int difference(MPI_Group group2, MPI_Group* newgroup);
int range_incl(int n, int ranges[][3], MPI_Group * newgroup);
int range_excl(int n, int ranges[][3], MPI_Group * newgroup);
int difference(MPI_Group group2, MPI_Group* newgroup);
int range_incl(int n, int ranges[][3], MPI_Group * newgroup);
int range_excl(int n, int ranges[][3], MPI_Group * newgroup);