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

int main(int argc, char **argv) {
  int rank, result, rc, numtasks;
  clock_t t1, t2;
  float ratio;

  ratio = 1./CLOCKS_PER_SEC;

  rc = MPI_Init(&argc, &argv);
  if (rc != MPI_SUCCESS) {
    printf("Error starting MPI program. Terminating.\n");
    MPI_Abort(MPI_COMM_WORLD, rc);
  }
  
  MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  
  if (rank == 0) {
    t1 = clock();
  }

  MPI_Allreduce(&rank, &result, 1, MPI_INTEGER, MPI_SUM, MPI_COMM_WORLD);
   
  MPI_Finalize();

  if (rank == 0) {
    t2 = clock();
    printf("result = %d\n", result);
    printf("time = %f\n", ratio*(long)t1 + ratio*(long)t2);
  }
}