COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/dfs.h @ 1663:f6741cfab647

Last change on this file since 1663:f6741cfab647 was 1663:f6741cfab647, checked in by Alpar Juttner, 14 years ago

Serious bugfix.

File size: 35.3 KB
Line 
1/* -*- C++ -*-
2 * lemon/dfs.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_DFS_H
18#define LEMON_DFS_H
19
20///\ingroup flowalgs
21///\file
22///\brief Dfs algorithm.
23
24#include <lemon/list_graph.h>
25#include <lemon/graph_utils.h>
26#include <lemon/invalid.h>
27#include <lemon/error.h>
28#include <lemon/maps.h>
29
30namespace lemon {
31
32
33 
34  ///Default traits class of Dfs class.
35
36  ///Default traits class of Dfs class.
37  ///\param GR Graph type.
38  template<class GR>
39  struct DfsDefaultTraits
40  {
41    ///The graph type the algorithm runs on.
42    typedef GR Graph;
43    ///\brief The type of the map that stores the last
44    ///edges of the %DFS paths.
45    ///
46    ///The type of the map that stores the last
47    ///edges of the %DFS paths.
48    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
49    ///
50    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
51    ///Instantiates a PredMap.
52 
53    ///This function instantiates a \ref PredMap.
54    ///\param G is the graph, to which we would like to define the PredMap.
55    ///\todo The graph alone may be insufficient to initialize
56    static PredMap *createPredMap(const GR &G)
57    {
58      return new PredMap(G);
59    }
60//     ///\brief The type of the map that stores the last but one
61//     ///nodes of the %DFS paths.
62//     ///
63//     ///The type of the map that stores the last but one
64//     ///nodes of the %DFS paths.
65//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
66//     ///
67//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
68//     ///Instantiates a PredNodeMap.
69   
70//     ///This function instantiates a \ref PredNodeMap.
71//     ///\param G is the graph, to which
72//     ///we would like to define the \ref PredNodeMap
73//     static PredNodeMap *createPredNodeMap(const GR &G)
74//     {
75//       return new PredNodeMap();
76//     }
77
78    ///The type of the map that indicates which nodes are processed.
79 
80    ///The type of the map that indicates which nodes are processed.
81    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
82    ///\todo named parameter to set this type, function to read and write.
83    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
84    ///Instantiates a ProcessedMap.
85 
86    ///This function instantiates a \ref ProcessedMap.
87    ///\param g is the graph, to which
88    ///we would like to define the \ref ProcessedMap
89#ifdef DOXYGEN
90    static ProcessedMap *createProcessedMap(const GR &g)
91#else
92    static ProcessedMap *createProcessedMap(const GR &)
93#endif
94    {
95      return new ProcessedMap();
96    }
97    ///The type of the map that indicates which nodes are reached.
98 
99    ///The type of the map that indicates which nodes are reached.
100    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
101    ///\todo named parameter to set this type, function to read and write.
102    typedef typename Graph::template NodeMap<bool> ReachedMap;
103    ///Instantiates a ReachedMap.
104 
105    ///This function instantiates a \ref ReachedMap.
106    ///\param G is the graph, to which
107    ///we would like to define the \ref ReachedMap.
108    static ReachedMap *createReachedMap(const GR &G)
109    {
110      return new ReachedMap(G);
111    }
112    ///The type of the map that stores the dists of the nodes.
113 
114    ///The type of the map that stores the dists of the nodes.
115    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
116    ///
117    typedef typename Graph::template NodeMap<int> DistMap;
118    ///Instantiates a DistMap.
119 
120    ///This function instantiates a \ref DistMap.
121    ///\param G is the graph, to which we would like to define the \ref DistMap
122    static DistMap *createDistMap(const GR &G)
123    {
124      return new DistMap(G);
125    }
126  };
127 
128  ///%DFS algorithm class.
129 
130  ///\ingroup flowalgs
131  ///This class provides an efficient implementation of the %DFS algorithm.
132  ///
133  ///\param GR The graph type the algorithm runs on. The default value is
134  ///\ref ListGraph. The value of GR is not used directly by Dfs, it
135  ///is only passed to \ref DfsDefaultTraits.
136  ///\param TR Traits class to set various data types used by the algorithm.
137  ///The default traits class is
138  ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>".
139  ///See \ref DfsDefaultTraits for the documentation of
140  ///a Dfs traits class.
141  ///
142  ///\author Jacint Szabo and Alpar Juttner
143  ///\todo A compare object would be nice.
144
145#ifdef DOXYGEN
146  template <typename GR,
147            typename TR>
148#else
149  template <typename GR=ListGraph,
150            typename TR=DfsDefaultTraits<GR> >
151#endif
152  class Dfs {
153  public:
154    /**
155     * \brief \ref Exception for uninitialized parameters.
