Change the "output_rank" int to see outputs from different ranks (only one is shown at the time)

ex6_template.c

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

int main(int argc, char *argv[]) {
  MPI_Init(&argc, &argv);
  MPI_Comm comm = MPI_COMM_WORLD;

  int rank, output_rank = 0;
  MPI_Comm_rank(comm, &rank);
  int n = 3;
  double a[] = { 1, 2, 3 };

  if(rank == output_rank) {
    printf("Outputting for rank %d\n", rank);
    for(int i = 0; i < n; i++) {
      printf("a[%d] = %f\n", i, a[i]);
    }
  }

  double sum = a[0];
  for (int i = 1; i < n; i++) sum += a[i];

  // MPI code/function to compute some partial sum required for rank

  double prefix_sum[n];
  // Local prefix -sums computation for rank in local array a
  
  
  if(rank == output_rank) {
    for(int i = 0; i < n; i++) {
      printf("prefix_sum[%d] = %f\n", i, prefix_sum[i]);
    }
  }

  MPI_Finalize();
  return 0;
}