COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/dijkstra.h @ 1236:fd24f16e0d73

Last change on this file since 1236:fd24f16e0d73 was 1236:fd24f16e0d73, checked in by Alpar Juttner, 15 years ago

Some more MS VC++ compatibility changes (suggested by Janos Tapolcai)

File size: 33.2 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 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_DIJKSTRA_H
18#define LEMON_DIJKSTRA_H
19
20///\ingroup flowalgs
21///\file
22///\brief Dijkstra algorithm.
23
24#include <lemon/list_graph.h>
25#include <lemon/bin_heap.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 Dijkstra class.
35
36  ///Default traits class of Dijkstra class.
37  ///\param GR Graph type.
38  ///\param LM Type of length map.
39  template<class GR, class LM>
40  struct DijkstraDefaultTraits
41  {
42    ///The graph type the algorithm runs on.
43    typedef GR Graph;
44    ///The type of the map that stores the edge lengths.
45
46    ///The type of the map that stores the edge lengths.
47    ///It must meet the \ref concept::ReadMap "ReadMap" concept.
48    typedef LM LengthMap;
49    //The type of the length of the edges.
50    typedef typename LM::Value Value;
51    ///The heap type used by Dijkstra algorithm.
52
53    ///The heap type used by Dijkstra algorithm.
54    ///
55    ///\sa BinHeap
56    ///\sa Dijkstra
57    typedef BinHeap<typename Graph::Node,
58                    typename LM::Value,
59                    typename GR::template NodeMap<int>,
60                    std::less<Value> > Heap;
61
62    ///\brief The type of the map that stores the last
63    ///edges of the shortest paths.
64    ///
65    ///The type of the map that stores the last
66    ///edges of the shortest paths.
67    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
68    ///
69    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
70    ///Instantiates a PredMap.
71 
72    ///This function instantiates a \ref PredMap.
73    ///\param G is the graph, to which we would like to define the PredMap.
74    ///\todo The graph alone may be insufficient for the initialization
75    static PredMap *createPredMap(const GR &G)
76    {
77      return new PredMap(G);
78    }
79//     ///\brief The type of the map that stores the last but one
80//     ///nodes of the shortest paths.
81//     ///
82//     ///The type of the map that stores the last but one
83//     ///nodes of the shortest paths.
84//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
85//     ///
86//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
87//     ///Instantiates a PredNodeMap.
88   
89//     ///This function instantiates a \ref PredNodeMap.
90//     ///\param G is the graph, to which
91//     ///we would like to define the \ref PredNodeMap
92//     static PredNodeMap *createPredNodeMap(const GR &G)
93//     {
94//       return new PredNodeMap();
95//     }
96
97    ///The type of the map that stores whether a nodes is processed.
98 
99    ///The type of the map that stores whether a nodes is processed.
100    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
101    ///By default it is a NullMap.
102    ///\todo If it is set to a real map,
103    ///Dijkstra::processed() should read this.
104    ///\todo named parameter to set this type, function to read and write.
105    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
106    ///Instantiates a ProcessedMap.
107 
108    ///This function instantiates a \ref ProcessedMap.
109    ///\param G is the graph, to which
110    ///we would like to define the \ref ProcessedMap
111    static ProcessedMap *createProcessedMap(const GR &G)
112    {
113      return new ProcessedMap();
114    }
115    ///The type of the map that stores the dists of the nodes.
116 
117    ///The type of the map that stores the dists of the nodes.
118    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
119    ///
120    typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
121    ///Instantiates a DistMap.
122 
123    ///This function instantiates a \ref DistMap.
124    ///\param G is the graph, to which we would like to define the \ref DistMap
125    static DistMap *createDistMap(const GR &G)
126    {
127      return new DistMap(G);
128    }
129  };
130 
131  ///%Dijkstra algorithm class.
132 
133  /// \ingroup flowalgs
134  ///This class provides an efficient implementation of %Dijkstra algorithm.
135  ///The edge lengths are passed to the algorithm using a
136  ///\ref concept::ReadMap "ReadMap",
137  ///so it is easy to change it to any kind of length.
