lemon/adaptors.h
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 29 Sep 2009 10:21:51 +0200
changeset 740 819ca5b50de0
parent 617 4137ef9aacc6
child 787 c2230649a493
child 997 761fe0846f49
permissions -rw-r--r--
Add a warning for List(Di)Graph::Snapshot (#311)
and extend tests for snapshots
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2009
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 #ifndef LEMON_ADAPTORS_H
    20 #define LEMON_ADAPTORS_H
    21 
    22 /// \ingroup graph_adaptors
    23 /// \file
    24 /// \brief Adaptor classes for digraphs and graphs
    25 ///
    26 /// This file contains several useful adaptors for digraphs and graphs.
    27 
    28 #include <lemon/core.h>
    29 #include <lemon/maps.h>
    30 #include <lemon/bits/variant.h>
    31 
    32 #include <lemon/bits/graph_adaptor_extender.h>
    33 #include <lemon/bits/map_extender.h>
    34 #include <lemon/tolerance.h>
    35 
    36 #include <algorithm>
    37 
    38 namespace lemon {
    39 
    40 #ifdef _MSC_VER
    41 #define LEMON_SCOPE_FIX(OUTER, NESTED) OUTER::NESTED
    42 #else
    43 #define LEMON_SCOPE_FIX(OUTER, NESTED) typename OUTER::template NESTED
    44 #endif
    45 
    46   template<typename DGR>
    47   class DigraphAdaptorBase {
    48   public:
    49     typedef DGR Digraph;
    50     typedef DigraphAdaptorBase Adaptor;
    51 
    52   protected:
    53     DGR* _digraph;
    54     DigraphAdaptorBase() : _digraph(0) { }
    55     void initialize(DGR& digraph) { _digraph = &digraph; }
    56 
    57   public:
    58     DigraphAdaptorBase(DGR& digraph) : _digraph(&digraph) { }
    59 
    60     typedef typename DGR::Node Node;
    61     typedef typename DGR::Arc Arc;
    62 
    63     void first(Node& i) const { _digraph->first(i); }
    64     void first(Arc& i) const { _digraph->first(i); }
    65     void firstIn(Arc& i, const Node& n) const { _digraph->firstIn(i, n); }
    66     void firstOut(Arc& i, const Node& n ) const { _digraph->firstOut(i, n); }
    67 
    68     void next(Node& i) const { _digraph->next(i); }
    69     void next(Arc& i) const { _digraph->next(i); }
    70     void nextIn(Arc& i) const { _digraph->nextIn(i); }
    71     void nextOut(Arc& i) const { _digraph->nextOut(i); }
    72 
    73     Node source(const Arc& a) const { return _digraph->source(a); }
    74     Node target(const Arc& a) const { return _digraph->target(a); }
    75 
    76     typedef NodeNumTagIndicator<DGR> NodeNumTag;
    77     int nodeNum() const { return _digraph->nodeNum(); }
    78 
    79     typedef ArcNumTagIndicator<DGR> ArcNumTag;
    80     int arcNum() const { return _digraph->arcNum(); }
    81 
    82     typedef FindArcTagIndicator<DGR> FindArcTag;
    83     Arc findArc(const Node& u, const Node& v, const Arc& prev = INVALID) const {
    84       return _digraph->findArc(u, v, prev);
    85     }
    86 
    87     Node addNode() { return _digraph->addNode(); }
    88     Arc addArc(const Node& u, const Node& v) { return _digraph->addArc(u, v); }
    89 
    90     void erase(const Node& n) { _digraph->erase(n); }
    91     void erase(const Arc& a) { _digraph->erase(a); }
    92 
    93     void clear() { _digraph->clear(); }
    94 
    95     int id(const Node& n) const { return _digraph->id(n); }
    96     int id(const Arc& a) const { return _digraph->id(a); }
    97 
    98     Node nodeFromId(int ix) const { return _digraph->nodeFromId(ix); }
    99     Arc arcFromId(int ix) const { return _digraph->arcFromId(ix); }
   100 
   101     int maxNodeId() const { return _digraph->maxNodeId(); }
   102     int maxArcId() const { return _digraph->maxArcId(); }
   103 
   104     typedef typename ItemSetTraits<DGR, Node>::ItemNotifier NodeNotifier;
   105     NodeNotifier& notifier(Node) const { return _digraph->notifier(Node()); }
   106 
   107     typedef typename ItemSetTraits<DGR, Arc>::ItemNotifier ArcNotifier;
   108     ArcNotifier& notifier(Arc) const { return _digraph->notifier(Arc()); }
   109 
   110     template <typename V>
   111     class NodeMap : public DGR::template NodeMap<V> {
   112       typedef typename DGR::template NodeMap<V> Parent;
   113 
   114     public:
   115       explicit NodeMap(const Adaptor& adaptor)
   116         : Parent(*adaptor._digraph) {}
   117       NodeMap(const Adaptor& adaptor, const V& value)
   118         : Parent(*adaptor._digraph, value) { }
   119 
   120     private:
   121       NodeMap& operator=(const NodeMap& cmap) {
   122         return operator=<NodeMap>(cmap);
   123       }
   124 
   125       template <typename CMap>
   126       NodeMap& operator=(const CMap& cmap) {
   127         Parent::operator=(cmap);
   128         return *this;
   129       }
   130 
   131     };
   132 
   133     template <typename V>
   134     class ArcMap : public DGR::template ArcMap<V> {
   135       typedef typename DGR::template ArcMap<V> Parent;
   136 
   137     public:
   138       explicit ArcMap(const DigraphAdaptorBase<DGR>& adaptor)
   139         : Parent(*adaptor._digraph) {}
   140       ArcMap(const DigraphAdaptorBase<DGR>& adaptor, const V& value)
   141         : Parent(*adaptor._digraph, value) {}
   142 
   143     private:
   144       ArcMap& operator=(const ArcMap& cmap) {
   145         return operator=<ArcMap>(cmap);
   146       }
   147 
   148       template <typename CMap>
   149       ArcMap& operator=(const CMap& cmap) {
   150         Parent::operator=(cmap);
   151         return *this;
   152       }
   153 
   154     };
   155 
   156   };
   157 
   158   template<typename GR>
   159   class GraphAdaptorBase {
   160   public:
   161     typedef GR Graph;
   162 
   163   protected:
   164     GR* _graph;
   165 
   166     GraphAdaptorBase() : _graph(0) {}
   167 
   168     void initialize(GR& graph) { _graph = &graph; }
   169 
   170   public:
   171     GraphAdaptorBase(GR& graph) : _graph(&graph) {}
   172 
   173     typedef typename GR::Node Node;
   174     typedef typename GR::Arc Arc;
   175     typedef typename GR::Edge Edge;
   176 
   177     void first(Node& i) const { _graph->first(i); }
   178     void first(Arc& i) const { _graph->first(i); }
   179     void first(Edge& i) const { _graph->first(i); }
   180     void firstIn(Arc& i, const Node& n) const { _graph->firstIn(i, n); }
   181     void firstOut(Arc& i, const Node& n ) const { _graph->firstOut(i, n); }
   182     void firstInc(Edge &i, bool &d, const Node &n) const {
   183       _graph->firstInc(i, d, n);
   184     }
   185 
   186     void next(Node& i) const { _graph->next(i); }
   187     void next(Arc& i) const { _graph->next(i); }
   188     void next(Edge& i) const { _graph->next(i); }
   189     void nextIn(Arc& i) const { _graph->nextIn(i); }
   190     void nextOut(Arc& i) const { _graph->nextOut(i); }
   191     void nextInc(Edge &i, bool &d) const { _graph->nextInc(i, d); }
   192 
   193     Node u(const Edge& e) const { return _graph->u(e); }
   194     Node v(const Edge& e) const { return _graph->v(e); }
   195 
   196     Node source(const Arc& a) const { return _graph->source(a); }
   197     Node target(const Arc& a) const { return _graph->target(a); }
   198 
   199     typedef NodeNumTagIndicator<Graph> NodeNumTag;
   200     int nodeNum() const { return _graph->nodeNum(); }
   201 
   202     typedef ArcNumTagIndicator<Graph> ArcNumTag;
   203     int arcNum() const { return _graph->arcNum(); }
   204 
   205     typedef EdgeNumTagIndicator<Graph> EdgeNumTag;
   206     int edgeNum() const { return _graph->edgeNum(); }
   207 
   208     typedef FindArcTagIndicator<Graph> FindArcTag;
   209     Arc findArc(const Node& u, const Node& v,
   210                 const Arc& prev = INVALID) const {
   211       return _graph->findArc(u, v, prev);
   212     }
   213 
   214     typedef FindEdgeTagIndicator<Graph> FindEdgeTag;
   215     Edge findEdge(const Node& u, const Node& v,
   216                   const Edge& prev = INVALID) const {
   217       return _graph->findEdge(u, v, prev);
   218     }
   219 
   220     Node addNode() { return _graph->addNode(); }
   221     Edge addEdge(const Node& u, const Node& v) { return _graph->addEdge(u, v); }
   222 
   223     void erase(const Node& i) { _graph->erase(i); }
   224     void erase(const Edge& i) { _graph->erase(i); }
   225 
   226     void clear() { _graph->clear(); }
   227 
   228     bool direction(const Arc& a) const { return _graph->direction(a); }
   229     Arc direct(const Edge& e, bool d) const { return _graph->direct(e, d); }
   230 
   231     int id(const Node& v) const { return _graph->id(v); }
   232     int id(const Arc& a) const { return _graph->id(a); }
   233     int id(const Edge& e) const { return _graph->id(e); }
   234 
   235     Node nodeFromId(int ix) const { return _graph->nodeFromId(ix); }
   236     Arc arcFromId(int ix) const { return _graph->arcFromId(ix); }
   237     Edge edgeFromId(int ix) const { return _graph->edgeFromId(ix); }
   238 
   239     int maxNodeId() const { return _graph->maxNodeId(); }
   240     int maxArcId() const { return _graph->maxArcId(); }
   241     int maxEdgeId() const { return _graph->maxEdgeId(); }
   242 
   243     typedef typename ItemSetTraits<GR, Node>::ItemNotifier NodeNotifier;
   244     NodeNotifier& notifier(Node) const { return _graph->notifier(Node()); }
   245 
   246     typedef typename ItemSetTraits<GR, Arc>::ItemNotifier ArcNotifier;
   247     ArcNotifier& notifier(Arc) const { return _graph->notifier(Arc()); }
   248 
   249     typedef typename ItemSetTraits<GR, Edge>::ItemNotifier EdgeNotifier;
   250     EdgeNotifier& notifier(Edge) const { return _graph->notifier(Edge()); }
   251 
   252     template <typename V>
   253     class NodeMap : public GR::template NodeMap<V> {
   254       typedef typename GR::template NodeMap<V> Parent;
   255 
   256     public:
   257       explicit NodeMap(const GraphAdaptorBase<GR>& adapter)
   258         : Parent(*adapter._graph) {}
   259       NodeMap(const GraphAdaptorBase<GR>& adapter, const V& value)
   260         : Parent(*adapter._graph, value) {}
   261 
   262     private:
   263       NodeMap& operator=(const NodeMap& cmap) {
   264         return operator=<NodeMap>(cmap);
   265       }
   266 
   267       template <typename CMap>
   268       NodeMap& operator=(const CMap& cmap) {
   269         Parent::operator=(cmap);
   270         return *this;
   271       }
   272 
   273     };
   274 
   275     template <typename V>
   276     class ArcMap : public GR::template ArcMap<V> {
   277       typedef typename GR::template ArcMap<V> Parent;
   278 
   279     public:
   280       explicit ArcMap(const GraphAdaptorBase<GR>& adapter)
   281         : Parent(*adapter._graph) {}
   282       ArcMap(const GraphAdaptorBase<GR>& adapter, const V& value)
   283         : Parent(*adapter._graph, value) {}
   284 
   285     private:
   286       ArcMap& operator=(const ArcMap& cmap) {
   287         return operator=<ArcMap>(cmap);
   288       }
   289 
   290       template <typename CMap>
   291       ArcMap& operator=(const CMap& cmap) {
   292         Parent::operator=(cmap);
   293         return *this;
   294       }
   295     };
   296 
   297     template <typename V>
   298     class EdgeMap : public GR::template EdgeMap<V> {
   299       typedef typename GR::template EdgeMap<V> Parent;
   300 
   301     public:
   302       explicit EdgeMap(const GraphAdaptorBase<GR>& adapter)
   303         : Parent(*adapter._graph) {}
   304       EdgeMap(const GraphAdaptorBase<GR>& adapter, const V& value)
   305         : Parent(*adapter._graph, value) {}
   306 
   307     private:
   308       EdgeMap& operator=(const EdgeMap& cmap) {
   309         return operator=<EdgeMap>(cmap);
   310       }
   311 
   312       template <typename CMap>
   313       EdgeMap& operator=(const CMap& cmap) {
   314         Parent::operator=(cmap);
   315         return *this;
   316       }
   317     };
   318 
   319   };
   320 
   321   template <typename DGR>
   322   class ReverseDigraphBase : public DigraphAdaptorBase<DGR> {
   323     typedef DigraphAdaptorBase<DGR> Parent;
   324   public:
   325     typedef DGR Digraph;
   326   protected:
   327     ReverseDigraphBase() : Parent() { }
   328   public:
   329     typedef typename Parent::Node Node;
   330     typedef typename Parent::Arc Arc;
   331 
   332     void firstIn(Arc& a, const Node& n) const { Parent::firstOut(a, n); }
   333     void firstOut(Arc& a, const Node& n ) const { Parent::firstIn(a, n); }
   334 
   335     void nextIn(Arc& a) const { Parent::nextOut(a); }
   336     void nextOut(Arc& a) const { Parent::nextIn(a); }
   337 
   338     Node source(const Arc& a) const { return Parent::target(a); }
   339     Node target(const Arc& a) const { return Parent::source(a); }
   340 
   341     Arc addArc(const Node& u, const Node& v) { return Parent::addArc(v, u); }
   342 
   343     typedef FindArcTagIndicator<DGR> FindArcTag;
   344     Arc findArc(const Node& u, const Node& v,
   345                 const Arc& prev = INVALID) const {
   346       return Parent::findArc(v, u, prev);
   347     }
   348 
   349   };
   350 
   351   /// \ingroup graph_adaptors
   352   ///
   353   /// \brief Adaptor class for reversing the orientation of the arcs in
   354   /// a digraph.
   355   ///
   356   /// ReverseDigraph can be used for reversing the arcs in a digraph.
   357   /// It conforms to the \ref concepts::Digraph "Digraph" concept.
   358   ///
   359   /// The adapted digraph can also be modified through this adaptor
   360   /// by adding or removing nodes or arcs, unless the \c GR template
   361   /// parameter is set to be \c const.
   362   ///
   363   /// \tparam DGR The type of the adapted digraph.
   364   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
   365   /// It can also be specified to be \c const.
   366   ///
   367   /// \note The \c Node and \c Arc types of this adaptor and the adapted
   368   /// digraph are convertible to each other.
   369   template<typename DGR>
   370 #ifdef DOXYGEN
   371   class ReverseDigraph {
   372 #else
   373   class ReverseDigraph :
   374     public DigraphAdaptorExtender<ReverseDigraphBase<DGR> > {
   375 #endif
   376     typedef DigraphAdaptorExtender<ReverseDigraphBase<DGR> > Parent;
   377   public:
   378     /// The type of the adapted digraph.
   379     typedef DGR Digraph;
   380   protected:
   381     ReverseDigraph() { }
   382   public:
   383 
   384     /// \brief Constructor
   385     ///
   386     /// Creates a reverse digraph adaptor for the given digraph.
   387     explicit ReverseDigraph(DGR& digraph) {
   388       Parent::initialize(digraph);
   389     }
   390   };
   391 
   392   /// \brief Returns a read-only ReverseDigraph adaptor
   393   ///
   394   /// This function just returns a read-only \ref ReverseDigraph adaptor.
