COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/dijkstra.h @ 1359:1581f961cfaa

Last change on this file since 1359:1581f961cfaa was 1359:1581f961cfaa, checked in by Alpar Juttner, 15 years ago

Correct the english name of EGRES.

File size: 33.9 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/dijkstra.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_DIJKSTRA_H
18#define LEMON_DIJKSTRA_H
19
20///\ingroup flowalgs
21///\file
22///\brief Dijkstra algorithm.
23///
24///\todo getPath() should be implemented! (also for BFS and DFS)
25
26#include <lemon/list_graph.h>
27#include <lemon/bin_heap.h>
28#include <lemon/invalid.h>
29#include <lemon/error.h>
30#include <lemon/maps.h>
31
32namespace lemon {
33
34
35 
36  ///Default traits class of Dijkstra class.
37
38  ///Default traits class of Dijkstra class.
39  ///\param GR Graph type.
40  ///\param LM Type of length map.
41  template<class GR, class LM>
42  struct DijkstraDefaultTraits
43  {
44    ///The graph type the algorithm runs on.
45    typedef GR Graph;
46    ///The type of the map that stores the edge lengths.
47
48    ///The type of the map that stores the edge lengths.
49    ///It must meet the \ref concept::ReadMap "ReadMap" concept.
50    typedef LM LengthMap;
51    //The type of the length of the edges.
52    typedef typename LM::Value Value;
53    ///The heap type used by Dijkstra algorithm.
54
55    ///The heap type used by Dijkstra algorithm.
56    ///
57    ///\sa BinHeap
58    ///\sa Dijkstra
59    typedef BinHeap<typename Graph::Node,
60                    typename LM::Value,
61                    typename GR::template NodeMap<int>,
62                    std::less<Value> > Heap;
63
64    ///\brief The type of the map that stores the last
65    ///edges of the shortest paths.
66    ///
67    ///The type of the map that stores the last
68    ///edges of the shortest paths.
69    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
70    ///
71    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
72    ///Instantiates a PredMap.
73 
74    ///This function instantiates a \ref PredMap.
75    ///\param G is the graph, to which we would like to define the PredMap.
76    ///\todo The graph alone may be insufficient for the initialization
77    static PredMap *createPredMap(const GR &G)
78    {
79      return new PredMap(G);
80    }
81//     ///\brief The type of the map that stores the last but one
82//     ///nodes of the shortest paths.
83//     ///
84//     ///The type of the map that stores the last but one
85//     ///nodes of the shortest paths.
86//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
87//     ///
88//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
89//     ///Instantiates a PredNodeMap.
90   
91//     ///This function instantiates a \ref PredNodeMap.
92//     ///\param G is the graph, to which
93//     ///we would like to define the \ref PredNodeMap
94//     static PredNodeMap *createPredNodeMap(const GR &G)
95//     {
96//       return new PredNodeMap();
97//     }
98
99    ///The type of the map that stores whether a nodes is processed.
100 
101    ///The type of the map that stores whether a nodes is processed.
102    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
103    ///By default it is a NullMap.
104    ///\todo If it is set to a real map,
105    ///Dijkstra::processed() should read this.
106    ///\todo named parameter to set this type, function to read and write.
107    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
108    ///Instantiates a ProcessedMap.
109 
110    ///This function instantiates a \ref ProcessedMap.
111    ///\param G is the graph, to which
112    ///we would like to define the \ref ProcessedMap
113    static ProcessedMap *createProcessedMap(const GR &G)
114    {
115      return new ProcessedMap();
116    }
117    ///The type of the map that stores the dists of the nodes.
118 
119    ///The type of the map that stores the dists of the nodes.
120    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
121    ///
122    typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
123    ///Instantiates a DistMap.
124 
125    ///This function instantiates a \ref DistMap.
126    ///\param G is the graph, to which we would like to define the \ref DistMap
127    static DistMap *createDistMap(const GR &G)
128    {
129      return new DistMap(G);
130    }
131  };
132 
133  ///%Dijkstra algorithm class.
134 
135  /// \ingroup flowalgs
136  ///This class provides an efficient implementation of %Dijkstra algorithm.
137  ///The edge lengths are passed to the algorithm using a
138  ///\ref concept::ReadMap "ReadMap",
139  ///so it is easy to change it to any kind of length.
