COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/bfs.h @ 1631:e15162d8eca1

Last change on this file since 1631:e15162d8eca1 was 1631:e15162d8eca1, checked in by Alpar Juttner, 14 years ago

Fixed most (but not all) of Doxygen warnings

File size: 35.1 KB
Line 
1/* -*- C++ -*-
2 * lemon/bfs.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_BFS_H
18#define LEMON_BFS_H
19
20///\ingroup flowalgs
21///\file
22///\brief Bfs 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 Bfs class.
35
36  ///Default traits class of Bfs class.
37  ///\param GR Graph type.
38  template<class GR>
39  struct BfsDefaultTraits
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 shortest paths.
45    ///
46    ///The type of the map that stores the last
47    ///edges of the shortest 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 shortest paths.
62//     ///
63//     ///The type of the map that stores the last but one
64//     ///nodes of the shortest 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  ///%BFS algorithm class.
129 
130  ///\ingroup flowalgs
131  ///This class provides an efficient implementation of the %BFS 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 Bfs, it
135  ///is only passed to \ref BfsDefaultTraits.
136  ///\param TR Traits class to set various data types used by the algorithm.
137  ///The default traits class is
138  ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>".
139  ///See \ref BfsDefaultTraits for the documentation of
140  ///a Bfs traits class.
141  ///
142  ///\author 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=BfsDefaultTraits<GR> >
151#endif
152  class Bfs {
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::Bfs::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 shortest paths.
181    typedef typename TR::PredMap PredMap;
182//     ///\brief The type of the map that stores the last but one
183//     ///nodes of the shortest 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::Node> _queue;
216    int _queue_head,_queue_tail,_queue_next_dist;
217    int _curr_dist;
218//     ///The source node of the last execution.
219//     Node source;
220
221    ///Creates the maps if necessary.
222   
223    ///\todo Error if \c G are \c NULL.
224    ///\todo Better memory allocation (instead of new).
225    void create_maps()
226    {
227      if(!_pred) {
228        local_pred = true;
229        _pred = Traits::createPredMap(*G);
230      }
231//       if(!_predNode) {
232//      local_predNode = true;
233//      _predNode = Traits::createPredNodeMap(*G);
234//       }
235      if(!_dist) {
236        local_dist = true;
237        _dist = Traits::createDistMap(*G);
238      }
239      if(!_reached) {
240        local_reached = true;
241        _reached = Traits::createReachedMap(*G);
242      }
243      if(!_processed) {
244        local_processed = true;
245        _processed = Traits::createProcessedMap(*G);
246      }
247    }
248   
249  public :
250 
251    ///\name Named template parameters
252
253    ///@{
254
255    template <class T>
256    struct DefPredMapTraits : public Traits {
257      typedef T PredMap;
258      static PredMap *createPredMap(const Graph &G)
259      {
260        throw UninitializedParameter();
261      }
262    };
263    ///\ref named-templ-param "Named parameter" for setting PredMap type
264
265    ///\ref named-templ-param "Named parameter" for setting PredMap type
266    ///
267    template <class T>
268    class DefPredMap : public Bfs< Graph, 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 Bfs< 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 Bfs< 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 Bfs< 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 Bfs< 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 explicitly, it will be automatically allocated.
355    template <class T>
356    class DefProcessedMapToBeDefaultMap :
357      public Bfs< Graph,
358                  DefGraphProcessedMapTraits> { };
359   
360    ///@}
361
362  public:     
363   
364    ///Constructor.
365   
366    ///\param _G the graph the algorithm will run on.
367    ///
368    Bfs(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    ~Bfs()
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 destructor deallocates this
392    ///automatically allocated map, of course.
393    ///\return <tt> (*this) </tt>
394    Bfs &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 indicating the reached nodes.
405
406    ///Sets the map indicating the reached nodes.
407    ///If you don't use this function before calling \ref run(),
408    ///it will allocate one. The destructor deallocates this
409    ///automatically allocated map, of course.