156     *
157     * This error represents problems in the initialization
158     * of the parameters of the algorithms.
159     */
160    class UninitializedParameter : public lemon::UninitializedParameter {
161    public:
162      virtual const char* exceptionName() const {
163        return "lemon::Dfs::UninitializedParameter";
164      }
165    };
166
167    typedef TR Traits;
168    ///The type of the underlying graph.
169    typedef typename TR::Graph Graph;
170    ///\e
171    typedef typename Graph::Node Node;
172    ///\e
173    typedef typename Graph::NodeIt NodeIt;
174    ///\e
175    typedef typename Graph::Edge Edge;
176    ///\e
177    typedef typename Graph::OutEdgeIt OutEdgeIt;
178   
179    ///\brief The type of the map that stores the last
180    ///edges of the %DFS paths.
181    typedef typename TR::PredMap PredMap;
182//     ///\brief The type of the map that stores the last but one
183//     ///nodes of the %DFS paths.
184//     typedef typename TR::PredNodeMap PredNodeMap;
185    ///The type of the map indicating which nodes are reached.
186    typedef typename TR::ReachedMap ReachedMap;
187    ///The type of the map indicating which nodes are processed.
188    typedef typename TR::ProcessedMap ProcessedMap;
189    ///The type of the map that stores the dists of the nodes.
190    typedef typename TR::DistMap DistMap;
191  private:
192    /// Pointer to the underlying graph.
193    const Graph *G;
194    ///Pointer to the map of predecessors edges.
195    PredMap *_pred;
196    ///Indicates if \ref _pred is locally allocated (\c true) or not.
197    bool local_pred;
198//     ///Pointer to the map of predecessors nodes.
199//     PredNodeMap *_predNode;
200//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
201//     bool local_predNode;
202    ///Pointer to the map of distances.
203    DistMap *_dist;
204    ///Indicates if \ref _dist is locally allocated (\c true) or not.
205    bool local_dist;
206    ///Pointer to the map of reached status of the nodes.
207    ReachedMap *_reached;
208    ///Indicates if \ref _reached is locally allocated (\c true) or not.
209    bool local_reached;
210    ///Pointer to the map of processed status of the nodes.
211    ProcessedMap *_processed;
212    ///Indicates if \ref _processed is locally allocated (\c true) or not.
213    bool local_processed;
214
215    std::vector<typename Graph::OutEdgeIt> _stack;
216    int _stack_head;
217//     ///The source node of the last execution.
218//     Node source;
219
220    ///Creates the maps if necessary.
221   
222    ///\todo Error if \c G are \c NULL.
223    ///\todo Better memory allocation (instead of new).
224    void create_maps()
225    {
226      if(!_pred) {
227        local_pred = true;
228        _pred = Traits::createPredMap(*G);
229      }
230//       if(!_predNode) {
231//      local_predNode = true;
232//      _predNode = Traits::createPredNodeMap(*G);
233//       }
234      if(!_dist) {
235        local_dist = true;
236        _dist = Traits::createDistMap(*G);
237      }
238      if(!_reached) {
239        local_reached = true;
240        _reached = Traits::createReachedMap(*G);
241      }
242      if(!_processed) {
243        local_processed = true;
244        _processed = Traits::createProcessedMap(*G);
245      }
246    }
247   
248  public :
249 
250    ///\name Named template parameters
251
252    ///@{
253
254    template <class T>
255    struct DefPredMapTraits : public Traits {
256      typedef T PredMap;
257      static PredMap *createPredMap(const Graph &G)
258      {
259        throw UninitializedParameter();
260      }
261    };
262    ///\ref named-templ-param "Named parameter" for setting PredMap type
263
264    ///\ref named-templ-param "Named parameter" for setting PredMap type
265    ///
266    template <class T>
267    class DefPredMap : public Dfs< Graph,
268                                        DefPredMapTraits<T> > { };
269   
270//     template <class T>
271//     struct DefPredNodeMapTraits : public Traits {
272//       typedef T PredNodeMap;
273//       static PredNodeMap *createPredNodeMap(const Graph &G)
274//       {
275//      throw UninitializedParameter();
276//       }
277//     };
278//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
279
280//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
281//     ///
282//     template <class T>
283//     class DefPredNodeMap : public Dfs< Graph,
284//                                          LengthMap,
285//                                          DefPredNodeMapTraits<T> > { };
286   
287    template <class T>
288    struct DefDistMapTraits : public Traits {
289      typedef T DistMap;
290      static DistMap *createDistMap(const Graph &G)
291      {
292        throw UninitializedParameter();
293      }
294    };
295    ///\ref named-templ-param "Named parameter" for setting DistMap type
296
297    ///\ref named-templ-param "Named parameter" for setting DistMap type
298    ///
299    template <class T>
300    class DefDistMap : public Dfs< Graph,
301                                   DefDistMapTraits<T> > { };
