slice-pack-external.c

mpi并行计算的c++代码 可用vc或gcc编译通过 可以用来搭建并行计算试验环境

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
#include "mpi.h"

static int verbose = 0;
int a[100][100][100], e[9][9][9];

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

/* helper functions */
static int parse_args(int argc, char **argv);

int main(int argc, char *argv[])
{
    /* Variable declarations */
    MPI_Datatype oneslice, twoslice, threeslice;
    int errs = 0;
    MPI_Aint sizeofint, bufsize, position;
    void *buffer;
	
    int i, j, k;
	
    /* Initialize a to some known values. */
    for (i = 0; i < 100; i++) {
	for (j = 0; j < 100; j++) {
	    for (k = 0; k < 100; k++) {
		a[i][j][k] = i*1000000+j*1000+k;
	    }
	}
    }
	
    /* Initialize MPI */
    MPI_Init(&argc, &argv);
    MPI_Type_extent(MPI_INT, &sizeofint);
  
    parse_args(argc, argv);

    /* Create data types. */
    /* NOTE: This differs from the way that it's done on the sheet. */
    /* On the sheet, the slice is a[0, 2, 4, ..., 16][2-10][1-9]. */
    /* Below, the slice is a[0-8][2-10][1, 3, 5, ..., 17]. */
    MPI_Type_vector(9, 1, 2, MPI_INT, &oneslice);
    MPI_Type_hvector(9, 1, 100*sizeofint, oneslice, &twoslice);
    MPI_Type_hvector(9, 1, 100*100*sizeofint, twoslice, &threeslice);
	
    MPI_Type_commit(&threeslice);
	
    /* Pack it into a buffer. */
    position = 0;
/*     MPI_Pack_size(1, threeslice, MPI_COMM_WORLD, &bufsize); */
    MPI_Pack_external_size("external32", 1, threeslice, &bufsize);
    if (bufsize != 2916)
    {
        fprintf(stderr," Error on pack size! Got %d; expecting %d\n", (int) bufsize, 2916);
    }
    buffer = (void *) malloc((unsigned) bufsize);

    /* -1 to indices on sheet to compensate for Fortran --> C */
    MPI_Pack_external("external32",
		      &(a[0][2][1]),
		      1, threeslice,
		      buffer,
		      bufsize,
		      &position);

    /* Unpack the buffer into e. */
    position = 0;
    MPI_Unpack_external("external32",
			buffer,
			bufsize,
			&position,
			e, 9*9*9,
			MPI_INT);
	
    /* Display errors, if any. */
    for (i = 0; i < 9; i++) {
	for (j = 0; j < 9; j++) {
	    for (k = 0; k < 9; k++) {
	       /* The truncation in integer division makes this safe. */
		if (e[i][j][k] != a[i][j+2][k*2+1]) {
		    errs++;
		    if (verbose) {
			printf("Error in location %d x %d x %d: %d, should be %d.\n",
			       i, j, k, e[i][j][k], a[i][j+2][k*2+1]);
		    }
		}
	    }
	}
    } 
  
    /* Release memory. */
    free(buffer);

    if (errs) {
	fprintf(stderr, "Found %d errors\n", errs);
    }
    else {
	printf(" No Errors\n");
    }

    MPI_Type_free(&oneslice);
    MPI_Type_free(&twoslice);
    MPI_Type_free(&threeslice);

    MPI_Finalize();
    return 0;
}

/* parse_args()
 */
static int parse_args(int argc, char **argv)
{
    int ret;

    while ((ret = getopt(argc, argv, "v")) >= 0)
    {
	switch (ret) {
	    case 'v':
		verbose = 1;
		break;
	}
    }
    return 0;
}