   395   /// \ingroup graph_adaptors
   396   /// \relates ReverseDigraph
   397   template<typename DGR>
   398   ReverseDigraph<const DGR> reverseDigraph(const DGR& digraph) {
   399     return ReverseDigraph<const DGR>(digraph);
   400   }
   401 
   402 
   403   template <typename DGR, typename NF, typename AF, bool ch = true>
   404   class SubDigraphBase : public DigraphAdaptorBase<DGR> {
   405     typedef DigraphAdaptorBase<DGR> Parent;
   406   public:
   407     typedef DGR Digraph;
   408     typedef NF NodeFilterMap;
   409     typedef AF ArcFilterMap;
   410 
   411     typedef SubDigraphBase Adaptor;
   412   protected:
   413     NF* _node_filter;
   414     AF* _arc_filter;
   415     SubDigraphBase()
   416       : Parent(), _node_filter(0), _arc_filter(0) { }
   417 
   418     void initialize(DGR& digraph, NF& node_filter, AF& arc_filter) {
   419       Parent::initialize(digraph);
   420       _node_filter = &node_filter;
   421       _arc_filter = &arc_filter;      
   422     }
   423 
   424   public:
   425 
   426     typedef typename Parent::Node Node;
   427     typedef typename Parent::Arc Arc;
   428 
   429     void first(Node& i) const {
   430       Parent::first(i);
   431       while (i != INVALID && !(*_node_filter)[i]) Parent::next(i);
   432     }
   433 
   434     void first(Arc& i) const {
   435       Parent::first(i);
   436       while (i != INVALID && (!(*_arc_filter)[i]
   437                               || !(*_node_filter)[Parent::source(i)]
   438                               || !(*_node_filter)[Parent::target(i)]))
   439         Parent::next(i);
   440     }
   441 
   442     void firstIn(Arc& i, const Node& n) const {
   443       Parent::firstIn(i, n);
   444       while (i != INVALID && (!(*_arc_filter)[i]
   445                               || !(*_node_filter)[Parent::source(i)]))
   446         Parent::nextIn(i);
   447     }
   448 
   449     void firstOut(Arc& i, const Node& n) const {
   450       Parent::firstOut(i, n);
   451       while (i != INVALID && (!(*_arc_filter)[i]
   452                               || !(*_node_filter)[Parent::target(i)]))
   453         Parent::nextOut(i);
   454     }
   455 
   456     void next(Node& i) const {
   457       Parent::next(i);
   458       while (i != INVALID && !(*_node_filter)[i]) Parent::next(i);
   459     }
   460 
   461     void next(Arc& i) const {
   462       Parent::next(i);
   463       while (i != INVALID && (!(*_arc_filter)[i]
   464                               || !(*_node_filter)[Parent::source(i)]
   465                               || !(*_node_filter)[Parent::target(i)]))
   466         Parent::next(i);
   467     }
   468 
   469     void nextIn(Arc& i) const {
   470       Parent::nextIn(i);
   471       while (i != INVALID && (!(*_arc_filter)[i]
   472                               || !(*_node_filter)[Parent::source(i)]))
   473         Parent::nextIn(i);
   474     }
   475 
   476     void nextOut(Arc& i) const {
   477       Parent::nextOut(i);
   478       while (i != INVALID && (!(*_arc_filter)[i]
   479                               || !(*_node_filter)[Parent::target(i)]))
   480         Parent::nextOut(i);
   481     }
   482 
   483     void status(const Node& n, bool v) const { _node_filter->set(n, v); }
   484     void status(const Arc& a, bool v) const { _arc_filter->set(a, v); }
   485 
   486     bool status(const Node& n) const { return (*_node_filter)[n]; }
   487     bool status(const Arc& a) const { return (*_arc_filter)[a]; }
   488 
   489     typedef False NodeNumTag;
   490     typedef False ArcNumTag;
   491 
   492     typedef FindArcTagIndicator<DGR> FindArcTag;
   493     Arc findArc(const Node& source, const Node& target,
   494                 const Arc& prev = INVALID) const {
   495       if (!(*_node_filter)[source] || !(*_node_filter)[target]) {
   496         return INVALID;
   497       }
   498       Arc arc = Parent::findArc(source, target, prev);
   499       while (arc != INVALID && !(*_arc_filter)[arc]) {
   500         arc = Parent::findArc(source, target, arc);
   501       }
   502       return arc;
   503     }
   504 
   505   public:
   506 
   507     template <typename V>
   508     class NodeMap 
   509       : public SubMapExtender<SubDigraphBase<DGR, NF, AF, ch>, 
   510 	      LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, NodeMap<V>)> {
   511       typedef SubMapExtender<SubDigraphBase<DGR, NF, AF, ch>,
   512 	LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, NodeMap<V>)> Parent;
   513 
   514     public:
   515       typedef V Value;
   516 
   517       NodeMap(const SubDigraphBase<DGR, NF, AF, ch>& adaptor)
   518         : Parent(adaptor) {}
   519       NodeMap(const SubDigraphBase<DGR, NF, AF, ch>& adaptor, const V& value)
   520         : Parent(adaptor, value) {}
   521 
   522     private:
   523       NodeMap& operator=(const NodeMap& cmap) {
   524         return operator=<NodeMap>(cmap);
   525       }
   526 
   527       template <typename CMap>
   528       NodeMap& operator=(const CMap& cmap) {
   529         Parent::operator=(cmap);
   530         return *this;
   531       }
   532     };
   533 
   534     template <typename V>
   535     class ArcMap 
   536       : public SubMapExtender<SubDigraphBase<DGR, NF, AF, ch>,
   537 	      LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, ArcMap<V>)> {
   538       typedef SubMapExtender<SubDigraphBase<DGR, NF, AF, ch>,
   539         LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, ArcMap<V>)> Parent;
   540 
   541     public:
   542       typedef V Value;
   543 
   544       ArcMap(const SubDigraphBase<DGR, NF, AF, ch>& adaptor)
   545         : Parent(adaptor) {}
   546       ArcMap(const SubDigraphBase<DGR, NF, AF, ch>& adaptor, const V& value)
   547         : Parent(adaptor, value) {}
   548 
   549     private:
   550       ArcMap& operator=(const ArcMap& cmap) {
   551         return operator=<ArcMap>(cmap);
   552       }
   553 
   554       template <typename CMap>
   555       ArcMap& operator=(const CMap& cmap) {
   556         Parent::operator=(cmap);
   557         return *this;
   558       }
   559     };
   560 
   561   };
   562 
   563   template <typename DGR, typename NF, typename AF>
   564   class SubDigraphBase<DGR, NF, AF, false>
   565     : public DigraphAdaptorBase<DGR> {
   566     typedef DigraphAdaptorBase<DGR> Parent;
   567   public:
   568     typedef DGR Digraph;
   569     typedef NF NodeFilterMap;
   570     typedef AF ArcFilterMap;
   571 
   572     typedef SubDigraphBase Adaptor;
   573   protected:
   574     NF* _node_filter;
   575     AF* _arc_filter;
   576     SubDigraphBase()
   577       : Parent(), _node_filter(0), _arc_filter(0) { }
   578 
   579     void initialize(DGR& digraph, NF& node_filter, AF& arc_filter) {
   580       Parent::initialize(digraph);
   581       _node_filter = &node_filter;
   582       _arc_filter = &arc_filter;      
   583     }
   584 
   585   public:
   586 
   587     typedef typename Parent::Node Node;
   588     typedef typename Parent::Arc Arc;
   589 
   590     void first(Node& i) const {
   591       Parent::first(i);
   592       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
   593     }
   594 
   595     void first(Arc& i) const {
   596       Parent::first(i);
   597       while (i!=INVALID && !(*_arc_filter)[i]) Parent::next(i);
   598     }
   599 
   600     void firstIn(Arc& i, const Node& n) const {
   601       Parent::firstIn(i, n);
   602       while (i!=INVALID && !(*_arc_filter)[i]) Parent::nextIn(i);
   603     }
   604 
   605     void firstOut(Arc& i, const Node& n) const {
   606       Parent::firstOut(i, n);
   607       while (i!=INVALID && !(*_arc_filter)[i]) Parent::nextOut(i);
   608     }
   609 
   610     void next(Node& i) const {
   611       Parent::next(i);
   612       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
   613     }
   614     void next(Arc& i) const {
   615       Parent::next(i);
   616       while (i!=INVALID && !(*_arc_filter)[i]) Parent::next(i);
   617     }
   618     void nextIn(Arc& i) const {
   619       Parent::nextIn(i);
   620       while (i!=INVALID && !(*_arc_filter)[i]) Parent::nextIn(i);
   621     }
   622 
   623     void nextOut(Arc& i) const {
   624       Parent::nextOut(i);
   625       while (i!=INVALID && !(*_arc_filter)[i]) Parent::nextOut(i);
   626     }
   627 
   628     void status(const Node& n, bool v) const { _node_filter->set(n, v); }
   629     void status(const Arc& a, bool v) const { _arc_filter->set(a, v); }
   630 
   631     bool status(const Node& n) const { return (*_node_filter)[n]; }
   632     bool status(const Arc& a) const { return (*_arc_filter)[a]; }
   633 
   634     typedef False NodeNumTag;
   635     typedef False ArcNumTag;
   636 
   637     typedef FindArcTagIndicator<DGR> FindArcTag;
   638     Arc findArc(const Node& source, const Node& target,
   639                 const Arc& prev = INVALID) const {
   640       if (!(*_node_filter)[source] || !(*_node_filter)[target]) {
   641         return INVALID;
   642       }
   643       Arc arc = Parent::findArc(source, target, prev);
   644       while (arc != INVALID && !(*_arc_filter)[arc]) {
   645         arc = Parent::findArc(source, target, arc);
   646       }
   647       return arc;
   648     }
   649 
   650     template <typename V>
   651     class NodeMap 
   652       : public SubMapExtender<SubDigraphBase<DGR, NF, AF, false>,
   653           LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, NodeMap<V>)> {
   654       typedef SubMapExtender<SubDigraphBase<DGR, NF, AF, false>, 
   655         LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, NodeMap<V>)> Parent;
   656 
   657     public:
   658       typedef V Value;
   659 
   660       NodeMap(const SubDigraphBase<DGR, NF, AF, false>& adaptor)
   661         : Parent(adaptor) {}
   662       NodeMap(const SubDigraphBase<DGR, NF, AF, false>& adaptor, const V& value)
   663         : Parent(adaptor, value) {}
   664 
   665     private:
   666       NodeMap& operator=(const NodeMap& cmap) {
   667         return operator=<NodeMap>(cmap);
   668       }
   669 
   670       template <typename CMap>
   671       NodeMap& operator=(const CMap& cmap) {
   672         Parent::operator=(cmap);
   673         return *this;
   674       }
   675     };
   676 
   677     template <typename V>
   678     class ArcMap 
   679       : public SubMapExtender<SubDigraphBase<DGR, NF, AF, false>,
   680           LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, ArcMap<V>)> {
   681       typedef SubMapExtender<SubDigraphBase<DGR, NF, AF, false>,
   682         LEMON_SCOPE_FIX(DigraphAdaptorBase<DGR>, ArcMap<V>)> Parent;
   683 
   684     public:
   685       typedef V Value;
   686 
   687       ArcMap(const SubDigraphBase<DGR, NF, AF, false>& adaptor)
   688         : Parent(adaptor) {}
   689       ArcMap(const SubDigraphBase<DGR, NF, AF, false>& adaptor, const V& value)
   690         : Parent(adaptor, value) {}
   691 
   692     private:
   693       ArcMap& operator=(const ArcMap& cmap) {
   694         return operator=<ArcMap>(cmap);
   695       }
   696 
   697       template <typename CMap>
   698       ArcMap& operator=(const CMap& cmap) {
   699         Parent::operator=(cmap);
   700         return *this;
   701       }
   702     };
   703 
   704   };
   705 
   706   /// \ingroup graph_adaptors
   707   ///
   708   /// \brief Adaptor class for hiding nodes and arcs in a digraph
   709   ///
   710   /// SubDigraph can be used for hiding nodes and arcs in a digraph.
   711   /// A \c bool node map and a \c bool arc map must be specified, which
   712   /// define the filters for nodes and arcs.
   713   /// Only the nodes and arcs with \c true filter value are
   714   /// shown in the subdigraph. The arcs that are incident to hidden
   715   /// nodes are also filtered out.
   716   /// This adaptor conforms to the \ref concepts::Digraph "Digraph" concept.
   717   ///
   718   /// The adapted digraph can also be modified through this adaptor
   719   /// by adding or removing nodes or arcs, unless the \c GR template
   720   /// parameter is set to be \c const.
   721   ///
   722   /// \tparam DGR The type of the adapted digraph.
   723   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
   724   /// It can also be specified to be \c const.
   725   /// \tparam NF The type of the node filter map.
   726   /// It must be a \c bool (or convertible) node map of the
   727   /// adapted digraph. The default type is
   728   /// \ref concepts::Digraph::NodeMap "DGR::NodeMap<bool>".
   729   /// \tparam AF The type of the arc filter map.
   730   /// It must be \c bool (or convertible) arc map of the
   731   /// adapted digraph. The default type is
   732   /// \ref concepts::Digraph::ArcMap "DGR::ArcMap<bool>".
   733   ///
   734   /// \note The \c Node and \c Arc types of this adaptor and the adapted
   735   /// digraph are convertible to each other.
   736   ///
   737   /// \see FilterNodes
   738   /// \see FilterArcs
   739 #ifdef DOXYGEN
   740   template<typename DGR, typename NF, typename AF>
   741   class SubDigraph {
   742 #else
   743   template<typename DGR,
   744            typename NF = typename DGR::template NodeMap<bool>,
   745            typename AF = typename DGR::template ArcMap<bool> >
   746   class SubDigraph :
   747     public DigraphAdaptorExtender<SubDigraphBase<DGR, NF, AF, true> > {
   748 #endif
   749   public:
   750     /// The type of the adapted digraph.
   751     typedef DGR Digraph;
   752     /// The type of the node filter map.
   753     typedef NF NodeFilterMap;
   754     /// The type of the arc filter map.
   755     typedef AF ArcFilterMap;
   756 
   757     typedef DigraphAdaptorExtender<SubDigraphBase<DGR, NF, AF, true> >
   758       Parent;
   759 
   760     typedef typename Parent::Node Node;
   761     typedef typename Parent::Arc Arc;
   762 
   763   protected:
   764     SubDigraph() { }
   765   public:
   766 
   767     /// \brief Constructor
   768     ///
   769     /// Creates a subdigraph for the given digraph with the
   770     /// given node and arc filter maps.
   771     SubDigraph(DGR& digraph, NF& node_filter, AF& arc_filter) {
   772       Parent::initialize(digraph, node_filter, arc_filter);
   773     }
   774 
   775     /// \brief Sets the status of the given node
   776     ///
   777     /// This function sets the status of the given node.
   778     /// It is done by simply setting the assigned value of \c n
   779     /// to \c v in the node filter map.
   780     void status(const Node& n, bool v) const { Parent::status(n, v); }
   781 
   782     /// \brief Sets the status of the given arc
   783     ///
   784     /// This function sets the status of the given arc.
   785     /// It is done by simply setting the assigned value of \c a
   786     /// to \c v in the arc filter map.
   787     void status(const Arc& a, bool v) const { Parent::status(a, v); }
   788 
   789     /// \brief Returns the status of the given node
   790     ///
   791     /// This function returns the status of the given node.
   792     /// It is \c true if the given node is enabled (i.e. not hidden).
   793     bool status(const Node& n) const { return Parent::status(n); }
   794 
   795     /// \brief Returns the status of the given arc
   796     ///
   797     /// This function returns the status of the given arc.
   798     /// It is \c true if the given arc is enabled (i.e. not hidden).
   799     bool status(const Arc& a) const { return Parent::status(a); }
   800 
   801     /// \brief Disables the given node
   802     ///
   803     /// This function disables the given node in the subdigraph,
   804     /// so the iteration jumps over it.
   805     /// It is the same as \ref status() "status(n, false)".
   806     void disable(const Node& n) const { Parent::status(n, false); }
   807 
   808     /// \brief Disables the given arc
   809     ///
   810     /// This function disables the given arc in the subdigraph,
   811     /// so the iteration jumps over it.
   812     /// It is the same as \ref status() "status(a, false)".
   813     void disable(const Arc& a) const { Parent::status(a, false); }
   814 
   815     /// \brief Enables the given node
   816     ///
   817     /// This function enables the given node in the subdigraph.
   818     /// It is the same as \ref status() "status(n, true)".
   819     void enable(const Node& n) const { Parent::status(n, true); }
   820 
   821     /// \brief Enables the given arc
   822     ///
   823     /// This function enables the given arc in the subdigraph.
   824     /// It is the same as \ref status() "status(a, true)".
   825     void enable(const Arc& a) const { Parent::status(a, true); }
   826 
   827   };
   828 
   829   /// \brief Returns a read-only SubDigraph adaptor
   830   ///
   831   /// This function just returns a read-only \ref SubDigraph adaptor.