302   
303    template <class T>
304    struct DefReachedMapTraits : public Traits {
305      typedef T ReachedMap;
306      static ReachedMap *createReachedMap(const Graph &G)
307      {
308        throw UninitializedParameter();
309      }
310    };
311    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
312
313    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
314    ///
315    template <class T>
316    class DefReachedMap : public Dfs< Graph,
317                                      DefReachedMapTraits<T> > { };
318   
319    struct DefGraphReachedMapTraits : public Traits {
320      typedef typename Graph::template NodeMap<bool> ReachedMap;
321      static ReachedMap *createReachedMap(const Graph &G)
322      {
323        return new ReachedMap(G);
324      }
325    };
326    template <class T>
327    struct DefProcessedMapTraits : public Traits {
328      typedef T ProcessedMap;
329      static ProcessedMap *createProcessedMap(const Graph &G)
330      {
331        throw UninitializedParameter();
332      }
333    };
334    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
335
336    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
337    ///
338    template <class T>
339    class DefProcessedMap : public Dfs< Graph,
340                                        DefProcessedMapTraits<T> > { };
341   
342    struct DefGraphProcessedMapTraits : public Traits {
343      typedef typename Graph::template NodeMap<bool> ProcessedMap;
344      static ProcessedMap *createProcessedMap(const Graph &G)
345      {
346        return new ProcessedMap(G);
347      }
348    };
349    ///\brief \ref named-templ-param "Named parameter"
350    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
351    ///
352    ///\ref named-templ-param "Named parameter"
353    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
354    ///If you don't set it explicitely, it will be automatically allocated.
355    template <class T>
356    class DefProcessedMapToBeDefaultMap :
357      public Dfs< Graph,
358                  DefGraphProcessedMapTraits> { };
359   
360    ///@}
361
362  public:     
363   
364    ///Constructor.
365   
366    ///\param _G the graph the algorithm will run on.
367    ///
368    Dfs(const Graph& _G) :
369      G(&_G),
370      _pred(NULL), local_pred(false),
371//       _predNode(NULL), local_predNode(false),
372      _dist(NULL), local_dist(false),
373      _reached(NULL), local_reached(false),
374      _processed(NULL), local_processed(false)
375    { }
376   
377    ///Destructor.
378    ~Dfs()
379    {
380      if(local_pred) delete _pred;
381//       if(local_predNode) delete _predNode;
382      if(local_dist) delete _dist;
383      if(local_reached) delete _reached;
384      if(local_processed) delete _processed;
385    }
386
387    ///Sets the map storing the predecessor edges.
388
389    ///Sets the map storing the predecessor edges.
390    ///If you don't use this function before calling \ref run(),
391    ///it will allocate one. The destuctor deallocates this
392    ///automatically allocated map, of course.
393    ///\return <tt> (*this) </tt>
394    Dfs &predMap(PredMap &m)
395    {
396      if(local_pred) {
397        delete _pred;
398        local_pred=false;
399      }
400      _pred = &m;
401      return *this;
402    }
403
404//     ///Sets the map storing the predecessor nodes.
405
406//     ///Sets the map storing the predecessor nodes.
407//     ///If you don't use this function before calling \ref run(),
408//     ///it will allocate one. The destuctor deallocates this
409//     ///automatically allocated map, of course.
410//     ///\return <tt> (*this) </tt>
411//     Dfs &predNodeMap(PredNodeMap &m)
412//     {
413//       if(local_predNode) {
414//      delete _predNode;
415//      local_predNode=false;
416//       }
417//       _predNode = &m;
418//       return *this;
419//     }
420
421    ///Sets the map storing the distances calculated by the algorithm.
422
423    ///Sets the map storing the distances calculated by the algorithm.
424    ///If you don't use this function before calling \ref run(),
425    ///it will allocate one. The destuctor deallocates this
426    ///automatically allocated map, of course.
427    ///\return <tt> (*this) </tt>
428    Dfs &distMap(DistMap &m)
429    {
430      if(local_dist) {
431        delete _dist;
432        local_dist=false;
433      }
434      _dist = &m;
435      return *this;
436    }
437
438    ///Sets the map indicating if a node is reached.
439
440    ///Sets the map indicating if a node is reached.
441    ///If you don't use this function before calling \ref run(),
442    ///it will allocate one. The destuctor deallocates this
443    ///automatically allocated map, of course.
444    ///\return <tt> (*this) </tt>
445    Dfs &reachedMap(ReachedMap &m)
446    {
447      if(local_reached) {
448        delete _reached;
449        local_reached=false;
450      }
451      _reached = &m;
452      return *this;
453    }
454
455    ///Sets the map indicating if a node is processed.
