COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/graph_utils.h @ 1756:b1f441f24d08

Last change on this file since 1756:b1f441f24d08 was 1756:b1f441f24d08, checked in by Alpar Juttner, 14 years ago

GRAPH_TYPEDEFS and UNDIRGRAPH_TYPEDEFS macros added to graph_utils.h.

File size: 45.3 KB
Line 
1/* -*- C++ -*-
2 * lemon/graph_utils.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Research Group on Combinatorial Optimization, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_GRAPH_UTILS_H
18#define LEMON_GRAPH_UTILS_H
19
20#include <iterator>
21#include <vector>
22#include <map>
23#include <cmath>
24
25#include <lemon/invalid.h>
26#include <lemon/utility.h>
27#include <lemon/maps.h>
28#include <lemon/traits.h>
29#include <lemon/bits/alteration_notifier.h>
30
31///\ingroup gutils
32///\file
33///\brief Graph utilities.
34///
35///
36
37
38namespace lemon {
39
40  /// \addtogroup gutils
41  /// @{
42
43  ///Creates convenience typedefs for the graph types and iterators
44
45  ///This \c \#define creates convenience typedefs for the following types
46  ///of \c Graph: \c Node,  \c NodeIt, \c Edge, \c EdgeIt, \c InEdgeIt,
47  ///\c OutEdgeIt.
48  ///\note If \c G it a template parameter, it should be used in this way.
49  ///\code
50  ///  GRAPH_TYPEDEFS(typename G)
51  ///\endcode
52  ///
53  ///\warning There are no typedefs for the graph maps because of the lack of
54  ///template typedefs in C++.
55#define GRAPH_TYPEDEFS(Graph)                   \
56  typedef Graph::     Node      Node;           \
57    typedef Graph::   NodeIt    NodeIt;         \
58    typedef Graph::   Edge      Edge;           \
59    typedef Graph::   EdgeIt    EdgeIt;         \
60    typedef Graph:: InEdgeIt  InEdgeIt;         \
61    typedef Graph::OutEdgeIt OutEdgeIt;
62 
63  ///Creates convenience typedefs for the undirected graph types and iterators
64
65  ///This \c \#define creates the same convenience typedefs as defined by
66  ///\ref GRAPH_TYPEDEFS(Graph) and three more, namely it creates
67  ///\c UndirEdge, \c UndirEdgeIt, \c IncEdgeIt,
68  ///
69  ///\note If \c G it a template parameter, it should be used in this way.
70  ///\code
71  ///  UNDIRGRAPH_TYPEDEFS(typename G)
72  ///\endcode
73  ///
74  ///\warning There are no typedefs for the graph maps because of the lack of
75  ///template typedefs in C++.
76#define UNDIRGRAPH_TYPEDEFS(Graph)                      \
77  GRAPH_TYPEDEFS(Graph)                                 \
78    typedef Graph:: UndirEdge   UndirEdge;              \
79    typedef Graph:: UndirEdgeIt UndirEdgeIt;            \
80    typedef Graph:: IncEdgeIt   IncEdgeIt;
81
82
83  /// \brief Function to count the items in the graph.
84  ///
85  /// This function counts the items (nodes, edges etc) in the graph.
86  /// The complexity of the function is O(n) because
87  /// it iterates on all of the items.
88
89  template <typename Graph, typename ItemIt>
90  inline int countItems(const Graph& g) {
91    int num = 0;
92    for (ItemIt it(g); it != INVALID; ++it) {
93      ++num;
94    }
95    return num;
96  }
97
98  // Node counting:
99
100  template <typename Graph>
101  inline
102  typename enable_if<typename Graph::NodeNumTag, int>::type
103  _countNodes(const Graph &g) {
104    return g.nodeNum();
105  }
106
107  template <typename Graph>
108  inline int _countNodes(Wrap<Graph> w) {
109    return countItems<Graph, typename Graph::NodeIt>(w.value);
110  }
111
112  /// \brief Function to count the nodes in the graph.
113  ///
114  /// This function counts the nodes in the graph.
115  /// The complexity of the function is O(n) but for some
116  /// graph structures it is specialized to run in O(1).
117  ///
118  /// \todo refer how to specialize it
119
120  template <typename Graph>
121  inline int countNodes(const Graph& g) {
122    return _countNodes<Graph>(g);
123  }
124
125  // Edge counting:
126
127  template <typename Graph>
128  inline
129  typename enable_if<typename Graph::EdgeNumTag, int>::type
130  _countEdges(const Graph &g) {
131    return g.edgeNum();
132  }
133
134  template <typename Graph>
135  inline int _countEdges(Wrap<Graph> w) {
136    return countItems<Graph, typename Graph::EdgeIt>(w.value);
137  }
138
139  /// \brief Function to count the edges in the graph.
140  ///
141  /// This function counts the edges in the graph.
142  /// The complexity of the function is O(e) but for some
143  /// graph structures it is specialized to run in O(1).
144
145  template <typename Graph>
146  inline int countEdges(const Graph& g) {
147    return _countEdges<Graph>(g);
148  }
149
150  // Undirected edge counting:
151
152  template <typename Graph>
153  inline
154  typename enable_if<typename Graph::EdgeNumTag, int>::type
155  _countUndirEdges(const Graph &g) {
156    return g.undirEdgeNum();
157  }
158
159  template <typename Graph>
160  inline int _countUndirEdges(Wrap<Graph> w) {
161    return countItems<Graph, typename Graph::UndirEdgeIt>(w.value);
162  }
163
164  /// \brief Function to count the undirected edges in the graph.
165  ///
166  /// This function counts the undirected edges in the graph.
167  /// The complexity of the function is O(e) but for some
168  /// graph structures it is specialized to run in O(1).
169
170  template <typename Graph>
171  inline int countUndirEdges(const Graph& g) {
172    return _countUndirEdges<Graph>(g);
173  }
174
175
176
177  template <typename Graph, typename DegIt>
178  inline int countNodeDegree(const Graph& _g, const typename Graph::Node& _n) {
179    int num = 0;
180    for (DegIt it(_g, _n); it != INVALID; ++it) {
181      ++num;
182    }
183    return num;
184  }
185
186  /// \brief Function to count the number of the out-edges from node \c n.
187  ///
188  /// This function counts the number of the out-edges from node \c n
189  /// in the graph. 
