COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/bfs.h @ 1283:fc20371677b9

Last change on this file since 1283:fc20371677b9 was 1283:fc20371677b9, checked in by Alpar Juttner, 15 years ago

getPath() added to Bfs/Dfs/Dijkstra?.

File size: 34.8 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/bfs.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, 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    static ProcessedMap *createProcessedMap(const GR &G)
90    {
91      return new ProcessedMap();
92    }
93    ///The type of the map that indicates which nodes are reached.
94 
95    ///The type of the map that indicates which nodes are reached.
96    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
97    ///\todo named parameter to set this type, function to read and write.
98    typedef typename Graph::template NodeMap<bool> ReachedMap;
99    ///Instantiates a ReachedMap.
100 
101    ///This function instantiates a \ref ReachedMap.
102    ///\param G is the graph, to which
103    ///we would like to define the \ref ReachedMap.
104    static ReachedMap *createReachedMap(const GR &G)
105    {
106      return new ReachedMap(G);
107    }
108    ///The type of the map that stores the dists of the nodes.
109 
110    ///The type of the map that stores the dists of the nodes.
111    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
112    ///
113    typedef typename Graph::template NodeMap<int> DistMap;
114    ///Instantiates a DistMap.
115 
116    ///This function instantiates a \ref DistMap.
117    ///\param G is the graph, to which we would like to define the \ref DistMap
118    static DistMap *createDistMap(const GR &G)
119    {
120      return new DistMap(G);
121    }
122  };
123 
124  ///%BFS algorithm class.
125 
126  ///\ingroup flowalgs
127  ///This class provides an efficient implementation of the %BFS algorithm.
128  ///
129  ///\param GR The graph type the algorithm runs on. The default value is
130  ///\ref ListGraph. The value of GR is not used directly by Bfs, it
131  ///is only passed to \ref BfsDefaultTraits.
132  ///\param TR Traits class to set various data types used by the algorithm.
133  ///The default traits class is
134  ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>".
135  ///See \ref BfsDefaultTraits for the documentation of
136  ///a Bfs traits class.
137  ///
138  ///\author Alpar Juttner
139  ///\todo A compare object would be nice.
140
141#ifdef DOXYGEN
142  template <typename GR,
143            typename TR>
144#else
145  template <typename GR=ListGraph,
146            typename TR=BfsDefaultTraits<GR> >
147#endif
148  class Bfs {
149  public:
150    /**
151     * \brief \ref Exception for uninitialized parameters.
152     *
153     * This error represents problems in the initialization
154     * of the parameters of the algorithms.
155     */
156    class UninitializedParameter : public lemon::UninitializedParameter {
157    public:
158      virtual const char* exceptionName() const {
159        return "lemon::Bfs::UninitializedParameter";
160      }
161    };
162
163    typedef TR Traits;
164    ///The type of the underlying graph.
165    typedef typename TR::Graph Graph;
166    ///\e
167    typedef typename Graph::Node Node;
168    ///\e
169    typedef typename Graph::NodeIt NodeIt;
170    ///\e
171    typedef typename Graph::Edge Edge;
172    ///\e
173    typedef typename Graph::OutEdgeIt OutEdgeIt;
174   
175    ///\brief The type of the map that stores the last
176    ///edges of the shortest paths.
177    typedef typename TR::PredMap PredMap;
178//     ///\brief The type of the map that stores the last but one
179//     ///nodes of the shortest paths.
180//     typedef typename TR::PredNodeMap PredNodeMap;
181    ///The type of the map indicating which nodes are reached.
182    typedef typename TR::ReachedMap ReachedMap;
183    ///The type of the map indicating which nodes are processed.
184    typedef typename TR::ProcessedMap ProcessedMap;
185    ///The type of the map that stores the dists of the nodes.
186    typedef typename TR::DistMap DistMap;
187  private:
188    /// Pointer to the underlying graph.
189    const Graph *G;
190    ///Pointer to the map of predecessors edges.
191    PredMap *_pred;
192    ///Indicates if \ref _pred is locally allocated (\c true) or not.
193    bool local_pred;
194//     ///Pointer to the map of predecessors nodes.
195//     PredNodeMap *_predNode;
196//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
197//     bool local_predNode;
198    ///Pointer to the map of distances.
199    DistMap *_dist;
200    ///Indicates if \ref _dist is locally allocated (\c true) or not.
