1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/lemon/attic/tight_edge_filter_map.h	Wed Sep 29 15:30:04 2004 +0000
     1.3 @@ -0,0 +1,63 @@
     1.4 +/* -*- C++ -*-
     1.5 + * src/lemon/tight_edge_filter_map.h - Part of LEMON, a generic C++ optimization library
     1.6 + *
     1.7 + * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     1.8 + * (Egervary Combinatorial Optimization Research Group, EGRES).
     1.9 + *
    1.10 + * Permission to use, modify and distribute this software is granted
    1.11 + * provided that this copyright notice appears in all copies. For
    1.12 + * precise terms see the accompanying LICENSE file.
    1.13 + *
    1.14 + * This software is provided "AS IS" with no warranty of any kind,
    1.15 + * express or implied, and with no claim as to its suitability for any
    1.16 + * purpose.
    1.17 + *
    1.18 + */
    1.19 +
    1.20 +#ifndef LEMON_TIGHT_EDGE_FILTER_MAP_H
    1.21 +#define LEMON_TIGHT_EDGE_FILTER_MAP_H
    1.22 +
    1.23 +#include <lemon/maps.h>
    1.24 +
    1.25 +// /// \file
    1.26 +// /// \brief Maximum flow algorithms.
    1.27 +// /// \ingroup galgs
    1.28 +
    1.29 +namespace lemon {
    1.30 +
    1.31 +  /// \brief A map for filtering the edge-set to those edges 
    1.32 +  /// which are tight w.r.t. some node_potential map and 
    1.33 +  /// edge_distance map.
    1.34 +  ///
    1.35 +  /// A node-map node_potential is said to be a potential w.r.t. 
    1.36 +  /// an edge-map edge_distance 
    1.37 +  /// if and only if for each edge e, node_potential[g.head(e)] 
    1.38 +  /// <= edge_distance[e]+node_potential[g.tail(e)] 
    1.39 +  /// (or the reverse inequality holds for each edge).
    1.40 +  /// An edge is said to be tight if this inequality holds with equality, 
    1.41 +  /// and the map returns true exactly for those edges.
    1.42 +  /// To avoid rounding errors, it is recommended to use this class with exact 
    1.43 +  /// types, e.g. with int.
    1.44 +  template<typename Graph, 
    1.45 +	   typename NodePotentialMap, typename EdgeDistanceMap>
    1.46 +  class TightEdgeFilterMap : public MapBase<typename Graph::Edge, bool> {
    1.47 +  protected:
    1.48 +    const Graph* g;
    1.49 +    NodePotentialMap* node_potential;
    1.50 +    EdgeDistanceMap* edge_distance;
    1.51 +  public:
    1.52 +    TightEdgeFilterMap(Graph& _g, NodePotentialMap& _node_potential, 
    1.53 +		       EdgeDistanceMap& _edge_distance) : 
    1.54 +      g(&_g), node_potential(&_node_potential), 
    1.55 +      edge_distance(&_edge_distance) { }
    1.56 +    bool operator[](const typename Graph::Edge& e) const {
    1.57 +      return ((*node_potential)[g->head(e)] == 
    1.58 +	      (*edge_distance)[e]+(*node_potential)[g->tail(e)]);
    1.59 +    }
    1.60 +  };
    1.61 +
    1.62 +} //namespace lemon
    1.63 +
    1.64 +#endif //LEMON_TIGHT_EDGE_FILTER_MAP_H
    1.65 +
    1.66 +