hello.c

#include <stdio.h>
#include <unistd.h> /* getpid() */
#include "mpi.h"

int main( int argc, char *argv[] )
{
    int rank,size,len;
    char name[MPI_MAX_PROCESSOR_NAME];
    MPI_Init( NULL, NULL );
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Get_processor_name(name, &len);
    printf( "Hello %s from rank %d of %d, in process %d running on %s.\n",argv[1], rank, size,getpid(),name );
    MPI_Finalize();
    return 0;
}

Using The Cluster