190  template <typename Graph>
191  inline int countOutEdges(const Graph& _g,  const typename Graph::Node& _n) {
192    return countNodeDegree<Graph, typename Graph::OutEdgeIt>(_g, _n);
193  }
194
195  /// \brief Function to count the number of the in-edges to node \c n.
196  ///
197  /// This function counts the number of the in-edges to node \c n
198  /// in the graph. 
199  template <typename Graph>
200  inline int countInEdges(const Graph& _g,  const typename Graph::Node& _n) {
201    return countNodeDegree<Graph, typename Graph::InEdgeIt>(_g, _n);
202  }
203
204  /// \brief Function to count the number of the inc-edges to node \c n.
205  ///
206  /// This function counts the number of the inc-edges to node \c n
207  /// in the graph. 
208  template <typename Graph>
209  inline int countIncEdges(const Graph& _g,  const typename Graph::Node& _n) {
210    return countNodeDegree<Graph, typename Graph::IncEdgeIt>(_g, _n);
211  }
212
213
214  template <typename Graph>
215  inline
216  typename enable_if<typename Graph::FindEdgeTag, typename Graph::Edge>::type
217  _findEdge(const Graph &g,
218            typename Graph::Node u, typename Graph::Node v,
219            typename Graph::Edge prev = INVALID) {
220    return g.findEdge(u, v, prev);
221  }
222
223  template <typename Graph>
224  inline typename Graph::Edge
225  _findEdge(Wrap<Graph> w,
226            typename Graph::Node u,
227            typename Graph::Node v,
228            typename Graph::Edge prev = INVALID) {
229    const Graph& g = w.value;
230    if (prev == INVALID) {
231      typename Graph::OutEdgeIt e(g, u);
232      while (e != INVALID && g.target(e) != v) ++e;
233      return e;
234    } else {
235      typename Graph::OutEdgeIt e(g, prev); ++e;
236      while (e != INVALID && g.target(e) != v) ++e;
237      return e;
238    }
239  }
240
241  /// \brief Finds an edge between two nodes of a graph.
242  ///
243  /// Finds an edge from node \c u to node \c v in graph \c g.
244  ///
245  /// If \c prev is \ref INVALID (this is the default value), then
246  /// it finds the first edge from \c u to \c v. Otherwise it looks for
247  /// the next edge from \c u to \c v after \c prev.
248  /// \return The found edge or \ref INVALID if there is no such an edge.
249  ///
250  /// Thus you can iterate through each edge from \c u to \c v as it follows.
251  /// \code
252  /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) {
253  ///   ...
254  /// }
255  /// \endcode
256  // /// \todo We may want to use the "GraphBase"
257  // /// interface here...
258  template <typename Graph>
259  inline typename Graph::Edge findEdge(const Graph &g,
260                                       typename Graph::Node u,
261                                       typename Graph::Node v,
262                                       typename Graph::Edge prev = INVALID) {
263    return _findEdge<Graph>(g, u, v, prev);
264  }
265
266  /// \brief Iterator for iterating on edges connected the same nodes.
267  ///
268  /// Iterator for iterating on edges connected the same nodes. It is
269  /// higher level interface for the findEdge() function. You can
270  /// use it the following way:
271  /// \code
272  /// for (ConEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
273  ///   ...
274  /// }
275  /// \endcode
276  ///
277  /// \author Balazs Dezso
278  template <typename _Graph>
279  class ConEdgeIt : public _Graph::Edge {
280  public:
281
282    typedef _Graph Graph;
283    typedef typename Graph::Edge Parent;
284
285    typedef typename Graph::Edge Edge;
286    typedef typename Graph::Node Node;
287
288    /// \brief Constructor.
289    ///
290    /// Construct a new ConEdgeIt iterating on the edges which
291    /// connects the \c u and \c v node.
292    ConEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
293      Parent::operator=(findEdge(graph, u, v));
294    }
295
296    /// \brief Constructor.
297    ///
298    /// Construct a new ConEdgeIt which continues the iterating from
299    /// the \c e edge.
300    ConEdgeIt(const Graph& g, Edge e) : Parent(e), graph(g) {}
301   
302    /// \brief Increment operator.
303    ///
304    /// It increments the iterator and gives back the next edge.
305    ConEdgeIt& operator++() {
306      Parent::operator=(findEdge(graph, graph.source(*this),
307                                 graph.target(*this), *this));
308      return *this;
309    }
310  private:
311    const Graph& graph;
312  };
313
314  template <typename Graph>
315  inline
316  typename enable_if<
317    typename Graph::FindEdgeTag,
318    typename Graph::UndirEdge>::type
319  _findUndirEdge(const Graph &g,
320            typename Graph::Node u, typename Graph::Node v,
321            typename Graph::UndirEdge prev = INVALID) {
322    return g.findUndirEdge(u, v, prev);
323  }
324
325  template <typename Graph>
326  inline typename Graph::UndirEdge
327  _findUndirEdge(Wrap<Graph> w,
328            typename Graph::Node u,
329            typename Graph::Node v,
330            typename Graph::UndirEdge prev = INVALID) {
331    const Graph& g = w.value;
332    if (prev == INVALID) {
333      typename Graph::OutEdgeIt e(g, u);
334      while (e != INVALID && g.target(e) != v) ++e;
335      return e;
336    } else {
337      typename Graph::OutEdgeIt e(g, g.direct(prev, u)); ++e;
338      while (e != INVALID && g.target(e) != v) ++e;
339      return e;
340    }
341  }
342
343  /// \brief Finds an undir edge between two nodes of a graph.
344  ///
345  /// Finds an undir edge from node \c u to node \c v in graph \c g.
346  ///
347  /// If \c prev is \ref INVALID (this is the default value), then
348  /// it finds the first edge from \c u to \c v. Otherwise it looks for
349  /// the next edge from \c u to \c v after \c prev.
350  /// \return The found edge or \ref INVALID if there is no such an edge.
351  ///
352  /// Thus you can iterate through each edge from \c u to \c v as it follows.
353  /// \code
354  /// for(UndirEdge e = findUndirEdge(g,u,v); e != INVALID;
355  ///     e = findUndirEdge(g,u,v,e)) {
356  ///   ...
357  /// }
358  /// \endcode
359  // /// \todo We may want to use the "GraphBase"
360  // /// interface here...
361  template <typename Graph>
362  inline typename Graph::UndirEdge
363  findUndirEdge(const Graph &g,
364                typename Graph::Node u,
365                typename Graph::Node v,
366                typename Graph::UndirEdge prev = INVALID) {
367    return _findUndirEdge<Graph>(g, u, v, prev);
368  }
369
370  /// \brief Iterator for iterating on undir edges connected the same nodes.
