int MPI_Cart_create (
    MPI_Comm comm_old,
    int ndims, const int dims [], const int periods [],
    int reorder, MPI_Comm *comm_cart);

int MPI_Cart_sub (MPI_Comm comm, const int remain_dims [], MPI_Comm *newcomm);

int MPI_Graph_create (
    MPI_Comm comm_old,
    int nnodes, const int index [], const int edges [],
    int reorder, MPI_Comm *comm_graph);

int MPI_Dist_graph_create_adjacent (
    MPI_Comm comm_old,
    int indegree, const int sources [], const int sourceweights [],
    int outdegree, const int destinations [], const int destweights [],
    MPI_Info info, int reorder, MPI_Comm *comm_dist_graph);

int MPI_Dist_graph_create (
    MPI_Comm comm_old,
    int n, const int sources [], const int degrees [], const int destinations [], const int weights [],
    MPI_Info info, int reorder, MPI_Comm *comm_dist_graph);