/* -*- Mode: C; -*- */
/* Creator: Bronis R. de Supinski (bronis@llnl.gov) Fri Mar  17 2000 */
/* no-error.c -- do some MPI calls without any errors */

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

#define buf_size 128

int
main (int argc, char **argv)
{
  int nprocs = -1;
  int rank = -1;
  char processor_name[128];
  int namelen = 128;
  int buf0[buf_size];
  int buf1[buf_size];
  MPI_Status status;

  /* init */
  MPI_Init (&argc, &argv);
  MPI_Comm_size (MPI_COMM_WORLD, &nprocs);
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);
  MPI_Get_processor_name (processor_name, &namelen);
  //  printf ("(%d) is alive on %s\n", rank, processor_name);
  fflush (stdout);

  if (nprocs < 2)
    {
      printf ("not enough tasks\n");
    }
  else
    {
      if (rank == 0)
	{
	  // memset (buf0, 0, buf_size);

	  MPI_Sendrecv (buf0, buf_size, MPI_INT, 1, 0,
			buf1, buf_size, MPI_INT, 1, 0,
			MPI_COMM_WORLD, &status);

	  MPI_Sendrecv (buf1, buf_size, MPI_INT, 1, 0,
			buf0, buf_size, MPI_INT, 1, 0,
			MPI_COMM_WORLD, &status);

	  MPI_Sendrecv (buf0, buf_size, MPI_INT, 1, 0,
			buf1, buf_size, MPI_INT, 1, 0,
			MPI_COMM_WORLD, &status);
	}
      else
	{
	  if (rank == 1)
	    {
	      // memset (buf1, 1, buf_size);

	      MPI_Sendrecv (buf1, buf_size, MPI_INT, 0, 0,
			    buf0, buf_size, MPI_INT, 0, 0,
			    MPI_COMM_WORLD, &status);

	      MPI_Sendrecv (buf0, buf_size, MPI_INT, 0, 0,
			    buf1, buf_size, MPI_INT, 0, 0,
			    MPI_COMM_WORLD, &status);

	      MPI_Sendrecv (buf1, buf_size, MPI_INT, 0, 0,
			    buf0, buf_size, MPI_INT, 0, 0,
			    MPI_COMM_WORLD, &status);
	    }
	}
    }

  MPI_Finalize ();
  printf ("(%d) Finished normally\n", rank);
}

/* EOF */