   832   /// \ingroup graph_adaptors
   833   /// \relates SubDigraph
   834   template<typename DGR, typename NF, typename AF>
   835   SubDigraph<const DGR, NF, AF>
   836   subDigraph(const DGR& digraph,
   837              NF& node_filter, AF& arc_filter) {
   838     return SubDigraph<const DGR, NF, AF>
   839       (digraph, node_filter, arc_filter);
   840   }
   841 
   842   template<typename DGR, typename NF, typename AF>
   843   SubDigraph<const DGR, const NF, AF>
   844   subDigraph(const DGR& digraph,
   845              const NF& node_filter, AF& arc_filter) {
   846     return SubDigraph<const DGR, const NF, AF>
   847       (digraph, node_filter, arc_filter);
   848   }
   849 
   850   template<typename DGR, typename NF, typename AF>
   851   SubDigraph<const DGR, NF, const AF>
   852   subDigraph(const DGR& digraph,
   853              NF& node_filter, const AF& arc_filter) {
   854     return SubDigraph<const DGR, NF, const AF>
   855       (digraph, node_filter, arc_filter);
   856   }
   857 
   858   template<typename DGR, typename NF, typename AF>
   859   SubDigraph<const DGR, const NF, const AF>
   860   subDigraph(const DGR& digraph,
   861              const NF& node_filter, const AF& arc_filter) {
   862     return SubDigraph<const DGR, const NF, const AF>
   863       (digraph, node_filter, arc_filter);
   864   }
   865 
   866 
   867   template <typename GR, typename NF, typename EF, bool ch = true>
   868   class SubGraphBase : public GraphAdaptorBase<GR> {
   869     typedef GraphAdaptorBase<GR> Parent;
   870   public:
   871     typedef GR Graph;
   872     typedef NF NodeFilterMap;
   873     typedef EF EdgeFilterMap;
   874 
   875     typedef SubGraphBase Adaptor;
   876   protected:
   877 
   878     NF* _node_filter;
   879     EF* _edge_filter;
   880 
   881     SubGraphBase()
   882       : Parent(), _node_filter(0), _edge_filter(0) { }
   883 
   884     void initialize(GR& graph, NF& node_filter, EF& edge_filter) {
   885       Parent::initialize(graph);
   886       _node_filter = &node_filter;
   887       _edge_filter = &edge_filter;
   888     }
   889 
   890   public:
   891 
   892     typedef typename Parent::Node Node;
   893     typedef typename Parent::Arc Arc;
   894     typedef typename Parent::Edge Edge;
   895 
   896     void first(Node& i) const {
   897       Parent::first(i);
   898       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
   899     }
   900 
   901     void first(Arc& i) const {
   902       Parent::first(i);
   903       while (i!=INVALID && (!(*_edge_filter)[i]
   904                             || !(*_node_filter)[Parent::source(i)]
   905                             || !(*_node_filter)[Parent::target(i)]))
   906         Parent::next(i);
   907     }
   908 
   909     void first(Edge& i) const {
   910       Parent::first(i);
   911       while (i!=INVALID && (!(*_edge_filter)[i]
   912                             || !(*_node_filter)[Parent::u(i)]
   913                             || !(*_node_filter)[Parent::v(i)]))
   914         Parent::next(i);
   915     }
   916 
   917     void firstIn(Arc& i, const Node& n) const {
   918       Parent::firstIn(i, n);
   919       while (i!=INVALID && (!(*_edge_filter)[i]
   920                             || !(*_node_filter)[Parent::source(i)]))
   921         Parent::nextIn(i);
   922     }
   923 
   924     void firstOut(Arc& i, const Node& n) const {
   925       Parent::firstOut(i, n);
   926       while (i!=INVALID && (!(*_edge_filter)[i]
   927                             || !(*_node_filter)[Parent::target(i)]))
   928         Parent::nextOut(i);
   929     }
   930 
   931     void firstInc(Edge& i, bool& d, const Node& n) const {
   932       Parent::firstInc(i, d, n);
   933       while (i!=INVALID && (!(*_edge_filter)[i]
   934                             || !(*_node_filter)[Parent::u(i)]
   935                             || !(*_node_filter)[Parent::v(i)]))
   936         Parent::nextInc(i, d);
   937     }
   938 
   939     void next(Node& i) const {
   940       Parent::next(i);
   941       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
   942     }
   943 
   944     void next(Arc& i) const {
   945       Parent::next(i);
   946       while (i!=INVALID && (!(*_edge_filter)[i]
   947                             || !(*_node_filter)[Parent::source(i)]
   948                             || !(*_node_filter)[Parent::target(i)]))
   949         Parent::next(i);
   950     }
   951 
   952     void next(Edge& i) const {
   953       Parent::next(i);
   954       while (i!=INVALID && (!(*_edge_filter)[i]
   955                             || !(*_node_filter)[Parent::u(i)]
   956                             || !(*_node_filter)[Parent::v(i)]))
   957         Parent::next(i);
   958     }
   959 
   960     void nextIn(Arc& i) const {
   961       Parent::nextIn(i);
   962       while (i!=INVALID && (!(*_edge_filter)[i]
   963                             || !(*_node_filter)[Parent::source(i)]))
   964         Parent::nextIn(i);
   965     }
   966 
   967     void nextOut(Arc& i) const {
   968       Parent::nextOut(i);
   969       while (i!=INVALID && (!(*_edge_filter)[i]
   970                             || !(*_node_filter)[Parent::target(i)]))
   971         Parent::nextOut(i);
   972     }
   973 
   974     void nextInc(Edge& i, bool& d) const {
   975       Parent::nextInc(i, d);
   976       while (i!=INVALID && (!(*_edge_filter)[i]
   977                             || !(*_node_filter)[Parent::u(i)]
   978                             || !(*_node_filter)[Parent::v(i)]))
   979         Parent::nextInc(i, d);
   980     }
   981 
   982     void status(const Node& n, bool v) const { _node_filter->set(n, v); }
   983     void status(const Edge& e, bool v) const { _edge_filter->set(e, v); }
   984 
   985     bool status(const Node& n) const { return (*_node_filter)[n]; }
   986     bool status(const Edge& e) const { return (*_edge_filter)[e]; }
   987 
   988     typedef False NodeNumTag;
   989     typedef False ArcNumTag;
   990     typedef False EdgeNumTag;
   991 
   992     typedef FindArcTagIndicator<Graph> FindArcTag;
   993     Arc findArc(const Node& u, const Node& v,
   994                 const Arc& prev = INVALID) const {
   995       if (!(*_node_filter)[u] || !(*_node_filter)[v]) {
   996         return INVALID;
   997       }
   998       Arc arc = Parent::findArc(u, v, prev);
   999       while (arc != INVALID && !(*_edge_filter)[arc]) {
  1000         arc = Parent::findArc(u, v, arc);
  1001       }
  1002       return arc;
  1003     }
  1004 
  1005     typedef FindEdgeTagIndicator<Graph> FindEdgeTag;
  1006     Edge findEdge(const Node& u, const Node& v,
  1007                   const Edge& prev = INVALID) const {
  1008       if (!(*_node_filter)[u] || !(*_node_filter)[v]) {
  1009         return INVALID;
  1010       }
  1011       Edge edge = Parent::findEdge(u, v, prev);
  1012       while (edge != INVALID && !(*_edge_filter)[edge]) {
  1013         edge = Parent::findEdge(u, v, edge);
  1014       }
  1015       return edge;
  1016     }
  1017 
  1018     template <typename V>
  1019     class NodeMap 
  1020       : public SubMapExtender<SubGraphBase<GR, NF, EF, ch>,
  1021           LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, NodeMap<V>)> {
  1022       typedef SubMapExtender<SubGraphBase<GR, NF, EF, ch>, 
  1023         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, NodeMap<V>)> Parent;
  1024 
  1025     public:
  1026       typedef V Value;
  1027 
  1028       NodeMap(const SubGraphBase<GR, NF, EF, ch>& adaptor)
  1029         : Parent(adaptor) {}
  1030       NodeMap(const SubGraphBase<GR, NF, EF, ch>& adaptor, const V& value)
  1031         : Parent(adaptor, value) {}
  1032 
  1033     private:
  1034       NodeMap& operator=(const NodeMap& cmap) {
  1035         return operator=<NodeMap>(cmap);
  1036       }
  1037 
  1038       template <typename CMap>
  1039       NodeMap& operator=(const CMap& cmap) {
  1040         Parent::operator=(cmap);
  1041         return *this;
  1042       }
  1043     };
  1044 
  1045     template <typename V>
  1046     class ArcMap 
  1047       : public SubMapExtender<SubGraphBase<GR, NF, EF, ch>,
  1048           LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, ArcMap<V>)> {
  1049       typedef SubMapExtender<SubGraphBase<GR, NF, EF, ch>, 
  1050         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, ArcMap<V>)> Parent;
  1051 
  1052     public:
  1053       typedef V Value;
  1054 
  1055       ArcMap(const SubGraphBase<GR, NF, EF, ch>& adaptor)
  1056         : Parent(adaptor) {}
  1057       ArcMap(const SubGraphBase<GR, NF, EF, ch>& adaptor, const V& value)
  1058         : Parent(adaptor, value) {}
  1059 
  1060     private:
  1061       ArcMap& operator=(const ArcMap& cmap) {
  1062         return operator=<ArcMap>(cmap);
  1063       }
  1064 
  1065       template <typename CMap>
  1066       ArcMap& operator=(const CMap& cmap) {
  1067         Parent::operator=(cmap);
  1068         return *this;
  1069       }
  1070     };
  1071 
  1072     template <typename V>
  1073     class EdgeMap 
  1074       : public SubMapExtender<SubGraphBase<GR, NF, EF, ch>,
  1075         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, EdgeMap<V>)> {
  1076       typedef SubMapExtender<SubGraphBase<GR, NF, EF, ch>, 
  1077         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, EdgeMap<V>)> Parent;
  1078 
  1079     public:
  1080       typedef V Value;
  1081 
  1082       EdgeMap(const SubGraphBase<GR, NF, EF, ch>& adaptor)
  1083         : Parent(adaptor) {}
  1084 
  1085       EdgeMap(const SubGraphBase<GR, NF, EF, ch>& adaptor, const V& value)
  1086         : Parent(adaptor, value) {}
  1087 
  1088     private:
  1089       EdgeMap& operator=(const EdgeMap& cmap) {
  1090         return operator=<EdgeMap>(cmap);
  1091       }
  1092 
  1093       template <typename CMap>
  1094       EdgeMap& operator=(const CMap& cmap) {
  1095         Parent::operator=(cmap);
  1096         return *this;
  1097       }
  1098     };
  1099 
  1100   };
  1101 
  1102   template <typename GR, typename NF, typename EF>
  1103   class SubGraphBase<GR, NF, EF, false>
  1104     : public GraphAdaptorBase<GR> {
  1105     typedef GraphAdaptorBase<GR> Parent;
  1106   public:
  1107     typedef GR Graph;
  1108     typedef NF NodeFilterMap;
  1109     typedef EF EdgeFilterMap;
  1110 
  1111     typedef SubGraphBase Adaptor;
  1112   protected:
  1113     NF* _node_filter;
  1114     EF* _edge_filter;
  1115     SubGraphBase() 
  1116 	  : Parent(), _node_filter(0), _edge_filter(0) { }
  1117 
  1118     void initialize(GR& graph, NF& node_filter, EF& edge_filter) {
  1119       Parent::initialize(graph);
  1120       _node_filter = &node_filter;
  1121       _edge_filter = &edge_filter;
  1122     }
  1123 
  1124   public:
  1125 
  1126     typedef typename Parent::Node Node;
  1127     typedef typename Parent::Arc Arc;
  1128     typedef typename Parent::Edge Edge;
  1129 
  1130     void first(Node& i) const {
  1131       Parent::first(i);
  1132       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
  1133     }
  1134 
  1135     void first(Arc& i) const {
  1136       Parent::first(i);
  1137       while (i!=INVALID && !(*_edge_filter)[i]) Parent::next(i);
  1138     }
  1139 
  1140     void first(Edge& i) const {
  1141       Parent::first(i);
  1142       while (i!=INVALID && !(*_edge_filter)[i]) Parent::next(i);
  1143     }
  1144 
  1145     void firstIn(Arc& i, const Node& n) const {
  1146       Parent::firstIn(i, n);
  1147       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextIn(i);
  1148     }
  1149 
  1150     void firstOut(Arc& i, const Node& n) const {
  1151       Parent::firstOut(i, n);
  1152       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextOut(i);
  1153     }
  1154 
  1155     void firstInc(Edge& i, bool& d, const Node& n) const {
  1156       Parent::firstInc(i, d, n);
  1157       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextInc(i, d);
  1158     }
  1159 
  1160     void next(Node& i) const {
  1161       Parent::next(i);
  1162       while (i!=INVALID && !(*_node_filter)[i]) Parent::next(i);
  1163     }
  1164     void next(Arc& i) const {
  1165       Parent::next(i);
  1166       while (i!=INVALID && !(*_edge_filter)[i]) Parent::next(i);
  1167     }
  1168     void next(Edge& i) const {
  1169       Parent::next(i);
  1170       while (i!=INVALID && !(*_edge_filter)[i]) Parent::next(i);
  1171     }
  1172     void nextIn(Arc& i) const {
  1173       Parent::nextIn(i);
  1174       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextIn(i);
  1175     }
  1176 
  1177     void nextOut(Arc& i) const {
  1178       Parent::nextOut(i);
  1179       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextOut(i);
  1180     }
  1181     void nextInc(Edge& i, bool& d) const {
  1182       Parent::nextInc(i, d);
  1183       while (i!=INVALID && !(*_edge_filter)[i]) Parent::nextInc(i, d);
  1184     }
  1185 
  1186     void status(const Node& n, bool v) const { _node_filter->set(n, v); }
  1187     void status(const Edge& e, bool v) const { _edge_filter->set(e, v); }
  1188 
  1189     bool status(const Node& n) const { return (*_node_filter)[n]; }
  1190     bool status(const Edge& e) const { return (*_edge_filter)[e]; }
  1191 
  1192     typedef False NodeNumTag;
  1193     typedef False ArcNumTag;
  1194     typedef False EdgeNumTag;
  1195 
  1196     typedef FindArcTagIndicator<Graph> FindArcTag;
  1197     Arc findArc(const Node& u, const Node& v,
  1198                 const Arc& prev = INVALID) const {
  1199       Arc arc = Parent::findArc(u, v, prev);
  1200       while (arc != INVALID && !(*_edge_filter)[arc]) {
  1201         arc = Parent::findArc(u, v, arc);
  1202       }
  1203       return arc;
  1204     }
  1205 
  1206     typedef FindEdgeTagIndicator<Graph> FindEdgeTag;
  1207     Edge findEdge(const Node& u, const Node& v,
  1208                   const Edge& prev = INVALID) const {
  1209       Edge edge = Parent::findEdge(u, v, prev);
  1210       while (edge != INVALID && !(*_edge_filter)[edge]) {
  1211         edge = Parent::findEdge(u, v, edge);
  1212       }
  1213       return edge;
  1214     }
  1215 
  1216     template <typename V>
  1217     class NodeMap 
  1218       : public SubMapExtender<SubGraphBase<GR, NF, EF, false>,
  1219           LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, NodeMap<V>)> {
  1220       typedef SubMapExtender<SubGraphBase<GR, NF, EF, false>, 
  1221         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, NodeMap<V>)> Parent;
  1222 
  1223     public:
  1224       typedef V Value;
  1225 
  1226       NodeMap(const SubGraphBase<GR, NF, EF, false>& adaptor)
  1227         : Parent(adaptor) {}
  1228       NodeMap(const SubGraphBase<GR, NF, EF, false>& adaptor, const V& value)
  1229         : Parent(adaptor, value) {}
  1230 
  1231     private:
  1232       NodeMap& operator=(const NodeMap& cmap) {
  1233         return operator=<NodeMap>(cmap);
  1234       }
  1235 
  1236       template <typename CMap>
  1237       NodeMap& operator=(const CMap& cmap) {
  1238         Parent::operator=(cmap);
  1239         return *this;
  1240       }
  1241     };
  1242 
  1243     template <typename V>
  1244     class ArcMap 
  1245       : public SubMapExtender<SubGraphBase<GR, NF, EF, false>,
  1246           LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, ArcMap<V>)> {
  1247       typedef SubMapExtender<SubGraphBase<GR, NF, EF, false>, 
  1248         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, ArcMap<V>)> Parent;
  1249 
  1250     public:
  1251       typedef V Value;
  1252 
  1253       ArcMap(const SubGraphBase<GR, NF, EF, false>& adaptor)
  1254         : Parent(adaptor) {}
  1255       ArcMap(const SubGraphBase<GR, NF, EF, false>& adaptor, const V& value)
  1256         : Parent(adaptor, value) {}
  1257 
  1258     private:
  1259       ArcMap& operator=(const ArcMap& cmap) {
  1260         return operator=<ArcMap>(cmap);
  1261       }
  1262 
  1263       template <typename CMap>
  1264       ArcMap& operator=(const CMap& cmap) {
  1265         Parent::operator=(cmap);
  1266         return *this;
  1267       }
  1268     };
  1269 
  1270     template <typename V>
  1271     class EdgeMap 
  1272       : public SubMapExtender<SubGraphBase<GR, NF, EF, false>,
  1273         LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, EdgeMap<V>)> {
  1274       typedef SubMapExtender<SubGraphBase<GR, NF, EF, false>, 
  1275 	LEMON_SCOPE_FIX(GraphAdaptorBase<GR>, EdgeMap<V>)> Parent;
  1276 
  1277     public:
  1278       typedef V Value;
  1279 
  1280       EdgeMap(const SubGraphBase<GR, NF, EF, false>& adaptor)
  1281         : Parent(adaptor) {}
  1282 
  1283       EdgeMap(const SubGraphBase<GR, NF, EF, false>& adaptor, const V& value)
  1284         : Parent(adaptor, value) {}
  1285 
  1286     private:
  1287       EdgeMap& operator=(const EdgeMap& cmap) {
  1288         return operator=<EdgeMap>(cmap);
  1289       }
  1290 
  1291       template <typename CMap>
  1292       EdgeMap& operator=(const CMap& cmap) {
  1293         Parent::operator=(cmap);
  1294         return *this;
  1295       }
  1296     };
  1297 
  1298   };
  1299 
  1300   /// \ingroup graph_adaptors
  1301   ///
  1302   /// \brief Adaptor class for hiding nodes and edges in an undirected
  1303   /// graph.
  1304   ///
  1305   /// SubGraph can be used for hiding nodes and edges in a graph.
  1306   /// A \c bool node map and a \c bool edge map must be specified, which
  1307   /// define the filters for nodes and edges.
  1308   /// Only the nodes and edges with \c true filter value are
  1309   /// shown in the subgraph. The edges that are incident to hidden
  1310   /// nodes are also filtered out.
  1311   /// This adaptor conforms to the \ref concepts::Graph "Graph" concept.
  1312   ///
  1313   /// The adapted graph can also be modified through this adaptor
  1314   /// by adding or removing nodes or edges, unless the \c GR template
  1315   /// parameter is set to be \c const.
  1316   ///
  1317   /// \tparam GR The type of the adapted graph.
  1318   /// It must conform to the \ref concepts::Graph "Graph" concept.
  1319   /// It can also be specified to be \c const.
  1320   /// \tparam NF The type of the node filter map.
  1321   /// It must be a \c bool (or convertible) node map of the
  1322   /// adapted graph. The default type is
  1323   /// \ref concepts::Graph::NodeMap "GR::NodeMap<bool>".
  1324   /// \tparam EF The type of the edge filter map.
  1325   /// It must be a \c bool (or convertible) edge map of the
  1326   /// adapted graph. The default type is
  1327   /// \ref concepts::Graph::EdgeMap "GR::EdgeMap<bool>".
  1328   ///
  1329   /// \note The \c Node, \c Edge and \c Arc types of this adaptor and the
  1330   /// adapted graph are convertible to each other.
  1331   ///
  1332   /// \see FilterNodes
  1333   /// \see FilterEdges
  1334 #ifdef DOXYGEN
  1335   template<typename GR, typename NF, typename EF>
  1336   class SubGraph {
  1337 #else
  1338   template<typename GR,
  1339            typename NF = typename GR::template NodeMap<bool>,
  1340            typename EF = typename GR::template EdgeMap<bool> >
  1341   class SubGraph :
  1342     public GraphAdaptorExtender<SubGraphBase<GR, NF, EF, true> > {
  1343 #endif
  1344   public:
  1345     /// The type of the adapted graph.
  1346     typedef GR Graph;
  1347     /// The type of the node filter map.