201    bool local_dist;
202    ///Pointer to the map of reached status of the nodes.
203    ReachedMap *_reached;
204    ///Indicates if \ref _reached is locally allocated (\c true) or not.
205    bool local_reached;
206    ///Pointer to the map of processed status of the nodes.
207    ProcessedMap *_processed;
208    ///Indicates if \ref _processed is locally allocated (\c true) or not.
209    bool local_processed;
210
211    std::vector<typename Graph::Node> _queue;
212    int _queue_head,_queue_tail,_queue_next_dist;
213    int _curr_dist;
214//     ///The source node of the last execution.
215//     Node source;
216
217    ///Creates the maps if necessary.
218   
219    ///\todo Error if \c G are \c NULL.
220    ///\todo Better memory allocation (instead of new).
221    void create_maps()
222    {
223      if(!_pred) {
224        local_pred = true;
225        _pred = Traits::createPredMap(*G);
226      }
227//       if(!_predNode) {
228//      local_predNode = true;
229//      _predNode = Traits::createPredNodeMap(*G);
230//       }
231      if(!_dist) {
232        local_dist = true;
233        _dist = Traits::createDistMap(*G);
234      }
235      if(!_reached) {
236        local_reached = true;
237        _reached = Traits::createReachedMap(*G);
238      }
239      if(!_processed) {
240        local_processed = true;
241        _processed = Traits::createProcessedMap(*G);
242      }
243    }
244   
245  public :
246 
247    ///\name Named template parameters
248
249    ///@{
250
251    template <class T>
252    struct DefPredMapTraits : public Traits {
253      typedef T PredMap;
254      static PredMap *createPredMap(const Graph &G)
255      {
256        throw UninitializedParameter();
257      }
258    };
259    ///\ref named-templ-param "Named parameter" for setting PredMap type
260
261    ///\ref named-templ-param "Named parameter" for setting PredMap type
262    ///
263    template <class T>
264    class DefPredMap : public Bfs< Graph,
265                                        DefPredMapTraits<T> > { };
266   
267//     template <class T>
268//     struct DefPredNodeMapTraits : public Traits {
269//       typedef T PredNodeMap;
270//       static PredNodeMap *createPredNodeMap(const Graph &G)
271//       {
272//      throw UninitializedParameter();
273//       }
274//     };
275//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
276
277//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
278//     ///
279//     template <class T>
280//     class DefPredNodeMap : public Bfs< Graph,
281//                                          LengthMap,
282//                                          DefPredNodeMapTraits<T> > { };
283   
284    template <class T>
285    struct DefDistMapTraits : public Traits {
286      typedef T DistMap;
287      static DistMap *createDistMap(const Graph &G)
288      {
289        throw UninitializedParameter();
290      }
291    };
292    ///\ref named-templ-param "Named parameter" for setting DistMap type
293
294    ///\ref named-templ-param "Named parameter" for setting DistMap type
295    ///
296    template <class T>
297    class DefDistMap : public Bfs< Graph,
298                                   DefDistMapTraits<T> > { };
299   
300    template <class T>
301    struct DefReachedMapTraits : public Traits {
302      typedef T ReachedMap;
303      static ReachedMap *createReachedMap(const Graph &G)
304      {
305        throw UninitializedParameter();
306      }
307    };
308    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
309
310    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
311    ///
312    template <class T>
313    class DefReachedMap : public Bfs< Graph,
314                                      DefReachedMapTraits<T> > { };
315   
316    struct DefGraphReachedMapTraits : public Traits {
317      typedef typename Graph::template NodeMap<bool> ReachedMap;
318      static ReachedMap *createReachedMap(const Graph &G)
319      {
320        return new ReachedMap(G);
321      }
322    };
323    template <class T>
324    struct DefProcessedMapTraits : public Traits {
325      typedef T ProcessedMap;
326      static ProcessedMap *createProcessedMap(const Graph &G)
327      {
328        throw UninitializedParameter();
329      }
330    };
331    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
332
333    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
334    ///
335    template <class T>
336    class DefProcessedMap : public Bfs< Graph,
337                                        DefProcessedMapTraits<T> > { };
338   
339    struct DefGraphProcessedMapTraits : public Traits {
340      typedef typename Graph::template NodeMap<bool> ProcessedMap;
341      static ProcessedMap *createProcessedMap(const Graph &G)
342      {
343        return new ProcessedMap(G);
344      }
345    };
346    ///\brief \ref named-templ-param "Named parameter"
347    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
348    ///
349    ///\ref named-templ-param "Named parameter"
350    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
351    ///If you don't set it explicitly, it will be automatically allocated.