138  ///
139  ///The type of the length is determined by the
140  ///\ref concept::ReadMap::Value "Value" of the length map.
141  ///
142  ///It is also possible to change the underlying priority heap.
143  ///
144  ///\param GR The graph type the algorithm runs on. The default value
145  ///is \ref ListGraph. The value of GR is not used directly by
146  ///Dijkstra, it is only passed to \ref DijkstraDefaultTraits.
147  ///\param LM This read-only EdgeMap determines the lengths of the
148  ///edges. It is read once for each edge, so the map may involve in
149  ///relatively time consuming process to compute the edge length if
150  ///it is necessary. The default map type is \ref
151  ///concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>".  The value
152  ///of LM is not used directly by Dijkstra, it is only passed to \ref
153  ///DijkstraDefaultTraits.  \param TR Traits class to set
154  ///various data types used by the algorithm.  The default traits
155  ///class is \ref DijkstraDefaultTraits
156  ///"DijkstraDefaultTraits<GR,LM>".  See \ref
157  ///DijkstraDefaultTraits for the documentation of a Dijkstra traits
158  ///class.
159  ///
160  ///\author Jacint Szabo and Alpar Juttner
161  ///\todo A compare object would be nice.
162
163#ifdef DOXYGEN
164  template <typename GR,
165            typename LM,
166            typename TR>
167#else
168  template <typename GR=ListGraph,
169            typename LM=typename GR::template EdgeMap<int>,
170            typename TR=DijkstraDefaultTraits<GR,LM> >
171#endif
172  class Dijkstra {
173  public:
174    /**
175     * \brief \ref Exception for uninitialized parameters.
176     *
177     * This error represents problems in the initialization
178     * of the parameters of the algorithms.
179     */
180    class UninitializedParameter : public lemon::UninitializedParameter {
181    public:
182      virtual const char* exceptionName() const {
183        return "lemon::Dijkstra::UninitializedParameter";
184      }
185    };
186
187    typedef TR Traits;
188    ///The type of the underlying graph.
189    typedef typename TR::Graph Graph;
190    ///\e
191    typedef typename Graph::Node Node;
192    ///\e
193    typedef typename Graph::NodeIt NodeIt;
194    ///\e
195    typedef typename Graph::Edge Edge;
196    ///\e
197    typedef typename Graph::OutEdgeIt OutEdgeIt;
198   
199    ///The type of the length of the edges.
200    typedef typename TR::LengthMap::Value Value;
201    ///The type of the map that stores the edge lengths.
202    typedef typename TR::LengthMap LengthMap;
203    ///\brief The type of the map that stores the last
204    ///edges of the shortest paths.
205    typedef typename TR::PredMap PredMap;
206//     ///\brief The type of the map that stores the last but one
207//     ///nodes of the shortest paths.
208//     typedef typename TR::PredNodeMap PredNodeMap;
209    ///The type of the map indicating if a node is processed.
210    typedef typename TR::ProcessedMap ProcessedMap;
211    ///The type of the map that stores the dists of the nodes.
212    typedef typename TR::DistMap DistMap;
213    ///The heap type used by the dijkstra algorithm.
214    typedef typename TR::Heap Heap;
215  private:
216    /// Pointer to the underlying graph.
217    const Graph *G;
218    /// Pointer to the length map
219    const LengthMap *length;
220    ///Pointer to the map of predecessors edges.
221    PredMap *_pred;
222    ///Indicates if \ref _pred is locally allocated (\c true) or not.
223    bool local_pred;
224//     ///Pointer to the map of predecessors nodes.
225//     PredNodeMap *_predNode;
226//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
227//     bool local_predNode;
228    ///Pointer to the map of distances.
229    DistMap *_dist;
230    ///Indicates if \ref _dist is locally allocated (\c true) or not.
231    bool local_dist;
232    ///Pointer to the map of processed status of the nodes.
233    ProcessedMap *_processed;
234    ///Indicates if \ref _processed is locally allocated (\c true) or not.
235    bool local_processed;
236
237//     ///The source node of the last execution.
238//     Node source;
239
240    ///Creates the maps if necessary.
241   
242    ///\todo Error if \c G or are \c NULL. What about \c length?
