+ void decrease_distance_in_heap(Vertex *v);
+ void increase_distance_in_heap(Vertex *v);
+
+ // Visit the vertices according to _dp_order and simply update their
+ // distance to the source
+ void dp_distance_propagation();
+
+ // Set in every vertex pred_edge_toward_source correspondingly to
+ // the path of shortest length. The current implementation is
+ // Dijkstra with a Binary Heap (and not with Fibonnaci heap (yet))
+ void find_shortest_path();
+
+ // Follows the path starting on edge e and returns the number of
+ // nodes to reach the sink. If path is non-null, stores in it the
+ // nodes met along the path, and computes path->length properly.
+ int retrieve_one_path(Edge *e, Path *path);
+
+ // Returns if the graph is a DAG, and set the last_change field of
+ // each vertex to the maximum number of iterations required to reach
+ // it
+ int check_DAG_and_set_last_change();