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

#define SIZE 1024 * 1024 * 32
#define DEFAULT_TAG 100

static int array[SIZE];

int main(int argc, char** argv) {
   int ierr;
   ierr = MPI_Init(&argc, &argv);

   int currentProcessID;
   int rootProcess = 0;
   int worldSize;

   ierr = MPI_Comm_rank(MPI_COMM_WORLD, &currentProcessID);
   ierr = MPI_Comm_size(MPI_COMM_WORLD, &worldSize);

   MPI_Request requests[2];
   MPI_Status stats[2];

   int startSize = 1;
   int part = 1024 * 7 + 999;// 1024 * 7;

   if (currentProcessID == 0) {
       MPI_Isend(
               &array[0],
               part,
               MPI_INT,
               1,
               DEFAULT_TAG,
               MPI_COMM_WORLD,
               &requests[0]
       );
   } else {
       clock_t start, end, end2;
       start = clock();
       MPI_Irecv(
               &array[0],
               part,
               MPI_INT,
               0,
               DEFAULT_TAG,
               MPI_COMM_WORLD,
               &requests[1]
       );
       MPI_Wait(&requests[1], &stats[1]);
       end = clock();
       printf("Time need to call isend(size = %d bytes) is %f sec \n",
              part * sizeof(int),
              ((double) (end - start)) / CLOCKS_PER_SEC
       );
   }

   return 0;
}