allred2.c

来自「fortran并行计算包」· C语言 代码 · 共 54 行

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *
 *  (C) 2003 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpitest.h"

static char MTEST_Descrip[] = "Test MPI_Allreduce with MPI_IN_PLACE";

int main( int argc, char *argv[] )
{
    int errs = 0;
    int rank, size;
    int minsize = 2, count; 
    MPI_Comm      comm;
    int *buf, i;

    MTest_Init( &argc, &argv );

    while (MTestGetIntracommGeneral( &comm, minsize, 1 )) {
	if (comm == MPI_COMM_NULL) continue;
	MPI_Comm_size( comm, &size );
	MPI_Comm_rank( comm, &rank );
	
	for (count = 1; count < 65000; count = count * 2) {
	    /* Contiguous data */
	    buf = (int *)malloc( count * sizeof(int) );
	    for (i=0; i<count; i++) buf[i] = rank + i;
	    MPI_Allreduce( MPI_IN_PLACE, buf, count, MPI_INT, MPI_SUM, comm );
	    /* Check the results */
	    for (i=0; i<count; i++) {
		int result = i * size + (size*(size-1))/2;
		if (buf[i] != result) {
		    errs ++;
		    if (errs < 10) {
			fprintf( stderr, "buf[%d] = %d expected %d\n",
				 i, buf[i], result );
		    }
		}
	    }
	    free( buf );
	}
	MTestFreeComm( &comm );
    }

    MTest_Finalize( errs );
    MPI_Finalize();
    return 0;
}