  1348     typedef NF NodeFilterMap;
  1349     /// The type of the edge filter map.
  1350     typedef EF EdgeFilterMap;
  1351 
  1352     typedef GraphAdaptorExtender<SubGraphBase<GR, NF, EF, true> >
  1353       Parent;
  1354 
  1355     typedef typename Parent::Node Node;
  1356     typedef typename Parent::Edge Edge;
  1357 
  1358   protected:
  1359     SubGraph() { }
  1360   public:
  1361 
  1362     /// \brief Constructor
  1363     ///
  1364     /// Creates a subgraph for the given graph with the given node
  1365     /// and edge filter maps.
  1366     SubGraph(GR& graph, NF& node_filter, EF& edge_filter) {
  1367       initialize(graph, node_filter, edge_filter);
  1368     }
  1369 
  1370     /// \brief Sets the status of the given node
  1371     ///
  1372     /// This function sets the status of the given node.
  1373     /// It is done by simply setting the assigned value of \c n
  1374     /// to \c v in the node filter map.
  1375     void status(const Node& n, bool v) const { Parent::status(n, v); }
  1376 
  1377     /// \brief Sets the status of the given edge
  1378     ///
  1379     /// This function sets the status of the given edge.
  1380     /// It is done by simply setting the assigned value of \c e
  1381     /// to \c v in the edge filter map.
  1382     void status(const Edge& e, bool v) const { Parent::status(e, v); }
  1383 
  1384     /// \brief Returns the status of the given node
  1385     ///
  1386     /// This function returns the status of the given node.
  1387     /// It is \c true if the given node is enabled (i.e. not hidden).
  1388     bool status(const Node& n) const { return Parent::status(n); }
  1389 
  1390     /// \brief Returns the status of the given edge
  1391     ///
  1392     /// This function returns the status of the given edge.
  1393     /// It is \c true if the given edge is enabled (i.e. not hidden).
  1394     bool status(const Edge& e) const { return Parent::status(e); }
  1395 
  1396     /// \brief Disables the given node
  1397     ///
  1398     /// This function disables the given node in the subdigraph,
  1399     /// so the iteration jumps over it.
  1400     /// It is the same as \ref status() "status(n, false)".
  1401     void disable(const Node& n) const { Parent::status(n, false); }
  1402 
  1403     /// \brief Disables the given edge
  1404     ///
  1405     /// This function disables the given edge in the subgraph,
  1406     /// so the iteration jumps over it.
  1407     /// It is the same as \ref status() "status(e, false)".
  1408     void disable(const Edge& e) const { Parent::status(e, false); }
  1409 
  1410     /// \brief Enables the given node
  1411     ///
  1412     /// This function enables the given node in the subdigraph.
  1413     /// It is the same as \ref status() "status(n, true)".
  1414     void enable(const Node& n) const { Parent::status(n, true); }
  1415 
  1416     /// \brief Enables the given edge
  1417     ///
  1418     /// This function enables the given edge in the subgraph.
  1419     /// It is the same as \ref status() "status(e, true)".
  1420     void enable(const Edge& e) const { Parent::status(e, true); }
  1421 
  1422   };
  1423 
  1424   /// \brief Returns a read-only SubGraph adaptor
  1425   ///
  1426   /// This function just returns a read-only \ref SubGraph adaptor.
  1427   /// \ingroup graph_adaptors
  1428   /// \relates SubGraph
  1429   template<typename GR, typename NF, typename EF>
  1430   SubGraph<const GR, NF, EF>
  1431   subGraph(const GR& graph, NF& node_filter, EF& edge_filter) {
  1432     return SubGraph<const GR, NF, EF>
  1433       (graph, node_filter, edge_filter);
  1434   }
  1435 
  1436   template<typename GR, typename NF, typename EF>
  1437   SubGraph<const GR, const NF, EF>
  1438   subGraph(const GR& graph, const NF& node_filter, EF& edge_filter) {
  1439     return SubGraph<const GR, const NF, EF>
  1440       (graph, node_filter, edge_filter);
  1441   }
  1442 
  1443   template<typename GR, typename NF, typename EF>
  1444   SubGraph<const GR, NF, const EF>
  1445   subGraph(const GR& graph, NF& node_filter, const EF& edge_filter) {
  1446     return SubGraph<const GR, NF, const EF>
  1447       (graph, node_filter, edge_filter);
  1448   }
  1449 
  1450   template<typename GR, typename NF, typename EF>
  1451   SubGraph<const GR, const NF, const EF>
  1452   subGraph(const GR& graph, const NF& node_filter, const EF& edge_filter) {
  1453     return SubGraph<const GR, const NF, const EF>
  1454       (graph, node_filter, edge_filter);
  1455   }
  1456 
  1457 
  1458   /// \ingroup graph_adaptors
  1459   ///
  1460   /// \brief Adaptor class for hiding nodes in a digraph or a graph.
  1461   ///
  1462   /// FilterNodes adaptor can be used for hiding nodes in a digraph or a
  1463   /// graph. A \c bool node map must be specified, which defines the filter
  1464   /// for the nodes. Only the nodes with \c true filter value and the
  1465   /// arcs/edges incident to nodes both with \c true filter value are shown
  1466   /// in the subgraph. This adaptor conforms to the \ref concepts::Digraph
  1467   /// "Digraph" concept or the \ref concepts::Graph "Graph" concept
  1468   /// depending on the \c GR template parameter.
  1469   ///
  1470   /// The adapted (di)graph can also be modified through this adaptor
  1471   /// by adding or removing nodes or arcs/edges, unless the \c GR template
  1472   /// parameter is set to be \c const.
  1473   ///
  1474   /// \tparam GR The type of the adapted digraph or graph.
  1475   /// It must conform to the \ref concepts::Digraph "Digraph" concept
  1476   /// or the \ref concepts::Graph "Graph" concept.
  1477   /// It can also be specified to be \c const.
  1478   /// \tparam NF The type of the node filter map.
  1479   /// It must be a \c bool (or convertible) node map of the
  1480   /// adapted (di)graph. The default type is
  1481   /// \ref concepts::Graph::NodeMap "GR::NodeMap<bool>".
  1482   ///
  1483   /// \note The \c Node and <tt>Arc/Edge</tt> types of this adaptor and the
  1484   /// adapted (di)graph are convertible to each other.
  1485 #ifdef DOXYGEN
  1486   template<typename GR, typename NF>
  1487   class FilterNodes {
  1488 #else
  1489   template<typename GR,
  1490            typename NF = typename GR::template NodeMap<bool>,
  1491            typename Enable = void>
  1492   class FilterNodes :
  1493     public DigraphAdaptorExtender<
  1494       SubDigraphBase<GR, NF, ConstMap<typename GR::Arc, Const<bool, true> >,
  1495                      true> > {
  1496 #endif
  1497     typedef DigraphAdaptorExtender<
  1498       SubDigraphBase<GR, NF, ConstMap<typename GR::Arc, Const<bool, true> >, 
  1499                      true> > Parent;
  1500 
  1501   public:
  1502 
  1503     typedef GR Digraph;
  1504     typedef NF NodeFilterMap;
  1505 
  1506     typedef typename Parent::Node Node;
  1507 
  1508   protected:
  1509     ConstMap<typename Digraph::Arc, Const<bool, true> > const_true_map;
  1510 
  1511     FilterNodes() : const_true_map() {}
  1512 
  1513   public:
  1514 
  1515     /// \brief Constructor
  1516     ///
  1517     /// Creates a subgraph for the given digraph or graph with the
  1518     /// given node filter map.
  1519     FilterNodes(GR& graph, NF& node_filter) 
  1520       : Parent(), const_true_map()
  1521     {
  1522       Parent::initialize(graph, node_filter, const_true_map);
  1523     }
  1524 
  1525     /// \brief Sets the status of the given node
  1526     ///
  1527     /// This function sets the status of the given node.
  1528     /// It is done by simply setting the assigned value of \c n
  1529     /// to \c v in the node filter map.
  1530     void status(const Node& n, bool v) const { Parent::status(n, v); }
  1531 
  1532     /// \brief Returns the status of the given node
  1533     ///
  1534     /// This function returns the status of the given node.
  1535     /// It is \c true if the given node is enabled (i.e. not hidden).
  1536     bool status(const Node& n) const { return Parent::status(n); }
  1537 
  1538     /// \brief Disables the given node
  1539     ///
  1540     /// This function disables the given node, so the iteration
  1541     /// jumps over it.
  1542     /// It is the same as \ref status() "status(n, false)".
  1543     void disable(const Node& n) const { Parent::status(n, false); }
  1544 
  1545     /// \brief Enables the given node
  1546     ///
  1547     /// This function enables the given node.
  1548     /// It is the same as \ref status() "status(n, true)".
  1549     void enable(const Node& n) const { Parent::status(n, true); }
  1550 
  1551   };
  1552 
  1553   template<typename GR, typename NF>
  1554   class FilterNodes<GR, NF,
  1555                     typename enable_if<UndirectedTagIndicator<GR> >::type> :
  1556     public GraphAdaptorExtender<
  1557       SubGraphBase<GR, NF, ConstMap<typename GR::Edge, Const<bool, true> >, 
  1558                    true> > {
  1559 
  1560     typedef GraphAdaptorExtender<
  1561       SubGraphBase<GR, NF, ConstMap<typename GR::Edge, Const<bool, true> >, 
  1562                    true> > Parent;
  1563 
  1564   public:
  1565 
  1566     typedef GR Graph;
  1567     typedef NF NodeFilterMap;
  1568 
  1569     typedef typename Parent::Node Node;
  1570 
  1571   protected:
  1572     ConstMap<typename GR::Edge, Const<bool, true> > const_true_map;
  1573 
  1574     FilterNodes() : const_true_map() {}
  1575 
  1576   public:
  1577 
  1578     FilterNodes(GR& graph, NodeFilterMap& node_filter) :
  1579       Parent(), const_true_map() {
  1580       Parent::initialize(graph, node_filter, const_true_map);
  1581     }
  1582 
  1583     void status(const Node& n, bool v) const { Parent::status(n, v); }
  1584     bool status(const Node& n) const { return Parent::status(n); }
  1585     void disable(const Node& n) const { Parent::status(n, false); }
  1586     void enable(const Node& n) const { Parent::status(n, true); }
  1587 
  1588   };
  1589 
  1590 
  1591   /// \brief Returns a read-only FilterNodes adaptor
  1592   ///
  1593   /// This function just returns a read-only \ref FilterNodes adaptor.
  1594   /// \ingroup graph_adaptors
  1595   /// \relates FilterNodes
  1596   template<typename GR, typename NF>
  1597   FilterNodes<const GR, NF>
  1598   filterNodes(const GR& graph, NF& node_filter) {
  1599     return FilterNodes<const GR, NF>(graph, node_filter);
  1600   }
  1601 
  1602   template<typename GR, typename NF>
  1603   FilterNodes<const GR, const NF>
  1604   filterNodes(const GR& graph, const NF& node_filter) {
  1605     return FilterNodes<const GR, const NF>(graph, node_filter);
  1606   }
  1607 
  1608   /// \ingroup graph_adaptors
  1609   ///
  1610   /// \brief Adaptor class for hiding arcs in a digraph.
  1611   ///
  1612   /// FilterArcs adaptor can be used for hiding arcs in a digraph.
  1613   /// A \c bool arc map must be specified, which defines the filter for
  1614   /// the arcs. Only the arcs with \c true filter value are shown in the
  1615   /// subdigraph. This adaptor conforms to the \ref concepts::Digraph
  1616   /// "Digraph" concept.
  1617   ///
  1618   /// The adapted digraph can also be modified through this adaptor
  1619   /// by adding or removing nodes or arcs, unless the \c GR template
  1620   /// parameter is set to be \c const.
  1621   ///
  1622   /// \tparam DGR The type of the adapted digraph.
  1623   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
  1624   /// It can also be specified to be \c const.
  1625   /// \tparam AF The type of the arc filter map.
  1626   /// It must be a \c bool (or convertible) arc map of the
  1627   /// adapted digraph. The default type is
  1628   /// \ref concepts::Digraph::ArcMap "DGR::ArcMap<bool>".
  1629   ///
  1630   /// \note The \c Node and \c Arc types of this adaptor and the adapted
  1631   /// digraph are convertible to each other.
  1632 #ifdef DOXYGEN
  1633   template<typename DGR,
  1634            typename AF>
  1635   class FilterArcs {
  1636 #else
  1637   template<typename DGR,
  1638            typename AF = typename DGR::template ArcMap<bool> >
  1639   class FilterArcs :
  1640     public DigraphAdaptorExtender<
  1641       SubDigraphBase<DGR, ConstMap<typename DGR::Node, Const<bool, true> >,
  1642                      AF, false> > {
  1643 #endif
  1644     typedef DigraphAdaptorExtender<
  1645       SubDigraphBase<DGR, ConstMap<typename DGR::Node, Const<bool, true> >, 
  1646                      AF, false> > Parent;
  1647 
  1648   public:
  1649 
  1650     /// The type of the adapted digraph.
  1651     typedef DGR Digraph;
  1652     /// The type of the arc filter map.
  1653     typedef AF ArcFilterMap;
  1654 
  1655     typedef typename Parent::Arc Arc;
  1656 
  1657   protected:
  1658     ConstMap<typename DGR::Node, Const<bool, true> > const_true_map;
  1659 
  1660     FilterArcs() : const_true_map() {}
  1661 
  1662   public:
  1663 
  1664     /// \brief Constructor
  1665     ///
  1666     /// Creates a subdigraph for the given digraph with the given arc
  1667     /// filter map.
  1668     FilterArcs(DGR& digraph, ArcFilterMap& arc_filter)
  1669       : Parent(), const_true_map() {
  1670       Parent::initialize(digraph, const_true_map, arc_filter);
  1671     }
  1672 
  1673     /// \brief Sets the status of the given arc
  1674     ///
  1675     /// This function sets the status of the given arc.
  1676     /// It is done by simply setting the assigned value of \c a
  1677     /// to \c v in the arc filter map.
  1678     void status(const Arc& a, bool v) const { Parent::status(a, v); }
  1679 
  1680     /// \brief Returns the status of the given arc
  1681     ///
  1682     /// This function returns the status of the given arc.
  1683     /// It is \c true if the given arc is enabled (i.e. not hidden).
  1684     bool status(const Arc& a) const { return Parent::status(a); }
  1685 
  1686     /// \brief Disables the given arc
  1687     ///
  1688     /// This function disables the given arc in the subdigraph,
  1689     /// so the iteration jumps over it.
  1690     /// It is the same as \ref status() "status(a, false)".
  1691     void disable(const Arc& a) const { Parent::status(a, false); }
  1692 
  1693     /// \brief Enables the given arc
  1694     ///
  1695     /// This function enables the given arc in the subdigraph.
  1696     /// It is the same as \ref status() "status(a, true)".
  1697     void enable(const Arc& a) const { Parent::status(a, true); }
  1698 
  1699   };
  1700 
  1701   /// \brief Returns a read-only FilterArcs adaptor
  1702   ///
  1703   /// This function just returns a read-only \ref FilterArcs adaptor.
  1704   /// \ingroup graph_adaptors
  1705   /// \relates FilterArcs
  1706   template<typename DGR, typename AF>
  1707   FilterArcs<const DGR, AF>
  1708   filterArcs(const DGR& digraph, AF& arc_filter) {
  1709     return FilterArcs<const DGR, AF>(digraph, arc_filter);
  1710   }
  1711 
  1712   template<typename DGR, typename AF>
  1713   FilterArcs<const DGR, const AF>
  1714   filterArcs(const DGR& digraph, const AF& arc_filter) {
  1715     return FilterArcs<const DGR, const AF>(digraph, arc_filter);
  1716   }
  1717 
  1718   /// \ingroup graph_adaptors
  1719   ///
  1720   /// \brief Adaptor class for hiding edges in a graph.
  1721   ///
  1722   /// FilterEdges adaptor can be used for hiding edges in a graph.
  1723   /// A \c bool edge map must be specified, which defines the filter for
  1724   /// the edges. Only the edges with \c true filter value are shown in the
  1725   /// subgraph. This adaptor conforms to the \ref concepts::Graph
  1726   /// "Graph" concept.
  1727   ///
  1728   /// The adapted graph can also be modified through this adaptor
  1729   /// by adding or removing nodes or edges, unless the \c GR template
  1730   /// parameter is set to be \c const.
  1731   ///
  1732   /// \tparam GR The type of the adapted graph.
  1733   /// It must conform to the \ref concepts::Graph "Graph" concept.
  1734   /// It can also be specified to be \c const.
  1735   /// \tparam EF The type of the edge filter map.
  1736   /// It must be a \c bool (or convertible) edge map of the
  1737   /// adapted graph. The default type is
  1738   /// \ref concepts::Graph::EdgeMap "GR::EdgeMap<bool>".
  1739   ///
  1740   /// \note The \c Node, \c Edge and \c Arc types of this adaptor and the
  1741   /// adapted graph are convertible to each other.
  1742 #ifdef DOXYGEN
  1743   template<typename GR,
  1744            typename EF>
  1745   class FilterEdges {
  1746 #else
  1747   template<typename GR,
  1748            typename EF = typename GR::template EdgeMap<bool> >
  1749   class FilterEdges :
  1750     public GraphAdaptorExtender<
  1751       SubGraphBase<GR, ConstMap<typename GR::Node, Const<bool, true> >, 
  1752                    EF, false> > {
  1753 #endif
  1754     typedef GraphAdaptorExtender<
  1755       SubGraphBase<GR, ConstMap<typename GR::Node, Const<bool, true > >, 
  1756                    EF, false> > Parent;
  1757 
  1758   public:
  1759 
  1760     /// The type of the adapted graph.
  1761     typedef GR Graph;
  1762     /// The type of the edge filter map.