410    ///\return <tt> (*this) </tt>
411    Bfs &reachedMap(ReachedMap &m)
412    {
413      if(local_reached) {
414        delete _reached;
415        local_reached=false;
416      }
417      _reached = &m;
418      return *this;
419    }
420
421    ///Sets the map indicating the processed nodes.
422
423    ///Sets the map indicating the processed nodes.
424    ///If you don't use this function before calling \ref run(),
425    ///it will allocate one. The destructor deallocates this
426    ///automatically allocated map, of course.
427    ///\return <tt> (*this) </tt>
428    Bfs &processedMap(ProcessedMap &m)
429    {
430      if(local_processed) {
431        delete _processed;
432        local_processed=false;
433      }
434      _processed = &m;
435      return *this;
436    }
437
438//     ///Sets the map storing the predecessor nodes.
439
440//     ///Sets the map storing the predecessor nodes.
441//     ///If you don't use this function before calling \ref run(),
442//     ///it will allocate one. The destructor deallocates this
443//     ///automatically allocated map, of course.
444//     ///\return <tt> (*this) </tt>
445//     Bfs &predNodeMap(PredNodeMap &m)
446//     {
447//       if(local_predNode) {
448//      delete _predNode;
449//      local_predNode=false;
450//       }
451//       _predNode = &m;
452//       return *this;
453//     }
454
455    ///Sets the map storing the distances calculated by the algorithm.
456
457    ///Sets the map storing the distances calculated by the algorithm.
458    ///If you don't use this function before calling \ref run(),
459    ///it will allocate one. The destructor deallocates this
460    ///automatically allocated map, of course.
461    ///\return <tt> (*this) </tt>
462    Bfs &distMap(DistMap &m)
463    {
464      if(local_dist) {
465        delete _dist;
466        local_dist=false;
467      }
468      _dist = &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      _queue.resize(countNodes(*G));
493      _queue_head=_queue_tail=0;
494      _curr_dist=1;
495      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
496        _pred->set(u,INVALID);
497//      _predNode->set(u,INVALID);
498        _reached->set(u,false);
499        _processed->set(u,false);
500      }
501    }
502   
503    ///Adds a new source node.
504
505    ///Adds a new source node to the set of nodes to be processed.
506    ///
507    void addSource(Node s)
508    {
509      if(!(*_reached)[s])
510        {
511          _reached->set(s,true);
512          _pred->set(s,INVALID);
513          _dist->set(s,0);
514          _queue[_queue_head++]=s;
515          _queue_next_dist=_queue_head;
516        }
517    }
518   
519    ///Processes the next node.
520
521    ///Processes the next node.
522    ///
523    ///\return The processed node.
524    ///
525    ///\warning The queue must not be empty!
526    Node processNextNode()
527    {
528      if(_queue_tail==_queue_next_dist) {
529        _curr_dist++;
530        _queue_next_dist=_queue_head;
531      }
532      Node n=_queue[_queue_tail++];
533      _processed->set(n,true);
534      Node m;
535      for(OutEdgeIt e(*G,n);e!=INVALID;++e)
536        if(!(*_reached)[m=G->target(e)]) {
537          _queue[_queue_head++]=m;
538          _reached->set(m,true);
539          _pred->set(m,e);
540//        _pred_node->set(m,n);
541          _dist->set(m,_curr_dist);
542        }
543      return n;
544    }
545     
546    ///\brief Returns \c false if there are nodes
547    ///to be processed in the queue
548    ///
549    ///Returns \c false if there are nodes
550    ///to be processed in the queue
551    bool emptyQueue() { return _queue_tail==_queue_head; }
552    ///Returns the number of the nodes to be processed.
553   
554    ///Returns the number of the nodes to be processed in the queue.
555    ///
556    int queueSize() { return _queue_head-_queue_tail; }
557   
558    ///Executes the algorithm.
559
560    ///Executes the algorithm.
561    ///
562    ///\pre init() must be called and at least one node should be added
563    ///with addSource() before using this function.
