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

int main (int argc, char **argv)
{
  MPI_Comm myComm;       /* intrakomunikator w grupie lokalnej */
  MPI_Comm myFirstComm;  /* interkomunikator */
  MPI_Comm mySecondComm; /* drugi interkomunikator */
  int membershipKey, rank, newrank, mtype, data;

  MPI_Status  recv_status;
  MPI_Request request;

  MPI_Init(&argc, &argv);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);

/* Generujemy klucz przynaleznosci membershipKey; nalezy on do zbioru
   [0, 1, 2] */
  membershipKey = rank % 3;
  printf("Procesor %2d membershipKey %d\n",rank,membershipKey);

/* Budujemy intrakomunikator dla grupy lokalnej */
  MPI_Comm_split(MPI_COMM_WORLD, membershipKey, rank, &myComm);
  MPI_Comm_rank( myComm, &newrank );

/* Budujemy interkomunikatory. Znaczniki sa zakodowane explicite */
  if (membershipKey == 0) {
    /* Grupa 0 komunikuje sie z grupa 1 */
    MPI_Intercomm_create(myComm, 0, MPI_COMM_WORLD, 1, 01, &myFirstComm);
    printf("Procesor %2d (%2d) membershipKey %d zakonczyl MPI_Intercomm_create\n",
     newrank,rank,membershipKey);
  }
  else if (membershipKey == 1) {
    /* Grupa 1 komunikuje sie z grupami 0 i 2 */
    MPI_Intercomm_create(myComm, 0, MPI_COMM_WORLD, 0, 01, &myFirstComm);
    MPI_Intercomm_create(myComm, 0, MPI_COMM_WORLD, 2, 12, &mySecondComm);
    printf("Procesor %2d (%2d) membershipKey %d zakonczyl MPI_Intercomm_create\n",
     newrank,rank,membershipKey);
  }
  else if (membershipKey == 2) {
    /* Grupa 2 komunikuje sie z grupa 1 */
    printf("Procesor %2d (%2d) membershipKey %d\n",newrank,rank,membershipKey);
    MPI_Intercomm_create(myComm, 0, MPI_COMM_WORLD, 1, 12, &myFirstComm);
    printf("Procesor %2d (%2d) membershipKey %d zakonczyl MPI_Intercomm_create\n",
     newrank,rank,membershipKey);
  }
  /* Wlasciwa robota; tutaj oczywiscie tylko maly przyklad */
  /* Dane beda "plynac" czterema kanalami od grupy 0 do grupy 2 */

  mtype = 1001;

  if (membershipKey == 0) {
    data = rank*rank;
    MPI_Send( &data, 1, MPI_INT, newrank, mtype, myFirstComm );
    printf ("Poczatek rury: procesor %2d (%1d) wyslal %4d\n",
      newrank, rank, data );
   }
  else if (membershipKey == 1) {
    MPI_Recv( &data, 1, MPI_INT, newrank, mtype, myFirstComm, &recv_status);
    printf ("Srodek rury: procesor %2d (%1d) odebral %4d\n",
      newrank, rank, data );
    MPI_Send( &data, 1, MPI_INT, newrank, mtype, mySecondComm );
    printf ("Srodek rury: procesor %2d (%1d) wyslal %4d\n",
      newrank, rank, data );
   }
  else if (membershipKey == 2) {
    MPI_Recv( &data, 1, MPI_INT, newrank, mtype, myFirstComm, &recv_status);
    printf ("Koniec rury: procesor %2d (%1d) odebral %4d\n",
      newrank, rank, data );
  }
  /* zwalniamy komunikatory */
  MPI_Comm_free( &myComm );
  MPI_Comm_free( &myFirstComm );
  if (membershipKey == 1)
    MPI_Comm_free(&mySecondComm);
  MPI_Finalize();
}