456
457    ///Sets the map indicating if a node is processed.
458    ///If you don't use this function before calling \ref run(),
459    ///it will allocate one. The destuctor deallocates this
460    ///automatically allocated map, of course.
461    ///\return <tt> (*this) </tt>
462    Dfs &processedMap(ProcessedMap &m)
463    {
464      if(local_processed) {
465        delete _processed;
466        local_processed=false;
467      }
468      _processed = &m;
469      return *this;
470    }
471
472  public:
473    ///\name Execution control
474    ///The simplest way to execute the algorithm is to use
475    ///one of the member functions called \c run(...).
476    ///\n
477    ///If you need more control on the execution,
478    ///first you must call \ref init(), then you can add several source nodes
479    ///with \ref addSource().
480    ///Finally \ref start() will perform the actual path
481    ///computation.
482
483    ///@{
484
485    ///Initializes the internal data structures.
486
487    ///Initializes the internal data structures.
488    ///
489    void init()
490    {
491      create_maps();
492      _stack.resize(countNodes(*G));
493      _stack_head=-1;
494      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
495        _pred->set(u,INVALID);
496        // _predNode->set(u,INVALID);
497        _reached->set(u,false);
498        _processed->set(u,false);
499      }
500    }
501   
502    ///Adds a new source node.
503
504    ///Adds a new source node to the set of nodes to be processed.
505    ///
506    ///\bug dists are wrong (or at least strange) in case of multiple sources.
507    void addSource(Node s)
508    {
509      if(!(*_reached)[s])
510        {
511          _reached->set(s,true);
512          _pred->set(s,INVALID);
513          // _predNode->set(u,INVALID);
514          _stack[++_stack_head]=OutEdgeIt(*G,s);
515          _dist->set(s,_stack_head);
516        }
517    }
518   
519    ///Processes the next edge.
520
521    ///Processes the next edge.
522    ///
523    ///\return The processed edge.
524    ///
525    ///\pre The stack must not be empty!
526    Edge processNextEdge()
527    {
528      Node m;
529      Edge e=_stack[_stack_head];
530      if(!(*_reached)[m=G->target(e)]) {
531        _pred->set(m,e);
532        _reached->set(m,true);
533        //        _pred_node->set(m,G->source(e));
534        ++_stack_head;
535        _stack[_stack_head] = OutEdgeIt(*G, m);
536        _dist->set(m,_stack_head);
537      }
538      else {
539        m=G->source(e);
540        ++_stack[_stack_head];
541      }
542      //'m' is now the (original) source of the _stack[_stack_head]
543      while(_stack_head>=0 && _stack[_stack_head]==INVALID) {
544        _processed->set(m,true);
545        --_stack_head;
546        if(_stack_head>=0) {
547          m=G->source(_stack[_stack_head]);
548          ++_stack[_stack_head];
549        }
550      }
551      return e;
552    }
553     
554    ///\brief Returns \c false if there are nodes
555    ///to be processed in the queue
556    ///
557    ///Returns \c false if there are nodes
558    ///to be processed in the queue
559    bool emptyQueue() { return _stack_head<0; }
560    ///Returns the number of the nodes to be processed.
561   
562    ///Returns the number of the nodes to be processed in the queue.
563    ///
564    int queueSize() { return _stack_head+1; }
565   
566    ///Executes the algorithm.
567
568    ///Executes the algorithm.
569    ///
570    ///\pre init() must be called and at least one node should be added
571    ///with addSource() before using this function.
572    ///
573    ///This method runs the %DFS algorithm from the root node(s)
574    ///in order to
575    ///compute the
576    ///%DFS path to each node. The algorithm computes
577    ///- The %DFS tree.
578    ///- The distance of each node from the root(s) in the %DFS tree.
579    ///
580    void start()
581    {
582      while ( !emptyQueue() ) processNextEdge();
583    }
584   
585    ///Executes the algorithm until \c dest is reached.
586
587    ///Executes the algorithm until \c dest is reached.
588    ///
589    ///\pre init() must be called and at least one node should be added
590    ///with addSource() before using this function.
591    ///
592    ///This method runs the %DFS algorithm from the root node(s)
593    ///in order to
594    ///compute the
595    ///%DFS path to \c dest. The algorithm computes
596    ///- The %DFS path to \c  dest.
597    ///- The distance of \c dest from the root(s) in the %DFS tree.
598    ///
599    void start(Node dest)
600    {
601      while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest )
602        processNextEdge();
603    }
604   
605    ///Executes the algorithm until a condition is met.
606
607    ///Executes the algorithm until a condition is met.