  1763     typedef EF EdgeFilterMap;
  1764 
  1765     typedef typename Parent::Edge Edge;
  1766 
  1767   protected:
  1768     ConstMap<typename GR::Node, Const<bool, true> > const_true_map;
  1769 
  1770     FilterEdges() : const_true_map(true) {
  1771       Parent::setNodeFilterMap(const_true_map);
  1772     }
  1773 
  1774   public:
  1775 
  1776     /// \brief Constructor
  1777     ///
  1778     /// Creates a subgraph for the given graph with the given edge
  1779     /// filter map.
  1780     FilterEdges(GR& graph, EF& edge_filter) 
  1781       : Parent(), const_true_map() {
  1782       Parent::initialize(graph, const_true_map, edge_filter);
  1783     }
  1784 
  1785     /// \brief Sets the status of the given edge
  1786     ///
  1787     /// This function sets the status of the given edge.
  1788     /// It is done by simply setting the assigned value of \c e
  1789     /// to \c v in the edge filter map.
  1790     void status(const Edge& e, bool v) const { Parent::status(e, v); }
  1791 
  1792     /// \brief Returns the status of the given edge
  1793     ///
  1794     /// This function returns the status of the given edge.
  1795     /// It is \c true if the given edge is enabled (i.e. not hidden).
  1796     bool status(const Edge& e) const { return Parent::status(e); }
  1797 
  1798     /// \brief Disables the given edge
  1799     ///
  1800     /// This function disables the given edge in the subgraph,
  1801     /// so the iteration jumps over it.
  1802     /// It is the same as \ref status() "status(e, false)".
  1803     void disable(const Edge& e) const { Parent::status(e, false); }
  1804 
  1805     /// \brief Enables the given edge
  1806     ///
  1807     /// This function enables the given edge in the subgraph.
  1808     /// It is the same as \ref status() "status(e, true)".
  1809     void enable(const Edge& e) const { Parent::status(e, true); }
  1810 
  1811   };
  1812 
  1813   /// \brief Returns a read-only FilterEdges adaptor
  1814   ///
  1815   /// This function just returns a read-only \ref FilterEdges adaptor.
  1816   /// \ingroup graph_adaptors
  1817   /// \relates FilterEdges
  1818   template<typename GR, typename EF>
  1819   FilterEdges<const GR, EF>
  1820   filterEdges(const GR& graph, EF& edge_filter) {
  1821     return FilterEdges<const GR, EF>(graph, edge_filter);
  1822   }
  1823 
  1824   template<typename GR, typename EF>
  1825   FilterEdges<const GR, const EF>
  1826   filterEdges(const GR& graph, const EF& edge_filter) {
  1827     return FilterEdges<const GR, const EF>(graph, edge_filter);
  1828   }
  1829 
  1830 
  1831   template <typename DGR>
  1832   class UndirectorBase {
  1833   public:
  1834     typedef DGR Digraph;
  1835     typedef UndirectorBase Adaptor;
  1836 
  1837     typedef True UndirectedTag;
  1838 
  1839     typedef typename Digraph::Arc Edge;
  1840     typedef typename Digraph::Node Node;
  1841 
  1842     class Arc {
  1843       friend class UndirectorBase;
  1844     protected:
  1845       Edge _edge;
  1846       bool _forward;
  1847 
  1848       Arc(const Edge& edge, bool forward) 
  1849         : _edge(edge), _forward(forward) {}
  1850 
  1851     public:
  1852       Arc() {}
  1853 
  1854       Arc(Invalid) : _edge(INVALID), _forward(true) {}
  1855 
  1856       operator const Edge&() const { return _edge; }
  1857 
  1858       bool operator==(const Arc &other) const {
  1859         return _forward == other._forward && _edge == other._edge;
  1860       }
  1861       bool operator!=(const Arc &other) const {
  1862         return _forward != other._forward || _edge != other._edge;
  1863       }
  1864       bool operator<(const Arc &other) const {
  1865         return _forward < other._forward ||
  1866           (_forward == other._forward && _edge < other._edge);
  1867       }
  1868     };
  1869 
  1870     void first(Node& n) const {
  1871       _digraph->first(n);
  1872     }
  1873 
  1874     void next(Node& n) const {
  1875       _digraph->next(n);
  1876     }
  1877 
  1878     void first(Arc& a) const {
  1879       _digraph->first(a._edge);
  1880       a._forward = true;
  1881     }
  1882 
  1883     void next(Arc& a) const {
  1884       if (a._forward) {
  1885         a._forward = false;
  1886       } else {
  1887         _digraph->next(a._edge);
  1888         a._forward = true;
  1889       }
  1890     }
  1891 
  1892     void first(Edge& e) const {
  1893       _digraph->first(e);
  1894     }
  1895 
  1896     void next(Edge& e) const {
  1897       _digraph->next(e);
  1898     }
  1899 
  1900     void firstOut(Arc& a, const Node& n) const {
  1901       _digraph->firstIn(a._edge, n);
  1902       if (a._edge != INVALID ) {
  1903         a._forward = false;
  1904       } else {
  1905         _digraph->firstOut(a._edge, n);
  1906         a._forward = true;
  1907       }
  1908     }
  1909     void nextOut(Arc &a) const {
  1910       if (!a._forward) {
  1911         Node n = _digraph->target(a._edge);
  1912         _digraph->nextIn(a._edge);
  1913         if (a._edge == INVALID) {
  1914           _digraph->firstOut(a._edge, n);
  1915           a._forward = true;
  1916         }
  1917       }
  1918       else {
  1919         _digraph->nextOut(a._edge);
  1920       }
  1921     }
  1922 
  1923     void firstIn(Arc &a, const Node &n) const {
  1924       _digraph->firstOut(a._edge, n);
  1925       if (a._edge != INVALID ) {
  1926         a._forward = false;
  1927       } else {
  1928         _digraph->firstIn(a._edge, n);
  1929         a._forward = true;
  1930       }
  1931     }
  1932     void nextIn(Arc &a) const {
  1933       if (!a._forward) {
  1934         Node n = _digraph->source(a._edge);
  1935         _digraph->nextOut(a._edge);
  1936         if (a._edge == INVALID ) {
  1937           _digraph->firstIn(a._edge, n);
  1938           a._forward = true;
  1939         }
  1940       }
  1941       else {
  1942         _digraph->nextIn(a._edge);
  1943       }
  1944     }
  1945 
  1946     void firstInc(Edge &e, bool &d, const Node &n) const {
  1947       d = true;
  1948       _digraph->firstOut(e, n);
  1949       if (e != INVALID) return;
  1950       d = false;
  1951       _digraph->firstIn(e, n);
  1952     }
  1953 
  1954     void nextInc(Edge &e, bool &d) const {
  1955       if (d) {
  1956         Node s = _digraph->source(e);
  1957         _digraph->nextOut(e);
  1958         if (e != INVALID) return;
  1959         d = false;
  1960         _digraph->firstIn(e, s);
  1961       } else {
  1962         _digraph->nextIn(e);
  1963       }
  1964     }
  1965 
  1966     Node u(const Edge& e) const {
  1967       return _digraph->source(e);
  1968     }
  1969 
  1970     Node v(const Edge& e) const {
  1971       return _digraph->target(e);
  1972     }
  1973 
  1974     Node source(const Arc &a) const {
  1975       return a._forward ? _digraph->source(a._edge) : _digraph->target(a._edge);
  1976     }
  1977 
  1978     Node target(const Arc &a) const {
  1979       return a._forward ? _digraph->target(a._edge) : _digraph->source(a._edge);
  1980     }
  1981 
  1982     static Arc direct(const Edge &e, bool d) {
  1983       return Arc(e, d);
  1984     }
  1985 
  1986     static bool direction(const Arc &a) { return a._forward; }
  1987 
  1988     Node nodeFromId(int ix) const { return _digraph->nodeFromId(ix); }
  1989     Arc arcFromId(int ix) const {
  1990       return direct(_digraph->arcFromId(ix >> 1), bool(ix & 1));
  1991     }
  1992     Edge edgeFromId(int ix) const { return _digraph->arcFromId(ix); }
  1993 
  1994     int id(const Node &n) const { return _digraph->id(n); }
  1995     int id(const Arc &a) const {
  1996       return  (_digraph->id(a) << 1) | (a._forward ? 1 : 0);
  1997     }
  1998     int id(const Edge &e) const { return _digraph->id(e); }
  1999 
  2000     int maxNodeId() const { return _digraph->maxNodeId(); }
  2001     int maxArcId() const { return (_digraph->maxArcId() << 1) | 1; }
  2002     int maxEdgeId() const { return _digraph->maxArcId(); }
  2003 
  2004     Node addNode() { return _digraph->addNode(); }
  2005     Edge addEdge(const Node& u, const Node& v) {
  2006       return _digraph->addArc(u, v);
  2007     }
  2008 
  2009     void erase(const Node& i) { _digraph->erase(i); }
  2010     void erase(const Edge& i) { _digraph->erase(i); }
  2011 
  2012     void clear() { _digraph->clear(); }
  2013 
  2014     typedef NodeNumTagIndicator<Digraph> NodeNumTag;
  2015     int nodeNum() const { return _digraph->nodeNum(); }
  2016 
  2017     typedef ArcNumTagIndicator<Digraph> ArcNumTag;
  2018     int arcNum() const { return 2 * _digraph->arcNum(); }
  2019 
  2020     typedef ArcNumTag EdgeNumTag;
  2021     int edgeNum() const { return _digraph->arcNum(); }
  2022 
  2023     typedef FindArcTagIndicator<Digraph> FindArcTag;
  2024     Arc findArc(Node s, Node t, Arc p = INVALID) const {
  2025       if (p == INVALID) {
  2026         Edge arc = _digraph->findArc(s, t);
  2027         if (arc != INVALID) return direct(arc, true);
  2028         arc = _digraph->findArc(t, s);
  2029         if (arc != INVALID) return direct(arc, false);
  2030       } else if (direction(p)) {
  2031         Edge arc = _digraph->findArc(s, t, p);
  2032         if (arc != INVALID) return direct(arc, true);
  2033         arc = _digraph->findArc(t, s);
  2034         if (arc != INVALID) return direct(arc, false);
  2035       } else {
  2036         Edge arc = _digraph->findArc(t, s, p);
  2037         if (arc != INVALID) return direct(arc, false);
  2038       }
  2039       return INVALID;
  2040     }
  2041 
  2042     typedef FindArcTag FindEdgeTag;
  2043     Edge findEdge(Node s, Node t, Edge p = INVALID) const {
  2044       if (s != t) {
  2045         if (p == INVALID) {
  2046           Edge arc = _digraph->findArc(s, t);
  2047           if (arc != INVALID) return arc;
  2048           arc = _digraph->findArc(t, s);
  2049           if (arc != INVALID) return arc;
  2050         } else if (_digraph->source(p) == s) {
  2051           Edge arc = _digraph->findArc(s, t, p);
  2052           if (arc != INVALID) return arc;
  2053           arc = _digraph->findArc(t, s);
  2054           if (arc != INVALID) return arc;
  2055         } else {
  2056           Edge arc = _digraph->findArc(t, s, p);
  2057           if (arc != INVALID) return arc;
  2058         }
  2059       } else {
  2060         return _digraph->findArc(s, t, p);
  2061       }
  2062       return INVALID;
  2063     }
  2064 
  2065   private:
  2066 
  2067     template <typename V>
  2068     class ArcMapBase {
  2069     private:
  2070 
  2071       typedef typename DGR::template ArcMap<V> MapImpl;
  2072 
  2073     public:
  2074 
  2075       typedef typename MapTraits<MapImpl>::ReferenceMapTag ReferenceMapTag;
  2076 
  2077       typedef V Value;
  2078       typedef Arc Key;
  2079       typedef typename MapTraits<MapImpl>::ConstReturnValue ConstReturnValue;
  2080       typedef typename MapTraits<MapImpl>::ReturnValue ReturnValue;
  2081       typedef typename MapTraits<MapImpl>::ConstReturnValue ConstReference;
  2082       typedef typename MapTraits<MapImpl>::ReturnValue Reference;
  2083 
  2084       ArcMapBase(const UndirectorBase<DGR>& adaptor) :
  2085         _forward(*adaptor._digraph), _backward(*adaptor._digraph) {}
  2086 
  2087       ArcMapBase(const UndirectorBase<DGR>& adaptor, const V& value)
  2088         : _forward(*adaptor._digraph, value), 
  2089           _backward(*adaptor._digraph, value) {}
  2090 
  2091       void set(const Arc& a, const V& value) {
  2092         if (direction(a)) {
  2093           _forward.set(a, value);
  2094         } else {
  2095           _backward.set(a, value);
  2096         }
  2097       }
  2098 
  2099       ConstReturnValue operator[](const Arc& a) const {
  2100         if (direction(a)) {
  2101           return _forward[a];
  2102         } else {
  2103           return _backward[a];
  2104         }
  2105       }
  2106 
  2107       ReturnValue operator[](const Arc& a) {
  2108         if (direction(a)) {
  2109           return _forward[a];
  2110         } else {
  2111           return _backward[a];
  2112         }
  2113       }
  2114 
  2115     protected:
  2116 
  2117       MapImpl _forward, _backward;
  2118 
  2119     };
  2120 
  2121   public:
  2122 
  2123     template <typename V>
  2124     class NodeMap : public DGR::template NodeMap<V> {
  2125       typedef typename DGR::template NodeMap<V> Parent;
  2126 
  2127     public:
  2128       typedef V Value;
  2129 
  2130       explicit NodeMap(const UndirectorBase<DGR>& adaptor)
  2131         : Parent(*adaptor._digraph) {}
  2132 
  2133       NodeMap(const UndirectorBase<DGR>& adaptor, const V& value)
  2134         : Parent(*adaptor._digraph, value) { }
  2135 
  2136     private:
  2137       NodeMap& operator=(const NodeMap& cmap) {
  2138         return operator=<NodeMap>(cmap);
  2139       }
  2140 
  2141       template <typename CMap>
  2142       NodeMap& operator=(const CMap& cmap) {
  2143         Parent::operator=(cmap);
  2144         return *this;
  2145       }
  2146 
  2147     };
  2148 
  2149     template <typename V>
  2150     class ArcMap
  2151       : public SubMapExtender<UndirectorBase<DGR>, ArcMapBase<V> > {
  2152       typedef SubMapExtender<UndirectorBase<DGR>, ArcMapBase<V> > Parent;
  2153 
  2154     public:
  2155       typedef V Value;
  2156 
  2157       explicit ArcMap(const UndirectorBase<DGR>& adaptor)
  2158         : Parent(adaptor) {}
  2159 
  2160       ArcMap(const UndirectorBase<DGR>& adaptor, const V& value)
  2161         : Parent(adaptor, value) {}
  2162 
  2163     private:
  2164       ArcMap& operator=(const ArcMap& cmap) {
  2165         return operator=<ArcMap>(cmap);
  2166       }
  2167 
  2168       template <typename CMap>
  2169       ArcMap& operator=(const CMap& cmap) {
  2170         Parent::operator=(cmap);
  2171         return *this;
  2172       }
  2173     };
  2174 
  2175     template <typename V>
  2176     class EdgeMap : public Digraph::template ArcMap<V> {
  2177       typedef typename Digraph::template ArcMap<V> Parent;
  2178 
  2179     public:
  2180       typedef V Value;
  2181 
  2182       explicit EdgeMap(const UndirectorBase<DGR>& adaptor)
  2183         : Parent(*adaptor._digraph) {}
  2184 
  2185       EdgeMap(const UndirectorBase<DGR>& adaptor, const V& value)
  2186         : Parent(*adaptor._digraph, value) {}
  2187 
  2188     private:
  2189       EdgeMap& operator=(const EdgeMap& cmap) {
  2190         return operator=<EdgeMap>(cmap);
  2191       }
  2192 
  2193       template <typename CMap>
  2194       EdgeMap& operator=(const CMap& cmap) {
  2195         Parent::operator=(cmap);
  2196         return *this;
  2197       }
  2198 
  2199     };
  2200 
  2201     typedef typename ItemSetTraits<DGR, Node>::ItemNotifier NodeNotifier;
  2202     NodeNotifier& notifier(Node) const { return _digraph->notifier(Node()); }
  2203 
  2204     typedef typename ItemSetTraits<DGR, Edge>::ItemNotifier EdgeNotifier;
  2205     EdgeNotifier& notifier(Edge) const { return _digraph->notifier(Edge()); }
  2206     
  2207     typedef EdgeNotifier ArcNotifier;
  2208     ArcNotifier& notifier(Arc) const { return _digraph->notifier(Edge()); }
  2209 
  2210   protected:
  2211 
  2212     UndirectorBase() : _digraph(0) {}
  2213 
  2214     DGR* _digraph;
  2215 
  2216     void initialize(DGR& digraph) {
  2217       _digraph = &digraph;
  2218     }
  2219 
  2220   };
  2221 
  2222   /// \ingroup graph_adaptors
  2223   ///
  2224   /// \brief Adaptor class for viewing a digraph as an undirected graph.
  2225   ///
  2226   /// Undirector adaptor can be used for viewing a digraph as an undirected
  2227   /// graph. All arcs of the underlying digraph are showed in the
  2228   /// adaptor as an edge (and also as a pair of arcs, of course).
  2229   /// This adaptor conforms to the \ref concepts::Graph "Graph" concept.
  2230   ///
  2231   /// The adapted digraph can also be modified through this adaptor
  2232   /// by adding or removing nodes or edges, unless the \c GR template
  2233   /// parameter is set to be \c const.
  2234   ///
  2235   /// \tparam DGR The type of the adapted digraph.
  2236   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
  2237   /// It can also be specified to be \c const.
  2238   ///
  2239   /// \note The \c Node type of this adaptor and the adapted digraph are
  2240   /// convertible to each other, moreover the \c Edge type of the adaptor
  2241   /// and the \c Arc type of the adapted digraph are also convertible to
  2242   /// each other.
  2243   /// (Thus the \c Arc type of the adaptor is convertible to the \c Arc type
  2244   /// of the adapted digraph.)
