ompi_coll_tree_t* ompi_coll_tuned_topo_build_tree(int fanout, MPI_Comm com, int root);
ompi_coll_tree_t* ompi_coll_tuned_topo_build_in_order_bintree(MPI_Comm comm);
ompi_coll_tree_t* ompi_coll_tuned_topo_build_tree(int fanout, MPI_Comm com, int root);
ompi_coll_tree_t* ompi_coll_tuned_topo_build_in_order_bintree(MPI_Comm comm);