371  ///
372  /// Iterator for iterating on undir edges connected the same nodes. It is
373  /// higher level interface for the findUndirEdge() function. You can
374  /// use it the following way:
375  /// \code
376  /// for (ConUndirEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
377  ///   ...
378  /// }
379  /// \endcode
380  ///
381  /// \author Balazs Dezso
382  template <typename _Graph>
383  class ConUndirEdgeIt : public _Graph::UndirEdge {
384  public:
385
386    typedef _Graph Graph;
387    typedef typename Graph::UndirEdge Parent;
388
389    typedef typename Graph::UndirEdge UndirEdge;
390    typedef typename Graph::Node Node;
391
392    /// \brief Constructor.
393    ///
394    /// Construct a new ConUndirEdgeIt iterating on the edges which
395    /// connects the \c u and \c v node.
396    ConUndirEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
397      Parent::operator=(findUndirEdge(graph, u, v));
398    }
399
400    /// \brief Constructor.
401    ///
402    /// Construct a new ConUndirEdgeIt which continues the iterating from
403    /// the \c e edge.
404    ConUndirEdgeIt(const Graph& g, UndirEdge e) : Parent(e), graph(g) {}
405   
406    /// \brief Increment operator.
407    ///
408    /// It increments the iterator and gives back the next edge.
409    ConUndirEdgeIt& operator++() {
410      Parent::operator=(findUndirEdge(graph, graph.source(*this),
411                                 graph.target(*this), *this));
412      return *this;
413    }
414  private:
415    const Graph& graph;
416  };
417
418  /// \brief Copy a map.
419  ///
420  /// This function copies the \c source map to the \c target map. It uses the
421  /// given iterator to iterate on the data structure and it uses the \c ref
422  /// mapping to convert the source's keys to the target's keys.
423  template <typename Target, typename Source,
424            typename ItemIt, typename Ref>         
425  void copyMap(Target& target, const Source& source,
426               ItemIt it, const Ref& ref) {
427    for (; it != INVALID; ++it) {
428      target[ref[it]] = source[it];
429    }
430  }
431
432  /// \brief Copy the source map to the target map.
433  ///
434  /// Copy the \c source map to the \c target map. It uses the given iterator
435  /// to iterate on the data structure.
436  template <typename Target, typename Source,
437            typename ItemIt>       
438  void copyMap(Target& target, const Source& source, ItemIt it) {
439    for (; it != INVALID; ++it) {
440      target[it] = source[it];
441    }
442  }
443
444  /// \brief Class to copy a graph.
445  ///
446  /// Class to copy a graph to an other graph (duplicate a graph). The
447  /// simplest way of using it is through the \c copyGraph() function.
448  template <typename Target, typename Source>
449  class GraphCopy {
450  public:
451    typedef typename Source::Node Node;
452    typedef typename Source::NodeIt NodeIt;
453    typedef typename Source::Edge Edge;
454    typedef typename Source::EdgeIt EdgeIt;
455
456    typedef typename Source::template NodeMap<typename Target::Node>NodeRefMap;
457    typedef typename Source::template EdgeMap<typename Target::Edge>EdgeRefMap;
458
459    /// \brief Constructor for the GraphCopy.
460    ///
461    /// It copies the content of the \c _source graph into the
462    /// \c _target graph. It creates also two references, one beetween
463    /// the two nodeset and one beetween the two edgesets.
464    GraphCopy(Target& _target, const Source& _source)
465      : source(_source), target(_target),
466        nodeRefMap(_source), edgeRefMap(_source) {
467      for (NodeIt it(source); it != INVALID; ++it) {
468        nodeRefMap[it] = target.addNode();
469      }
470      for (EdgeIt it(source); it != INVALID; ++it) {
471        edgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
472                                        nodeRefMap[source.target(it)]);
473      }
474    }
475
476    /// \brief Copies the node references into the given map.
477    ///
478    /// Copies the node references into the given map.
479    template <typename NodeRef>
480    const GraphCopy& nodeRef(NodeRef& map) const {
481      for (NodeIt it(source); it != INVALID; ++it) {
482        map.set(it, nodeRefMap[it]);
483      }
484      return *this;
485    }
486
487    /// \brief Reverse and copies the node references into the given map.
488    ///
489    /// Reverse and copies the node references into the given map.
490    template <typename NodeRef>
491    const GraphCopy& nodeCrossRef(NodeRef& map) const {
492      for (NodeIt it(source); it != INVALID; ++it) {
493        map.set(nodeRefMap[it], it);
494      }
495      return *this;
496    }
497
498    /// \brief Copies the edge references into the given map.
499    ///
500    /// Copies the edge references into the given map.
501    template <typename EdgeRef>
502    const GraphCopy& edgeRef(EdgeRef& map) const {
503      for (EdgeIt it(source); it != INVALID; ++it) {
504        map.set(it, edgeRefMap[it]);
505      }
506      return *this;
507    }
508
509    /// \brief Reverse and copies the edge references into the given map.
510    ///
511    /// Reverse and copies the edge references into the given map.
512    template <typename EdgeRef>
513    const GraphCopy& edgeCrossRef(EdgeRef& map) const {
514      for (EdgeIt it(source); it != INVALID; ++it) {
515        map.set(edgeRefMap[it], it);
516      }
517      return *this;
518    }
519
520    /// \brief Make copy of the given map.
521    ///
522    /// Makes copy of the given map for the newly created graph.
523    /// The new map's key type is the target graph's node type,
524    /// and the copied map's key type is the source graph's node
525    /// type. 
526    template <typename TargetMap, typename SourceMap>
527    const GraphCopy& nodeMap(TargetMap& tMap, const SourceMap& sMap) const {
528      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
529      return *this;
530    }
531
532    /// \brief Make copy of the given map.
533    ///
534    /// Makes copy of the given map for the newly created graph.
535    /// The new map's key type is the target graph's edge type,
536    /// and the copied map's key type is the source graph's edge
537    /// type. 
538    template <typename TargetMap, typename SourceMap>
539    const GraphCopy& edgeMap(TargetMap& tMap, const SourceMap& sMap) const {
540      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
541      return *this;
542    }
543
544    /// \brief Gives back the stored node references.
545    ///
546    /// Gives back the stored node references.
547    const NodeRefMap& nodeRef() const {
548      return nodeRefMap;
549    }
550
551    /// \brief Gives back the stored edge references.
