60 строки
1.4 KiB
C
60 строки
1.4 KiB
C
/*
|
|
* Copyright (c) 2004-2007 High Performance Computing Center Stuttgart,
|
|
* University of Stuttgart. All rights reserved.
|
|
* $COPYRIGHT$
|
|
*
|
|
* Additional copyrights may follow
|
|
*
|
|
* $HEADER$
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include "mpi.h"
|
|
|
|
int main( int argc, char *argv[] )
|
|
{
|
|
int rank, size;
|
|
int send_value,recv_value;
|
|
|
|
MPI_Status status;
|
|
MPI_Request send_request;
|
|
MPI_Request recv_request;
|
|
|
|
MPI_Init( &argc, &argv );
|
|
|
|
MPI_Comm_rank( MPI_COMM_WORLD, &rank );
|
|
MPI_Comm_size( MPI_COMM_WORLD, &size );
|
|
|
|
send_value = 10;
|
|
recv_value = 0;
|
|
|
|
if (size != 2) {
|
|
fprintf (stderr, "Error: Need 2 processes\n");
|
|
MPI_Finalize ();
|
|
}
|
|
|
|
MPI_Isend (&send_value, 1, MPI_INT,
|
|
(rank + 1) % size, 4711, MPI_COMM_WORLD, &send_request);
|
|
MPI_Irecv (&recv_value, 1, MPI_INT,
|
|
(rank + size - 1) % size, 4711, MPI_COMM_WORLD, &recv_request);
|
|
|
|
/*
|
|
* Reading or writing of the receive buffer before
|
|
* non blocking send finished will cause an error.
|
|
*/
|
|
printf("\nsent: %d\n",recv_value);
|
|
recv_value = 12;
|
|
|
|
MPI_Wait (&send_request, &status);
|
|
MPI_Wait (&recv_request, &status);
|
|
/*
|
|
* Using of receive buffer after non blocking send
|
|
* is finished will be ok.
|
|
*/
|
|
printf("\nsent: %d\n",recv_value);
|
|
recv_value = 16;
|
|
|
|
MPI_Finalize ();
|
|
return 0;
|
|
}
|