Hilfesystem für den Message Passing Interface Standard MPI

MPI_Pack_size

Syntax:

MPI_Pack_size( incount, datatype, comm, size )

incount - Anzahl zu packende Elemente (integer)
datatype - Datentyp (handle)
comm - Kommunikator (handle)

size - Größe der gepackten Nachricht in Bytes (integer)

(Ermitteln der Puffergröße für eine gepufferte Sendeoperation)

#include "mpi.h"

#define MAX1  32
#define MAX2  16

    int           intsize, charsize;
    ...
    MPI_Datatype  datatype1, datatype2;
    MPI_Comm      comm;
    MPI_Status    stat;

    ...
    MPI_Comm_rank(comm, &myid);
    if (myid==0) {
        ...
        MPI_Pack_size(MAX1, datatype1, comm, &size1);
	MPI_Pack_size(MAX2, datatype2, comm, &size2);

	bufsize = size1 + size2 + (2 * MPI_BSEND_OVERHEAD);
	buf=(void *)malloc(bufsize*sizeof(void));
	MPI_Buffer_attach(buf, bufsize);

	MPI_Bsend(msg1, MAX1, datatype1, 1, 0, comm);
	MPI_Bsend(msg2, MAX2, datatype2, 1, 1, comm);
    }
    ...