352    template <class T>
353    class DefProcessedMapToBeDefaultMap :
354      public Bfs< Graph,
355                  DefGraphProcessedMapTraits> { };
356   
357    ///@}
358
359  public:     
360   
361    ///Constructor.
362   
363    ///\param _G the graph the algorithm will run on.
364    ///
365    Bfs(const Graph& _G) :
366      G(&_G),
367      _pred(NULL), local_pred(false),
368//       _predNode(NULL), local_predNode(false),
369      _dist(NULL), local_dist(false),
370      _reached(NULL), local_reached(false),
371      _processed(NULL), local_processed(false)
372    { }
373   
374    ///Destructor.
375    ~Bfs()
376    {
377      if(local_pred) delete _pred;
378//       if(local_predNode) delete _predNode;
379      if(local_dist) delete _dist;
380      if(local_reached) delete _reached;
381      if(local_processed) delete _processed;
382    }
383
384    ///Sets the map storing the predecessor edges.
385
386    ///Sets the map storing the predecessor edges.
387    ///If you don't use this function before calling \ref run(),
388    ///it will allocate one. The destructor deallocates this
389    ///automatically allocated map, of course.
390    ///\return <tt> (*this) </tt>
391    Bfs &predMap(PredMap &m)
392    {
393      if(local_pred) {
394        delete _pred;
395        local_pred=false;
396      }
397      _pred = &m;
398      return *this;
399    }
400
401    ///Sets the map indicating the reached nodes.
402
403    ///Sets the map indicating the reached nodes.
404    ///If you don't use this function before calling \ref run(),
405    ///it will allocate one. The destructor deallocates this
406    ///automatically allocated map, of course.
407    ///\return <tt> (*this) </tt>
408    Bfs &reachedMap(ReachedMap &m)
409    {
410      if(local_reached) {
411        delete _reached;
412        local_reached=false;
413      }
414      _reached = &m;
415      return *this;
416    }
417
418    ///Sets the map indicating the processed nodes.
419
420    ///Sets the map indicating the processed nodes.
421    ///If you don't use this function before calling \ref run(),
422    ///it will allocate one. The destructor deallocates this
423    ///automatically allocated map, of course.
424    ///\return <tt> (*this) </tt>
425    Bfs &processedMap(ProcessedMap &m)
426    {
427      if(local_processed) {
428        delete _processed;
429        local_processed=false;
430      }
431      _processed = &m;
432      return *this;
433    }
434
435//     ///Sets the map storing the predecessor nodes.
436
437//     ///Sets the map storing the predecessor nodes.
438//     ///If you don't use this function before calling \ref run(),
439//     ///it will allocate one. The destructor deallocates this
440//     ///automatically allocated map, of course.
441//     ///\return <tt> (*this) </tt>
442//     Bfs &predNodeMap(PredNodeMap &m)
443//     {
444//       if(local_predNode) {
445//      delete _predNode;
446//      local_predNode=false;
447//       }
448//       _predNode = &m;
449//       return *this;
450//     }
451
452    ///Sets the map storing the distances calculated by the algorithm.
453
454    ///Sets the map storing the distances calculated by the algorithm.
455    ///If you don't use this function before calling \ref run(),
456    ///it will allocate one. The destructor deallocates this
457    ///automatically allocated map, of course.
458    ///\return <tt> (*this) </tt>
459    Bfs &distMap(DistMap &m)
460    {
461      if(local_dist) {
462        delete _dist;
463        local_dist=false;
464      }
465      _dist = &m;
466      return *this;
467    }
468
469  public:
470    ///\name Execution control
471    ///The simplest way to execute the algorithm is to use
472    ///one of the member functions called \c run(...).
473    ///\n
474    ///If you need more control on the execution,
475    ///first you must call \ref init(), then you can add several source nodes
476    ///with \ref addSource().
477    ///Finally \ref start() will perform the actual path
478    ///computation.
479
480    ///@{
481
482    ///Initializes the internal data structures.
