mpi_ex5.c

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

int main(int argc, char *argv[]) {
  int att = 1; // Change me
  MPI_Init(&argc, &argv);
  MPI_Comm comm = MPI_COMM_WORLD;
  MPI_Win win;
  int rank;
  MPI_Comm_rank(comm, &rank);
  int counter = 0; // counter resides with process 0
  if (rank == 0) {
    printf("Running Attempt %d\n", att);
    MPI_Win_create (&counter, sizeof(int), sizeof(int), MPI_INFO_NULL, comm, &win);
  } else {
    MPI_Win_create (NULL, 0, sizeof(int), MPI_INFO_NULL, comm, &win);
  }
  int inc = 1;
  int val = rank, new;
  // Attempt 1:
  if(att == 1) {
    //printf("RANK[%d]: outside\n", rank);
    MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);
    //printf("RANK[%d]: *hacker voice* im in\n", rank);
    //printf("Rank[%d]: before_get_val <= %d\n", rank, val);
    MPI_Get (&val, 1, MPI_INT, 0, 0, 1, MPI_INT, win);
    //printf("Rank[%d]: after_get_val <= %d\n", rank, val);
    new = val+inc;
    //printf("Rank[%d]: new <= %d\n", rank, new);
    MPI_Put (&new, 1, MPI_INT, 0, 0, 1, MPI_INT, win);
    //printf("RANK[%d]: brb\n", rank);
    MPI_Win_unlock (0, win);
    //printf("Rank[%d]: after_unlock_val <= %d\n", rank, val);
    //printf("RANK[%d]: left the chat\n", rank);
  }
  // Attempt 2:
  else if(att == 2) {
    //printf("RANK[%d]: outside get lock\n", rank);
    MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);
    //printf("RANK[%d]: inside get lock\n", rank);
    MPI_Get (&val , 1, MPI_INT, 0, 0, 1, MPI_INT, win);
    //printf("RANK[%d]: brb get lock\n", rank);
    MPI_Win_unlock (0, win);
    //printf("RANK[%d]: left get lock\n", rank);
    //printf("Rank[%d]: val <= %d\n", rank, val);
    new = val+inc;
    //printf("RANK[%d]: outside put lock\n", rank);
    MPI_Win_lock(MPI_LOCK_EXCLUSIVE, 0, 0, win);
    //printf("RANK[%d]: inside put lock\n", rank);
    MPI_Put (&new, 1, MPI_INT, 0, 0, 1, MPI_INT, win);
    //printf("RANK[%d]: brb put lock\n", rank);
    MPI_Win_unlock (0, win);
    //printf("RANK[%d]: left put lock\n", rank);
  }
  MPI_Win_free(&win);
  MPI_Finalize();
  if(rank == 0) {
    printf("counter = %d\n", counter);
  }
  return 0;
}