ProgramasMPI/ejercicio4.c at master · brenda151295/ProgramasMPI · GitHub

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/*butterlfy
 */
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>

const int MAX_CONTRIB = 20;

int Global_sum(int my_contrib, int my_rank, int p, MPI_Comm comm);
void Print_results(char title[], int value, int my_rank, int p,
      MPI_Comm comm);

int main(void) {
   int      p, my_rank;
   MPI_Comm comm;
   int      my_contrib;
   int      sum;

   MPI_Init(NULL, NULL);
   comm = MPI_COMM_WORLD;
   MPI_Comm_size(comm, &p);
   MPI_Comm_rank(comm, &my_rank);

   srandom(my_rank);
   my_contrib = random() % MAX_CONTRIB;

   Print_results("Valores de procesos ", my_contrib, my_rank, p, comm);

   sum = Global_sum(my_contrib, my_rank, p, comm);

   Print_results("Procesos totales ", sum, my_rank, p, comm);

   MPI_Finalize();
   return 0;
}

void Print_results(char title[], int value, int my_rank, int p, MPI_Comm comm) {
   int* vals = NULL, q;

   if (my_rank == 0) {
      vals = malloc(p*sizeof(int));
      MPI_Gather(&value, 1, MPI_INT, vals, 1, MPI_INT, 0, comm);
      printf("%s:\n", title);
      for (q = 0; q < p; q++)
         printf("Proc %d > %d\n", q, vals[q]);
      printf("\n");
      free(vals);
   } else {
      MPI_Gather(&value, 1, MPI_INT, vals, 1, MPI_INT, 0, comm);
   }
}
int Global_sum(int my_contrib, int my_rank, int p, MPI_Comm comm) {
    int        sum = my_contrib;
    int        temp;
    int        partner;
    unsigned   bitmask = 1;

    while (bitmask < p) {
        partner = my_rank ^ bitmask;
        MPI_Sendrecv(&sum, 1, MPI_INT, partner, 0,
               		&temp, 1, MPI_INT, partner, 0,
                    comm, MPI_STATUS_IGNORE);
        sum += temp;
        bitmask <<= 1;
    }

    return sum;
}