483
484    ///Initializes the internal data structures.
485    ///
486    void init()
487    {
488      create_maps();
489      _queue.resize(countNodes(*G));
490      _queue_head=_queue_tail=0;
491      _curr_dist=1;
492      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
493        _pred->set(u,INVALID);
494//      _predNode->set(u,INVALID);
495        _reached->set(u,false);
496        _processed->set(u,false);
497      }
498    }
499   
500    ///Adds a new source node.
501
502    ///Adds a new source node to the set of nodes to be processed.
503    ///
504    void addSource(Node s)
505    {
506      if(!(*_reached)[s])
507        {
508          _reached->set(s,true);
509          _pred->set(s,INVALID);
510          _dist->set(s,0);
511          _queue[_queue_head++]=s;
512          _queue_next_dist=_queue_head;
513        }
514    }
515   
516    ///Processes the next node.
517
518    ///Processes the next node.
519    ///
520    ///\warning The queue must not be empty!
521    void processNextNode()
522    {
523      if(_queue_tail==_queue_next_dist) {
524        _curr_dist++;
525        _queue_next_dist=_queue_head;
526      }
527      Node n=_queue[_queue_tail++];
528      _processed->set(n,true);
529      Node m;
530      for(OutEdgeIt e(*G,n);e!=INVALID;++e)
531        if(!(*_reached)[m=G->target(e)]) {
532          _queue[_queue_head++]=m;
533          _reached->set(m,true);
534          _pred->set(m,e);
535//        _pred_node->set(m,n);
536          _dist->set(m,_curr_dist);
537        }
538    }
539     
540    ///\brief Returns \c false if there are nodes
541    ///to be processed in the queue
542    ///
543    ///Returns \c false if there are nodes
544    ///to be processed in the queue
545    bool emptyQueue() { return _queue_tail==_queue_head; }
546    ///Returns the number of the nodes to be processed.
547   
548    ///Returns the number of the nodes to be processed in the queue.
549    ///
550    int queueSize() { return _queue_head-_queue_tail; }
551   
552    ///Executes the algorithm.
553
554    ///Executes the algorithm.
555    ///
556    ///\pre init() must be called and at least one node should be added
557    ///with addSource() before using this function.
558    ///
559    ///This method runs the %BFS algorithm from the root node(s)
560    ///in order to
561    ///compute the
562    ///shortest path to each node. The algorithm computes
563    ///- The shortest path tree.
564    ///- The distance of each node from the root(s).
565    ///
566    void start()
567    {
568      while ( !emptyQueue() ) processNextNode();
569    }
570   
571    ///Executes the algorithm until \c dest is reached.
572
573    ///Executes the algorithm until \c dest is reached.
574    ///
575    ///\pre init() must be called and at least one node should be added
576    ///with addSource() before using this function.
577    ///
578    ///This method runs the %BFS algorithm from the root node(s)
579    ///in order to
580    ///compute the
581    ///shortest path to \c dest. The algorithm computes
582    ///- The shortest path to \c  dest.
583    ///- The distance of \c dest from the root(s).
584    ///
585    void start(Node dest)
586    {
587      while ( !emptyQueue() && _queue[_queue_tail]!=dest ) processNextNode();
588    }
589   
590    ///Executes the algorithm until a condition is met.
591
592    ///Executes the algorithm until a condition is met.
593    ///
594    ///\pre init() must be called and at least one node should be added
595    ///with addSource() before using this function.
596    ///
597    ///\param nm must be a bool (or convertible) node map. The algorithm
598    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
599    template<class NM>
600      void start(const NM &nm)
601      {
602        while ( !emptyQueue() && !nm[_queue[_queue_tail]] ) processNextNode();
603      }
604   
605    ///Runs %BFS algorithm from node \c s.
606   
607    ///This method runs the %BFS algorithm from a root node \c s
608    ///in order to
609    ///compute the
610    ///shortest path to each node. The algorithm computes
611    ///- The shortest path tree.
612    ///- The distance of each node from the root.
613    ///
614    ///\note d.run(s) is just a shortcut of the following code.
615    ///\code
616    ///  d.init();
617    ///  d.addSource(s);
618    ///  d.start();
619    ///\endcode
620    void run(Node s) {
621      init();
622      addSource(s);
623      start();
624    }
625   
626    ///Finds the shortest path between \c s and \c t.