564    ///
565    ///This method runs the %BFS algorithm from the root node(s)
566    ///in order to
567    ///compute the
568    ///shortest path to each node. The algorithm computes
569    ///- The shortest path tree.
570    ///- The distance of each node from the root(s).
571    ///
572    void start()
573    {
574      while ( !emptyQueue() ) processNextNode();
575    }
576   
577    ///Executes the algorithm until \c dest is reached.
578
579    ///Executes the algorithm until \c dest is reached.
580    ///
581    ///\pre init() must be called and at least one node should be added
582    ///with addSource() before using this function.
583    ///
584    ///This method runs the %BFS algorithm from the root node(s)
585    ///in order to
586    ///compute the
587    ///shortest path to \c dest. The algorithm computes
588    ///- The shortest path to \c  dest.
589    ///- The distance of \c dest from the root(s).
590    ///
591    void start(Node dest)
592    {
593      while ( !emptyQueue() && _queue[_queue_tail]!=dest ) processNextNode();
594    }
595   
596    ///Executes the algorithm until a condition is met.
597
598    ///Executes the algorithm until a condition is met.
599    ///
600    ///\pre init() must be called and at least one node should be added
601    ///with addSource() before using this function.
602    ///
603    ///\param nm must be a bool (or convertible) node map. The algorithm
604    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
605    template<class NM>
606      void start(const NM &nm)
607      {
608        while ( !emptyQueue() && !nm[_queue[_queue_tail]] ) processNextNode();
609      }
610   
611    ///Runs %BFS algorithm from node \c s.
612   
613    ///This method runs the %BFS algorithm from a root node \c s
614    ///in order to
615    ///compute the
616    ///shortest path to each node. The algorithm computes
617    ///- The shortest path tree.
618    ///- The distance of each node from the root.
619    ///
620    ///\note d.run(s) is just a shortcut of the following code.
621    ///\code
622    ///  d.init();
623    ///  d.addSource(s);
624    ///  d.start();
625    ///\endcode
626    void run(Node s) {
627      init();
628      addSource(s);
629      start();
630    }
631   
632    ///Finds the shortest path between \c s and \c t.
633   
634    ///Finds the shortest path between \c s and \c t.
635    ///
636    ///\return The length of the shortest s---t path if there exists one,
637    ///0 otherwise.
638    ///\note Apart from the return value, d.run(s) is
639    ///just a shortcut of the following code.
640    ///\code
641    ///  d.init();
642    ///  d.addSource(s);
643    ///  d.start(t);
644    ///\endcode
645    int run(Node s,Node t) {
646      init();
647      addSource(s);
648      start(t);
649      return reached(t)?_curr_dist-1+(_queue_tail==_queue_next_dist):0;
650    }
651   
652    ///@}
653
654    ///\name Query Functions
655    ///The result of the %BFS algorithm can be obtained using these
656    ///functions.\n
657    ///Before the use of these functions,
658    ///either run() or start() must be called.
659   
660    ///@{
661
662    ///Copies the shortest path to \c t into \c p
663   
664    ///This function copies the shortest path to \c t into \c p.
665    ///If \c t is a source itself or unreachable, then it does not
666    ///alter \c p.
667    ///\todo Is it the right way to handle unreachable nodes?
668    ///\return Returns \c true if a path to \c t was actually copied to \c p,
669    ///\c false otherwise.
670    ///\sa DirPath
671    template<class P>
672    bool getPath(P &p,Node t)
673    {
674      if(reached(t)) {
675        p.clear();
676        typename P::Builder b(p);
677        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
678          b.pushFront(pred(t));
679        b.commit();
680        return true;
681      }
682      return false;
683    }
684
685    ///The distance of a node from the root(s).
686
687    ///Returns the distance of a node from the root(s).
688    ///\pre \ref run() must be called before using this function.
689    ///\warning If node \c v in unreachable from the root(s) the return value
690    ///of this function is undefined.