608    ///
609    ///\pre init() must be called and at least one node should be added
610    ///with addSource() before using this function.
611    ///
612    ///\param nm must be a bool (or convertible) edge map. The algorithm
613    ///will stop when it reaches an edge \c e with <tt>nm[e]==true</tt>.
614    ///
615    ///\warning Contrary to \ref Dfs and \ref Dijkstra, \c nm is an edge map,
616    ///not a node map.
617    template<class NM>
618      void start(const NM &nm)
619      {
620        while ( !emptyQueue() && !nm[_stack[_stack_head]] ) processNextEdge();
621      }
622   
623    ///Runs %DFS algorithm from node \c s.
624   
625    ///This method runs the %DFS algorithm from a root node \c s
626    ///in order to
627    ///compute the
628    ///%DFS path to each node. The algorithm computes
629    ///- The %DFS tree.
630    ///- The distance of each node from the root in the %DFS tree.
631    ///
632    ///\note d.run(s) is just a shortcut of the following code.
633    ///\code
634    ///  d.init();
635    ///  d.addSource(s);
636    ///  d.start();
637    ///\endcode
638    void run(Node s) {
639      init();
640      addSource(s);
641      start();
642    }
643   
644    ///Finds the %DFS path between \c s and \c t.
645   
646    ///Finds the %DFS path between \c s and \c t.
647    ///
648    ///\return The length of the %DFS s---t path if there exists one,
649    ///0 otherwise.
650    ///\note Apart from the return value, d.run(s,t) is
651    ///just a shortcut of the following code.
652    ///\code
653    ///  d.init();
654    ///  d.addSource(s);
655    ///  d.start(t);
656    ///\endcode
657    int run(Node s,Node t) {
658      init();
659      addSource(s);
660      start(t);
661      return reached(t)?_stack_head+1:0;
662    }
663   
664    ///@}
665
666    ///\name Query Functions
667    ///The result of the %DFS algorithm can be obtained using these
668    ///functions.\n
669    ///Before the use of these functions,
670    ///either run() or start() must be called.
671   
672    ///@{
673
674    ///Copies the path to \c t on the DFS tree into \c p
675   
676    ///This function copies the path to \c t on the DFS tree  into \c p.
677    ///If \c t is a source itself or unreachable, then it does not
678    ///alter \c p.
679    ///\todo Is this the right way to handle unreachable nodes?
680    ///
681    ///\return Returns \c true if a path to \c t was actually copied to \c p,
682    ///\c false otherwise.
683    ///\sa DirPath
684    template<class P>
685    bool getPath(P &p,Node t)
686    {
687      if(reached(t)) {
688        p.clear();
689        typename P::Builder b(p);
690        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
691          b.pushFront(pred(t));
692        b.commit();
693        return true;
694      }
695      return false;
696    }
697
698    ///The distance of a node from the root(s).
699
700    ///Returns the distance of a node from the root(s).
701    ///\pre \ref run() must be called before using this function.
702    ///\warning If node \c v is unreachable from the root(s) then the return value
703    ///of this funcion is undefined.
704    int dist(Node v) const { return (*_dist)[v]; }
705
706    ///Returns the 'previous edge' of the %DFS tree.
707
708    ///For a node \c v it returns the 'previous edge'
709    ///of the %DFS path,
710    ///i.e. it returns the last edge of a %DFS path from the root(s) to \c
711    ///v. It is \ref INVALID
712    ///if \c v is unreachable from the root(s) or \c v is a root. The
713    ///%DFS tree used here is equal to the %DFS tree used in
714    ///\ref predNode().
715    ///\pre Either \ref run() or \ref start() must be called before using
716    ///this function.
717    ///\todo predEdge could be a better name.
718    Edge pred(Node v) const { return (*_pred)[v];}
719
720    ///Returns the 'previous node' of the %DFS tree.
721
722    ///For a node \c v it returns the 'previous node'
723    ///of the %DFS tree,
724    ///i.e. it returns the last but one node from a %DFS path from the
725    ///root(a) to \c /v.
726    ///It is INVALID if \c v is unreachable from the root(s) or
727    ///if \c v itself a root.
728    ///The %DFS tree used here is equal to the %DFS
729    ///tree used in \ref pred().
730    ///\pre Either \ref run() or \ref start() must be called before
731    ///using this function.
732    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
733                                  G->source((*_pred)[v]); }
734   
735    ///Returns a reference to the NodeMap of distances.
736
737    ///Returns a reference to the NodeMap of distances.
738    ///\pre Either \ref run() or \ref init() must
739    ///be called before using this function.
740    const DistMap &distMap() const { return *_dist;}
741 
742    ///Returns a reference to the %DFS edge-tree map.
743
744    ///Returns a reference to the NodeMap of the edges of the
745    ///%DFS tree.