  2245   template<typename DGR>
  2246 #ifdef DOXYGEN
  2247   class Undirector {
  2248 #else
  2249   class Undirector :
  2250     public GraphAdaptorExtender<UndirectorBase<DGR> > {
  2251 #endif
  2252     typedef GraphAdaptorExtender<UndirectorBase<DGR> > Parent;
  2253   public:
  2254     /// The type of the adapted digraph.
  2255     typedef DGR Digraph;
  2256   protected:
  2257     Undirector() { }
  2258   public:
  2259 
  2260     /// \brief Constructor
  2261     ///
  2262     /// Creates an undirected graph from the given digraph.
  2263     Undirector(DGR& digraph) {
  2264       initialize(digraph);
  2265     }
  2266 
  2267     /// \brief Arc map combined from two original arc maps
  2268     ///
  2269     /// This map adaptor class adapts two arc maps of the underlying
  2270     /// digraph to get an arc map of the undirected graph.
  2271     /// Its value type is inherited from the first arc map type (\c FW).
  2272     /// \tparam FW The type of the "foward" arc map.
  2273     /// \tparam BK The type of the "backward" arc map.
  2274     template <typename FW, typename BK>
  2275     class CombinedArcMap {
  2276     public:
  2277 
  2278       /// The key type of the map
  2279       typedef typename Parent::Arc Key;
  2280       /// The value type of the map
  2281       typedef typename FW::Value Value;
  2282 
  2283       typedef typename MapTraits<FW>::ReferenceMapTag ReferenceMapTag;
  2284 
  2285       typedef typename MapTraits<FW>::ReturnValue ReturnValue;
  2286       typedef typename MapTraits<FW>::ConstReturnValue ConstReturnValue;
  2287       typedef typename MapTraits<FW>::ReturnValue Reference;
  2288       typedef typename MapTraits<FW>::ConstReturnValue ConstReference;
  2289 
  2290       /// Constructor
  2291       CombinedArcMap(FW& forward, BK& backward)
  2292         : _forward(&forward), _backward(&backward) {}
  2293 
  2294       /// Sets the value associated with the given key.
  2295       void set(const Key& e, const Value& a) {
  2296         if (Parent::direction(e)) {
  2297           _forward->set(e, a);
  2298         } else {
  2299           _backward->set(e, a);
  2300         }
  2301       }
  2302 
  2303       /// Returns the value associated with the given key.
  2304       ConstReturnValue operator[](const Key& e) const {
  2305         if (Parent::direction(e)) {
  2306           return (*_forward)[e];
  2307         } else {
  2308           return (*_backward)[e];
  2309         }
  2310       }
  2311 
  2312       /// Returns a reference to the value associated with the given key.
  2313       ReturnValue operator[](const Key& e) {
  2314         if (Parent::direction(e)) {
  2315           return (*_forward)[e];
  2316         } else {
  2317           return (*_backward)[e];
  2318         }
  2319       }
  2320 
  2321     protected:
  2322 
  2323       FW* _forward;
  2324       BK* _backward;
  2325 
  2326     };
  2327 
  2328     /// \brief Returns a combined arc map
  2329     ///
  2330     /// This function just returns a combined arc map.
  2331     template <typename FW, typename BK>
  2332     static CombinedArcMap<FW, BK>
  2333     combinedArcMap(FW& forward, BK& backward) {
  2334       return CombinedArcMap<FW, BK>(forward, backward);
  2335     }
  2336 
  2337     template <typename FW, typename BK>
  2338     static CombinedArcMap<const FW, BK>
  2339     combinedArcMap(const FW& forward, BK& backward) {
  2340       return CombinedArcMap<const FW, BK>(forward, backward);
  2341     }
  2342 
  2343     template <typename FW, typename BK>
  2344     static CombinedArcMap<FW, const BK>
  2345     combinedArcMap(FW& forward, const BK& backward) {
  2346       return CombinedArcMap<FW, const BK>(forward, backward);
  2347     }
  2348 
  2349     template <typename FW, typename BK>
  2350     static CombinedArcMap<const FW, const BK>
  2351     combinedArcMap(const FW& forward, const BK& backward) {
  2352       return CombinedArcMap<const FW, const BK>(forward, backward);
  2353     }
  2354 
  2355   };
  2356 
  2357   /// \brief Returns a read-only Undirector adaptor
  2358   ///
  2359   /// This function just returns a read-only \ref Undirector adaptor.
  2360   /// \ingroup graph_adaptors
  2361   /// \relates Undirector
  2362   template<typename DGR>
  2363   Undirector<const DGR> undirector(const DGR& digraph) {
  2364     return Undirector<const DGR>(digraph);
  2365   }
  2366 
  2367 
  2368   template <typename GR, typename DM>
  2369   class OrienterBase {
  2370   public:
  2371 
  2372     typedef GR Graph;
  2373     typedef DM DirectionMap;
  2374 
  2375     typedef typename GR::Node Node;
  2376     typedef typename GR::Edge Arc;
  2377 
  2378     void reverseArc(const Arc& arc) {
  2379       _direction->set(arc, !(*_direction)[arc]);
  2380     }
  2381 
  2382     void first(Node& i) const { _graph->first(i); }
  2383     void first(Arc& i) const { _graph->first(i); }
  2384     void firstIn(Arc& i, const Node& n) const {
  2385       bool d = true;
  2386       _graph->firstInc(i, d, n);
  2387       while (i != INVALID && d == (*_direction)[i]) _graph->nextInc(i, d);
  2388     }
  2389     void firstOut(Arc& i, const Node& n ) const {
  2390       bool d = true;
  2391       _graph->firstInc(i, d, n);
  2392       while (i != INVALID && d != (*_direction)[i]) _graph->nextInc(i, d);
  2393     }
  2394 
  2395     void next(Node& i) const { _graph->next(i); }
  2396     void next(Arc& i) const { _graph->next(i); }
  2397     void nextIn(Arc& i) const {
  2398       bool d = !(*_direction)[i];
  2399       _graph->nextInc(i, d);
  2400       while (i != INVALID && d == (*_direction)[i]) _graph->nextInc(i, d);
  2401     }
  2402     void nextOut(Arc& i) const {
  2403       bool d = (*_direction)[i];
  2404       _graph->nextInc(i, d);
  2405       while (i != INVALID && d != (*_direction)[i]) _graph->nextInc(i, d);
  2406     }
  2407 
  2408     Node source(const Arc& e) const {
  2409       return (*_direction)[e] ? _graph->u(e) : _graph->v(e);
  2410     }
  2411     Node target(const Arc& e) const {
  2412       return (*_direction)[e] ? _graph->v(e) : _graph->u(e);
  2413     }
  2414 
  2415     typedef NodeNumTagIndicator<Graph> NodeNumTag;
  2416     int nodeNum() const { return _graph->nodeNum(); }
  2417 
  2418     typedef EdgeNumTagIndicator<Graph> ArcNumTag;
  2419     int arcNum() const { return _graph->edgeNum(); }
  2420 
  2421     typedef FindEdgeTagIndicator<Graph> FindArcTag;
  2422     Arc findArc(const Node& u, const Node& v,
  2423                 const Arc& prev = INVALID) const {
  2424       Arc arc = _graph->findEdge(u, v, prev);
  2425       while (arc != INVALID && source(arc) != u) {
  2426         arc = _graph->findEdge(u, v, arc);
  2427       }
  2428       return arc;
  2429     }
  2430 
  2431     Node addNode() {
  2432       return Node(_graph->addNode());
  2433     }
  2434 
  2435     Arc addArc(const Node& u, const Node& v) {
  2436       Arc arc = _graph->addEdge(u, v);
  2437       _direction->set(arc, _graph->u(arc) == u);
  2438       return arc;
  2439     }
  2440 
  2441     void erase(const Node& i) { _graph->erase(i); }
  2442     void erase(const Arc& i) { _graph->erase(i); }
  2443 
  2444     void clear() { _graph->clear(); }
  2445 
  2446     int id(const Node& v) const { return _graph->id(v); }
  2447     int id(const Arc& e) const { return _graph->id(e); }
  2448 
  2449     Node nodeFromId(int idx) const { return _graph->nodeFromId(idx); }
  2450     Arc arcFromId(int idx) const { return _graph->edgeFromId(idx); }
  2451 
  2452     int maxNodeId() const { return _graph->maxNodeId(); }
  2453     int maxArcId() const { return _graph->maxEdgeId(); }
  2454 
  2455     typedef typename ItemSetTraits<GR, Node>::ItemNotifier NodeNotifier;
  2456     NodeNotifier& notifier(Node) const { return _graph->notifier(Node()); }
  2457 
  2458     typedef typename ItemSetTraits<GR, Arc>::ItemNotifier ArcNotifier;
  2459     ArcNotifier& notifier(Arc) const { return _graph->notifier(Arc()); }
  2460 
  2461     template <typename V>
  2462     class NodeMap : public GR::template NodeMap<V> {
  2463       typedef typename GR::template NodeMap<V> Parent;
  2464 
  2465     public:
  2466 
  2467       explicit NodeMap(const OrienterBase<GR, DM>& adapter)
  2468         : Parent(*adapter._graph) {}
  2469 
  2470       NodeMap(const OrienterBase<GR, DM>& adapter, const V& value)
  2471         : Parent(*adapter._graph, value) {}
  2472 
  2473     private:
  2474       NodeMap& operator=(const NodeMap& cmap) {
  2475         return operator=<NodeMap>(cmap);
  2476       }
  2477 
  2478       template <typename CMap>
  2479       NodeMap& operator=(const CMap& cmap) {
  2480         Parent::operator=(cmap);
  2481         return *this;
  2482       }
  2483 
  2484     };
  2485 
  2486     template <typename V>
  2487     class ArcMap : public GR::template EdgeMap<V> {
  2488       typedef typename Graph::template EdgeMap<V> Parent;
  2489 
  2490     public:
  2491 
  2492       explicit ArcMap(const OrienterBase<GR, DM>& adapter)
  2493         : Parent(*adapter._graph) { }
  2494 
  2495       ArcMap(const OrienterBase<GR, DM>& adapter, const V& value)
  2496         : Parent(*adapter._graph, value) { }
  2497 
  2498     private:
  2499       ArcMap& operator=(const ArcMap& cmap) {
  2500         return operator=<ArcMap>(cmap);
  2501       }
  2502 
  2503       template <typename CMap>
  2504       ArcMap& operator=(const CMap& cmap) {
  2505         Parent::operator=(cmap);
  2506         return *this;
  2507       }
  2508     };
  2509 
  2510 
  2511 
  2512   protected:
  2513     Graph* _graph;
  2514     DM* _direction;
  2515 
  2516     void initialize(GR& graph, DM& direction) {
  2517       _graph = &graph;
  2518       _direction = &direction;
  2519     }
  2520 
  2521   };
  2522 
  2523   /// \ingroup graph_adaptors
  2524   ///
  2525   /// \brief Adaptor class for orienting the edges of a graph to get a digraph
  2526   ///
  2527   /// Orienter adaptor can be used for orienting the edges of a graph to
  2528   /// get a digraph. A \c bool edge map of the underlying graph must be
  2529   /// specified, which define the direction of the arcs in the adaptor.
  2530   /// The arcs can be easily reversed by the \c reverseArc() member function
  2531   /// of the adaptor.
  2532   /// This class conforms to the \ref concepts::Digraph "Digraph" concept.
  2533   ///
  2534   /// The adapted graph can also be modified through this adaptor
  2535   /// by adding or removing nodes or arcs, unless the \c GR template
  2536   /// parameter is set to be \c const.
  2537   ///
  2538   /// \tparam GR The type of the adapted graph.
  2539   /// It must conform to the \ref concepts::Graph "Graph" concept.
  2540   /// It can also be specified to be \c const.
  2541   /// \tparam DM The type of the direction map.
  2542   /// It must be a \c bool (or convertible) edge map of the
  2543   /// adapted graph. The default type is
  2544   /// \ref concepts::Graph::EdgeMap "GR::EdgeMap<bool>".
  2545   ///
  2546   /// \note The \c Node type of this adaptor and the adapted graph are
  2547   /// convertible to each other, moreover the \c Arc type of the adaptor
  2548   /// and the \c Edge type of the adapted graph are also convertible to
  2549   /// each other.
  2550 #ifdef DOXYGEN
  2551   template<typename GR,
  2552            typename DM>
  2553   class Orienter {
  2554 #else
  2555   template<typename GR,
  2556            typename DM = typename GR::template EdgeMap<bool> >
  2557   class Orienter :
  2558     public DigraphAdaptorExtender<OrienterBase<GR, DM> > {
  2559 #endif
  2560     typedef DigraphAdaptorExtender<OrienterBase<GR, DM> > Parent;
  2561   public:
  2562 
  2563     /// The type of the adapted graph.
  2564     typedef GR Graph;
  2565     /// The type of the direction edge map.
  2566     typedef DM DirectionMap;
  2567 
  2568     typedef typename Parent::Arc Arc;
  2569 
  2570   protected:
  2571     Orienter() { }
  2572 
  2573   public:
  2574 
  2575     /// \brief Constructor
  2576     ///
  2577     /// Constructor of the adaptor.
  2578     Orienter(GR& graph, DM& direction) {
  2579       Parent::initialize(graph, direction);
  2580     }
  2581 
  2582     /// \brief Reverses the given arc
  2583     ///
  2584     /// This function reverses the given arc.
  2585     /// It is done by simply negate the assigned value of \c a
  2586     /// in the direction map.
  2587     void reverseArc(const Arc& a) {
  2588       Parent::reverseArc(a);
  2589     }
  2590   };
  2591 
  2592   /// \brief Returns a read-only Orienter adaptor
  2593   ///
  2594   /// This function just returns a read-only \ref Orienter adaptor.
  2595   /// \ingroup graph_adaptors
  2596   /// \relates Orienter
  2597   template<typename GR, typename DM>
  2598   Orienter<const GR, DM>
  2599   orienter(const GR& graph, DM& direction) {
  2600     return Orienter<const GR, DM>(graph, direction);
  2601   }
  2602 
  2603   template<typename GR, typename DM>
  2604   Orienter<const GR, const DM>
  2605   orienter(const GR& graph, const DM& direction) {
  2606     return Orienter<const GR, const DM>(graph, direction);
  2607   }
  2608 
  2609   namespace _adaptor_bits {
  2610 
  2611     template <typename DGR, typename CM, typename FM, typename TL>
  2612     class ResForwardFilter {
  2613     public:
  2614 
  2615       typedef typename DGR::Arc Key;
  2616       typedef bool Value;
  2617 
  2618     private:
  2619 
  2620       const CM* _capacity;
  2621       const FM* _flow;
  2622       TL _tolerance;
  2623 
  2624     public:
  2625 
  2626       ResForwardFilter(const CM& capacity, const FM& flow,
  2627                        const TL& tolerance = TL())
  2628         : _capacity(&capacity), _flow(&flow), _tolerance(tolerance) { }
  2629 
  2630       bool operator[](const typename DGR::Arc& a) const {
  2631         return _tolerance.positive((*_capacity)[a] - (*_flow)[a]);
  2632       }
  2633     };
  2634 
  2635     template<typename DGR,typename CM, typename FM, typename TL>
  2636     class ResBackwardFilter {
  2637     public:
  2638 
  2639       typedef typename DGR::Arc Key;
  2640       typedef bool Value;
  2641 
  2642     private:
  2643 
  2644       const CM* _capacity;
  2645       const FM* _flow;
  2646       TL _tolerance;
  2647 
  2648     public:
  2649 
  2650       ResBackwardFilter(const CM& capacity, const FM& flow,
  2651                         const TL& tolerance = TL())
  2652         : _capacity(&capacity), _flow(&flow), _tolerance(tolerance) { }
  2653 
  2654       bool operator[](const typename DGR::Arc& a) const {
  2655         return _tolerance.positive((*_flow)[a]);
  2656       }
  2657     };
  2658 
  2659   }
  2660 
  2661   /// \ingroup graph_adaptors
  2662   ///
  2663   /// \brief Adaptor class for composing the residual digraph for directed
  2664   /// flow and circulation problems.
  2665   ///
  2666   /// ResidualDigraph can be used for composing the \e residual digraph
  2667   /// for directed flow and circulation problems. Let \f$ G=(V, A) \f$
  2668   /// be a directed graph and let \f$ F \f$ be a number type.
  2669   /// Let \f$ flow, cap: A\to F \f$ be functions on the arcs.
  2670   /// This adaptor implements a digraph structure with node set \f$ V \f$
  2671   /// and arc set \f$ A_{forward}\cup A_{backward} \f$,
  2672   /// where \f$ A_{forward}=\{uv : uv\in A, flow(uv)<cap(uv)\} \f$ and
  2673   /// \f$ A_{backward}=\{vu : uv\in A, flow(uv)>0\} \f$, i.e. the so
  2674   /// called residual digraph.
  2675   /// When the union \f$ A_{forward}\cup A_{backward} \f$ is taken,
  2676   /// multiplicities are counted, i.e. the adaptor has exactly
  2677   /// \f$ |A_{forward}| + |A_{backward}|\f$ arcs (it may have parallel
  2678   /// arcs).
  2679   /// This class conforms to the \ref concepts::Digraph "Digraph" concept.
  2680   ///
  2681   /// \tparam DGR The type of the adapted digraph.
  2682   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
  2683   /// It is implicitly \c const.
  2684   /// \tparam CM The type of the capacity map.
  2685   /// It must be an arc map of some numerical type, which defines
  2686   /// the capacities in the flow problem. It is implicitly \c const.
  2687   /// The default type is
  2688   /// \ref concepts::Digraph::ArcMap "GR::ArcMap<int>".
  2689   /// \tparam FM The type of the flow map.
  2690   /// It must be an arc map of some numerical type, which defines
  2691   /// the flow values in the flow problem. The default type is \c CM.