552    ///
553    /// Gives back the stored edge references.
554    const EdgeRefMap& edgeRef() const {
555      return edgeRefMap;
556    }
557
558    void run() {}
559
560  private:
561   
562    const Source& source;
563    Target& target;
564
565    NodeRefMap nodeRefMap;
566    EdgeRefMap edgeRefMap;
567  };
568
569  /// \brief Copy a graph to an other graph.
570  ///
571  /// Copy a graph to an other graph.
572  /// The usage of the function:
573  ///
574  /// \code
575  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
576  /// \endcode
577  ///
578  /// After the copy the \c nr map will contain the mapping from the
579  /// source graph's nodes to the target graph's nodes and the \c ecr will
580  /// contain the mapping from the target graph's edges to the source's
581  /// edges.
582  template <typename Target, typename Source>
583  GraphCopy<Target, Source> copyGraph(Target& target, const Source& source) {
584    return GraphCopy<Target, Source>(target, source);
585  }
586
587  /// \brief Class to copy an undirected graph.
588  ///
589  /// Class to copy an undirected graph to an other graph (duplicate a graph).
590  /// The simplest way of using it is through the \c copyUndirGraph() function.
591  template <typename Target, typename Source>
592  class UndirGraphCopy {
593  public:
594    typedef typename Source::Node Node;
595    typedef typename Source::NodeIt NodeIt;
596    typedef typename Source::Edge Edge;
597    typedef typename Source::EdgeIt EdgeIt;
598    typedef typename Source::UndirEdge UndirEdge;
599    typedef typename Source::UndirEdgeIt UndirEdgeIt;
600
601    typedef typename Source::
602    template NodeMap<typename Target::Node> NodeRefMap;
603   
604    typedef typename Source::
605    template UndirEdgeMap<typename Target::UndirEdge> UndirEdgeRefMap;
606
607  private:
608
609    struct EdgeRefMap {
610      EdgeRefMap(UndirGraphCopy& _gc) : gc(_gc) {}
611      typedef typename Source::Edge Key;
612      typedef typename Target::Edge Value;
613
614      Value operator[](const Key& key) {
615        return gc.target.direct(gc.undirEdgeRef[key],
616                                gc.target.direction(key));
617      }
618     
619      UndirGraphCopy& gc;
620    };
621   
622  public:
623
624    /// \brief Constructor for the UndirGraphCopy.
625    ///
626    /// It copies the content of the \c _source graph into the
627    /// \c _target graph. It creates also two references, one beetween
628    /// the two nodeset and one beetween the two edgesets.
629    UndirGraphCopy(Target& _target, const Source& _source)
630      : source(_source), target(_target),
631        nodeRefMap(_source), edgeRefMap(*this), undirEdgeRefMap(_source) {
632      for (NodeIt it(source); it != INVALID; ++it) {
633        nodeRefMap[it] = target.addNode();
634      }
635      for (UndirEdgeIt it(source); it != INVALID; ++it) {
636        undirEdgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
637                                        nodeRefMap[source.target(it)]);
638      }
639    }
640
641    /// \brief Copies the node references into the given map.
642    ///
643    /// Copies the node references into the given map.
644    template <typename NodeRef>
645    const UndirGraphCopy& nodeRef(NodeRef& map) const {
646      for (NodeIt it(source); it != INVALID; ++it) {
647        map.set(it, nodeRefMap[it]);
648      }
649      return *this;
650    }
651
652    /// \brief Reverse and copies the node references into the given map.
653    ///
654    /// Reverse and copies the node references into the given map.
655    template <typename NodeRef>
656    const UndirGraphCopy& nodeCrossRef(NodeRef& map) const {
657      for (NodeIt it(source); it != INVALID; ++it) {
658        map.set(nodeRefMap[it], it);
659      }
660      return *this;
661    }
662
663    /// \brief Copies the edge references into the given map.
664    ///
665    /// Copies the edge references into the given map.
666    template <typename EdgeRef>
667    const UndirGraphCopy& edgeRef(EdgeRef& map) const {
668      for (EdgeIt it(source); it != INVALID; ++it) {
669        map.set(edgeRefMap[it], it);
670      }
671      return *this;
672    }
673
674    /// \brief Reverse and copies the undirected edge references into the
675    /// given map.
676    ///
677    /// Reverse and copies the undirected edge references into the given map.
678    template <typename EdgeRef>
679    const UndirGraphCopy& edgeCrossRef(EdgeRef& map) const {
680      for (EdgeIt it(source); it != INVALID; ++it) {
681        map.set(it, edgeRefMap[it]);
682      }
683      return *this;
684    }
685
686    /// \brief Copies the undirected edge references into the given map.
687    ///
688    /// Copies the undirected edge references into the given map.
689    template <typename EdgeRef>
690    const UndirGraphCopy& undirEdgeRef(EdgeRef& map) const {
691      for (UndirEdgeIt it(source); it != INVALID; ++it) {
692        map.set(it, undirEdgeRefMap[it]);
693      }
694      return *this;
695    }
696
697    /// \brief Reverse and copies the undirected edge references into the
698    /// given map.
699    ///
700    /// Reverse and copies the undirected edge references into the given map.
701    template <typename EdgeRef>
702    const UndirGraphCopy& undirEdgeCrossRef(EdgeRef& map) const {
703      for (UndirEdgeIt it(source); it != INVALID; ++it) {
704        map.set(undirEdgeRefMap[it], it);
705      }
706      return *this;
707    }
708
709    /// \brief Make copy of the given map.
710    ///
711    /// Makes copy of the given map for the newly created graph.
712    /// The new map's key type is the target graph's node type,
713    /// and the copied map's key type is the source graph's node
714    /// type. 
715    template <typename TargetMap, typename SourceMap>
716    const UndirGraphCopy& nodeMap(TargetMap& tMap,
717                                  const SourceMap& sMap) const {
718      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
719      return *this;
720    }
721
722    /// \brief Make copy of the given map.
723    ///
724    /// Makes copy of the given map for the newly created graph.
725    /// The new map's key type is the target graph's edge type,
726    /// and the copied map's key type is the source graph's edge
727    /// type. 
728    template <typename TargetMap, typename SourceMap>
729    const UndirGraphCopy& edgeMap(TargetMap& tMap,
730                                  const SourceMap& sMap) const {
731      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
732      return *this;
733    }
734
735    /// \brief Make copy of the given map.
736    ///
737    /// Makes copy of the given map for the newly created graph.