140  ///
141  ///The type of the length is determined by the
142  ///\ref concept::ReadMap::Value "Value" of the length map.
143  ///
144  ///It is also possible to change the underlying priority heap.
145  ///
146  ///\param GR The graph type the algorithm runs on. The default value
147  ///is \ref ListGraph. The value of GR is not used directly by
148  ///Dijkstra, it is only passed to \ref DijkstraDefaultTraits.
149  ///\param LM This read-only EdgeMap determines the lengths of the
150  ///edges. It is read once for each edge, so the map may involve in
151  ///relatively time consuming process to compute the edge length if
152  ///it is necessary. The default map type is \ref
153  ///concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>".  The value
154  ///of LM is not used directly by Dijkstra, it is only passed to \ref
155  ///DijkstraDefaultTraits.  \param TR Traits class to set
156  ///various data types used by the algorithm.  The default traits
157  ///class is \ref DijkstraDefaultTraits
158  ///"DijkstraDefaultTraits<GR,LM>".  See \ref
159  ///DijkstraDefaultTraits for the documentation of a Dijkstra traits
160  ///class.
161  ///
162  ///\author Jacint Szabo and Alpar Juttner
163  ///\todo A compare object would be nice.
164
165#ifdef DOXYGEN
166  template <typename GR,
167            typename LM,
168            typename TR>
169#else
170  template <typename GR=ListGraph,
171            typename LM=typename GR::template EdgeMap<int>,
172            typename TR=DijkstraDefaultTraits<GR,LM> >
173#endif
174  class Dijkstra {
175  public:
176    /**
177     * \brief \ref Exception for uninitialized parameters.
178     *
179     * This error represents problems in the initialization
180     * of the parameters of the algorithms.
181     */
182    class UninitializedParameter : public lemon::UninitializedParameter {
183    public:
184      virtual const char* exceptionName() const {
185        return "lemon::Dijkstra::UninitializedParameter";
186      }
187    };
188
189    typedef TR Traits;
190    ///The type of the underlying graph.
191    typedef typename TR::Graph Graph;
192    ///\e
193    typedef typename Graph::Node Node;
194    ///\e
195    typedef typename Graph::NodeIt NodeIt;
196    ///\e
197    typedef typename Graph::Edge Edge;
198    ///\e
199    typedef typename Graph::OutEdgeIt OutEdgeIt;
200   
201    ///The type of the length of the edges.
202    typedef typename TR::LengthMap::Value Value;
203    ///The type of the map that stores the edge lengths.
204    typedef typename TR::LengthMap LengthMap;
205    ///\brief The type of the map that stores the last
206    ///edges of the shortest paths.
207    typedef typename TR::PredMap PredMap;
208//     ///\brief The type of the map that stores the last but one
209//     ///nodes of the shortest paths.
210//     typedef typename TR::PredNodeMap PredNodeMap;
211    ///The type of the map indicating if a node is processed.
212    typedef typename TR::ProcessedMap ProcessedMap;
213    ///The type of the map that stores the dists of the nodes.
214    typedef typename TR::DistMap DistMap;
215    ///The heap type used by the dijkstra algorithm.
216    typedef typename TR::Heap Heap;
217  private:
218    /// Pointer to the underlying graph.
219    const Graph *G;
220    /// Pointer to the length map
221    const LengthMap *length;
222    ///Pointer to the map of predecessors edges.
223    PredMap *_pred;
224    ///Indicates if \ref _pred is locally allocated (\c true) or not.
225    bool local_pred;
226//     ///Pointer to the map of predecessors nodes.
227//     PredNodeMap *_predNode;
228//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
229//     bool local_predNode;
230    ///Pointer to the map of distances.
231    DistMap *_dist;
232    ///Indicates if \ref _dist is locally allocated (\c true) or not.
233    bool local_dist;
234    ///Pointer to the map of processed status of the nodes.
235    ProcessedMap *_processed;
236    ///Indicates if \ref _processed is locally allocated (\c true) or not.
237    bool local_processed;
238
239//     ///The source node of the last execution.
240//     Node source;
241
242    ///Creates the maps if necessary.
243   
244    ///\todo Error if \c G or are \c NULL. What about \c length?
245    ///\todo Better memory allocation (instead of new).
