Copyright header added.
2 * src/hugo/tight_edge_filter_map.h - Part of HUGOlib, a generic C++ optimization library
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
17 #ifndef HUGO_TIGHT_EDGE_FILTER_MAP_H
18 #define HUGO_TIGHT_EDGE_FILTER_MAP_H
21 // /// \brief Maximum flow algorithms.
26 /// \brief A map for filtering the edge-set to those edges
27 /// which are tight w.r.t. some node_potential map and
28 /// edge_distance map.
30 /// A node-map node_potential is said to be a potential w.r.t.
31 /// an edge-map edge_distance
32 /// if and only if for each edge e, node_potential[g.head(e)]
33 /// <= edge_distance[e]+node_potential[g.tail(e)]
34 /// (or the reverse inequality holds for each edge).
35 /// An edge is said to be tight if this inequality holds with equality,
36 /// and the map returns true exactly for those edges.
37 /// To avoid rounding errors, it is recommended to use this class with exact
38 /// types, e.g. with int.
39 template<typename Graph,
40 typename NodePotentialMap, typename EdgeDistanceMap>
41 class TightEdgeFilterMap {
44 NodePotentialMap* node_potential;
45 EdgeDistanceMap* edge_distance;
47 TightEdgeFilterMap(Graph& _g, NodePotentialMap& _node_potential,
48 EdgeDistanceMap& _edge_distance) :
49 g(&_g), node_potential(&_node_potential),
50 edge_distance(&_edge_distance) { }
51 bool operator[](const typename Graph::Edge& e) const {
52 return ((*node_potential)[g->head(e)] ==
53 (*edge_distance)[e]+(*node_potential)[g->tail(e)]);
59 #endif //HUGO_TIGHT_EDGE_FILTER_MAP_H