mpi funkcje send recv

#include <mpi.h>
#include <stdio.h>
#include <math.h>

int main( int argc, char *argv[] )
{
    int id,from,to,tag,numproc;
    double data;

    MPI_Init(&argc,&argv);
    MPI_Status status;
    MPI_Comm_rank(MPI_COMM_WORLD, &id);

    if( id == 0 )
    {
        to = 3; tag = 2012; data = 10.12;
        MPI_Send(&data, 1, MPI_DOUBLE, to, tag, MPI_COMM_WORLD);
    }
    else if (id == 3)
    {
        from = 0; tag = 2012;
        MPI_Recv(&data,1,MPI_DOUBLE,from,tag,MPI_COMM_WORLD,&status);
        printf("Proces %d odebral %f\n", id,data);
    }
    else {}
    MPI_Finalize();

    return 0;
}