246    void create_maps()
247    {
248      if(!_pred) {
249        local_pred = true;
250        _pred = Traits::createPredMap(*G);
251      }
252//       if(!_predNode) {
253//      local_predNode = true;
254//      _predNode = Traits::createPredNodeMap(*G);
255//       }
256      if(!_dist) {
257        local_dist = true;
258        _dist = Traits::createDistMap(*G);
259      }
260      if(!_processed) {
261        local_processed = true;
262        _processed = Traits::createProcessedMap(*G);
263      }
264    }
265   
266  public :
267 
268    ///\name Named template parameters
269
270    ///@{
271
272    template <class T>
273    struct DefPredMapTraits : public Traits {
274      typedef T PredMap;
275      static PredMap *createPredMap(const Graph &G)
276      {
277        throw UninitializedParameter();
278      }
279    };
280    ///\ref named-templ-param "Named parameter" for setting PredMap type
281
282    ///\ref named-templ-param "Named parameter" for setting PredMap type
283    ///
284    template <class T>
285    class DefPredMap : public Dijkstra< Graph,
286                                        LengthMap,
287                                        DefPredMapTraits<T> > { };
288   
289//     template <class T>
290//     struct DefPredNodeMapTraits : public Traits {
291//       typedef T PredNodeMap;
292//       static PredNodeMap *createPredNodeMap(const Graph &G)
293//       {
294//      throw UninitializedParameter();
295//       }
296//     };
297//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
298
299//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
300//     ///
301//     template <class T>
302//     class DefPredNodeMap : public Dijkstra< Graph,
303//                                          LengthMap,
304//                                          DefPredNodeMapTraits<T> > { };
305   
306    template <class T>
307    struct DefDistMapTraits : public Traits {
308      typedef T DistMap;
309      static DistMap *createDistMap(const Graph &G)
310      {
311        throw UninitializedParameter();
312      }
313    };
314    ///\ref named-templ-param "Named parameter" for setting DistMap type
315
316    ///\ref named-templ-param "Named parameter" for setting DistMap type
317    ///
318    template <class T>
319    class DefDistMap : public Dijkstra< Graph,
320                                        LengthMap,
321                                        DefDistMapTraits<T> > { };
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 Dijkstra< Graph,
337                                        LengthMap,
338                                        DefProcessedMapTraits<T> > { };
339   
340    struct DefGraphProcessedMapTraits : public Traits {
341      typedef typename Graph::template NodeMap<bool> ProcessedMap;
342      static ProcessedMap *createProcessedMap(const Graph &G)
343      {
344        return new ProcessedMap(G);
345      }
346    };
347    ///\brief \ref named-templ-param "Named parameter"
348    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
349    ///
350    ///\ref named-templ-param "Named parameter"
351    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
352    ///If you don't set it explicitely, it will be automatically allocated.
353    template <class T>
354    class DefProcessedMapToBeDefaultMap :
355      public Dijkstra< Graph,
356                       LengthMap,
357                       DefGraphProcessedMapTraits> { };
358   
359    ///@}
360
361
362  private:
363    typename Graph::template NodeMap<int> _heap_map;
364    Heap _heap;
365  public:     
366   
367    ///Constructor.
368   
369    ///\param _G the graph the algorithm will run on.
370    ///\param _length the length map used by the algorithm.
371    Dijkstra(const Graph& _G, const LengthMap& _length) :
372      G(&_G), length(&_length),
373      _pred(NULL), local_pred(false),
374//       _predNode(NULL), local_predNode(false),
375      _dist(NULL), local_dist(false),
376      _processed(NULL), local_processed(false),
377      _heap_map(*G,-1),_heap(_heap_map)
378    { }
379   
380    ///Destructor.
381    ~Dijkstra()
382    {
383      if(local_pred) delete _pred;
384//       if(local_predNode) delete _predNode;
385      if(local_dist) delete _dist;
386      if(local_processed) delete _processed;
387    }
388
389    ///Sets the length map.
390
391    ///Sets the length map.
392    ///\return <tt> (*this) </tt>
393    Dijkstra &lengthMap(const LengthMap &m)
394    {
395      length = &m;
396      return *this;
397    }
398
399    ///Sets the map storing the predecessor edges.
400
401    ///Sets the map storing the predecessor edges.
402    ///If you don't use this function before calling \ref run(),
403    ///it will allocate one. The destuctor deallocates this
404    ///automatically allocated map, of course.