243    ///\todo Better memory allocation (instead of new).
244    void create_maps()
245    {
246      if(!_pred) {
247        local_pred = true;
248        _pred = Traits::createPredMap(*G);
249      }
250//       if(!_predNode) {
251//      local_predNode = true;
252//      _predNode = Traits::createPredNodeMap(*G);
253//       }
254      if(!_dist) {
255        local_dist = true;
256        _dist = Traits::createDistMap(*G);
257      }
258      if(!_processed) {
259        local_processed = true;
260        _processed = Traits::createProcessedMap(*G);
261      }
262    }
263   
264  public :
265 
266    ///\name Named template parameters
267
268    ///@{
269
270    template <class T>
271    struct DefPredMapTraits : public Traits {
272      typedef T PredMap;
273      static PredMap *createPredMap(const Graph &G)
274      {
275        throw UninitializedParameter();
276      }
277    };
278    ///\ref named-templ-param "Named parameter" for setting PredMap type
279
280    ///\ref named-templ-param "Named parameter" for setting PredMap type
281    ///
282    template <class T>
283    class DefPredMap : public Dijkstra< Graph,
284                                        LengthMap,
285                                        DefPredMapTraits<T> > { };
286   
287//     template <class T>
288//     struct DefPredNodeMapTraits : public Traits {
289//       typedef T PredNodeMap;
290//       static PredNodeMap *createPredNodeMap(const Graph &G)
291//       {
292//      throw UninitializedParameter();
293//       }
294//     };
295//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
296
297//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
298//     ///
299//     template <class T>
300//     class DefPredNodeMap : public Dijkstra< Graph,
301//                                          LengthMap,
302//                                          DefPredNodeMapTraits<T> > { };
303   
304    template <class T>
305    struct DefDistMapTraits : public Traits {
306      typedef T DistMap;
307      static DistMap *createDistMap(const Graph &G)
308      {
309        throw UninitializedParameter();
310      }
311    };
312    ///\ref named-templ-param "Named parameter" for setting DistMap type
313
314    ///\ref named-templ-param "Named parameter" for setting DistMap type
315    ///
316    template <class T>
317    class DefDistMap : public Dijkstra< Graph,
318                                        LengthMap,
319                                        DefDistMapTraits<T> > { };
320   
321    template <class T>
322    struct DefProcessedMapTraits : public Traits {
323      typedef T ProcessedMap;
324      static ProcessedMap *createProcessedMap(const Graph &G)
325      {
326        throw UninitializedParameter();
327      }
328    };
329    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
330
331    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
332    ///
333    template <class T>
334    class DefProcessedMap : public Dijkstra< Graph,
335                                        LengthMap,
336                                        DefProcessedMapTraits<T> > { };
337   
338    struct DefGraphProcessedMapTraits : public Traits {
339      typedef typename Graph::template NodeMap<bool> ProcessedMap;
340      static ProcessedMap *createProcessedMap(const Graph &G)
341      {
342        return new ProcessedMap(G);
343      }
344    };
345    ///\brief \ref named-templ-param "Named parameter"
346    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
347    ///
348    ///\ref named-templ-param "Named parameter"
349    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
350    ///If you don't set it explicitely, it will be automatically allocated.
351    template <class T>
352    class DefProcessedMapToBeDefaultMap :
353      public Dijkstra< Graph,
354                       LengthMap,
355                       DefGraphProcessedMapTraits> { };
356   
357    ///@}
358
359
360  private:
361    typename Graph::template NodeMap<int> _heap_map;
362    Heap _heap;
363  public:     
364   
365    ///Constructor.
366   
367    ///\param _G the graph the algorithm will run on.
368    ///\param _length the length map used by the algorithm.
369    Dijkstra(const Graph& _G, const LengthMap& _length) :
370      G(&_G), length(&_length),
371      _pred(NULL), local_pred(false),
372//       _predNode(NULL), local_predNode(false),
373      _dist(NULL), local_dist(false),
374      _processed(NULL), local_processed(false),
375      _heap_map(*G,-1),_heap(_heap_map)
376    { }
377   
378    ///Destructor.