691    int dist(Node v) const { return (*_dist)[v]; }
692
693    ///Returns the 'previous edge' of the shortest path tree.
694
695    ///For a node \c v it returns the 'previous edge'
696    ///of the shortest path tree,
697    ///i.e. it returns the last edge of a shortest path from the root(s) to \c
698    ///v. It is \ref INVALID
699    ///if \c v is unreachable from the root(s) or \c v is a root. The
700    ///shortest path tree used here is equal to the shortest path tree used in
701    ///\ref predNode().
702    ///\pre Either \ref run() or \ref start() must be called before using
703    ///this function.
704    ///\todo predEdge could be a better name.
705    Edge pred(Node v) const { return (*_pred)[v];}
706
707    ///Returns the 'previous node' of the shortest path tree.
708
709    ///For a node \c v it returns the 'previous node'
710    ///of the shortest path tree,
711    ///i.e. it returns the last but one node from a shortest path from the
712    ///root(a) to \c /v.
713    ///It is INVALID if \c v is unreachable from the root(s) or
714    ///if \c v itself a root.
715    ///The shortest path tree used here is equal to the shortest path
716    ///tree used in \ref pred().
717    ///\pre Either \ref run() or \ref start() must be called before
718    ///using this function.
719    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
720                                  G->source((*_pred)[v]); }
721   
722    ///Returns a reference to the NodeMap of distances.
723
724    ///Returns a reference to the NodeMap of distances.
725    ///\pre Either \ref run() or \ref init() must
726    ///be called before using this function.
727    const DistMap &distMap() const { return *_dist;}
728 
729    ///Returns a reference to the shortest path tree map.
730
731    ///Returns a reference to the NodeMap of the edges of the
732    ///shortest path tree.
733    ///\pre Either \ref run() or \ref init()
734    ///must be called before using this function.
735    const PredMap &predMap() const { return *_pred;}
736 
737//     ///Returns a reference to the map of nodes of shortest paths.
738
739//     ///Returns a reference to the NodeMap of the last but one nodes of the
740//     ///shortest path tree.
741//     ///\pre \ref run() must be called before using this function.
742//     const PredNodeMap &predNodeMap() const { return *_predNode;}
743
744    ///Checks if a node is reachable from the root.
745
746    ///Returns \c true if \c v is reachable from the root.
747    ///\warning The source nodes are indicated as unreached.
748    ///\pre Either \ref run() or \ref start()
749    ///must be called before using this function.
750    ///
751    bool reached(Node v) { return (*_reached)[v]; }
752   
753    ///@}
754  };
755
756  ///Default traits class of Bfs function.
757
758  ///Default traits class of Bfs function.
759  ///\param GR Graph type.
760  template<class GR>
761  struct BfsWizardDefaultTraits
762  {
763    ///The graph type the algorithm runs on.
764    typedef GR Graph;
765    ///\brief The type of the map that stores the last
766    ///edges of the shortest paths.
767    ///
768    ///The type of the map that stores the last
769    ///edges of the shortest paths.
770    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
771    ///
772    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
773    ///Instantiates a PredMap.
774 
775    ///This function instantiates a \ref PredMap.
776    ///\param g is the graph, to which we would like to define the PredMap.
777    ///\todo The graph alone may be insufficient to initialize
778#ifdef DOXYGEN
779    static PredMap *createPredMap(const GR &g)
780#else
781    static PredMap *createPredMap(const GR &)
782#endif
783    {
784      return new PredMap();
785    }
786//     ///\brief The type of the map that stores the last but one
787//     ///nodes of the shortest paths.
788//     ///
789//     ///The type of the map that stores the last but one
790//     ///nodes of the shortest paths.
791//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
792//     ///
793//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
794//     ///Instantiates a PredNodeMap.
795   
796//     ///This function instantiates a \ref PredNodeMap.