405    ///\return <tt> (*this) </tt>
406    Dijkstra &predMap(PredMap &m)
407    {
408      if(local_pred) {
409        delete _pred;
410        local_pred=false;
411      }
412      _pred = &m;
413      return *this;
414    }
415
416//     ///Sets the map storing the predecessor nodes.
417
418//     ///Sets the map storing the predecessor nodes.
419//     ///If you don't use this function before calling \ref run(),
420//     ///it will allocate one. The destuctor deallocates this
421//     ///automatically allocated map, of course.
422//     ///\return <tt> (*this) </tt>
423//     Dijkstra &predNodeMap(PredNodeMap &m)
424//     {
425//       if(local_predNode) {
426//      delete _predNode;
427//      local_predNode=false;
428//       }
429//       _predNode = &m;
430//       return *this;
431//     }
432
433    ///Sets the map storing the distances calculated by the algorithm.
434
435    ///Sets the map storing the distances calculated by the algorithm.
436    ///If you don't use this function before calling \ref run(),
437    ///it will allocate one. The destuctor deallocates this
438    ///automatically allocated map, of course.
439    ///\return <tt> (*this) </tt>
440    Dijkstra &distMap(DistMap &m)
441    {
442      if(local_dist) {
443        delete _dist;
444        local_dist=false;
445      }
446      _dist = &m;
447      return *this;
448    }
449
450  private:
451    void finalizeNodeData(Node v,Value dst)
452    {
453      _processed->set(v,true);
454      _dist->set(v, dst);
455//       if((*_pred)[v]!=INVALID)
456//       _predNode->set(v,G->source((*_pred)[v])); ///\todo What to do?
457    }
458
459  public:
460    ///\name Execution control
461    ///The simplest way to execute the algorithm is to use
462    ///one of the member functions called \c run(...).
463    ///\n
464    ///If you need more control on the execution,
465    ///first you must call \ref init(), then you can add several source nodes
466    ///with \ref addSource().
467    ///Finally \ref start() will perform the actual path
468    ///computation.
469
470    ///@{
471
472    ///Initializes the internal data structures.
473
474    ///Initializes the internal data structures.
475    ///
476    ///\todo _heap_map's type could also be in the traits class.
477    ///\todo The heaps should be able to make themselves empty directly.
478    void init()
479    {
480      create_maps();
481      while(!_heap.empty()) _heap.pop();
482      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
483        _pred->set(u,INVALID);
484//      _predNode->set(u,INVALID);
485        _processed->set(u,false);
486        _heap_map.set(u,Heap::PRE_HEAP);
487      }
488    }
489   
490    ///Adds a new source node.
491
492    ///Adds a new source node to the priority heap.
493    ///
494    ///The optional second parameter is the initial distance of the node.
495    ///
496    ///It checks if the node has already been added to the heap and
497    ///It is pushed to the heap only if either it was not in the heap
498    ///or the shortest path found till then is longer then \c dst.
499    void addSource(Node s,Value dst=0)
500    {
501//       source = s;
502      if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst);
503      else if(_heap[s]<dst) {
504        _heap.push(s,dst);
505        _pred->set(s,INVALID);
506      }
507    }
508   
509    ///Processes the next node in the priority heap
510
511    ///Processes the next node in the priority heap.
512    ///
513    ///\warning The priority heap must not be empty!
514    void processNextNode()
515    {
516      Node v=_heap.top();
517      Value oldvalue=_heap[v];
518      _heap.pop();
519      finalizeNodeData(v,oldvalue);
520     
521      for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
522        Node w=G->target(e);
523        switch(_heap.state(w)) {
524        case Heap::PRE_HEAP:
525          _heap.push(w,oldvalue+(*length)[e]);
526          _pred->set(w,e);
527//        _predNode->set(w,v);
528          break;
529        case Heap::IN_HEAP:
530          if ( oldvalue+(*length)[e] < _heap[w] ) {
531            _heap.decrease(w, oldvalue+(*length)[e]);
532            _pred->set(w,e);
533//          _predNode->set(w,v);
534          }
535          break;
536        case Heap::POST_HEAP:
537          break;
538        }
539      }
540    }
541
542    ///\brief Returns \c false if there are nodes
543    ///to be processed in the priority heap
544    ///
545    ///Returns \c false if there are nodes
546    ///to be processed in the priority heap
547    bool emptyQueue() { return _heap.empty(); }
548    ///Returns the number of the nodes to be processed in the priority heap
549
550    ///Returns the number of the nodes to be processed in the priority heap
551    ///
552    int queueSize() { return _heap.size(); }
553   
554    ///Executes the algorithm.
