barrier(MPI_COMM_WORLD);
        secs += MPI_Wtime();

        if (self == 0) {
            secs = secs / (double) NUM_RUNS;
            MTestPrintfMsg(1, "length = %d ints\n", size);
        }
    }

    /* Simple completion is all that we normally ask of this program */

    MTest_Finalize(0);

    MPI_Finalize();
    return 0;
}