738    /// The new map's key type is the target graph's edge type,
739    /// and the copied map's key type is the source graph's edge
740    /// type. 
741    template <typename TargetMap, typename SourceMap>
742    const UndirGraphCopy& undirEdgeMap(TargetMap& tMap,
743                                  const SourceMap& sMap) const {
744      copyMap(tMap, sMap, UndirEdgeIt(source), undirEdgeRefMap);
745      return *this;
746    }
747
748    /// \brief Gives back the stored node references.
749    ///
750    /// Gives back the stored node references.
751    const NodeRefMap& nodeRef() const {
752      return nodeRefMap;
753    }
754
755    /// \brief Gives back the stored edge references.
756    ///
757    /// Gives back the stored edge references.
758    const EdgeRefMap& edgeRef() const {
759      return edgeRefMap;
760    }
761
762    /// \brief Gives back the stored undir edge references.
763    ///
764    /// Gives back the stored undir edge references.
765    const UndirEdgeRefMap& undirEdgeRef() const {
766      return undirEdgeRefMap;
767    }
768
769    void run() {}
770
771  private:
772   
773    const Source& source;
774    Target& target;
775
776    NodeRefMap nodeRefMap;
777    EdgeRefMap edgeRefMap;
778    UndirEdgeRefMap undirEdgeRefMap;
779  };
780
781  /// \brief Copy a graph to an other graph.
782  ///
783  /// Copy a graph to an other graph.
784  /// The usage of the function:
785  ///
786  /// \code
787  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
788  /// \endcode
789  ///
790  /// After the copy the \c nr map will contain the mapping from the
791  /// source graph's nodes to the target graph's nodes and the \c ecr will
792  /// contain the mapping from the target graph's edges to the source's
793  /// edges.
794  template <typename Target, typename Source>
795  UndirGraphCopy<Target, Source>
796  copyUndirGraph(Target& target, const Source& source) {
797    return UndirGraphCopy<Target, Source>(target, source);
798  }
799
800
801  /// @}
802
803  /// \addtogroup graph_maps
804  /// @{
805
806  /// Provides an immutable and unique id for each item in the graph.
807
808  /// The IdMap class provides a unique and immutable id for each item of the
809  /// same type (e.g. node) in the graph. This id is <ul><li>\b unique:
810  /// different items (nodes) get different ids <li>\b immutable: the id of an
811  /// item (node) does not change (even if you delete other nodes).  </ul>
812  /// Through this map you get access (i.e. can read) the inner id values of
813  /// the items stored in the graph. This map can be inverted with its member
814  /// class \c InverseMap.
815  ///
816  template <typename _Graph, typename _Item>
817  class IdMap {
818  public:
819    typedef _Graph Graph;
820    typedef int Value;
821    typedef _Item Item;
822    typedef _Item Key;
823
824    /// \brief Constructor.
825    ///
826    /// Constructor for creating id map.
827    IdMap(const Graph& _graph) : graph(&_graph) {}
828
829    /// \brief Gives back the \e id of the item.
830    ///
831    /// Gives back the immutable and unique \e id of the map.
832    int operator[](const Item& item) const { return graph->id(item);}
833
834
835  private:
836    const Graph* graph;
837
838  public:
839
840    /// \brief The class represents the inverse of its owner (IdMap).
841    ///
842    /// The class represents the inverse of its owner (IdMap).
843    /// \see inverse()
844    class InverseMap {
845    public:
846
847      /// \brief Constructor.
848      ///
849      /// Constructor for creating an id-to-item map.
850      InverseMap(const Graph& _graph) : graph(&_graph) {}
851
852      /// \brief Constructor.
853      ///
854      /// Constructor for creating an id-to-item map.
855      InverseMap(const IdMap& idMap) : graph(idMap.graph) {}
856
857      /// \brief Gives back the given item from its id.
858      ///
859      /// Gives back the given item from its id.
860      ///
861      Item operator[](int id) const { return graph->fromId(id, Item());}
862    private:
863      const Graph* graph;
864    };
865
866    /// \brief Gives back the inverse of the map.
867    ///
868    /// Gives back the inverse of the IdMap.
869    InverseMap inverse() const { return InverseMap(*graph);}
870
871  };
872
873 
874  /// \brief General invertable graph-map type.
875
876  /// This type provides simple invertable graph-maps.
877  /// The InvertableMap wraps an arbitrary ReadWriteMap
878  /// and if a key is set to a new value then store it
879  /// in the inverse map.
880  /// \param _Graph The graph type.
881  /// \param _Map The map to extend with invertable functionality.
882  template <
883    typename _Graph,
884    typename _Item,
885    typename _Value,
886    typename _Map
887    = typename ItemSetTraits<_Graph, _Item>::template Map<_Value>::Parent
888  >
889  class InvertableMap : protected _Map {
890
891  public:
892 
893    typedef _Map Map;
894    typedef _Graph Graph;
895
896    /// The key type of InvertableMap (Node, Edge, UndirEdge).
897    typedef typename _Map::Key Key;
898    /// The value type of the InvertableMap.
899    typedef typename _Map::Value Value;
900
901    /// \brief Constructor.
902    ///
903    /// Construct a new InvertableMap for the graph.
904    ///
905    InvertableMap(const Graph& graph) : Map(graph) {}
906   
907    /// \brief The setter function of the map.
908    ///
909    /// Sets the mapped value.
910    void set(const Key& key, const Value& val) {
911      Value oldval = Map::operator[](key);
912      typename Container::iterator it = invMap.find(oldval);
913      if (it != invMap.end() && it->second == key) {
914        invMap.erase(it);
915      }     
916      invMap.insert(make_pair(val, key));
917      Map::set(key, val);
918    }
919
920    /// \brief The getter function of the map.
921    ///
922    /// It gives back the value associated with the key.
923    Value operator[](const Key& key) const {
924      return Map::operator[](key);
925    }
926
927  protected:
928
929    /// \brief Add a new key to the map.
930    ///
931    /// Add a new key to the map. It is called by the
932    /// \c AlterationNotifier.
933    virtual void add(const Key& key) {
934      Map::add(key);
935    }
936
937    /// \brief Erase the key from the map.
938    ///
939    /// Erase the key to the map. It is called by the
940    /// \c AlterationNotifier.
941    virtual void erase(const Key& key) {
942      Value val = Map::operator[](key);
943      typename Container::iterator it = invMap.find(val);
944      if (it != invMap.end() && it->second == key) {
945        invMap.erase(it);
946      }
947      Map::erase(key);
948    }
949
950    /// \brief Clear the keys from the map and inverse map.