555
556    ///Executes the algorithm.
557    ///
558    ///\pre init() must be called and at least one node should be added
559    ///with addSource() before using this function.
560    ///
561    ///This method runs the %Dijkstra algorithm from the root node(s)
562    ///in order to
563    ///compute the
564    ///shortest path to each node. The algorithm computes
565    ///- The shortest path tree.
566    ///- The distance of each node from the root(s).
567    ///
568    void start()
569    {
570      while ( !_heap.empty() ) processNextNode();
571    }
572   
573    ///Executes the algorithm until \c dest is reached.
574
575    ///Executes the algorithm until \c dest is reached.
576    ///
577    ///\pre init() must be called and at least one node should be added
578    ///with addSource() before using this function.
579    ///
580    ///This method runs the %Dijkstra algorithm from the root node(s)
581    ///in order to
582    ///compute the
583    ///shortest path to \c dest. The algorithm computes
584    ///- The shortest path to \c  dest.
585    ///- The distance of \c dest from the root(s).
586    ///
587    void start(Node dest)
588    {
589      while ( !_heap.empty() && _heap.top()!=dest ) processNextNode();
590      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
591    }
592   
593    ///Executes the algorithm until a condition is met.
594
595    ///Executes the algorithm until a condition is met.
596    ///
597    ///\pre init() must be called and at least one node should be added
598    ///with addSource() before using this function.
599    ///
600    ///\param nm must be a bool (or convertible) node map. The algorithm
601    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
602    template<class NodeBoolMap>
603    void start(const NodeBoolMap &nm)
604    {
605      while ( !_heap.empty() && !nm[_heap.top()] ) processNextNode();
606      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
607    }
608   
609    ///Runs %Dijkstra algorithm from node \c s.
610   
611    ///This method runs the %Dijkstra algorithm from a root node \c s
612    ///in order to
613    ///compute the
614    ///shortest path to each node. The algorithm computes
615    ///- The shortest path tree.
616    ///- The distance of each node from the root.
617    ///
618    ///\note d.run(s) is just a shortcut of the following code.
619    ///\code
620    ///  d.init();
621    ///  d.addSource(s);
622    ///  d.start();
623    ///\endcode
624    void run(Node s) {
625      init();
626      addSource(s);
627      start();
628    }
629   
630    ///Finds the shortest path between \c s and \c t.
631   
632    ///Finds the shortest path between \c s and \c t.
633    ///
634    ///\return The length of the shortest s---t path if there exists one,
635    ///0 otherwise.
636    ///\note Apart from the return value, d.run(s) is
637    ///just a shortcut of the following code.
638    ///\code
639    ///  d.init();
640    ///  d.addSource(s);
641    ///  d.start(t);
642    ///\endcode
643    Value run(Node s,Node t) {
644      init();
645      addSource(s);
646      start(t);
647      return (*_pred)[t]==INVALID?0:(*_dist)[t];
648    }
649   
650    ///@}
651
652    ///\name Query Functions
653    ///The result of the %Dijkstra algorithm can be obtained using these
654    ///functions.\n
655    ///Before the use of these functions,
656    ///either run() or start() must be called.
657   
658    ///@{
659
660    ///Copies the shortest path to \c t into \c p
661   
662    ///This function copies the shortest path to \c t into \c p.
663    ///If it \c \t is a source itself or unreachable, then it does not
664    ///alter \c p.
665    ///\todo Is it the right way to handle unreachable nodes?
666    ///\return Returns \c true if a path to \c t was actually copied to \c p,
667    ///\c false otherwise.
668    ///\sa DirPath
669    template<class P>
670    bool getPath(P &p,Node t)
671    {
672      if(reached(t)) {
673        p.clear();
674        typename P::Builder b(p);
675        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
676          b.pushFront(pred(t));
677        b.commit();
678        return true;
679      }
680      return false;
681    }
682         
683    ///The distance of a node from the root.
684
685    ///Returns the distance of a node from the root.
686    ///\pre \ref run() must be called before using this function.
687    ///\warning If node \c v in unreachable from the root the return value
688    ///of this funcion is undefined.
689    Value dist(Node v) const { return (*_dist)[v]; }
690
691    ///Returns the 'previous edge' of the shortest path tree.