627   
628    ///Finds the shortest path between \c s and \c t.
629    ///
630    ///\return The length of the shortest s---t path if there exists one,
631    ///0 otherwise.
632    ///\note Apart from the return value, d.run(s) is
633    ///just a shortcut of the following code.
634    ///\code
635    ///  d.init();
636    ///  d.addSource(s);
637    ///  d.start(t);
638    ///\endcode
639    int run(Node s,Node t) {
640      init();
641      addSource(s);
642      start(t);
643      return reached(t)?_curr_dist-1+(_queue_tail==_queue_next_dist):0;
644    }
645   
646    ///@}
647
648    ///\name Query Functions
649    ///The result of the %BFS algorithm can be obtained using these
650    ///functions.\n
651    ///Before the use of these functions,
652    ///either run() or start() must be called.
653   
654    ///@{
655
656    ///Copies the shortest path to \c t into \c p
657   
658    ///This function copies the shortest path to \c t into \c p.
659    ///If it \c \t is a source itself or unreachable, then it does not
660    ///alter \c p.
661    ///\todo Is it the right way to handle unreachable nodes?
662    ///\return Returns \c true if a path to \c t was actually copied to \c p,
663    ///\c false otherwise.
664    ///\sa DirPath
665    template<class P>
666    bool getPath(P &p,Node t)
667    {
668      if(reached(t)) {
669        p.clear();
670        typename P::Builder b(p);
671        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
672          b.pushFront(pred(t));
673        b.commit();
674        return true;
675      }
676      return false;
677    }
678
679    ///The distance of a node from the root(s).
680
681    ///Returns the distance of a node from the root(s).
682    ///\pre \ref run() must be called before using this function.
683    ///\warning If node \c v in unreachable from the root(s) the return value
684    ///of this function is undefined.
685    int dist(Node v) const { return (*_dist)[v]; }
686
687    ///Returns the 'previous edge' of the shortest path tree.
688
689    ///For a node \c v it returns the 'previous edge'
690    ///of the shortest path tree,
691    ///i.e. it returns the last edge of a shortest path from the root(s) to \c
692    ///v. It is \ref INVALID
693    ///if \c v is unreachable from the root(s) or \c v is a root. The
694    ///shortest path tree used here is equal to the shortest path tree used in
695    ///\ref predNode(Node v).
696    ///\pre Either \ref run() or \ref start() must be called before using
697    ///this function.
698    ///\todo predEdge could be a better name.
699    Edge pred(Node v) const { return (*_pred)[v];}
700
701    ///Returns the 'previous node' of the shortest path tree.
702
703    ///For a node \c v it returns the 'previous node'
704    ///of the shortest path tree,
705    ///i.e. it returns the last but one node from a shortest path from the
706    ///root(a) to \c /v.
707    ///It is INVALID if \c v is unreachable from the root(s) or
708    ///if \c v itself a root.
709    ///The shortest path tree used here is equal to the shortest path
710    ///tree used in \ref pred(Node v).
711    ///\pre Either \ref run() or \ref start() must be called before
712    ///using this function.
713    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
714                                  G->source((*_pred)[v]); }
715   
716    ///Returns a reference to the NodeMap of distances.
717
718    ///Returns a reference to the NodeMap of distances.
719    ///\pre Either \ref run() or \ref init() must
720    ///be called before using this function.
721    const DistMap &distMap() const { return *_dist;}
722 
723    ///Returns a reference to the shortest path tree map.
724
725    ///Returns a reference to the NodeMap of the edges of the
726    ///shortest path tree.
727    ///\pre Either \ref run() or \ref init()
728    ///must be called before using this function.
729    const PredMap &predMap() const { return *_pred;}
730 
731//     ///Returns a reference to the map of nodes of shortest paths.
732
733//     ///Returns a reference to the NodeMap of the last but one nodes of the
734//     ///shortest path tree.
735//     ///\pre \ref run() must be called before using this function.
736//     const PredNodeMap &predNodeMap() const { return *_predNode;}
737
738    ///Checks if a node is reachable from the root.
739
740    ///Returns \c true if \c v is reachable from the root.
741    ///\warning The source nodes are indicated as unreached.
742    ///\pre Either \ref run() or \ref start()
743    ///must be called before using this function.
