void update_positivized_lengths();
void force_positivized_lengths();
// Set the edge pred_edge_toward_source correspondingly to the path
- // of shortest length.
+ // of shortest length. The current implementation is not Dijkstra's!
void find_shortest_path();
// Follows the path starting on edge e and returns its length. If
// nodes is non-null, stores in it the nodes met along the path.