951    ///
952    /// Clear the keys from the map and inverse map. It is called by the
953    /// \c AlterationNotifier.
954    virtual void clear() {
955      invMap.clear();
956      Map::clear();
957    }
958
959  private:
960   
961    typedef std::map<Value, Key> Container;
962    Container invMap;   
963
964  public:
965
966    /// \brief The inverse map type.
967    ///
968    /// The inverse of this map. The subscript operator of the map
969    /// gives back always the item what was last assigned to the value.
970    class InverseMap {
971    public:
972      /// \brief Constructor of the InverseMap.
973      ///
974      /// Constructor of the InverseMap.
975      InverseMap(const InvertableMap& _inverted) : inverted(_inverted) {}
976
977      /// The value type of the InverseMap.
978      typedef typename InvertableMap::Key Value;
979      /// The key type of the InverseMap.
980      typedef typename InvertableMap::Value Key;
981
982      /// \brief Subscript operator.
983      ///
984      /// Subscript operator. It gives back always the item
985      /// what was last assigned to the value.
986      Value operator[](const Key& key) const {
987        typename Container::const_iterator it = inverted.invMap.find(key);
988        return it->second;
989      }
990     
991    private:
992      const InvertableMap& inverted;
993    };
994
995    /// \brief It gives back the just readeable inverse map.
996    ///
997    /// It gives back the just readeable inverse map.
998    InverseMap inverse() const {
999      return InverseMap(*this);
1000    }
1001
1002
1003   
1004  };
1005
1006  /// \brief Provides a mutable, continuous and unique descriptor for each
1007  /// item in the graph.
1008  ///
1009  /// The DescriptorMap class provides a unique and continuous (but mutable)
1010  /// descriptor (id) for each item of the same type (e.g. node) in the
1011  /// graph. This id is <ul><li>\b unique: different items (nodes) get
1012  /// different ids <li>\b continuous: the range of the ids is the set of
1013  /// integers between 0 and \c n-1, where \c n is the number of the items of
1014  /// this type (e.g. nodes) (so the id of a node can change if you delete an
1015  /// other node, i.e. this id is mutable).  </ul> This map can be inverted
1016  /// with its member class \c InverseMap.
1017  ///
1018  /// \param _Graph The graph class the \c DescriptorMap belongs to.
1019  /// \param _Item The Item is the Key of the Map. It may be Node, Edge or
1020  /// UndirEdge.
1021  /// \param _Map A ReadWriteMap mapping from the item type to integer.
1022  template <
1023    typename _Graph,   
1024    typename _Item,
1025    typename _Map
1026    = typename ItemSetTraits<_Graph, _Item>::template Map<int>::Parent
1027  >
1028  class DescriptorMap : protected _Map {
1029
1030    typedef _Item Item;
1031    typedef _Map Map;
1032
1033  public:
1034    /// The graph class of DescriptorMap.
1035    typedef _Graph Graph;
1036
1037    /// The key type of DescriptorMap (Node, Edge, UndirEdge).
1038    typedef typename _Map::Key Key;
1039    /// The value type of DescriptorMap.
1040    typedef typename _Map::Value Value;
1041
1042    /// \brief Constructor.
1043    ///
1044    /// Constructor for descriptor map.
1045    DescriptorMap(const Graph& _graph) : Map(_graph) {
1046      build();
1047    }
1048
1049  protected:
1050
1051    /// \brief Add a new key to the map.
1052    ///
1053    /// Add a new key to the map. It is called by the
1054    /// \c AlterationNotifier.
1055    virtual void add(const Item& item) {
1056      Map::add(item);
1057      Map::set(item, invMap.size());
1058      invMap.push_back(item);
1059    }
1060
1061    /// \brief Erase the key from the map.
1062    ///
1063    /// Erase the key to the map. It is called by the
1064    /// \c AlterationNotifier.
1065    virtual void erase(const Item& item) {
1066      Map::set(invMap.back(), Map::operator[](item));
1067      invMap[Map::operator[](item)] = invMap.back();
1068      invMap.pop_back();
1069      Map::erase(item);
1070    }
1071
1072    /// \brief Build the unique map.
1073    ///
1074    /// Build the unique map. It is called by the
1075    /// \c AlterationNotifier.
1076    virtual void build() {
1077      Map::build();
1078      Item it;
1079      const typename Map::Graph* graph = Map::getGraph();
1080      for (graph->first(it); it != INVALID; graph->next(it)) {
1081        Map::set(it, invMap.size());
1082        invMap.push_back(it);   
1083      }     
1084    }
1085   
1086    /// \brief Clear the keys from the map.
1087    ///
1088    /// Clear the keys from the map. It is called by the
1089    /// \c AlterationNotifier.
1090    virtual void clear() {
1091      invMap.clear();
1092      Map::clear();
1093    }
1094
1095  public:
1096
1097    /// \brief Swaps the position of the two items in the map.
1098    ///
1099    /// Swaps the position of the two items in the map.
1100    void swap(const Item& p, const Item& q) {
1101      int pi = Map::operator[](p);
1102      int qi = Map::operator[](q);
1103      Map::set(p, qi);
1104      invMap[qi] = p;
1105      Map::set(q, pi);
1106      invMap[pi] = q;
1107    }
1108
1109    /// \brief Gives back the \e descriptor of the item.
1110    ///
1111    /// Gives back the mutable and unique \e descriptor of the map.
1112    int operator[](const Item& item) const {
1113      return Map::operator[](item);
1114    }
1115   
1116  private:
1117
1118    typedef std::vector<Item> Container;
1119    Container invMap;
1120
1121  public:
1122    /// \brief The inverse map type of DescriptorMap.
1123    ///
1124    /// The inverse map type of DescriptorMap.
1125    class InverseMap {
1126    public:
1127      /// \brief Constructor of the InverseMap.
1128      ///
1129      /// Constructor of the InverseMap.
1130      InverseMap(const DescriptorMap& _inverted)
1131        : inverted(_inverted) {}
1132
1133
1134      /// The value type of the InverseMap.
1135      typedef typename DescriptorMap::Key Value;
1136      /// The key type of the InverseMap.
1137      typedef typename DescriptorMap::Value Key;
1138
1139      /// \brief Subscript operator.
1140      ///
1141      /// Subscript operator. It gives back the item
1142      /// that the descriptor belongs to currently.
