greq1.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) 2003 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include "mpitest.h"

static char MTEST_Descrip[] = "Simple test of generalized requests";


int query_fn( void *extra_state, MPI_Status *status )
{
    /* Set a default status */
    status->MPI_SOURCE = MPI_UNDEFINED;
    status->MPI_TAG    = MPI_UNDEFINED;
    MPI_Status_set_cancelled( status, 0 );
    MPI_Status_set_elements( status, MPI_BYTE, 0 );
    return 0;
}
int free_fn( void *extra_state )
{
    int *b = (int *)extra_state;
    if (b) *b = *b - 1;
    /* The value returned by the free function is the error code
       returned by the wait/test function */
    return 0;
}
int cancel_fn( void *extra_state, int complete )
{
    return 0;
}

/*
 * This is a very simple test of generalized requests.  Normally, the
 * MPI_Grequest_complete function would be called from another routine,
 * often running in a separate thread.  This simple code allows us to
 * check that requests can be created, tested, and waited on in the
 * case where the request is complete before the wait is called.  
 *
 * Note that MPI did *not* define a routine that can be called within
 * test or wait to advance the state of a generalized request.  
 * Most uses of generalized requests will need to use a separate thread.
 */
int main( int argc, char *argv[] )
{
    int errs = 0;
    int counter, flag;
    MPI_Status    status;
    MPI_Request   request;

    MTest_Init( &argc, &argv );

    MPI_Grequest_start( query_fn, free_fn, cancel_fn, NULL, &request );
    
    MPI_Test( &request, &flag, &status );
    if (flag) {
	errs++;
	fprintf( stderr, "Generalized request marked as complete\n" );
    }

    MPI_Grequest_complete( request );

    MPI_Wait( &request, &status );

    counter = 1;
    MPI_Grequest_start( query_fn, free_fn, cancel_fn, &counter, &request );
    MPI_Grequest_complete( request );
    MPI_Wait( &request, MPI_STATUS_IGNORE );
    
    if (counter) {
	errs++;
	fprintf( stderr, "Free routine not called, or not called with extra_data" );
    }

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