4 int main(int argc, char *argv[]) {
5 int worldrank, localrank;
7 MPI_Init(&argc, &argv);
8 MPI_Comm_rank(MPI_COMM_WORLD, &worldrank);
9 MPI_Comm_split(MPI_COMM_WORLD, worldrank % 2, worldrank, &localcomm);
10 MPI_Comm_rank(localcomm, &localrank);
11 printf("node with world rank %d has local rank %d\n", worldrank, localrank);