/*
 ============================================================================
 Name        : Lab4.c
 Author      : Gabi
 Version     :
 Copyright   : Your copyright notice
 Description : Hello MPI World in C
 ============================================================================
 */
#include <stdio.h>
#include <string.h>
#include "mpi.h"

int main(int argc, char* argv[]){
	int  my_rank; /* rank of process */
	int  p;       /* number of processes */
	int tag=0;    /* tag for messages */
	MPI_Status status ;   /* return status for receive */
	char mes[100];
	int dim;
	int id;
	int s_id;
	int id_virtual;
	int masca;
	int k;
	int destinatie_virtuala;
	int sursa_virtuala;

	MPI_Init(&argc, &argv); /* start up MPI */
	MPI_Comm_rank(MPI_COMM_WORLD, &my_rank); /* find out process rank */
	MPI_Comm_size(MPI_COMM_WORLD, &p); /* find out number of processes */

	id_virtual = id ^ s_id;
	masca = (2<<dim)-1;

	for(k=dim-1; k>=0; k--)
	{
		masca = masca ^ (2<<k);
		if((id_virtual & masca) ==0)
		{
			if((id_virtual & (2<<k)) == 0)
			{
				destinatie_virtuala = id_virtual ^ (2<<k);
				sprintf(mes, "Hello MPI World from process %d!", my_rank);
				MPI_Send(mes, strlen(mes)+1, MPI_CHAR, destinatie_virtuala, tag, MPI_COMM_WORLD);
			}
			else
			{
				sursa_virtuala = id_virtual ^ (2<<k);
				MPI_Recv(mes, 100, MPI_CHAR, sursa_virtuala, tag, MPI_COMM_WORLD, &status);
				printf("%s\n",mes);
			}
		}
	}

	MPI_Finalize(); /* shut down MPI */

	return 0;
}