379    ~Dijkstra()
380    {
381      if(local_pred) delete _pred;
382//       if(local_predNode) delete _predNode;
383      if(local_dist) delete _dist;
384      if(local_processed) delete _processed;
385    }
386
387    ///Sets the length map.
388
389    ///Sets the length map.
390    ///\return <tt> (*this) </tt>
391    Dijkstra &lengthMap(const LengthMap &m)
392    {
393      length = &m;
394      return *this;
395    }
396
397    ///Sets the map storing the predecessor edges.
398
399    ///Sets the map storing the predecessor edges.
400    ///If you don't use this function before calling \ref run(),
401    ///it will allocate one. The destuctor deallocates this
402    ///automatically allocated map, of course.
403    ///\return <tt> (*this) </tt>
404    Dijkstra &predMap(PredMap &m)
405    {
406      if(local_pred) {
407        delete _pred;
408        local_pred=false;
409      }
410      _pred = &m;
411      return *this;
412    }
413
414//     ///Sets the map storing the predecessor nodes.
415
416//     ///Sets the map storing the predecessor nodes.
417//     ///If you don't use this function before calling \ref run(),
418//     ///it will allocate one. The destuctor deallocates this
419//     ///automatically allocated map, of course.
420//     ///\return <tt> (*this) </tt>
421//     Dijkstra &predNodeMap(PredNodeMap &m)
422//     {
423//       if(local_predNode) {
424//      delete _predNode;
425//      local_predNode=false;
426//       }
427//       _predNode = &m;
428//       return *this;
429//     }
430
431    ///Sets the map storing the distances calculated by the algorithm.
432
433    ///Sets the map storing the distances calculated by the algorithm.
434    ///If you don't use this function before calling \ref run(),
435    ///it will allocate one. The destuctor deallocates this
436    ///automatically allocated map, of course.
437    ///\return <tt> (*this) </tt>
438    Dijkstra &distMap(DistMap &m)
439    {
440      if(local_dist) {
441        delete _dist;
442        local_dist=false;
443      }
444      _dist = &m;
445      return *this;
446    }
447
448  private:
449    void finalizeNodeData(Node v,Value dst)
450    {
451      _processed->set(v,true);
452      _dist->set(v, dst);
453//       if((*_pred)[v]!=INVALID)
454//       _predNode->set(v,G->source((*_pred)[v])); ///\todo What to do?
455    }
456
457  public:
458    ///\name Execution control
459    ///The simplest way to execute the algorithm is to use
460    ///one of the member functions called \c run(...).
461    ///\n
462    ///If you need more control on the execution,
463    ///first you must call \ref init(), then you can add several source nodes
464    ///with \ref addSource().
465    ///Finally \ref start() will perform the actual path
466    ///computation.
467
468    ///@{
469
470    ///Initializes the internal data structures.
471
472    ///Initializes the internal data structures.
473    ///
474    ///\todo _heap_map's type could also be in the traits class.
475    ///\todo The heaps should be able to make themselves empty directly.
476    void init()
477    {
478      create_maps();
479      while(!_heap.empty()) _heap.pop();
480      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
481        _pred->set(u,INVALID);
482//      _predNode->set(u,INVALID);
483        _processed->set(u,false);
484        _heap_map.set(u,Heap::PRE_HEAP);
485      }
486    }
487   
488    ///Adds a new source node.
489
490    ///Adds a new source node to the priority heap.
491    ///
492    ///The optional second parameter is the initial distance of the node.
493    ///
494    ///It checks if the node has already been added to the heap and
495    ///It is pushed to the heap only if either it was not in the heap
496    ///or the shortest path found till then is longer then \c dst.
497    void addSource(Node s,Value dst=0)
498    {
499//       source = s;
500      if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst);
501      else if(_heap[s]<dst) {
502        _heap.push(s,dst);
503        _pred->set(s,INVALID);
504      }
505    }
506   
507    ///Processes the next node in the priority heap
508
509    ///Processes the next node in the priority heap.
510    ///
511    ///\warning The priority heap must not be empty!