692
693    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
694    ///i.e. it returns the last edge of a shortest path from the root to \c
695    ///v. It is \ref INVALID
696    ///if \c v is unreachable from the root or if \c v=s. The
697    ///shortest path tree used here is equal to the shortest path tree used in
698    ///\ref predNode(Node v).  \pre \ref run() must be called before using
699    ///this function.
700    ///\todo predEdge could be a better name.
701    Edge pred(Node v) const { return (*_pred)[v]; }
702
703    ///Returns the 'previous node' of the shortest path tree.
704
705    ///For a node \c v it returns the 'previous node' of the shortest path tree,
706    ///i.e. it returns the last but one node from a shortest path from the
707    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
708    ///\c v=s. The shortest path tree used here is equal to the shortest path
709    ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
710    ///using this function.
711    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
712                                  G->source((*_pred)[v]); }
713   
714    ///Returns a reference to the NodeMap of distances.
715
716    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
717    ///be called before using this function.
718    const DistMap &distMap() const { return *_dist;}
719 
720    ///Returns a reference to the shortest path tree map.
721
722    ///Returns a reference to the NodeMap of the edges of the
723    ///shortest path tree.
724    ///\pre \ref run() must be called before using this function.
725    const PredMap &predMap() const { return *_pred;}
726 
727//     ///Returns a reference to the map of nodes of shortest paths.
728
729//     ///Returns a reference to the NodeMap of the last but one nodes of the
730//     ///shortest path tree.
731//     ///\pre \ref run() must be called before using this function.
732//     const PredNodeMap &predNodeMap() const { return *_predNode;}
733
734    ///Checks if a node is reachable from the root.
735
736    ///Returns \c true if \c v is reachable from the root.
737    ///\warning The source nodes are inditated as unreached.
738    ///\pre \ref run() must be called before using this function.
739    ///
740    bool reached(Node v) { return _heap_map[v]!=Heap::PRE_HEAP; }
741   
742    ///@}
743  };
744
745
746
747
748 
749  ///Default traits class of Dijkstra function.
750
751  ///Default traits class of Dijkstra function.
752  ///\param GR Graph type.
753  ///\param LM Type of length map.
754  template<class GR, class LM>
755  struct DijkstraWizardDefaultTraits
756  {
757    ///The graph type the algorithm runs on.
758    typedef GR Graph;
759    ///The type of the map that stores the edge lengths.
760
761    ///The type of the map that stores the edge lengths.
762    ///It must meet the \ref concept::ReadMap "ReadMap" concept.
763    typedef LM LengthMap;
764    //The type of the length of the edges.
765    typedef typename LM::Value Value;
766    ///The heap type used by Dijkstra algorithm.
767
768    ///The heap type used by Dijkstra algorithm.
769    ///
770    ///\sa BinHeap
771    ///\sa Dijkstra
772    typedef BinHeap<typename Graph::Node,
773                    typename LM::Value,
774                    typename GR::template NodeMap<int>,
775                    std::less<Value> > Heap;
776
777    ///\brief The type of the map that stores the last
778    ///edges of the shortest paths.
779    ///
780    ///The type of the map that stores the last
781    ///edges of the shortest paths.
782    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
783    ///
784    typedef NullMap <typename GR::Node,typename GR::Edge> PredMap;
785    ///Instantiates a PredMap.
786 
787    ///This function instantiates a \ref PredMap.
788    ///\param G is the graph, to which we would like to define the PredMap.
789    ///\todo The graph alone may be insufficient for the initialization
790    static PredMap *createPredMap(const GR &G)
791    {
792      return new PredMap();
793    }
794    ///The type of the map that stores whether a nodes is processed.
795 
796    ///The type of the map that stores whether a nodes is processed.
797    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
798    ///By default it is a NullMap.
799    ///\todo If it is set to a real map,
800    ///Dijkstra::processed() should read this.
801    ///\todo named parameter to set this type, function to read and write.
802    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
803    ///Instantiates a ProcessedMap.
804 
805    ///This function instantiates a \ref ProcessedMap.
806    ///\param G is the graph, to which
807    ///we would like to define the \ref ProcessedMap
808    static ProcessedMap *createProcessedMap(const GR &G)
809    {
810      return new ProcessedMap();
811    }
812    ///The type of the map that stores the dists of the nodes.
813 
814    ///The type of the map that stores the dists of the nodes.
