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

int main(int argc, char **argv) {
  int rank, size, err, n, sum;

  MPI_Init(&argc, &argv);

  MPI_Comm_size(MPI_COMM_WORLD, &size);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);

  printf("rank=%d size=%d\n", rank, size);

  n = rank + 1;

  sum = 4710;

  MPI_Barrier(MPI_COMM_WORLD);

  MPI_Reduce(&n, &sum, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
  printf("Received in reduction=%d\n", sum);

  MPI_Barrier(MPI_COMM_WORLD);

  sum = 3710;

  MPI_Allreduce(&n, &sum, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
  printf("Received in allreduction =%d\n", sum);

  MPI_Finalize();

  return 0;
}