746    ///\pre Either \ref run() or \ref init()
747    ///must be called before using this function.
748    const PredMap &predMap() const { return *_pred;}
749 
750//     ///Returns a reference to the map of nodes of %DFS paths.
751
752//     ///Returns a reference to the NodeMap of the last but one nodes of the
753//     ///%DFS tree.
754//     ///\pre \ref run() must be called before using this function.
755//     const PredNodeMap &predNodeMap() const { return *_predNode;}
756
757    ///Checks if a node is reachable from the root.
758
759    ///Returns \c true if \c v is reachable from the root(s).
760    ///\warning The source nodes are inditated as unreachable.
761    ///\pre Either \ref run() or \ref start()
762    ///must be called before using this function.
763    ///
764    bool reached(Node v) { return (*_reached)[v]; }
765   
766    ///@}
767  };
768
769  ///Default traits class of Dfs function.
770
771  ///Default traits class of Dfs function.
772  ///\param GR Graph type.
773  template<class GR>
774  struct DfsWizardDefaultTraits
775  {
776    ///The graph type the algorithm runs on.
777    typedef GR Graph;
778    ///\brief The type of the map that stores the last
779    ///edges of the %DFS paths.
780    ///
781    ///The type of the map that stores the last
782    ///edges of the %DFS paths.
783    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
784    ///
785    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
786    ///Instantiates a PredMap.
787 
788    ///This function instantiates a \ref PredMap.
789    ///\param g is the graph, to which we would like to define the PredMap.
790    ///\todo The graph alone may be insufficient to initialize
791#ifdef DOXYGEN
792    static PredMap *createPredMap(const GR &g)
793#else
794    static PredMap *createPredMap(const GR &)
795#endif
796    {
797      return new PredMap();
798    }
799//     ///\brief The type of the map that stores the last but one
800//     ///nodes of the %DFS paths.
801//     ///
802//     ///The type of the map that stores the last but one
803//     ///nodes of the %DFS paths.
804//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
805//     ///
806//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
807//     ///Instantiates a PredNodeMap.
808   
809//     ///This function instantiates a \ref PredNodeMap.
810//     ///\param G is the graph, to which
811//     ///we would like to define the \ref PredNodeMap
812//     static PredNodeMap *createPredNodeMap(const GR &G)
813//     {
814//       return new PredNodeMap();
815//     }
816
817    ///The type of the map that indicates which nodes are processed.
818 
819    ///The type of the map that indicates which nodes are processed.
820    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
821    ///\todo named parameter to set this type, function to read and write.
822    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
823    ///Instantiates a ProcessedMap.
824 
825    ///This function instantiates a \ref ProcessedMap.
826    ///\param g is the graph, to which
827    ///we would like to define the \ref ProcessedMap
828#ifdef DOXYGEN
829    static ProcessedMap *createProcessedMap(const GR &g)
830#else
831    static ProcessedMap *createProcessedMap(const GR &)
832#endif
833    {
834      return new ProcessedMap();
835    }
836    ///The type of the map that indicates which nodes are reached.
837 
838    ///The type of the map that indicates which nodes are reached.
839    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
840    ///\todo named parameter to set this type, function to read and write.
841    typedef typename Graph::template NodeMap<bool> ReachedMap;
842    ///Instantiates a ReachedMap.
843 
844    ///This function instantiates a \ref ReachedMap.
845    ///\param G is the graph, to which
846    ///we would like to define the \ref ReachedMap.
847    static ReachedMap *createReachedMap(const GR &G)
848    {
849      return new ReachedMap(G);
850    }
851    ///The type of the map that stores the dists of the nodes.
852 
853    ///The type of the map that stores the dists of the nodes.
854    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
855    ///
856    typedef NullMap<typename Graph::Node,int> DistMap;
857    ///Instantiates a DistMap.
858 
859    ///This function instantiates a \ref DistMap.
860    ///\param g is the graph, to which we would like to define the \ref DistMap
861#ifdef DOXYGEN
862    static DistMap *createDistMap(const GR &g)
863#else
864    static DistMap *createDistMap(const GR &)
865#endif
866    {
867      return new DistMap();
868    }
869  };
870 
871  /// Default traits used by \ref DfsWizard
872
873  /// To make it easier to use Dfs algorithm
874  ///we have created a wizard class.
875  /// This \ref DfsWizard class needs default traits,
876  ///as well as the \ref Dfs class.
877  /// The \ref DfsWizardBase is a class to be the default traits of the
878  /// \ref DfsWizard class.
879  template<class GR>
880  class DfsWizardBase : public DfsWizardDefaultTraits<GR>
881  {
882
883    typedef DfsWizardDefaultTraits<GR> Base;
884  protected:
885    /// Type of the nodes in the graph.