815    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
816    ///
817    typedef NullMap<typename Graph::Node,typename LM::Value> DistMap;
818    ///Instantiates a DistMap.
819 
820    ///This function instantiates a \ref DistMap.
821    ///\param G is the graph, to which we would like to define the \ref DistMap
822    static DistMap *createDistMap(const GR &G)
823    {
824      return new DistMap();
825    }
826  };
827 
828  /// Default traits used by \ref DijkstraWizard
829
830  /// To make it easier to use Dijkstra algorithm
831  ///we have created a wizard class.
832  /// This \ref DijkstraWizard class needs default traits,
833  ///as well as the \ref Dijkstra class.
834  /// The \ref DijkstraWizardBase is a class to be the default traits of the
835  /// \ref DijkstraWizard class.
836  /// \todo More named parameters are required...
837  template<class GR,class LM>
838  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>
839  {
840
841    typedef DijkstraWizardDefaultTraits<GR,LM> Base;
842  protected:
843    /// Type of the nodes in the graph.
844    typedef typename Base::Graph::Node Node;
845
846    /// Pointer to the underlying graph.
847    void *_g;
848    /// Pointer to the length map
849    void *_length;
850    ///Pointer to the map of predecessors edges.
851    void *_pred;
852//     ///Pointer to the map of predecessors nodes.
853//     void *_predNode;
854    ///Pointer to the map of distances.
855    void *_dist;
856    ///Pointer to the source node.
857    Node _source;
858
859    public:
860    /// Constructor.
861   
862    /// This constructor does not require parameters, therefore it initiates
863    /// all of the attributes to default values (0, INVALID).
864    DijkstraWizardBase() : _g(0), _length(0), _pred(0),
865//                         _predNode(0),
866                           _dist(0), _source(INVALID) {}
867
868    /// Constructor.
869   
870    /// This constructor requires some parameters,
871    /// listed in the parameters list.
872    /// Others are initiated to 0.
873    /// \param g is the initial value of  \ref _g
874    /// \param l is the initial value of  \ref _length
875    /// \param s is the initial value of  \ref _source
876    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
877      _g((void *)&g), _length((void *)&l), _pred(0),
878//       _predNode(0),
879      _dist(0), _source(s) {}
880
881  };
882 
883  /// A class to make the usage of Dijkstra algorithm easier
884
885  /// This class is created to make it easier to use Dijkstra algorithm.
886  /// It uses the functions and features of the plain \ref Dijkstra,
887  /// but it is much simpler to use it.
888  ///
889  /// Simplicity means that the way to change the types defined
890  /// in the traits class is based on functions that returns the new class
891  /// and not on templatable built-in classes.
892  /// When using the plain \ref Dijkstra
893  /// the new class with the modified type comes from
894  /// the original class by using the ::
895  /// operator. In the case of \ref DijkstraWizard only
896  /// a function have to be called and it will
897  /// return the needed class.
898  ///
899  /// It does not have own \ref run method. When its \ref run method is called
900  /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
901  /// method of it.
902  template<class TR>
903  class DijkstraWizard : public TR
904  {
905    typedef TR Base;
906
907    ///The type of the underlying graph.
908    typedef typename TR::Graph Graph;
909    //\e
910    typedef typename Graph::Node Node;
911    //\e
912    typedef typename Graph::NodeIt NodeIt;
913    //\e
914    typedef typename Graph::Edge Edge;
915    //\e
916    typedef typename Graph::OutEdgeIt OutEdgeIt;
917   
918    ///The type of the map that stores the edge lengths.
919    typedef typename TR::LengthMap LengthMap;
920    ///The type of the length of the edges.
921    typedef typename LengthMap::Value Value;
922    ///\brief The type of the map that stores the last
923    ///edges of the shortest paths.
924    typedef typename TR::PredMap PredMap;
925//     ///\brief The type of the map that stores the last but one
926//     ///nodes of the shortest paths.
927//     typedef typename TR::PredNodeMap PredNodeMap;
928    ///The type of the map that stores the dists of the nodes.
929    typedef typename TR::DistMap DistMap;
930
931    ///The heap type used by the dijkstra algorithm.
932    typedef typename TR::Heap Heap;
933public:
934    /// Constructor.
935    DijkstraWizard() : TR() {}
936
937    /// Constructor that requires parameters.
938
939    /// Constructor that requires parameters.