  2692   /// \tparam TL The tolerance type for handling inexact computation.
  2693   /// The default tolerance type depends on the value type of the
  2694   /// capacity map.
  2695   ///
  2696   /// \note This adaptor is implemented using Undirector and FilterArcs
  2697   /// adaptors.
  2698   ///
  2699   /// \note The \c Node type of this adaptor and the adapted digraph are
  2700   /// convertible to each other, moreover the \c Arc type of the adaptor
  2701   /// is convertible to the \c Arc type of the adapted digraph.
  2702 #ifdef DOXYGEN
  2703   template<typename DGR, typename CM, typename FM, typename TL>
  2704   class ResidualDigraph
  2705 #else
  2706   template<typename DGR,
  2707            typename CM = typename DGR::template ArcMap<int>,
  2708            typename FM = CM,
  2709            typename TL = Tolerance<typename CM::Value> >
  2710   class ResidualDigraph 
  2711     : public SubDigraph<
  2712         Undirector<const DGR>,
  2713         ConstMap<typename DGR::Node, Const<bool, true> >,
  2714         typename Undirector<const DGR>::template CombinedArcMap<
  2715           _adaptor_bits::ResForwardFilter<const DGR, CM, FM, TL>,
  2716           _adaptor_bits::ResBackwardFilter<const DGR, CM, FM, TL> > >
  2717 #endif
  2718   {
  2719   public:
  2720 
  2721     /// The type of the underlying digraph.
  2722     typedef DGR Digraph;
  2723     /// The type of the capacity map.
  2724     typedef CM CapacityMap;
  2725     /// The type of the flow map.
  2726     typedef FM FlowMap;
  2727     /// The tolerance type.
  2728     typedef TL Tolerance;
  2729 
  2730     typedef typename CapacityMap::Value Value;
  2731     typedef ResidualDigraph Adaptor;
  2732 
  2733   protected:
  2734 
  2735     typedef Undirector<const Digraph> Undirected;
  2736 
  2737     typedef ConstMap<typename DGR::Node, Const<bool, true> > NodeFilter;
  2738 
  2739     typedef _adaptor_bits::ResForwardFilter<const DGR, CM,
  2740                                             FM, TL> ForwardFilter;
  2741 
  2742     typedef _adaptor_bits::ResBackwardFilter<const DGR, CM,
  2743                                              FM, TL> BackwardFilter;
  2744 
  2745     typedef typename Undirected::
  2746       template CombinedArcMap<ForwardFilter, BackwardFilter> ArcFilter;
  2747 
  2748     typedef SubDigraph<Undirected, NodeFilter, ArcFilter> Parent;
  2749 
  2750     const CapacityMap* _capacity;
  2751     FlowMap* _flow;
  2752 
  2753     Undirected _graph;
  2754     NodeFilter _node_filter;
  2755     ForwardFilter _forward_filter;
  2756     BackwardFilter _backward_filter;
  2757     ArcFilter _arc_filter;
  2758 
  2759   public:
  2760 
  2761     /// \brief Constructor
  2762     ///
  2763     /// Constructor of the residual digraph adaptor. The parameters are the
  2764     /// digraph, the capacity map, the flow map, and a tolerance object.
  2765     ResidualDigraph(const DGR& digraph, const CM& capacity,
  2766                     FM& flow, const TL& tolerance = Tolerance())
  2767       : Parent(), _capacity(&capacity), _flow(&flow), 
  2768         _graph(digraph), _node_filter(),
  2769         _forward_filter(capacity, flow, tolerance),
  2770         _backward_filter(capacity, flow, tolerance),
  2771         _arc_filter(_forward_filter, _backward_filter)
  2772     {
  2773       Parent::initialize(_graph, _node_filter, _arc_filter);
  2774     }
  2775 
  2776     typedef typename Parent::Arc Arc;
  2777 
  2778     /// \brief Returns the residual capacity of the given arc.
  2779     ///
  2780     /// Returns the residual capacity of the given arc.
  2781     Value residualCapacity(const Arc& a) const {
  2782       if (Undirected::direction(a)) {
  2783         return (*_capacity)[a] - (*_flow)[a];
  2784       } else {
  2785         return (*_flow)[a];
  2786       }
  2787     }
  2788 
  2789     /// \brief Augments on the given arc in the residual digraph.
  2790     ///
  2791     /// Augments on the given arc in the residual digraph. It increases
  2792     /// or decreases the flow value on the original arc according to the
  2793     /// direction of the residual arc.
  2794     void augment(const Arc& a, const Value& v) const {
  2795       if (Undirected::direction(a)) {
  2796         _flow->set(a, (*_flow)[a] + v);
  2797       } else {
  2798         _flow->set(a, (*_flow)[a] - v);
  2799       }
  2800     }
  2801 
  2802     /// \brief Returns \c true if the given residual arc is a forward arc.
  2803     ///
  2804     /// Returns \c true if the given residual arc has the same orientation
  2805     /// as the original arc, i.e. it is a so called forward arc.
  2806     static bool forward(const Arc& a) {
  2807       return Undirected::direction(a);
  2808     }
  2809 
  2810     /// \brief Returns \c true if the given residual arc is a backward arc.
  2811     ///
  2812     /// Returns \c true if the given residual arc has the opposite orientation
  2813     /// than the original arc, i.e. it is a so called backward arc.
  2814     static bool backward(const Arc& a) {
  2815       return !Undirected::direction(a);
  2816     }
  2817 
  2818     /// \brief Returns the forward oriented residual arc.
  2819     ///
  2820     /// Returns the forward oriented residual arc related to the given
  2821     /// arc of the underlying digraph.
  2822     static Arc forward(const typename Digraph::Arc& a) {
  2823       return Undirected::direct(a, true);
  2824     }
  2825 
  2826     /// \brief Returns the backward oriented residual arc.
  2827     ///
  2828     /// Returns the backward oriented residual arc related to the given
  2829     /// arc of the underlying digraph.
  2830     static Arc backward(const typename Digraph::Arc& a) {
  2831       return Undirected::direct(a, false);
  2832     }
  2833 
  2834     /// \brief Residual capacity map.
  2835     ///
  2836     /// This map adaptor class can be used for obtaining the residual
  2837     /// capacities as an arc map of the residual digraph.
  2838     /// Its value type is inherited from the capacity map.
  2839     class ResidualCapacity {
  2840     protected:
  2841       const Adaptor* _adaptor;
  2842     public:
  2843       /// The key type of the map
  2844       typedef Arc Key;
  2845       /// The value type of the map
  2846       typedef typename CapacityMap::Value Value;
  2847 
  2848       /// Constructor
  2849       ResidualCapacity(const ResidualDigraph<DGR, CM, FM, TL>& adaptor) 
  2850         : _adaptor(&adaptor) {}
  2851 
  2852       /// Returns the value associated with the given residual arc
  2853       Value operator[](const Arc& a) const {
  2854         return _adaptor->residualCapacity(a);
  2855       }
  2856 
  2857     };
  2858 
  2859     /// \brief Returns a residual capacity map
  2860     ///
  2861     /// This function just returns a residual capacity map.
  2862     ResidualCapacity residualCapacity() const {
  2863       return ResidualCapacity(*this);
  2864     }
  2865 
  2866   };
  2867 
  2868   /// \brief Returns a (read-only) Residual adaptor
  2869   ///
  2870   /// This function just returns a (read-only) \ref ResidualDigraph adaptor.
  2871   /// \ingroup graph_adaptors
  2872   /// \relates ResidualDigraph
  2873     template<typename DGR, typename CM, typename FM>
  2874   ResidualDigraph<DGR, CM, FM>
  2875   residualDigraph(const DGR& digraph, const CM& capacity_map, FM& flow_map) {
  2876     return ResidualDigraph<DGR, CM, FM> (digraph, capacity_map, flow_map);
  2877   }
  2878 
  2879 
  2880   template <typename DGR>
  2881   class SplitNodesBase {
  2882     typedef DigraphAdaptorBase<const DGR> Parent;
  2883 
  2884   public:
  2885 
  2886     typedef DGR Digraph;
  2887     typedef SplitNodesBase Adaptor;
  2888 
  2889     typedef typename DGR::Node DigraphNode;
  2890     typedef typename DGR::Arc DigraphArc;
  2891 
  2892     class Node;
  2893     class Arc;
  2894 
  2895   private:
  2896 
  2897     template <typename T> class NodeMapBase;
  2898     template <typename T> class ArcMapBase;
  2899 
  2900   public:
  2901 
  2902     class Node : public DigraphNode {
  2903       friend class SplitNodesBase;
  2904       template <typename T> friend class NodeMapBase;
  2905     private:
  2906 
  2907       bool _in;
  2908       Node(DigraphNode node, bool in)
  2909         : DigraphNode(node), _in(in) {}
  2910 
  2911     public:
  2912 
  2913       Node() {}
  2914       Node(Invalid) : DigraphNode(INVALID), _in(true) {}
  2915 
  2916       bool operator==(const Node& node) const {
  2917         return DigraphNode::operator==(node) && _in == node._in;
  2918       }
  2919 
  2920       bool operator!=(const Node& node) const {
  2921         return !(*this == node);
  2922       }
  2923 
  2924       bool operator<(const Node& node) const {
  2925         return DigraphNode::operator<(node) ||
  2926           (DigraphNode::operator==(node) && _in < node._in);
  2927       }
  2928     };
  2929 
  2930     class Arc {
  2931       friend class SplitNodesBase;
  2932       template <typename T> friend class ArcMapBase;
  2933     private:
  2934       typedef BiVariant<DigraphArc, DigraphNode> ArcImpl;
  2935 
  2936       explicit Arc(const DigraphArc& arc) : _item(arc) {}
  2937       explicit Arc(const DigraphNode& node) : _item(node) {}
  2938 
  2939       ArcImpl _item;
  2940 
  2941     public:
  2942       Arc() {}
  2943       Arc(Invalid) : _item(DigraphArc(INVALID)) {}
  2944 
  2945       bool operator==(const Arc& arc) const {
  2946         if (_item.firstState()) {
  2947           if (arc._item.firstState()) {
  2948             return _item.first() == arc._item.first();
  2949           }
  2950         } else {
  2951           if (arc._item.secondState()) {
  2952             return _item.second() == arc._item.second();
  2953           }
  2954         }
  2955         return false;
  2956       }
  2957 
  2958       bool operator!=(const Arc& arc) const {
  2959         return !(*this == arc);
  2960       }
  2961 
  2962       bool operator<(const Arc& arc) const {
  2963         if (_item.firstState()) {
  2964           if (arc._item.firstState()) {
  2965             return _item.first() < arc._item.first();
  2966           }
  2967           return false;
  2968         } else {
  2969           if (arc._item.secondState()) {
  2970             return _item.second() < arc._item.second();
  2971           }
  2972           return true;
  2973         }
  2974       }
  2975 
  2976       operator DigraphArc() const { return _item.first(); }
  2977       operator DigraphNode() const { return _item.second(); }
  2978 
  2979     };
  2980 
  2981     void first(Node& n) const {
  2982       _digraph->first(n);
  2983       n._in = true;
  2984     }
  2985 
  2986     void next(Node& n) const {
  2987       if (n._in) {
  2988         n._in = false;
  2989       } else {
  2990         n._in = true;
  2991         _digraph->next(n);
  2992       }
  2993     }
  2994 
  2995     void first(Arc& e) const {
  2996       e._item.setSecond();
  2997       _digraph->first(e._item.second());
  2998       if (e._item.second() == INVALID) {
  2999         e._item.setFirst();
  3000         _digraph->first(e._item.first());
  3001       }
  3002     }
  3003 
  3004     void next(Arc& e) const {
  3005       if (e._item.secondState()) {
  3006         _digraph->next(e._item.second());
  3007         if (e._item.second() == INVALID) {
  3008           e._item.setFirst();
  3009           _digraph->first(e._item.first());
  3010         }
  3011       } else {
  3012         _digraph->next(e._item.first());
  3013       }
  3014     }
  3015 
  3016     void firstOut(Arc& e, const Node& n) const {
  3017       if (n._in) {
  3018         e._item.setSecond(n);
  3019       } else {
  3020         e._item.setFirst();
  3021         _digraph->firstOut(e._item.first(), n);
  3022       }
  3023     }
  3024 
  3025     void nextOut(Arc& e) const {
  3026       if (!e._item.firstState()) {
  3027         e._item.setFirst(INVALID);
  3028       } else {
  3029         _digraph->nextOut(e._item.first());
  3030       }
  3031     }
  3032 
  3033     void firstIn(Arc& e, const Node& n) const {
  3034       if (!n._in) {
  3035         e._item.setSecond(n);
  3036       } else {
  3037         e._item.setFirst();
  3038         _digraph->firstIn(e._item.first(), n);
  3039       }
  3040     }
  3041 
  3042     void nextIn(Arc& e) const {
  3043       if (!e._item.firstState()) {
  3044         e._item.setFirst(INVALID);
  3045       } else {
  3046         _digraph->nextIn(e._item.first());
  3047       }
  3048     }
  3049 
  3050     Node source(const Arc& e) const {
  3051       if (e._item.firstState()) {
  3052         return Node(_digraph->source(e._item.first()), false);
  3053       } else {
  3054         return Node(e._item.second(), true);
  3055       }
  3056     }
  3057 
  3058     Node target(const Arc& e) const {
  3059       if (e._item.firstState()) {
  3060         return Node(_digraph->target(e._item.first()), true);
  3061       } else {
  3062         return Node(e._item.second(), false);
  3063       }
  3064     }
  3065 
  3066     int id(const Node& n) const {
  3067       return (_digraph->id(n) << 1) | (n._in ? 0 : 1);
  3068     }
  3069     Node nodeFromId(int ix) const {
  3070       return Node(_digraph->nodeFromId(ix >> 1), (ix & 1) == 0);
  3071     }
  3072     int maxNodeId() const {
  3073       return 2 * _digraph->maxNodeId() + 1;
  3074     }
  3075 
  3076     int id(const Arc& e) const {
  3077       if (e._item.firstState()) {
  3078         return _digraph->id(e._item.first()) << 1;
  3079       } else {
  3080         return (_digraph->id(e._item.second()) << 1) | 1;
  3081       }
  3082     }
  3083     Arc arcFromId(int ix) const {
  3084       if ((ix & 1) == 0) {
  3085         return Arc(_digraph->arcFromId(ix >> 1));
  3086       } else {
  3087         return Arc(_digraph->nodeFromId(ix >> 1));
  3088       }
  3089     }
  3090     int maxArcId() const {
  3091       return std::max(_digraph->maxNodeId() << 1,
  3092                       (_digraph->maxArcId() << 1) | 1);
  3093     }
  3094 
  3095     static bool inNode(const Node& n) {
  3096       return n._in;
  3097     }
  3098 
  3099     static bool outNode(const Node& n) {
  3100       return !n._in;
  3101     }
  3102 
  3103     static bool origArc(const Arc& e) {
  3104       return e._item.firstState();
  3105     }
  3106 
  3107     static bool bindArc(const Arc& e) {
  3108       return e._item.secondState();
  3109     }
  3110 
  3111     static Node inNode(const DigraphNode& n) {
  3112       return Node(n, true);
  3113     }
  3114 
  3115     static Node outNode(const DigraphNode& n) {
  3116       return Node(n, false);
  3117     }
  3118 
  3119     static Arc arc(const DigraphNode& n) {
  3120       return Arc(n);
  3121     }
  3122 
  3123     static Arc arc(const DigraphArc& e) {
  3124       return Arc(e);
  3125     }
  3126 
  3127     typedef True NodeNumTag;
  3128     int nodeNum() const {
  3129       return  2 * countNodes(*_digraph);
  3130     }
  3131 
  3132     typedef True ArcNumTag;
  3133     int arcNum() const {
  3134       return countArcs(*_digraph) + countNodes(*_digraph);
  3135     }
  3136 
  3137     typedef True FindArcTag;
  3138     Arc findArc(const Node& u, const Node& v,
  3139                 const Arc& prev = INVALID) const {
  3140       if (inNode(u) && outNode(v)) {
  3141         if (static_cast<const DigraphNode&>(u) ==
  3142             static_cast<const DigraphNode&>(v) && prev == INVALID) {
  3143           return Arc(u);
  3144         }
  3145       }
  3146       else if (outNode(u) && inNode(v)) {
  3147         return Arc(::lemon::findArc(*_digraph, u, v, prev));
  3148       }
  3149       return INVALID;
  3150     }
  3151 
  3152   private:
  3153 
  3154     template <typename V>
  3155     class NodeMapBase
  3156       : public MapTraits<typename Parent::template NodeMap<V> > {
  3157       typedef typename Parent::template NodeMap<V> NodeImpl;
  3158     public:
  3159       typedef Node Key;
  3160       typedef V Value;
  3161       typedef typename MapTraits<NodeImpl>::ReferenceMapTag ReferenceMapTag;
  3162       typedef typename MapTraits<NodeImpl>::ReturnValue ReturnValue;
  3163       typedef typename MapTraits<NodeImpl>::ConstReturnValue ConstReturnValue;
  3164       typedef typename MapTraits<NodeImpl>::ReturnValue Reference;
  3165       typedef typename MapTraits<NodeImpl>::ConstReturnValue ConstReference;
  3166 
  3167       NodeMapBase(const SplitNodesBase<DGR>& adaptor)
  3168         : _in_map(*adaptor._digraph), _out_map(*adaptor._digraph) {}
  3169       NodeMapBase(const SplitNodesBase<DGR>& adaptor, const V& value)
  3170         : _in_map(*adaptor._digraph, value),
  3171           _out_map(*adaptor._digraph, value) {}
  3172 
  3173       void set(const Node& key, const V& val) {
  3174         if (SplitNodesBase<DGR>::inNode(key)) { _in_map.set(key, val); }
  3175         else {_out_map.set(key, val); }
  3176       }
  3177 
  3178       ReturnValue operator[](const Node& key) {
  3179         if (SplitNodesBase<DGR>::inNode(key)) { return _in_map[key]; }
  3180         else { return _out_map[key]; }
  3181       }
  3182 
  3183       ConstReturnValue operator[](const Node& key) const {
  3184         if (Adaptor::inNode(key)) { return _in_map[key]; }
  3185         else { return _out_map[key]; }
  3186       }
  3187 
  3188     private:
  3189       NodeImpl _in_map, _out_map;
  3190     };
  3191 
  3192     template <typename V>
  3193     class ArcMapBase
  3194       : public MapTraits<typename Parent::template ArcMap<V> > {
  3195       typedef typename Parent::template ArcMap<V> ArcImpl;
  3196       typedef typename Parent::template NodeMap<V> NodeImpl;
  3197     public:
  3198       typedef Arc Key;
  3199       typedef V Value;
  3200       typedef typename MapTraits<ArcImpl>::ReferenceMapTag ReferenceMapTag;
  3201       typedef typename MapTraits<ArcImpl>::ReturnValue ReturnValue;
  3202       typedef typename MapTraits<ArcImpl>::ConstReturnValue ConstReturnValue;
  3203       typedef typename MapTraits<ArcImpl>::ReturnValue Reference;
  3204       typedef typename MapTraits<ArcImpl>::ConstReturnValue ConstReference;
  3205 
  3206       ArcMapBase(const SplitNodesBase<DGR>& adaptor)
  3207         : _arc_map(*adaptor._digraph), _node_map(*adaptor._digraph) {}
  3208       ArcMapBase(const SplitNodesBase<DGR>& adaptor, const V& value)
  3209         : _arc_map(*adaptor._digraph, value),
  3210           _node_map(*adaptor._digraph, value) {}
  3211 
  3212       void set(const Arc& key, const V& val) {
  3213         if (SplitNodesBase<DGR>::origArc(key)) {
  3214           _arc_map.set(static_cast<const DigraphArc&>(key), val);
  3215         } else {
  3216           _node_map.set(static_cast<const DigraphNode&>(key), val);
  3217         }
  3218       }
  3219 
  3220       ReturnValue operator[](const Arc& key) {
  3221         if (SplitNodesBase<DGR>::origArc(key)) {
  3222           return _arc_map[static_cast<const DigraphArc&>(key)];
  3223         } else {
  3224           return _node_map[static_cast<const DigraphNode&>(key)];
  3225         }
  3226       }
  3227 
  3228       ConstReturnValue operator[](const Arc& key) const {
  3229         if (SplitNodesBase<DGR>::origArc(key)) {
  3230           return _arc_map[static_cast<const DigraphArc&>(key)];
  3231         } else {
  3232           return _node_map[static_cast<const DigraphNode&>(key)];
  3233         }
  3234       }
  3235 
  3236     private:
  3237       ArcImpl _arc_map;
  3238       NodeImpl _node_map;
  3239     };
  3240 
  3241   public:
  3242 
  3243     template <typename V>
  3244     class NodeMap
  3245       : public SubMapExtender<SplitNodesBase<DGR>, NodeMapBase<V> > {
  3246       typedef SubMapExtender<SplitNodesBase<DGR>, NodeMapBase<V> > Parent;
  3247 
  3248     public:
  3249       typedef V Value;
  3250 
  3251       NodeMap(const SplitNodesBase<DGR>& adaptor)
  3252         : Parent(adaptor) {}
  3253 
  3254       NodeMap(const SplitNodesBase<DGR>& adaptor, const V& value)
  3255         : Parent(adaptor, value) {}
  3256 
  3257     private:
  3258       NodeMap& operator=(const NodeMap& cmap) {
  3259         return operator=<NodeMap>(cmap);
  3260       }
  3261 
  3262       template <typename CMap>
  3263       NodeMap& operator=(const CMap& cmap) {
  3264         Parent::operator=(cmap);
  3265         return *this;
  3266       }
  3267     };
  3268 
  3269     template <typename V>
  3270     class ArcMap
  3271       : public SubMapExtender<SplitNodesBase<DGR>, ArcMapBase<V> > {
  3272       typedef SubMapExtender<SplitNodesBase<DGR>, ArcMapBase<V> > Parent;
  3273 
  3274     public:
  3275       typedef V Value;
  3276 
  3277       ArcMap(const SplitNodesBase<DGR>& adaptor)
  3278         : Parent(adaptor) {}
  3279 
  3280       ArcMap(const SplitNodesBase<DGR>& adaptor, const V& value)
  3281         : Parent(adaptor, value) {}
  3282 
  3283     private:
  3284       ArcMap& operator=(const ArcMap& cmap) {
  3285         return operator=<ArcMap>(cmap);
  3286       }
  3287 
  3288       template <typename CMap>
  3289       ArcMap& operator=(const CMap& cmap) {
  3290         Parent::operator=(cmap);
  3291         return *this;
  3292       }
  3293     };
  3294 
  3295   protected:
  3296 
  3297     SplitNodesBase() : _digraph(0) {}
  3298 
  3299     DGR* _digraph;
  3300 
  3301     void initialize(Digraph& digraph) {
  3302       _digraph = &digraph;
  3303     }
  3304 
  3305   };
  3306 
  3307   /// \ingroup graph_adaptors
  3308   ///
  3309   /// \brief Adaptor class for splitting the nodes of a digraph.
