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

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include "stdio.h"

#include "stdlib.h"

#include "mpitest.h"

/* Fetch and add example from Using MPI-2 (the non-scalable version,

   Fig. 6.12). */

#define NTIMES 20       /* no of times each process calls the counter

                         * routine */

int localvalue = 0;             /* contribution of this process to the counter. We

                                 * define it as a global variable because attribute

                                 * caching on the window is not enabled yet. */

void Get_nextval(MPI_Win win, int *val_array, MPI_Datatype get_type,

                 int rank, int nprocs, int *value);

int compar(const void *a, const void *b);

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

{

    int rank, nprocs, i, blens[2], disps[2], *counter_mem, *val_array, *results, *counter_vals;

    MPI_Datatype get_type;

    MPI_Win win;

    int errs = 0;

    MTest_Init(&argc, &argv);

    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    if (rank == 0) {

        /* allocate counter memory and initialize to 0 */

        counter_mem = (int *) calloc(nprocs, sizeof(int));

        MPI_Win_create(counter_mem, nprocs * sizeof(int), sizeof(int),

                       MPI_INFO_NULL, MPI_COMM_WORLD, &win);

        MPI_Win_free(&win);

        free(counter_mem);

        /* gather the results from other processes, sort them, and check

         * whether they represent a counter being incremented by 1 */

        results = (int *) malloc(NTIMES * nprocs * sizeof(int));

        for (i = 0; i < NTIMES * nprocs; i++)

            results[i] = -1;

        MPI_Gather(MPI_IN_PLACE, 0, MPI_DATATYPE_NULL, results, NTIMES, MPI_INT, 0, MPI_COMM_WORLD);

        qsort(results + NTIMES, NTIMES * (nprocs - 1), sizeof(int), compar);

        for (i = NTIMES + 1; i < (NTIMES * nprocs); i++)

            if (results[i] != results[i - 1] + 1)

                errs++;

        free(results);

    }

    else {

        blens[0] = rank;

        disps[0] = 0;

        blens[1] = nprocs - rank - 1;

        disps[1] = rank + 1;

        MPI_Type_indexed(2, blens, disps, MPI_INT, &get_type);

        MPI_Type_commit(&get_type);

        val_array = (int *) malloc(nprocs * sizeof(int));

        /* allocate array to store the values obtained from the

         * fetch-and-add counter */

        counter_vals = (int *) malloc(NTIMES * sizeof(int));

        MPI_Win_create(NULL, 0, 1, MPI_INFO_NULL, MPI_COMM_WORLD, &win);

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

            Get_nextval(win, val_array, get_type, rank, nprocs, counter_vals + i);

            /* printf("Rank %d, counter %d\n", rank, value); */

        }

        MPI_Win_free(&win);

        free(val_array);

        MPI_Type_free(&get_type);

        /* gather the results to the root */

        MPI_Gather(counter_vals, NTIMES, MPI_INT, NULL, 0, MPI_DATATYPE_NULL, 0, MPI_COMM_WORLD);

        free(counter_vals);

    }

    MTest_Finalize(errs);

    MPI_Finalize();

    return 0;

}

void Get_nextval(MPI_Win win, int *val_array, MPI_Datatype get_type,

                 int rank, int nprocs, int *value)

{

    int one = 1, i;

    MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);

    MPI_Accumulate(&one, 1, MPI_INT, 0, rank, 1, MPI_INT, MPI_SUM, win);

    MPI_Get(val_array, 1, get_type, 0, 0, 1, get_type, win);

    MPI_Win_unlock(0, win);

    *value = 0;

    val_array[rank] = localvalue;

    for (i = 0; i < nprocs; i++)

        *value = *value + val_array[i];

    localvalue++;

}

int compar(const void *a, const void *b)

{

    return (*((int *) a) - *((int *) b));

}