744    ///
745    bool reached(Node v) { return (*_reached)[v]; }
746   
747    ///@}
748  };
749
750  ///Default traits class of Bfs function.
751
752  ///Default traits class of Bfs function.
753  ///\param GR Graph type.
754  template<class GR>
755  struct BfsWizardDefaultTraits
756  {
757    ///The graph type the algorithm runs on.
758    typedef GR Graph;
759    ///\brief The type of the map that stores the last
760    ///edges of the shortest paths.
761    ///
762    ///The type of the map that stores the last
763    ///edges of the shortest paths.
764    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
765    ///
766    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
767    ///Instantiates a PredMap.
768 
769    ///This function instantiates a \ref PredMap.
770    ///\param G is the graph, to which we would like to define the PredMap.
771    ///\todo The graph alone may be insufficient to initialize
772    static PredMap *createPredMap(const GR &G)
773    {
774      return new PredMap();
775    }
776//     ///\brief The type of the map that stores the last but one
777//     ///nodes of the shortest paths.
778//     ///
779//     ///The type of the map that stores the last but one
780//     ///nodes of the shortest paths.
781//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
782//     ///
783//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
784//     ///Instantiates a PredNodeMap.
785   
786//     ///This function instantiates a \ref PredNodeMap.
787//     ///\param G is the graph, to which
788//     ///we would like to define the \ref PredNodeMap
789//     static PredNodeMap *createPredNodeMap(const GR &G)
790//     {
791//       return new PredNodeMap();
792//     }
793
794    ///The type of the map that indicates which nodes are processed.
795 
796    ///The type of the map that indicates which nodes are processed.
797    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
798    ///\todo named parameter to set this type, function to read and write.
799    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
800    ///Instantiates a ProcessedMap.
801 
802    ///This function instantiates a \ref ProcessedMap.
803    ///\param G is the graph, to which
804    ///we would like to define the \ref ProcessedMap
805    static ProcessedMap *createProcessedMap(const GR &G)
806    {
807      return new ProcessedMap();
808    }
809    ///The type of the map that indicates which nodes are reached.
810 
811    ///The type of the map that indicates which nodes are reached.
812    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
813    ///\todo named parameter to set this type, function to read and write.
814    typedef typename Graph::template NodeMap<bool> ReachedMap;
815    ///Instantiates a ReachedMap.
816 
817    ///This function instantiates a \ref ReachedMap.
818    ///\param G is the graph, to which
819    ///we would like to define the \ref ReachedMap.
820    static ReachedMap *createReachedMap(const GR &G)
821    {
822      return new ReachedMap(G);
823    }
824    ///The type of the map that stores the dists of the nodes.
825 
826    ///The type of the map that stores the dists of the nodes.
827    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
828    ///
829    typedef NullMap<typename Graph::Node,int> DistMap;
830    ///Instantiates a DistMap.
831 
832    ///This function instantiates a \ref DistMap.
833    ///\param G is the graph, to which we would like to define the \ref DistMap
834    static DistMap *createDistMap(const GR &G)
835    {
836      return new DistMap();
837    }
838  };
839 
840  /// Default traits used by \ref BfsWizard
841
842  /// To make it easier to use Bfs algorithm
843  ///we have created a wizard class.
844  /// This \ref BfsWizard class needs default traits,
845  ///as well as the \ref Bfs class.
846  /// The \ref BfsWizardBase is a class to be the default traits of the
847  /// \ref BfsWizard class.
848  template<class GR>
849  class BfsWizardBase : public BfsWizardDefaultTraits<GR>
850  {
851
852    typedef BfsWizardDefaultTraits<GR> Base;
853  protected:
854    /// Type of the nodes in the graph.
855    typedef typename Base::Graph::Node Node;
856
857    /// Pointer to the underlying graph.
858    void *_g;
859    ///Pointer to the map of reached nodes.
860    void *_reached;
861    ///Pointer to the map of processed nodes.
862    void *_processed;
863    ///Pointer to the map of predecessors edges.
864    void *_pred;
865//     ///Pointer to the map of predecessors nodes.
866//     void *_predNode;
867    ///Pointer to the map of distances.
868    void *_dist;
869    ///Pointer to the source node.
870    Node _source;
871   
872    public:
873    /// Constructor.
874   
875    /// This constructor does not require parameters, therefore it initiates
876    /// all of the attributes to default values (0, INVALID).
