exception NegativeCycle of tval shortest_path : Topology.t ‑> Topology.vertex ‑> Topology.vertex ‑> t optionval all_shortest_paths : Topology.t ‑> Topology.vertex ‑> Topology.vertex Topology.VertexHash.tval all_pairs_shortest_paths : topo:Topology.t ‑> f:(Topology.vertex ‑> Topology.vertex ‑> bool) ‑> (weight * Topology.vertex * Topology.vertex * Topology.edge list) list