source: CIVL/examples/messagePassing/ring2.cvl@ e51fd2f

/* Create nprocs processes.  Have them exchange data in a cycle.
 * Commandline example:
 *     civl verify -input_NP=3 ring2.cvl -simplify=false
 */
#include<civlc.h>
#include "mp_root2.cvh"

void MPI_Process (int __rank) {
#include "mp_proc2.cvh"

// ******************* BEGIN PROGRAM SOURCE *************************

  int rank, nprocs, count;
  double x, y;
  MPI_Status stat;
  
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
  x = rank;
  MPI_Send(&x, 1, MPI_DOUBLE, (rank+1)%nprocs, 0, MPI_COMM_WORLD);
  MPI_Recv(&y, 1, MPI_DOUBLE, (rank+nprocs-1)%nprocs, 0, MPI_COMM_WORLD, &stat);
  $assert y == (rank+nprocs-1)%nprocs;
  MPI_Get_count(&stat, MPI_DOUBLE, &count);
  $assert count == 1;
  $assert stat.MPI_SOURCE == (rank+nprocs-1)%nprocs;
  $assert stat.MPI_TAG == 0;

// ******************** END PROGRAM SOURCE ***************************

}