877    BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
878//                         _predNode(0),
879                           _dist(0), _source(INVALID) {}
880
881    /// Constructor.
882   
883    /// This constructor requires some parameters,
884    /// listed in the parameters list.
885    /// Others are initiated to 0.
886    /// \param g is the initial value of  \ref _g
887    /// \param s is the initial value of  \ref _source
888    BfsWizardBase(const GR &g, Node s=INVALID) :
889      _g((void *)&g), _reached(0), _processed(0), _pred(0),
890//       _predNode(0),
891      _dist(0), _source(s) {}
892
893  };
894 
895  /// A class to make the usage of Bfs algorithm easier
896
897  /// This class is created to make it easier to use Bfs algorithm.
898  /// It uses the functions and features of the plain \ref Bfs,
899  /// but it is much simpler to use it.
900  ///
901  /// Simplicity means that the way to change the types defined
902  /// in the traits class is based on functions that returns the new class
903  /// and not on templatable built-in classes.
904  /// When using the plain \ref Bfs
905  /// the new class with the modified type comes from
906  /// the original class by using the ::
907  /// operator. In the case of \ref BfsWizard only
908  /// a function have to be called and it will
909  /// return the needed class.
910  ///
911  /// It does not have own \ref run method. When its \ref run method is called
912  /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run
913  /// method of it.
914  template<class TR>
915  class BfsWizard : public TR
916  {
917    typedef TR Base;
918
919    ///The type of the underlying graph.
920    typedef typename TR::Graph Graph;
921    //\e
922    typedef typename Graph::Node Node;
923    //\e
924    typedef typename Graph::NodeIt NodeIt;
925    //\e
926    typedef typename Graph::Edge Edge;
927    //\e
928    typedef typename Graph::OutEdgeIt OutEdgeIt;
929   
930    ///\brief The type of the map that stores
931    ///the reached nodes
932    typedef typename TR::ReachedMap ReachedMap;
933    ///\brief The type of the map that stores
934    ///the processed nodes
935    typedef typename TR::ProcessedMap ProcessedMap;
936    ///\brief The type of the map that stores the last
937    ///edges of the shortest paths.
938    typedef typename TR::PredMap PredMap;
939//     ///\brief The type of the map that stores the last but one
940//     ///nodes of the shortest paths.
941//     typedef typename TR::PredNodeMap PredNodeMap;
942    ///The type of the map that stores the dists of the nodes.
943    typedef typename TR::DistMap DistMap;
944
945public:
946    /// Constructor.
947    BfsWizard() : TR() {}
948
949    /// Constructor that requires parameters.
950
951    /// Constructor that requires parameters.
952    /// These parameters will be the default values for the traits class.
953    BfsWizard(const Graph &g, Node s=INVALID) :
954      TR(g,s) {}
955
956    ///Copy constructor
957    BfsWizard(const TR &b) : TR(b) {}
958
959    ~BfsWizard() {}
960
961    ///Runs Bfs algorithm from a given node.
962   
963    ///Runs Bfs algorithm from a given node.
964    ///The node can be given by the \ref source function.
965    void run()
966    {
967      if(Base::_source==INVALID) throw UninitializedParameter();
968      Bfs<Graph,TR> alg(*(Graph*)Base::_g);
969      if(Base::_reached)
970        alg.reachedMap(*(ReachedMap*)Base::_reached);
971      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
972      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
973//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
974      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
975      alg.run(Base::_source);
976    }
977
978    ///Runs Bfs algorithm from the given node.
979
980    ///Runs Bfs algorithm from the given node.
981    ///\param s is the given source.
