/* -*- 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 <string.h>

#include <stdlib.h>

#define COUNT (200)

#undef TIMING

void handle_error(int errcode, const char *str);

void handle_error(int errcode, const char *str)

{

    char msg[MPI_MAX_ERROR_STRING];

    int resultlen;

    MPI_Error_string(errcode, msg, &resultlen);

    fprintf(stderr, "%s: %s\n", str, msg);

}

/* tests shared file pointer functions */

int main(int argc, char **argv)

{

    int *buf, i, rank, nprocs, len, sum;

    int global_sum;

    int errs = 0, toterrs, errcode;

    char *filename;

    MPI_File fh;

    MPI_Status status;

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    double wr_stime, wr_etime, wr_time, wr_sumtime;

    double rd_stime, rd_etime, rd_time, rd_sumtime;

/* process 0 takes the file name as a command-line argument and

   broadcasts it to other processes */

    if (!rank) {

        i = 1;

        while ((i < argc) && strcmp("-fname", *argv)) {

            i++;

            argv++;

        }

        if (i >= argc) {

            fprintf(stderr, "\n*#  Usage: shared_fp -fname filename\n\n");

            MPI_Abort(MPI_COMM_WORLD, 1);

        }

        argv++;

        len = strlen(*argv);

        filename = (char *) malloc(len + 10);

        strcpy(filename, *argv);

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        MPI_Bcast(filename, len + 10, MPI_CHAR, 0, MPI_COMM_WORLD);

    } else {

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        filename = (char *) malloc(len + 10);

        MPI_Bcast(filename, len + 10, MPI_CHAR, 0, MPI_COMM_WORLD);

    }

    buf = (int *) malloc(COUNT * sizeof(int));

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

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

        buf[i] = COUNT * rank + i;

    errcode = MPI_File_open(MPI_COMM_WORLD, filename,

                            MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh;;

    if (errcode != MPI_SUCCESS) {

        handle_error(errcode, "MPI_File_open");

    }

    wr_stime = MPI_Wtime();

    errcode = MPI_File_write_ordered(fh, buf, COUNT, MPI_INT, &status);

    if (errcode != MPI_SUCCESS) {

        handle_error(errcode, "MPI_File_write_shared");

    }

    wr_etime = MPI_Wtime();

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

        buf[i] = 0;

    MPI_Barrier(MPI_COMM_WORLD);

    rd_stime = MPI_Wtime();

    errcode = MPI_File_seek_shared(fh, 0, MPI_SEEK_SET);

    if (errcode != MPI_SUCCESS) {

        handle_error(errcode, "MPI_File_seek_shared");

    }

    errcode = MPI_File_read_ordered(fh, buf, COUNT, MPI_INT, &status);

    if (errcode != MPI_SUCCESS) {

        handle_error(errcode, "MPI_File_read_shared");

    }

    rd_etime = MPI_Wtime();

    MPI_File_close(&fh;;

    sum = 0;

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

        sum += buf[i];

    MPI_Allreduce(&sum, &global_sum, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);

    wr_time = wr_etime - wr_stime;

    rd_time = rd_etime - rd_stime;

    MPI_Allreduce(&wr_time, &wr_sumtime, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);

    MPI_Allreduce(&rd_time, &rd_sumtime, 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);

    if (global_sum != (((COUNT * nprocs - 1) * (COUNT * nprocs)) / 2)) {

        errs++;

        fprintf(stderr, "Error: sum %d, global_sum %d, %d\n",

                sum, global_sum, (((COUNT * nprocs - 1) * (COUNT * nprocs)) / 2));

    }

    free(buf);

    free(filename);

    MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);

    if (rank == 0) {

        if (toterrs > 0) {

            fprintf(stderr, "Found %d errors\n", toterrs);

        } else {

            fprintf(stdout, " No Errors\n");

#ifdef TIMING

            fprintf(stderr, "nprocs: %d bytes: %d write: %f read %f\n",

                    nprocs, COUNT * sizeof(int), wr_sumtime, rd_sumtime);

#endif

        }

    }

    MPI_Finalize();

    return 0;

}