886    typedef typename Base::Graph::Node Node;
887
888    /// Pointer to the underlying graph.
889    void *_g;
890    ///Pointer to the map of reached nodes.
891    void *_reached;
892    ///Pointer to the map of processed nodes.
893    void *_processed;
894    ///Pointer to the map of predecessors edges.
895    void *_pred;
896//     ///Pointer to the map of predecessors nodes.
897//     void *_predNode;
898    ///Pointer to the map of distances.
899    void *_dist;
900    ///Pointer to the source node.
901    Node _source;
902   
903    public:
904    /// Constructor.
905   
906    /// This constructor does not require parameters, therefore it initiates
907    /// all of the attributes to default values (0, INVALID).
908    DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
909//                         _predNode(0),
910                           _dist(0), _source(INVALID) {}
911
912    /// Constructor.
913   
914    /// This constructor requires some parameters,
915    /// listed in the parameters list.
916    /// Others are initiated to 0.
917    /// \param g is the initial value of  \ref _g
918    /// \param s is the initial value of  \ref _source
919    DfsWizardBase(const GR &g, Node s=INVALID) :
920      _g((void *)&g), _reached(0), _processed(0), _pred(0),
921//       _predNode(0),
922      _dist(0), _source(s) {}
923
924  };
925 
926  /// A class to make the usage of the Dfs algorithm easier
927
928  /// This class is created to make it easier to use the Dfs algorithm.
929  /// It uses the functions and features of the plain \ref Dfs,
930  /// but it is much simpler to use it.
931  ///
932  /// Simplicity means that the way to change the types defined
933  /// in the traits class is based on functions that returns the new class
934  /// and not on templatable built-in classes.
935  /// When using the plain \ref Dfs
936  /// the new class with the modified type comes from
937  /// the original class by using the ::
938  /// operator. In the case of \ref DfsWizard only
939  /// a function have to be called and it will
940  /// return the needed class.
941  ///
942  /// It does not have own \ref run method. When its \ref run method is called
943  /// it initiates a plain \ref Dfs object, and calls the \ref Dfs::run
944  /// method of it.
945  template<class TR>
946  class DfsWizard : public TR
947  {
948    typedef TR Base;
949
950    ///The type of the underlying graph.
951    typedef typename TR::Graph Graph;
952    //\e
953    typedef typename Graph::Node Node;
954    //\e
955    typedef typename Graph::NodeIt NodeIt;
956    //\e
957    typedef typename Graph::Edge Edge;
958    //\e
959    typedef typename Graph::OutEdgeIt OutEdgeIt;
960   
961    ///\brief The type of the map that stores
962    ///the reached nodes
963    typedef typename TR::ReachedMap ReachedMap;
964    ///\brief The type of the map that stores
965    ///the processed nodes
966    typedef typename TR::ProcessedMap ProcessedMap;
967    ///\brief The type of the map that stores the last
968    ///edges of the %DFS paths.
969    typedef typename TR::PredMap PredMap;
970//     ///\brief The type of the map that stores the last but one
971//     ///nodes of the %DFS paths.
972//     typedef typename TR::PredNodeMap PredNodeMap;
973    ///The type of the map that stores the distances of the nodes.
974    typedef typename TR::DistMap DistMap;
975
976public:
977    /// Constructor.
978    DfsWizard() : TR() {}
979
980    /// Constructor that requires parameters.
981
982    /// Constructor that requires parameters.
983    /// These parameters will be the default values for the traits class.
984    DfsWizard(const Graph &g, Node s=INVALID) :
985      TR(g,s) {}
986
987    ///Copy constructor
988    DfsWizard(const TR &b) : TR(b) {}
989
990    ~DfsWizard() {}
991
992    ///Runs Dfs algorithm from a given node.
993   
994    ///Runs Dfs algorithm from a given node.
995    ///The node can be given by the \ref source function.
996    void run()
997    {
998      if(Base::_source==INVALID) throw UninitializedParameter();
999      Dfs<Graph,TR> alg(*(Graph*)Base::_g);
1000      if(Base::_reached) alg.reachedMap(*(ReachedMap*)Base::_reached);
1001      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
1002      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
1003//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
1004      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
1005      alg.run(Base::_source);
1006    }
1007
1008    ///Runs Dfs algorithm from the given node.
1009
1010    ///Runs Dfs algorithm from the given node.
1011    ///\param s is the given source.