797//     ///\param G is the graph, to which
798//     ///we would like to define the \ref PredNodeMap
799//     static PredNodeMap *createPredNodeMap(const GR &G)
800//     {
801//       return new PredNodeMap();
802//     }
803
804    ///The type of the map that indicates which nodes are processed.
805 
806    ///The type of the map that indicates which nodes are processed.
807    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
808    ///\todo named parameter to set this type, function to read and write.
809    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
810    ///Instantiates a ProcessedMap.
811 
812    ///This function instantiates a \ref ProcessedMap.
813    ///\param g is the graph, to which
814    ///we would like to define the \ref ProcessedMap
815#ifdef DOXYGEN
816    static ProcessedMap *createProcessedMap(const GR &g)
817#else
818    static ProcessedMap *createProcessedMap(const GR &)
819#endif
820    {
821      return new ProcessedMap();
822    }
823    ///The type of the map that indicates which nodes are reached.
824 
825    ///The type of the map that indicates which nodes are reached.
826    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
827    ///\todo named parameter to set this type, function to read and write.
828    typedef typename Graph::template NodeMap<bool> ReachedMap;
829    ///Instantiates a ReachedMap.
830 
831    ///This function instantiates a \ref ReachedMap.
832    ///\param G is the graph, to which
833    ///we would like to define the \ref ReachedMap.
834    static ReachedMap *createReachedMap(const GR &G)
835    {
836      return new ReachedMap(G);
837    }
838    ///The type of the map that stores the dists of the nodes.
839 
840    ///The type of the map that stores the dists of the nodes.
841    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
842    ///
843    typedef NullMap<typename Graph::Node,int> DistMap;
844    ///Instantiates a DistMap.
845 
846    ///This function instantiates a \ref DistMap.
847    ///\param g is the graph, to which we would like to define the \ref DistMap
848#ifdef DOXYGEN
849    static DistMap *createDistMap(const GR &g)
850#else
851    static DistMap *createDistMap(const GR &)
852#endif
853    {
854      return new DistMap();
855    }
856  };
857 
858  /// Default traits used by \ref BfsWizard
859
860  /// To make it easier to use Bfs algorithm
861  ///we have created a wizard class.
862  /// This \ref BfsWizard class needs default traits,
863  ///as well as the \ref Bfs class.
864  /// The \ref BfsWizardBase is a class to be the default traits of the
865  /// \ref BfsWizard class.
866  template<class GR>
867  class BfsWizardBase : public BfsWizardDefaultTraits<GR>
868  {
869
870    typedef BfsWizardDefaultTraits<GR> Base;
871  protected:
872    /// Type of the nodes in the graph.
873    typedef typename Base::Graph::Node Node;
874
875    /// Pointer to the underlying graph.
876    void *_g;
877    ///Pointer to the map of reached nodes.
878    void *_reached;
879    ///Pointer to the map of processed nodes.
880    void *_processed;
881    ///Pointer to the map of predecessors edges.
882    void *_pred;
883//     ///Pointer to the map of predecessors nodes.
884//     void *_predNode;
885    ///Pointer to the map of distances.
886    void *_dist;
887    ///Pointer to the source node.
888    Node _source;
889   
890    public:
891    /// Constructor.
892   
893    /// This constructor does not require parameters, therefore it initiates
894    /// all of the attributes to default values (0, INVALID).
895    BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
896//                         _predNode(0),
897                           _dist(0), _source(INVALID) {}
898
899    /// Constructor.
900   
901    /// This constructor requires some parameters,
902    /// listed in the parameters list.
903    /// Others are initiated to 0.
904    /// \param g is the initial value of  \ref _g
905    /// \param s is the initial value of  \ref _source
906    BfsWizardBase(const GR &g, Node s=INVALID) :
907      _g((void *)&g), _reached(0), _processed(0), _pred(0),
908//       _predNode(0),
909      _dist(0), _source(s) {}
910
911  };
912 
913  /// A class to make the usage of Bfs algorithm easier
914
915  /// This class is created to make it easier to use Bfs algorithm.