940    /// These parameters will be the default values for the traits class.
941    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
942      TR(g,l,s) {}
943
944    ///Copy constructor
945    DijkstraWizard(const TR &b) : TR(b) {}
946
947    ~DijkstraWizard() {}
948
949    ///Runs Dijkstra algorithm from a given node.
950   
951    ///Runs Dijkstra algorithm from a given node.
952    ///The node can be given by the \ref source function.
953    void run()
954    {
955      if(Base::_source==INVALID) throw UninitializedParameter();
956      Dijkstra<Graph,LengthMap,TR>
957        dij(*(Graph*)Base::_g,*(LengthMap*)Base::_length);
958      if(Base::_pred) dij.predMap(*(PredMap*)Base::_pred);
959//       if(Base::_predNode) Dij.predNodeMap(*(PredNodeMap*)Base::_predNode);
960      if(Base::_dist) dij.distMap(*(DistMap*)Base::_dist);
961      dij.run(Base::_source);
962    }
963
964    ///Runs Dijkstra algorithm from the given node.
965
966    ///Runs Dijkstra algorithm from the given node.
967    ///\param s is the given source.
968    void run(Node s)
969    {
970      Base::_source=s;
971      run();
972    }
973
974    template<class T>
975    struct DefPredMapBase : public Base {
976      typedef T PredMap;
977      static PredMap *createPredMap(const Graph &G) { return 0; };
978      DefPredMapBase(const TR &b) : TR(b) {}
979    };
980   
981    ///\brief \ref named-templ-param "Named parameter"
982    ///function for setting PredMap type
983    ///
984    /// \ref named-templ-param "Named parameter"
985    ///function for setting PredMap type
986    ///
987    template<class T>
988    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
989    {
990      Base::_pred=(void *)&t;
991      return DijkstraWizard<DefPredMapBase<T> >(*this);
992    }
993   
994
995//     template<class T>
996//     struct DefPredNodeMapBase : public Base {
997//       typedef T PredNodeMap;
998//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
999//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1000//     };
1001   
1002//     ///\brief \ref named-templ-param "Named parameter"
1003//     ///function for setting PredNodeMap type
1004//     ///
1005//     /// \ref named-templ-param "Named parameter"
1006//     ///function for setting PredNodeMap type
1007//     ///
1008//     template<class T>
1009//     DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1010//     {
1011//       Base::_predNode=(void *)&t;
1012//       return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
1013//     }
1014   
1015    template<class T>
1016    struct DefDistMapBase : public Base {
1017      typedef T DistMap;
1018      static DistMap *createDistMap(const Graph &G) { return 0; };
1019      DefDistMapBase(const TR &b) : TR(b) {}
1020    };
1021   
1022    ///\brief \ref named-templ-param "Named parameter"
1023    ///function for setting DistMap type
1024    ///
1025    /// \ref named-templ-param "Named parameter"
1026    ///function for setting DistMap type
1027    ///
1028    template<class T>
1029    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
1030    {
1031      Base::_dist=(void *)&t;
1032      return DijkstraWizard<DefDistMapBase<T> >(*this);
1033    }
1034   
1035    /// Sets the source node, from which the Dijkstra algorithm runs.
1036
1037    /// Sets the source node, from which the Dijkstra algorithm runs.
1038    /// \param s is the source node.
1039    DijkstraWizard<TR> &source(Node s)
1040    {
1041      Base::_source=s;
1042      return *this;
1043    }
1044   
1045  };
1046 
1047  ///Function type interface for Dijkstra algorithm.
1048
1049  /// \ingroup flowalgs
1050  ///Function type interface for Dijkstra algorithm.
1051  ///
1052  ///This function also has several
1053  ///\ref named-templ-func-param "named parameters",
1054  ///they are declared as the members of class \ref DijkstraWizard.
1055  ///The following
1056  ///example shows how to use these parameters.
1057  ///\code
1058  ///  dijkstra(g,length,source).predMap(preds).run();
1059  ///\endcode
1060  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"
1061  ///to the end of the parameter list.
1062  ///\sa DijkstraWizard
1063  ///\sa Dijkstra
1064  template<class GR, class LM>
1065  DijkstraWizard<DijkstraWizardBase<GR,LM> >
1066  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
1067  {
1068    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
1069  }
1070
1071} //END OF NAMESPACE LEMON
1072
1073#endif
1074
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