  3310   ///
  3311   /// SplitNodes adaptor can be used for splitting each node into an
  3312   /// \e in-node and an \e out-node in a digraph. Formaly, the adaptor
  3313   /// replaces each node \f$ u \f$ in the digraph with two nodes,
  3314   /// namely node \f$ u_{in} \f$ and node \f$ u_{out} \f$.
  3315   /// If there is a \f$ (v, u) \f$ arc in the original digraph, then the
  3316   /// new target of the arc will be \f$ u_{in} \f$ and similarly the
  3317   /// source of each original \f$ (u, v) \f$ arc will be \f$ u_{out} \f$.
  3318   /// The adaptor adds an additional \e bind \e arc from \f$ u_{in} \f$
  3319   /// to \f$ u_{out} \f$ for each node \f$ u \f$ of the original digraph.
  3320   ///
  3321   /// The aim of this class is running an algorithm with respect to node
  3322   /// costs or capacities if the algorithm considers only arc costs or
  3323   /// capacities directly.
  3324   /// In this case you can use \c SplitNodes adaptor, and set the node
  3325   /// costs/capacities of the original digraph to the \e bind \e arcs
  3326   /// in the adaptor.
  3327   ///
  3328   /// \tparam DGR The type of the adapted digraph.
  3329   /// It must conform to the \ref concepts::Digraph "Digraph" concept.
  3330   /// It is implicitly \c const.
  3331   ///
  3332   /// \note The \c Node type of this adaptor is converible to the \c Node
  3333   /// type of the adapted digraph.
  3334   template <typename DGR>
  3335 #ifdef DOXYGEN
  3336   class SplitNodes {
  3337 #else
  3338   class SplitNodes
  3339     : public DigraphAdaptorExtender<SplitNodesBase<const DGR> > {
  3340 #endif
  3341     typedef DigraphAdaptorExtender<SplitNodesBase<const DGR> > Parent;
  3342 
  3343   public:
  3344     typedef DGR Digraph;
  3345 
  3346     typedef typename DGR::Node DigraphNode;
  3347     typedef typename DGR::Arc DigraphArc;
  3348 
  3349     typedef typename Parent::Node Node;
  3350     typedef typename Parent::Arc Arc;
  3351 
  3352     /// \brief Constructor
  3353     ///
  3354     /// Constructor of the adaptor.
  3355     SplitNodes(const DGR& g) {
  3356       Parent::initialize(g);
  3357     }
  3358 
  3359     /// \brief Returns \c true if the given node is an in-node.
  3360     ///
  3361     /// Returns \c true if the given node is an in-node.
  3362     static bool inNode(const Node& n) {
  3363       return Parent::inNode(n);
  3364     }
  3365 
  3366     /// \brief Returns \c true if the given node is an out-node.
  3367     ///
  3368     /// Returns \c true if the given node is an out-node.
  3369     static bool outNode(const Node& n) {
  3370       return Parent::outNode(n);
  3371     }
  3372 
  3373     /// \brief Returns \c true if the given arc is an original arc.
  3374     ///
  3375     /// Returns \c true if the given arc is one of the arcs in the
  3376     /// original digraph.
  3377     static bool origArc(const Arc& a) {
  3378       return Parent::origArc(a);
  3379     }
  3380 
  3381     /// \brief Returns \c true if the given arc is a bind arc.
  3382     ///
  3383     /// Returns \c true if the given arc is a bind arc, i.e. it connects
  3384     /// an in-node and an out-node.
  3385     static bool bindArc(const Arc& a) {
  3386       return Parent::bindArc(a);
  3387     }
  3388 
  3389     /// \brief Returns the in-node created from the given original node.
  3390     ///
  3391     /// Returns the in-node created from the given original node.
  3392     static Node inNode(const DigraphNode& n) {
  3393       return Parent::inNode(n);
  3394     }
  3395 
  3396     /// \brief Returns the out-node created from the given original node.
  3397     ///
  3398     /// Returns the out-node created from the given original node.
  3399     static Node outNode(const DigraphNode& n) {
  3400       return Parent::outNode(n);
  3401     }
  3402 
  3403     /// \brief Returns the bind arc that corresponds to the given
  3404     /// original node.
  3405     ///
  3406     /// Returns the bind arc in the adaptor that corresponds to the given
  3407     /// original node, i.e. the arc connecting the in-node and out-node
  3408     /// of \c n.
  3409     static Arc arc(const DigraphNode& n) {
  3410       return Parent::arc(n);
  3411     }
  3412 
  3413     /// \brief Returns the arc that corresponds to the given original arc.
  3414     ///
  3415     /// Returns the arc in the adaptor that corresponds to the given
  3416     /// original arc.
  3417     static Arc arc(const DigraphArc& a) {
  3418       return Parent::arc(a);
  3419     }
  3420 
  3421     /// \brief Node map combined from two original node maps
  3422     ///
  3423     /// This map adaptor class adapts two node maps of the original digraph
  3424     /// to get a node map of the split digraph.
  3425     /// Its value type is inherited from the first node map type (\c IN).
  3426     /// \tparam IN The type of the node map for the in-nodes. 
  3427     /// \tparam OUT The type of the node map for the out-nodes.
  3428     template <typename IN, typename OUT>
  3429     class CombinedNodeMap {
  3430     public:
  3431 
  3432       /// The key type of the map
  3433       typedef Node Key;
  3434       /// The value type of the map
  3435       typedef typename IN::Value Value;
  3436 
  3437       typedef typename MapTraits<IN>::ReferenceMapTag ReferenceMapTag;
  3438       typedef typename MapTraits<IN>::ReturnValue ReturnValue;
  3439       typedef typename MapTraits<IN>::ConstReturnValue ConstReturnValue;
  3440       typedef typename MapTraits<IN>::ReturnValue Reference;
  3441       typedef typename MapTraits<IN>::ConstReturnValue ConstReference;
  3442 
  3443       /// Constructor
  3444       CombinedNodeMap(IN& in_map, OUT& out_map)
  3445         : _in_map(in_map), _out_map(out_map) {}
  3446 
  3447       /// Returns the value associated with the given key.
  3448       Value operator[](const Key& key) const {
  3449         if (SplitNodesBase<const DGR>::inNode(key)) {
  3450           return _in_map[key];
  3451         } else {
  3452           return _out_map[key];
  3453         }
  3454       }
  3455 
  3456       /// Returns a reference to the value associated with the given key.
  3457       Value& operator[](const Key& key) {
  3458         if (SplitNodesBase<const DGR>::inNode(key)) {
  3459           return _in_map[key];
  3460         } else {
  3461           return _out_map[key];
  3462         }
  3463       }
  3464 
  3465       /// Sets the value associated with the given key.
  3466       void set(const Key& key, const Value& value) {
  3467         if (SplitNodesBase<const DGR>::inNode(key)) {
  3468           _in_map.set(key, value);
  3469         } else {
  3470           _out_map.set(key, value);
  3471         }
  3472       }
  3473 
  3474     private:
  3475 
  3476       IN& _in_map;
  3477       OUT& _out_map;
  3478 
  3479     };
  3480 
  3481 
  3482     /// \brief Returns a combined node map
  3483     ///
  3484     /// This function just returns a combined node map.
  3485     template <typename IN, typename OUT>
  3486     static CombinedNodeMap<IN, OUT>
  3487     combinedNodeMap(IN& in_map, OUT& out_map) {
  3488       return CombinedNodeMap<IN, OUT>(in_map, out_map);
  3489     }
  3490 
  3491     template <typename IN, typename OUT>
  3492     static CombinedNodeMap<const IN, OUT>
  3493     combinedNodeMap(const IN& in_map, OUT& out_map) {
  3494       return CombinedNodeMap<const IN, OUT>(in_map, out_map);
  3495     }
  3496 
  3497     template <typename IN, typename OUT>
  3498     static CombinedNodeMap<IN, const OUT>
  3499     combinedNodeMap(IN& in_map, const OUT& out_map) {
  3500       return CombinedNodeMap<IN, const OUT>(in_map, out_map);
  3501     }
  3502 
  3503     template <typename IN, typename OUT>
  3504     static CombinedNodeMap<const IN, const OUT>
  3505     combinedNodeMap(const IN& in_map, const OUT& out_map) {
  3506       return CombinedNodeMap<const IN, const OUT>(in_map, out_map);
  3507     }
  3508 
  3509     /// \brief Arc map combined from an arc map and a node map of the
  3510     /// original digraph.
  3511     ///
  3512     /// This map adaptor class adapts an arc map and a node map of the
  3513     /// original digraph to get an arc map of the split digraph.
  3514     /// Its value type is inherited from the original arc map type (\c AM).
  3515     /// \tparam AM The type of the arc map.
  3516     /// \tparam NM the type of the node map.
  3517     template <typename AM, typename NM>
  3518     class CombinedArcMap {
  3519     public:
  3520 
  3521       /// The key type of the map
  3522       typedef Arc Key;
  3523       /// The value type of the map
  3524       typedef typename AM::Value Value;
  3525 
  3526       typedef typename MapTraits<AM>::ReferenceMapTag ReferenceMapTag;
  3527       typedef typename MapTraits<AM>::ReturnValue ReturnValue;
  3528       typedef typename MapTraits<AM>::ConstReturnValue ConstReturnValue;
  3529       typedef typename MapTraits<AM>::ReturnValue Reference;
  3530       typedef typename MapTraits<AM>::ConstReturnValue ConstReference;
  3531 
  3532       /// Constructor
  3533       CombinedArcMap(AM& arc_map, NM& node_map)
  3534         : _arc_map(arc_map), _node_map(node_map) {}
  3535 
  3536       /// Returns the value associated with the given key.
  3537       Value operator[](const Key& arc) const {
  3538         if (SplitNodesBase<const DGR>::origArc(arc)) {
  3539           return _arc_map[arc];
  3540         } else {
  3541           return _node_map[arc];
  3542         }
  3543       }
  3544 
  3545       /// Returns a reference to the value associated with the given key.
  3546       Value& operator[](const Key& arc) {
  3547         if (SplitNodesBase<const DGR>::origArc(arc)) {
  3548           return _arc_map[arc];
  3549         } else {
  3550           return _node_map[arc];
  3551         }
  3552       }
  3553 
  3554       /// Sets the value associated with the given key.
  3555       void set(const Arc& arc, const Value& val) {
  3556         if (SplitNodesBase<const DGR>::origArc(arc)) {
  3557           _arc_map.set(arc, val);
  3558         } else {
  3559           _node_map.set(arc, val);
  3560         }
  3561       }
  3562 
  3563     private:
  3564 
  3565       AM& _arc_map;
  3566       NM& _node_map;
  3567 
  3568     };
  3569 
  3570     /// \brief Returns a combined arc map
  3571     ///
  3572     /// This function just returns a combined arc map.
  3573     template <typename ArcMap, typename NodeMap>
  3574     static CombinedArcMap<ArcMap, NodeMap>
  3575     combinedArcMap(ArcMap& arc_map, NodeMap& node_map) {
  3576       return CombinedArcMap<ArcMap, NodeMap>(arc_map, node_map);
  3577     }
  3578 
  3579     template <typename ArcMap, typename NodeMap>
  3580     static CombinedArcMap<const ArcMap, NodeMap>
  3581     combinedArcMap(const ArcMap& arc_map, NodeMap& node_map) {
  3582       return CombinedArcMap<const ArcMap, NodeMap>(arc_map, node_map);
  3583     }
  3584 
  3585     template <typename ArcMap, typename NodeMap>
  3586     static CombinedArcMap<ArcMap, const NodeMap>
  3587     combinedArcMap(ArcMap& arc_map, const NodeMap& node_map) {
  3588       return CombinedArcMap<ArcMap, const NodeMap>(arc_map, node_map);
  3589     }
  3590 
  3591     template <typename ArcMap, typename NodeMap>
  3592     static CombinedArcMap<const ArcMap, const NodeMap>
  3593     combinedArcMap(const ArcMap& arc_map, const NodeMap& node_map) {
  3594       return CombinedArcMap<const ArcMap, const NodeMap>(arc_map, node_map);
  3595     }
  3596 
  3597   };
  3598 
  3599   /// \brief Returns a (read-only) SplitNodes adaptor
  3600   ///
  3601   /// This function just returns a (read-only) \ref SplitNodes adaptor.
  3602   /// \ingroup graph_adaptors
  3603   /// \relates SplitNodes
  3604   template<typename DGR>
  3605   SplitNodes<DGR>
  3606   splitNodes(const DGR& digraph) {
  3607     return SplitNodes<DGR>(digraph);
  3608   }
  3609 
  3610 #undef LEMON_SCOPE_FIX
  3611 
  3612 } //namespace lemon
  3613 
  3614 #endif //LEMON_ADAPTORS_H