/* -*- 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 <stdlib.h>

#include <string.h>

#include <stdio.h>

/* A 32^3 array. For other array sizes, change array_of_gsizes below. */

/* Uses collective I/O. Writes a 3D block-distributed array to a file

   corresponding to the global array in row-major (C) order, reads it

   back, and checks that the data read is correct. */

/* The file name is taken as a command-line argument. */

/* Note that the file access pattern is noncontiguous. */

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);

    MPI_Abort(MPI_COMM_WORLD, 1);

}

int main(int argc, char **argv)

{

    MPI_Datatype newtype;

    int i, ndims, array_of_gsizes[3], array_of_distribs[3];

    int order, nprocs, j, len;

    int array_of_dargs[3], array_of_psizes[3];

    int *readbuf, *writebuf, mynod, *tmpbuf, array_size;

    MPI_Count bufcount;

    char *filename;

    int errs = 0, toterrs;

    MPI_File fh;

    MPI_Status status;

    MPI_Request request;

    MPI_Info info = MPI_INFO_NULL;

    int errcode;

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &mynod);

    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

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

   broadcasts it to other processes */

    if (!mynod) {

        i = 1;

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

            i++;

            argv++;

        }

        if (i >= argc) {

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

            MPI_Abort(MPI_COMM_WORLD, 1);

        }

        argv++;

        len = strlen(*argv);

        filename = (char *) malloc(len + 1);

        strcpy(filename, *argv);

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

        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);

    } else {

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

        filename = (char *) malloc(len + 1);

        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);

    }

/* create the distributed array filetype */

    ndims = 3;

    order = MPI_ORDER_C;

    array_of_gsizes[0] = 32;

    array_of_gsizes[1] = 32;

    array_of_gsizes[2] = 32;

    array_of_distribs[0] = MPI_DISTRIBUTE_BLOCK;

    array_of_distribs[1] = MPI_DISTRIBUTE_BLOCK;

    array_of_distribs[2] = MPI_DISTRIBUTE_BLOCK;

    array_of_dargs[0] = MPI_DISTRIBUTE_DFLT_DARG;

    array_of_dargs[1] = MPI_DISTRIBUTE_DFLT_DARG;

    array_of_dargs[2] = MPI_DISTRIBUTE_DFLT_DARG;

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

        array_of_psizes[i] = 0;

    MPI_Dims_create(nprocs, ndims, array_of_psizes);

    MPI_Type_create_darray(nprocs, mynod, ndims, array_of_gsizes,

                           array_of_distribs, array_of_dargs,

                           array_of_psizes, order, MPI_INT, &newtype);

    MPI_Type_commit(&newtype);

/* initialize writebuf */

    MPI_Type_size_x(newtype, &bufcount);

    bufcount = bufcount / sizeof(int);

    writebuf = (int *) malloc(bufcount * sizeof(int));

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

        writebuf[i] = 1;

    array_size = array_of_gsizes[0] * array_of_gsizes[1] * array_of_gsizes[2];

    tmpbuf = (int *) calloc(array_size, sizeof(int));

    MPI_Irecv(tmpbuf, 1, newtype, mynod, 10, MPI_COMM_WORLD, &request);

    MPI_Send(writebuf, bufcount, MPI_INT, mynod, 10, MPI_COMM_WORLD);

    MPI_Wait(&request, &status);

    j = 0;

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

        if (tmpbuf[i]) {

            writebuf[j] = i;

            j++;

        }

    free(tmpbuf);

    if (j != bufcount) {

        fprintf(stderr, "Error in initializing writebuf on process %d\n", mynod);

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

/* end of initialization */

    /* write the array to the file */

    errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh;;

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_open");

    errcode = MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info);

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_set_view");

    errcode = MPI_File_write_all(fh, writebuf, bufcount, MPI_INT, &status);

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_write_all");

    errcode = MPI_File_close(&fh;;

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_close");

    if (!mynod) {

        /* wkl suggests potential for false " No Errors" if both read

         * and write use the same file view */

        /* solution: rank 0 reads entire file and checks write values */

        errcode = MPI_File_open(MPI_COMM_SELF, filename, MPI_MODE_RDONLY, info, &fh;;

        if (errcode != MPI_SUCCESS)

            handle_error(errcode, "MPI_File_open");

        readbuf = (int *) malloc(array_size * sizeof(int));

        errcode = MPI_File_read(fh, readbuf, array_size, MPI_INT, &status);

        if (errcode != MPI_SUCCESS)

            handle_error(errcode, "MPI_File_read");

        errcode = MPI_File_close(&fh;;

        if (errcode != MPI_SUCCESS)

            handle_error(errcode, "MPI_File_close");

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

            if (readbuf[i] != i) {

                errs++;

                fprintf(stderr, "Error: write integer %d but read %d\n", i, readbuf[i]);

                break;

            }

        free(readbuf);

    }

    MPI_Barrier(MPI_COMM_WORLD);

    /* now read it back */

    readbuf = (int *) malloc(bufcount * sizeof(int));

    errcode = MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE | MPI_MODE_RDWR, info, &fh;;

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_open");

    errcode = MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", info);

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_set_view");

    errcode = MPI_File_read_all(fh, readbuf, bufcount, MPI_INT, &status);

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_read_all");

    errcode = MPI_File_close(&fh;;

    if (errcode != MPI_SUCCESS)

        handle_error(errcode, "MPI_File_close");

    /* check the data read */

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

        if (readbuf[i] != writebuf[i]) {

            errs++;

            fprintf(stderr, "Process %d, readbuf %d, writebuf %d, i %d\n", mynod, readbuf[i],

                    writebuf[i], i);

        }

    }

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

    if (mynod == 0) {

        if (toterrs > 0) {

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

        } else {

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

        }

    }

    MPI_Type_free(&newtype);

    free(readbuf);

    free(writebuf);

    free(filename);

    MPI_Finalize();

    return 0;

}