/* 
Jonathan Hauenstein - University of Notre Dame
Center for Applied Mathematics Minicourse on Parallel Computing
April 24, May 1, May 8, 2008
Sample programs are designed for educational use 
*/

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

int main(int argc, char **argv)
{ 
  int my_id, num_proc, my_value, tag = 101;
  MPI_Status status;
  MPI_Request request;

  // initialize MPI
  MPI_Init(&argc, &argv);

  // find unique id
  MPI_Comm_rank(MPI_COMM_WORLD, &my_id);

  // find the number of processes running
  MPI_Comm_size(MPI_COMM_WORLD, &num_proc);

  // setup my_value & print it
  my_value = pow(my_id + 1, num_proc);
  printf("id: %d num: %d value: %d\n", my_id, num_proc, my_value);
  
  // send from id 0 to id 1
  if (my_id == 0)
  {
    MPI_Isend(&my_value, 1, MPI_INT, 1, tag, MPI_COMM_WORLD, &request);
  
    // Perform extra processing while waiting on the communication to complete

    MPI_Wait(&request, &status);
  }
  else if (my_id == 1)
    MPI_Recv(&my_value, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);

  // print my_value
  printf("id: %d num: %d value: %d\n", my_id, num_proc, my_value);

  if (my_id == 1)
    printf("source: %d tag: %d error: %d\n", 
        status.MPI_SOURCE, status.MPI_TAG, status.MPI_ERROR);

  // finalize MPI
  MPI_Finalize();

  return 0;
}