512    void processNextNode()
513    {
514      Node v=_heap.top();
515      Value oldvalue=_heap[v];
516      _heap.pop();
517      finalizeNodeData(v,oldvalue);
518     
519      for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
520        Node w=G->target(e);
521        switch(_heap.state(w)) {
522        case Heap::PRE_HEAP:
523          _heap.push(w,oldvalue+(*length)[e]);
524          _pred->set(w,e);
525//        _predNode->set(w,v);
526          break;
527        case Heap::IN_HEAP:
528          if ( oldvalue+(*length)[e] < _heap[w] ) {
529            _heap.decrease(w, oldvalue+(*length)[e]);
530            _pred->set(w,e);
531//          _predNode->set(w,v);
532          }
533          break;
534        case Heap::POST_HEAP:
535          break;
536        }
537      }
538    }
539
540    ///\brief Returns \c false if there are nodes
541    ///to be processed in the priority heap
542    ///
543    ///Returns \c false if there are nodes
544    ///to be processed in the priority heap
545    bool emptyQueue() { return _heap.empty(); }
546    ///Returns the number of the nodes to be processed in the priority heap
547
548    ///Returns the number of the nodes to be processed in the priority heap
549    ///
550    int queueSize() { return _heap.size(); }
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 %Dijkstra 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 ( !_heap.empty() ) 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 %Dijkstra 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 ( !_heap.empty() && _heap.top()!=dest ) processNextNode();
588      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
589    }
590   
591    ///Executes the algorithm until a condition is met.
592
593    ///Executes the algorithm until a condition is met.
594    ///
595    ///\pre init() must be called and at least one node should be added
596    ///with addSource() before using this function.
597    ///
598    ///\param nm must be a bool (or convertible) node map. The algorithm
599    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
600    template<class NM>
601    void start(const NM &nm)
602    {
603      while ( !_heap.empty() && !nm[_heap.top()] ) processNextNode();
604      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
605    }
606   
607    ///Runs %Dijkstra algorithm from node \c s.
608   
609    ///This method runs the %Dijkstra algorithm from a root node \c s
610    ///in order to
611    ///compute the
612    ///shortest path to each node. The algorithm computes
613    ///- The shortest path tree.
614    ///- The distance of each node from the root.
615    ///
616    ///\note d.run(s) is just a shortcut of the following code.
617    ///\code
618    ///  d.init();
619    ///  d.addSource(s);
620    ///  d.start();
621    ///\endcode
622    void run(Node s) {
623      init();
624      addSource(s);
625      start();
626    }
627   
628    ///Finds the shortest path between \c s and \c t.
629   
630    ///Finds the shortest path between \c s and \c t.
631    ///
632    ///\return The length of the shortest s---t path if there exists one,
633    ///0 otherwise.
634    ///\note Apart from the return value, d.run(s) is
635    ///just a shortcut of the following code.
636    ///\code
637    ///  d.init();
638    ///  d.addSource(s);
639    ///  d.start(t);
640    ///\endcode
641    Value run(Node s,Node t) {
642      init();
643      addSource(s);
644      start(t);
645      return (*_pred)[t]==INVALID?0:(*_dist)[t];
646    }
647   
648    ///@}
649
650    ///\name Query Functions
651    ///The result of the %Dijkstra algorithm can be obtained using these
652    ///functions.\n
653    ///Before the use of these functions,
654    ///either run() or start() must be called.
655   
656    ///@{
657
658    ///The distance of a node from the root.
659
660    ///Returns the distance of a node from the root.
661    ///\pre \ref run() must be called before using this function.
662    ///\warning If node \c v in unreachable from the root the return value
663    ///of this funcion is undefined.
664    Value dist(Node v) const { return (*_dist)[v]; }
665
666    ///Returns the 'previous edge' of the shortest path tree.
667
668    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
669    ///i.e. it returns the last edge of a shortest path from the root to \c
670    ///v. It is \ref INVALID
671    ///if \c v is unreachable from the root or if \c v=s. The
672    ///shortest path tree used here is equal to the shortest path tree used in
673    ///\ref predNode(Node v).  \pre \ref run() must be called before using
674    ///this function.
675    ///\todo predEdge could be a better name.