1012    void run(Node s)
1013    {
1014      Base::_source=s;
1015      run();
1016    }
1017
1018    template<class T>
1019    struct DefPredMapBase : public Base {
1020      typedef T PredMap;
1021      static PredMap *createPredMap(const Graph &) { return 0; };
1022      DefPredMapBase(const TR &b) : TR(b) {}
1023    };
1024   
1025    ///\brief \ref named-templ-param "Named parameter"
1026    ///function for setting PredMap type
1027    ///
1028    /// \ref named-templ-param "Named parameter"
1029    ///function for setting PredMap type
1030    ///
1031    template<class T>
1032    DfsWizard<DefPredMapBase<T> > predMap(const T &t)
1033    {
1034      Base::_pred=(void *)&t;
1035      return DfsWizard<DefPredMapBase<T> >(*this);
1036    }
1037   
1038 
1039    template<class T>
1040    struct DefReachedMapBase : public Base {
1041      typedef T ReachedMap;
1042      static ReachedMap *createReachedMap(const Graph &) { return 0; };
1043      DefReachedMapBase(const TR &b) : TR(b) {}
1044    };
1045   
1046    ///\brief \ref named-templ-param "Named parameter"
1047    ///function for setting ReachedMap
1048    ///
1049    /// \ref named-templ-param "Named parameter"
1050    ///function for setting ReachedMap
1051    ///
1052    template<class T>
1053    DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1054    {
1055      Base::_pred=(void *)&t;
1056      return DfsWizard<DefReachedMapBase<T> >(*this);
1057    }
1058   
1059
1060    template<class T>
1061    struct DefProcessedMapBase : public Base {
1062      typedef T ProcessedMap;
1063      static ProcessedMap *createProcessedMap(const Graph &) { return 0; };
1064      DefProcessedMapBase(const TR &b) : TR(b) {}
1065    };
1066   
1067    ///\brief \ref named-templ-param "Named parameter"
1068    ///function for setting ProcessedMap
1069    ///
1070    /// \ref named-templ-param "Named parameter"
1071    ///function for setting ProcessedMap
1072    ///
1073    template<class T>
1074    DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1075    {
1076      Base::_pred=(void *)&t;
1077      return DfsWizard<DefProcessedMapBase<T> >(*this);
1078    }
1079   
1080
1081//     template<class T>
1082//     struct DefPredNodeMapBase : public Base {
1083//       typedef T PredNodeMap;
1084//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1085//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1086//     };
1087   
1088//     ///\brief \ref named-templ-param "Named parameter"
1089//     ///function for setting PredNodeMap type
1090//     ///
1091//     /// \ref named-templ-param "Named parameter"
1092//     ///function for setting PredNodeMap type
1093//     ///
1094//     template<class T>
1095//     DfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1096//     {
1097//       Base::_predNode=(void *)&t;
1098//       return DfsWizard<DefPredNodeMapBase<T> >(*this);
1099//     }
1100   
1101    template<class T>
1102    struct DefDistMapBase : public Base {
1103      typedef T DistMap;
1104      static DistMap *createDistMap(const Graph &) { return 0; };
1105      DefDistMapBase(const TR &b) : TR(b) {}
1106    };
1107   
1108    ///\brief \ref named-templ-param "Named parameter"
1109    ///function for setting DistMap type
1110    ///
1111    /// \ref named-templ-param "Named parameter"
1112    ///function for setting DistMap type
1113    ///
1114    template<class T>
1115    DfsWizard<DefDistMapBase<T> > distMap(const T &t)
1116    {
1117      Base::_dist=(void *)&t;
1118      return DfsWizard<DefDistMapBase<T> >(*this);
1119    }
1120   
1121    /// Sets the source node, from which the Dfs algorithm runs.
1122
1123    /// Sets the source node, from which the Dfs algorithm runs.
1124    /// \param s is the source node.
1125    DfsWizard<TR> &source(Node s)
1126    {
1127      Base::_source=s;
1128      return *this;
1129    }
1130   
1131  };
1132 
1133  ///Function type interface for Dfs algorithm.
1134
1135  /// \ingroup flowalgs
1136  ///Function type interface for Dfs algorithm.
1137  ///
1138  ///This function also has several
1139  ///\ref named-templ-func-param "named parameters",
1140  ///they are declared as the members of class \ref DfsWizard.
1141  ///The following
1142  ///example shows how to use these parameters.
1143  ///\code
1144  ///  dfs(g,source).predMap(preds).run();
1145  ///\endcode
1146  ///\warning Don't forget to put the \ref DfsWizard::run() "run()"
1147  ///to the end of the parameter list.
1148  ///\sa DfsWizard
1149  ///\sa Dfs
1150  template<class GR>
1151  DfsWizard<DfsWizardBase<GR> >
1152  dfs(const GR &g,typename GR::Node s=INVALID)
1153  {
1154    return DfsWizard<DfsWizardBase<GR> >(g,s);
1155  }
1156
1157} //END OF NAMESPACE LEMON
1158
1159#endif
1160
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