982    void run(Node s)
983    {
984      Base::_source=s;
985      run();
986    }
987
988    template<class T>
989    struct DefPredMapBase : public Base {
990      typedef T PredMap;
991      static PredMap *createPredMap(const Graph &G) { return 0; };
992      DefPredMapBase(const TR &b) : TR(b) {}
993    };
994   
995    ///\brief \ref named-templ-param "Named parameter"
996    ///function for setting PredMap
997    ///
998    /// \ref named-templ-param "Named parameter"
999    ///function for setting PredMap
1000    ///
1001    template<class T>
1002    BfsWizard<DefPredMapBase<T> > predMap(const T &t)
1003    {
1004      Base::_pred=(void *)&t;
1005      return BfsWizard<DefPredMapBase<T> >(*this);
1006    }
1007   
1008 
1009    template<class T>
1010    struct DefReachedMapBase : public Base {
1011      typedef T ReachedMap;
1012      static ReachedMap *createReachedMap(const Graph &G) { return 0; };
1013      DefReachedMapBase(const TR &b) : TR(b) {}
1014    };
1015   
1016    ///\brief \ref named-templ-param "Named parameter"
1017    ///function for setting ReachedMap
1018    ///
1019    /// \ref named-templ-param "Named parameter"
1020    ///function for setting ReachedMap
1021    ///
1022    template<class T>
1023    BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1024    {
1025      Base::_pred=(void *)&t;
1026      return BfsWizard<DefReachedMapBase<T> >(*this);
1027    }
1028   
1029
1030    template<class T>
1031    struct DefProcessedMapBase : public Base {
1032      typedef T ProcessedMap;
1033      static ProcessedMap *createProcessedMap(const Graph &G) { return 0; };
1034      DefProcessedMapBase(const TR &b) : TR(b) {}
1035    };
1036   
1037    ///\brief \ref named-templ-param "Named parameter"
1038    ///function for setting ProcessedMap
1039    ///
1040    /// \ref named-templ-param "Named parameter"
1041    ///function for setting ProcessedMap
1042    ///
1043    template<class T>
1044    BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1045    {
1046      Base::_pred=(void *)&t;
1047      return BfsWizard<DefProcessedMapBase<T> >(*this);
1048    }
1049   
1050
1051//     template<class T>
1052//     struct DefPredNodeMapBase : public Base {
1053//       typedef T PredNodeMap;
1054//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1055//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1056//     };
1057   
1058//     ///\brief \ref named-templ-param "Named parameter"
1059//     ///function for setting PredNodeMap type
1060//     ///
1061//     /// \ref named-templ-param "Named parameter"
1062//     ///function for setting PredNodeMap type
1063//     ///
1064//     template<class T>
1065//     BfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1066//     {
1067//       Base::_predNode=(void *)&t;
1068//       return BfsWizard<DefPredNodeMapBase<T> >(*this);
1069//     }
1070   
1071    template<class T>
1072    struct DefDistMapBase : public Base {
1073      typedef T DistMap;
1074      static DistMap *createDistMap(const Graph &G) { return 0; };
1075      DefDistMapBase(const TR &b) : TR(b) {}
1076    };
1077   
1078    ///\brief \ref named-templ-param "Named parameter"
1079    ///function for setting DistMap type
1080    ///
1081    /// \ref named-templ-param "Named parameter"
1082    ///function for setting DistMap type
1083    ///
1084    template<class T>
1085    BfsWizard<DefDistMapBase<T> > distMap(const T &t)
1086    {
1087      Base::_dist=(void *)&t;
1088      return BfsWizard<DefDistMapBase<T> >(*this);
1089    }
1090   
1091    /// Sets the source node, from which the Bfs algorithm runs.
1092
1093    /// Sets the source node, from which the Bfs algorithm runs.
1094    /// \param s is the source node.
1095    BfsWizard<TR> &source(Node s)
1096    {
1097      Base::_source=s;
1098      return *this;
1099    }
1100   
1101  };
1102 
1103  ///Function type interface for Bfs algorithm.
1104
1105  /// \ingroup flowalgs
1106  ///Function type interface for Bfs algorithm.
1107  ///
1108  ///This function also has several
1109  ///\ref named-templ-func-param "named parameters",
1110  ///they are declared as the members of class \ref BfsWizard.
1111  ///The following
1112  ///example shows how to use these parameters.
1113  ///\code
1114  ///  bfs(g,source).predMap(preds).run();
1115  ///\endcode
1116  ///\warning Don't forget to put the \ref BfsWizard::run() "run()"
1117  ///to the end of the parameter list.
1118  ///\sa BfsWizard
1119  ///\sa Bfs
1120  template<class GR>
1121  BfsWizard<BfsWizardBase<GR> >
1122  bfs(const GR &g,typename GR::Node s=INVALID)
1123  {
1124    return BfsWizard<BfsWizardBase<GR> >(g,s);
1125  }
1126
1127} //END OF NAMESPACE LEMON
1128
1129#endif
1130
Note: See TracBrowser for help on using the repository browser.