916  /// It uses the functions and features of the plain \ref Bfs,
917  /// but it is much simpler to use it.
918  ///
919  /// Simplicity means that the way to change the types defined
920  /// in the traits class is based on functions that returns the new class
921  /// and not on templatable built-in classes.
922  /// When using the plain \ref Bfs
923  /// the new class with the modified type comes from
924  /// the original class by using the ::
925  /// operator. In the case of \ref BfsWizard only
926  /// a function have to be called and it will
927  /// return the needed class.
928  ///
929  /// It does not have own \ref run method. When its \ref run method is called
930  /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run
931  /// method of it.
932  template<class TR>
933  class BfsWizard : public TR
934  {
935    typedef TR Base;
936
937    ///The type of the underlying graph.
938    typedef typename TR::Graph Graph;
939    //\e
940    typedef typename Graph::Node Node;
941    //\e
942    typedef typename Graph::NodeIt NodeIt;
943    //\e
944    typedef typename Graph::Edge Edge;
945    //\e
946    typedef typename Graph::OutEdgeIt OutEdgeIt;
947   
948    ///\brief The type of the map that stores
949    ///the reached nodes
950    typedef typename TR::ReachedMap ReachedMap;
951    ///\brief The type of the map that stores
952    ///the processed nodes
953    typedef typename TR::ProcessedMap ProcessedMap;
954    ///\brief The type of the map that stores the last
955    ///edges of the shortest paths.
956    typedef typename TR::PredMap PredMap;
957//     ///\brief The type of the map that stores the last but one
958//     ///nodes of the shortest paths.
959//     typedef typename TR::PredNodeMap PredNodeMap;
960    ///The type of the map that stores the dists of the nodes.
961    typedef typename TR::DistMap DistMap;
962
963public:
964    /// Constructor.
965    BfsWizard() : TR() {}
966
967    /// Constructor that requires parameters.
968
969    /// Constructor that requires parameters.
970    /// These parameters will be the default values for the traits class.
971    BfsWizard(const Graph &g, Node s=INVALID) :
972      TR(g,s) {}
973
974    ///Copy constructor
975    BfsWizard(const TR &b) : TR(b) {}
976
977    ~BfsWizard() {}
978
979    ///Runs Bfs algorithm from a given node.
980   
981    ///Runs Bfs algorithm from a given node.
982    ///The node can be given by the \ref source function.
983    void run()
984    {
985      if(Base::_source==INVALID) throw UninitializedParameter();
986      Bfs<Graph,TR> alg(*(Graph*)Base::_g);
987      if(Base::_reached)
988        alg.reachedMap(*(ReachedMap*)Base::_reached);
989      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
990      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
991//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
992      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
993      alg.run(Base::_source);
994    }
995
996    ///Runs Bfs algorithm from the given node.
997
998    ///Runs Bfs algorithm from the given node.
999    ///\param s is the given source.