1143      Value operator[](const Key& key) const {
1144        return inverted.invMap[key];
1145      }
1146
1147      /// \brief Size of the map.
1148      ///
1149      /// Returns the size of the map.
1150      int size() const {
1151        return inverted.invMap.size();
1152      }
1153     
1154    private:
1155      const DescriptorMap& inverted;
1156    };
1157
1158    /// \brief Gives back the inverse of the map.
1159    ///
1160    /// Gives back the inverse of the map.
1161    const InverseMap inverse() const {
1162      return InverseMap(*this);
1163    }
1164  };
1165
1166  /// \brief Returns the source of the given edge.
1167  ///
1168  /// The SourceMap gives back the source Node of the given edge.
1169  /// \author Balazs Dezso
1170  template <typename Graph>
1171  class SourceMap {
1172  public:
1173
1174    typedef typename Graph::Node Value;
1175    typedef typename Graph::Edge Key;
1176
1177    /// \brief Constructor
1178    ///
1179    /// Constructor
1180    /// \param _graph The graph that the map belongs to.
1181    SourceMap(const Graph& _graph) : graph(_graph) {}
1182
1183    /// \brief The subscript operator.
1184    ///
1185    /// The subscript operator.
1186    /// \param edge The edge
1187    /// \return The source of the edge
1188    Value operator[](const Key& edge) const {
1189      return graph.source(edge);
1190    }
1191
1192  private:
1193    const Graph& graph;
1194  };
1195
1196  /// \brief Returns a \ref SourceMap class
1197  ///
1198  /// This function just returns an \ref SourceMap class.
1199  /// \relates SourceMap
1200  template <typename Graph>
1201  inline SourceMap<Graph> sourceMap(const Graph& graph) {
1202    return SourceMap<Graph>(graph);
1203  }
1204
1205  /// \brief Returns the target of the given edge.
1206  ///
1207  /// The TargetMap gives back the target Node of the given edge.
1208  /// \author Balazs Dezso
1209  template <typename Graph>
1210  class TargetMap {
1211  public:
1212
1213    typedef typename Graph::Node Value;
1214    typedef typename Graph::Edge Key;
1215
1216    /// \brief Constructor
1217    ///
1218    /// Constructor
1219    /// \param _graph The graph that the map belongs to.
1220    TargetMap(const Graph& _graph) : graph(_graph) {}
1221
1222    /// \brief The subscript operator.
1223    ///
1224    /// The subscript operator.
1225    /// \param e The edge
1226    /// \return The target of the edge
1227    Value operator[](const Key& e) const {
1228      return graph.target(e);
1229    }
1230
1231  private:
1232    const Graph& graph;
1233  };
1234
1235  /// \brief Returns a \ref TargetMap class
1236  ///
1237  /// This function just returns a \ref TargetMap class.
1238  /// \relates TargetMap
1239  template <typename Graph>
1240  inline TargetMap<Graph> targetMap(const Graph& graph) {
1241    return TargetMap<Graph>(graph);
1242  }
1243
1244  /// \brief Returns the "forward" directed edge view of an undirected edge.
1245  ///
1246  /// Returns the "forward" directed edge view of an undirected edge.
1247  /// \author Balazs Dezso
1248  template <typename Graph>
1249  class ForwardMap {
1250  public:
1251
1252    typedef typename Graph::Edge Value;
1253    typedef typename Graph::UndirEdge Key;
1254
1255    /// \brief Constructor
1256    ///
1257    /// Constructor
1258    /// \param _graph The graph that the map belongs to.
1259    ForwardMap(const Graph& _graph) : graph(_graph) {}
1260
1261    /// \brief The subscript operator.
1262    ///
1263    /// The subscript operator.
1264    /// \param key An undirected edge
1265    /// \return The "forward" directed edge view of undirected edge
1266    Value operator[](const Key& key) const {
1267      return graph.direct(key, true);
1268    }
1269
1270  private:
1271    const Graph& graph;
1272  };
1273
1274  /// \brief Returns a \ref ForwardMap class
1275  ///
1276  /// This function just returns an \ref ForwardMap class.
1277  /// \relates ForwardMap
1278  template <typename Graph>
1279  inline ForwardMap<Graph> forwardMap(const Graph& graph) {
1280    return ForwardMap<Graph>(graph);
1281  }
1282
1283  /// \brief Returns the "backward" directed edge view of an undirected edge.
1284  ///
1285  /// Returns the "backward" directed edge view of an undirected edge.
1286  /// \author Balazs Dezso
1287  template <typename Graph>
1288  class BackwardMap {
1289  public:
1290
1291    typedef typename Graph::Edge Value;
1292    typedef typename Graph::UndirEdge Key;
1293
1294    /// \brief Constructor
1295    ///
1296    /// Constructor
1297    /// \param _graph The graph that the map belongs to.
1298    BackwardMap(const Graph& _graph) : graph(_graph) {}
1299
1300    /// \brief The subscript operator.
1301    ///
1302    /// The subscript operator.
1303    /// \param key An undirected edge
1304    /// \return The "backward" directed edge view of undirected edge
1305    Value operator[](const Key& key) const {
1306      return graph.direct(key, false);
1307    }
1308
1309  private:
1310    const Graph& graph;
1311  };
1312
1313  /// \brief Returns a \ref BackwardMap class
1314
1315  /// This function just returns a \ref BackwardMap class.
1316  /// \relates BackwardMap
1317  template <typename Graph>
1318  inline BackwardMap<Graph> backwardMap(const Graph& graph) {
1319    return BackwardMap<Graph>(graph);
1320  }
1321
1322  /// \brief Potential difference map
1323  ///
1324  /// If there is an potential map on the nodes then we
1325  /// can get an edge map as we get the substraction of the
1326  /// values of the target and source.
1327  template <typename Graph, typename NodeMap>
1328  class PotentialDifferenceMap {
1329  public:
1330    typedef typename Graph::Edge Key;
1331    typedef typename NodeMap::Value Value;
1332
1333    /// \brief Constructor
1334    ///
1335    /// Contructor of the map
1336    PotentialDifferenceMap(const Graph& _graph, const NodeMap& _potential)
1337      : graph(_graph), potential(_potential) {}
1338
1339    /// \brief Const subscription operator
1340    ///
1341    /// Const subscription operator
1342    Value operator[](const Key& edge) const {
1343      return potential[graph.target(edge)] - potential[graph.source(edge)];
1344    }
1345
1346  private:
1347    const Graph& graph;
1348    const NodeMap& potential;
1349  };
1350
1351  /// \brief Just returns a PotentialDifferenceMap
1352  ///
1353  /// Just returns a PotentialDifferenceMap
1354  /// \relates PotentialDifferenceMap
1355  template <typename Graph, typename NodeMap>
1356  PotentialDifferenceMap<Graph, NodeMap>
1357  potentialDifferenceMap(const Graph& graph, const NodeMap& potential) {
1358    return PotentialDifferenceMap<Graph, NodeMap>(graph, potential);
1359  }
1360
1361  /// \brief Map of the node in-degrees.
