MPIsumavg.c

#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#define ARRAY_SIZE 1000
int main(int argc, char* argv[]) {
 int rank, size, i;
 int array[ARRAY_SIZE];
 int local_sum = 0, total_sum;
 float average;
 
 MPI_Init(&argc, &argv);
 
 MPI_Comm_size(MPI_COMM_WORLD, &size);

 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
 
 srand(rank + time(NULL));
 
 for(i = 0; i < ARRAY_SIZE; i++) {
 array[i] = rand() % 100;
 local_sum += array[i];
 }
 
 printf("Local sum for process %d is %d\n", rank, local_sum);
 
 MPI_Reduce(&local_sum, &total_sum, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
 
 average = total_sum / (float)(ARRAY_SIZE * size);
 
 if (rank == 0) {
 printf("Total sum = %d\n", total_sum);
 printf("Average = %.2f\n", average);
 }
 
 MPI_Finalize();
 return 0;
}