#include <mpi.h>
#include <stdio.h>
int main(int argc, char **argv) {
int *sendbuffer, *recvbuffer;
int size, rank, i;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
sendbuffer = (int *)malloc(size*sizeof(int));
recvbuffer = (int *)malloc(size*sizeof(int));
for(i=0; i<size; i++) sendbuffer[i] = i*i+rank;

printf("I´m %d: ",rank);
for(i=0; i<size; i++)
  printf(" %d ", sendbuffer[i]);
  printf("\n");

  MPI_Alltoall(sendbuffer, 1, MPI_INT, recvbuffer, 1, MPI_INT, MPI_COMM_WORLD);

  printf("I´m %d: ",rank);
  for(i=0; i<size; i++)
    printf(" %d ", recvbuffer[i]);
    printf("\n");

    MPI_Finalize();
    return 0;
    }