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

/*

 *  (C) 2015 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include "mpitest.h"

#include <stdio.h>

#include <stdlib.h>

#define ROOT 7

#if 0

/* Following should always work for -n 8  256, -N 32, using longs */

#define COUNT 1048576*32

#endif

#if 1

/* Following will fail for -n 8 unless gather path is 64 bit clean */

#define COUNT (1024*1024*128+1)

#endif

#define VERIFY_CONST 100000000L

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

{

    int rank, size;

    int i, j;

    long *sendbuf = NULL;

    long *recvbuf = NULL;

    MTest_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    if (size < (ROOT + 1)) {

        fprintf(stderr, "At least %d processes required\n", ROOT + 1);

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

    sendbuf = malloc(COUNT * sizeof(long));

    if (sendbuf == NULL) {

        fprintf(stderr, "PE %d:ERROR: malloc of sendbuf failed\n", rank);

    }

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

        sendbuf[i] = (long) i + (long) rank *VERIFY_CONST;

    }

    if (rank == ROOT) {

        recvbuf = malloc(COUNT * sizeof(long) * size);

        if (recvbuf == NULL) {

            fprintf(stderr, "PE %d:ERROR: malloc of recvbuf failed\n", rank);

        }

        for (i = 0; i < COUNT * size; i++) {

            recvbuf[i] = -456789L;

        }

    }

    MPI_Gather(sendbuf, COUNT, MPI_LONG, recvbuf, COUNT, MPI_LONG, ROOT, MPI_COMM_WORLD);

    int errs = 0;

    if (rank == ROOT) {

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

            for (j = 0; j < COUNT; j++) {

                if (recvbuf[i * COUNT + j] != i * VERIFY_CONST + j) {

                    printf("PE 0: mis-match error");

                    printf("  recbuf[%d * %d + %d] = ", i, COUNT, j);

                    printf("  %ld,", recvbuf[i * COUNT + j]);

                    printf("  should be %ld\n", i * VERIFY_CONST + j);

                    errs++;

                    if (errs > 10) {

                        j = COUNT;

                    }

                }

            }

        }

        free(recvbuf);

    }

    MPI_Barrier(MPI_COMM_WORLD);

    MTest_Finalize(errs);

    free(sendbuf);

    return MTestReturnValue(errs);

}