1362  ///
1363  /// This map returns the in-degree of a node. Once it is constructed,
1364  /// the degrees are stored in a standard NodeMap, so each query is done
1365  /// in constant time. On the other hand, the values are updated automatically
1366  /// whenever the graph changes.
1367  ///
1368  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1369  /// alternative ways to modify the graph. The correct behavior of InDegMap
1370  /// is not guarantied if these additional featureas are used. For example
1371  /// the funstions \ref ListGraph::changeSource() "changeSource()",
1372  /// \ref ListGraph::changeTarget() "changeTarget()" and
1373  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1374  /// of \ref ListGraph will \e not update the degree values correctly.
1375  ///
1376  /// \sa OutDegMap
1377
1378  template <typename _Graph>
1379  class InDegMap 
1380    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1381
1382  public:
1383   
1384    typedef _Graph Graph;
1385    typedef int Value;
1386    typedef typename Graph::Node Key;
1387
1388  private:
1389
1390    class AutoNodeMap : public Graph::template NodeMap<int> {
1391    public:
1392
1393      typedef typename Graph::template NodeMap<int> Parent;
1394
1395      typedef typename Parent::Key Key;
1396      typedef typename Parent::Value Value;
1397     
1398      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1399     
1400      void add(const Key& key) {
1401        Parent::add(key);
1402        Parent::set(key, 0);
1403      }
1404    };
1405
1406  public:
1407
1408    /// \brief Constructor.
1409    ///
1410    /// Constructor for creating in-degree map.
1411    InDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1412      AlterationNotifier<typename _Graph::Edge>
1413        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1414     
1415      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1416        deg[it] = countInEdges(graph, it);
1417      }
1418    }
1419
1420    virtual ~InDegMap() {
1421      AlterationNotifier<typename _Graph::Edge>::
1422        ObserverBase::detach();
1423    }
1424   
1425    /// Gives back the in-degree of a Node.
1426    int operator[](const Key& key) const {
1427      return deg[key];
1428    }
1429
1430  protected:
1431   
1432    typedef typename Graph::Edge Edge;
1433
1434    virtual void add(const Edge& edge) {
1435      ++deg[graph.target(edge)];
1436    }
1437
1438    virtual void erase(const Edge& edge) {
1439      --deg[graph.target(edge)];
1440    }
1441
1442    virtual void signalChange(const Edge& edge) {
1443      erase(edge);
1444    }
1445
1446    virtual void commitChange(const Edge& edge) {
1447      add(edge);
1448    }
1449
1450    virtual void build() {
1451      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1452        deg[it] = countInEdges(graph, it);
1453      }     
1454    }
1455
1456    virtual void clear() {
1457      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1458        deg[it] = 0;
1459      }
1460    }
1461  private:
1462   
1463    const _Graph& graph;
1464    AutoNodeMap deg;
1465  };
1466
1467  /// \brief Map of the node out-degrees.
1468  ///
1469  /// This map returns the out-degree of a node. Once it is constructed,
1470  /// the degrees are stored in a standard NodeMap, so each query is done
1471  /// in constant time. On the other hand, the values are updated automatically
1472  /// whenever the graph changes.
1473  ///
1474  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1475  /// alternative ways to modify the graph. The correct behavior of OutDegMap
1476  /// is not guarantied if these additional featureas are used. For example
1477  /// the funstions \ref ListGraph::changeSource() "changeSource()",
1478  /// \ref ListGraph::changeTarget() "changeTarget()" and
1479  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1480  /// of \ref ListGraph will \e not update the degree values correctly.
1481  ///
1482  /// \sa InDegMap
1483
1484  template <typename _Graph>
1485  class OutDegMap 
1486    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1487
1488  public:
1489   
1490    typedef _Graph Graph;
1491    typedef int Value;
1492    typedef typename Graph::Node Key;
1493
1494  private:
1495
1496    class AutoNodeMap : public Graph::template NodeMap<int> {
1497    public:
1498
1499      typedef typename Graph::template NodeMap<int> Parent;
1500
1501      typedef typename Parent::Key Key;
1502      typedef typename Parent::Value Value;
1503     
1504      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1505     
1506      void add(const Key& key) {
1507        Parent::add(key);
1508        Parent::set(key, 0);
1509      }
1510    };
1511
1512  public:
1513
1514    /// \brief Constructor.
1515    ///
1516    /// Constructor for creating out-degree map.
1517    OutDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1518      AlterationNotifier<typename _Graph::Edge>
1519        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1520     
1521      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1522        deg[it] = countOutEdges(graph, it);
1523      }
1524    }
1525
1526    virtual ~OutDegMap() {
1527      AlterationNotifier<typename _Graph::Edge>::
1528        ObserverBase::detach();
1529    }
1530   
1531    /// Gives back the in-degree of a Node.
1532    int operator[](const Key& key) const {
1533      return deg[key];
1534    }
1535
1536  protected:
1537   
1538    typedef typename Graph::Edge Edge;
1539
1540    virtual void add(const Edge& edge) {
1541      ++deg[graph.source(edge)];
1542    }
1543
1544    virtual void erase(const Edge& edge) {
1545      --deg[graph.source(edge)];
1546    }
1547
1548    virtual void signalChange(const Edge& edge) {
1549      erase(edge);
1550    }
1551
1552    virtual void commitChange(const Edge& edge) {
1553      add(edge);
1554    }
1555
1556
1557    virtual void build() {
1558      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1559        deg[it] = countOutEdges(graph, it);
1560      }     
1561    }
1562
1563    virtual void clear() {
1564      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1565        deg[it] = 0;
1566      }
1567    }
1568  private:
1569   
1570    const _Graph& graph;
1571    AutoNodeMap deg;
1572  };
1573
1574
1575  /// @}
1576
1577} //END OF NAMESPACE LEMON
1578
1579#endif
Note: See TracBrowser for help on using the repository browser.