////////////////////////////////////////////////////////////////////// 
// A very short MPI test routine to show the involved hosts
//////////////////////////////////////////////////////////////////////
#include <mpi.h>
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv){ 
	int size,rank; 
	char hostname[50]; 

	MPI_Init(&argc,&argv); 
	MPI_Comm_rank(MPI_COMM_WORLD, &rank); //Who am I? 
	MPI_Comm_size(MPI_COMM_WORLD, &size); //How many processes? 
	gethostname (hostname, 50); 

	printf ("Hello World! I'm number %2d of %2d running on host %s\n", rank, size, hostname); 
	MPI_Finalize(); 

	return 0;
}