1000    void run(Node s)
1001    {
1002      Base::_source=s;
1003      run();
1004    }
1005
1006    template<class T>
1007    struct DefPredMapBase : public Base {
1008      typedef T PredMap;
1009      static PredMap *createPredMap(const Graph &) { return 0; };
1010      DefPredMapBase(const TR &b) : TR(b) {}
1011    };
1012   
1013    ///\brief \ref named-templ-param "Named parameter"
1014    ///function for setting PredMap
1015    ///
1016    /// \ref named-templ-param "Named parameter"
1017    ///function for setting PredMap
1018    ///
1019    template<class T>
1020    BfsWizard<DefPredMapBase<T> > predMap(const T &t)
1021    {
1022      Base::_pred=(void *)&t;
1023      return BfsWizard<DefPredMapBase<T> >(*this);
1024    }
1025   
1026 
1027    template<class T>
1028    struct DefReachedMapBase : public Base {
1029      typedef T ReachedMap;
1030      static ReachedMap *createReachedMap(const Graph &) { return 0; };
1031      DefReachedMapBase(const TR &b) : TR(b) {}
1032    };
1033   
1034    ///\brief \ref named-templ-param "Named parameter"
1035    ///function for setting ReachedMap
1036    ///
1037    /// \ref named-templ-param "Named parameter"
1038    ///function for setting ReachedMap
1039    ///
1040    template<class T>
1041    BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1042    {
1043      Base::_pred=(void *)&t;
1044      return BfsWizard<DefReachedMapBase<T> >(*this);
1045    }
1046   
1047
1048    template<class T>
1049    struct DefProcessedMapBase : public Base {
1050      typedef T ProcessedMap;
1051      static ProcessedMap *createProcessedMap(const Graph &) { return 0; };
1052      DefProcessedMapBase(const TR &b) : TR(b) {}
1053    };
1054   
1055    ///\brief \ref named-templ-param "Named parameter"
1056    ///function for setting ProcessedMap
1057    ///
1058    /// \ref named-templ-param "Named parameter"
1059    ///function for setting ProcessedMap
1060    ///
1061    template<class T>
1062    BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1063    {
1064      Base::_pred=(void *)&t;
1065      return BfsWizard<DefProcessedMapBase<T> >(*this);
1066    }
1067   
1068
1069//     template<class T>
1070//     struct DefPredNodeMapBase : public Base {
1071//       typedef T PredNodeMap;
1072//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1073//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1074//     };
1075   
1076//     ///\brief \ref named-templ-param "Named parameter"
1077//     ///function for setting PredNodeMap type
1078//     ///
1079//     /// \ref named-templ-param "Named parameter"
1080//     ///function for setting PredNodeMap type
1081//     ///
1082//     template<class T>
1083//     BfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1084//     {
1085//       Base::_predNode=(void *)&t;
1086//       return BfsWizard<DefPredNodeMapBase<T> >(*this);
1087//     }
1088   
1089    template<class T>
1090    struct DefDistMapBase : public Base {
1091      typedef T DistMap;
1092      static DistMap *createDistMap(const Graph &) { return 0; };
1093      DefDistMapBase(const TR &b) : TR(b) {}
1094    };
1095   
1096    ///\brief \ref named-templ-param "Named parameter"
1097    ///function for setting DistMap type
1098    ///
1099    /// \ref named-templ-param "Named parameter"
1100    ///function for setting DistMap type
1101    ///
1102    template<class T>
1103    BfsWizard<DefDistMapBase<T> > distMap(const T &t)
1104    {
1105      Base::_dist=(void *)&t;
1106      return BfsWizard<DefDistMapBase<T> >(*this);
1107    }
1108   
1109    /// Sets the source node, from which the Bfs algorithm runs.
1110
1111    /// Sets the source node, from which the Bfs algorithm runs.
1112    /// \param s is the source node.
1113    BfsWizard<TR> &source(Node s)
1114    {
1115      Base::_source=s;
1116      return *this;
1117    }
1118   
1119  };
1120 
1121  ///Function type interface for Bfs algorithm.
1122
1123  /// \ingroup flowalgs
1124  ///Function type interface for Bfs algorithm.
1125  ///
1126  ///This function also has several
1127  ///\ref named-templ-func-param "named parameters",
1128  ///they are declared as the members of class \ref BfsWizard.
1129  ///The following
1130  ///example shows how to use these parameters.
1131  ///\code
1132  ///  bfs(g,source).predMap(preds).run();
1133  ///\endcode
1134  ///\warning Don't forget to put the \ref BfsWizard::run() "run()"
1135  ///to the end of the parameter list.
1136  ///\sa BfsWizard
1137  ///\sa Bfs
1138  template<class GR>
1139  BfsWizard<BfsWizardBase<GR> >
1140  bfs(const GR &g,typename GR::Node s=INVALID)
1141  {
1142    return BfsWizard<BfsWizardBase<GR> >(g,s);
1143  }
1144
1145} //END OF NAMESPACE LEMON
1146
1147#endif
1148
Note: See TracBrowser for help on using the repository browser.