676    Edge pred(Node v) const { return (*_pred)[v]; }
677
678    ///Returns the 'previous node' of the shortest path tree.
679
680    ///For a node \c v it returns the 'previous node' of the shortest path tree,
681    ///i.e. it returns the last but one node from a shortest path from the
682    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
683    ///\c v=s. The shortest path tree used here is equal to the shortest path
684    ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
685    ///using this function.
686    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
687                                  G->source((*_pred)[v]); }
688   
689    ///Returns a reference to the NodeMap of distances.
690
691    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
692    ///be called before using this function.
693    const DistMap &distMap() const { return *_dist;}
694 
695    ///Returns a reference to the shortest path tree map.
696
697    ///Returns a reference to the NodeMap of the edges of the
698    ///shortest path tree.
699    ///\pre \ref run() must be called before using this function.
700    const PredMap &predMap() const { return *_pred;}
701 
702//     ///Returns a reference to the map of nodes of shortest paths.
703
704//     ///Returns a reference to the NodeMap of the last but one nodes of the
705//     ///shortest path tree.
706//     ///\pre \ref run() must be called before using this function.
707//     const PredNodeMap &predNodeMap() const { return *_predNode;}
708
709    ///Checks if a node is reachable from the root.
710
711    ///Returns \c true if \c v is reachable from the root.
712    ///\warning The source nodes are inditated as unreached.
713    ///\pre \ref run() must be called before using this function.
714    ///
715    bool reached(Node v) { return _heap_map[v]!=Heap::PRE_HEAP; }
716   
717    ///@}
718  };
719
720
721
722
723 
724  ///Default traits class of Dijkstra function.
725
726  ///Default traits class of Dijkstra function.
727  ///\param GR Graph type.
728  ///\param LM Type of length map.
729  template<class GR, class LM>
730  struct DijkstraWizardDefaultTraits
731  {
732    ///The graph type the algorithm runs on.
733    typedef GR Graph;
734    ///The type of the map that stores the edge lengths.
735
736    ///The type of the map that stores the edge lengths.
737    ///It must meet the \ref concept::ReadMap "ReadMap" concept.
738    typedef LM LengthMap;
739    //The type of the length of the edges.
740    typedef typename LM::Value Value;
741    ///The heap type used by Dijkstra algorithm.
742
743    ///The heap type used by Dijkstra algorithm.
744    ///
745    ///\sa BinHeap
746    ///\sa Dijkstra
747    typedef BinHeap<typename Graph::Node,
748                    typename LM::Value,
749                    typename GR::template NodeMap<int>,
750                    std::less<Value> > Heap;
751
752    ///\brief The type of the map that stores the last
753    ///edges of the shortest paths.
754    ///
755    ///The type of the map that stores the last
756    ///edges of the shortest paths.
757    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
758    ///
759    typedef NullMap <typename GR::Node,typename GR::Edge> PredMap;
760    ///Instantiates a PredMap.
761 
762    ///This function instantiates a \ref PredMap.
763    ///\param G is the graph, to which we would like to define the PredMap.
764    ///\todo The graph alone may be insufficient for the initialization
765    static PredMap *createPredMap(const GR &G)
766    {
767      return new PredMap();
768    }
769    ///The type of the map that stores whether a nodes is processed.
770 
771    ///The type of the map that stores whether a nodes is processed.
772    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
773    ///By default it is a NullMap.
774    ///\todo If it is set to a real map,
775    ///Dijkstra::processed() should read this.
776    ///\todo named parameter to set this type, function to read and write.
777    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
778    ///Instantiates a ProcessedMap.
779 
780    ///This function instantiates a \ref ProcessedMap.
781    ///\param G is the graph, to which
782    ///we would like to define the \ref ProcessedMap
783    static ProcessedMap *createProcessedMap(const GR &G)
784    {
785      return new ProcessedMap();
786    }
787    ///The type of the map that stores the dists of the nodes.
788 
789    ///The type of the map that stores the dists of the nodes.
790    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
791    ///
792    typedef NullMap<typename Graph::Node,typename LM::Value> DistMap;
793    ///Instantiates a DistMap.
794 
795    ///This function instantiates a \ref DistMap.
796    ///\param G is the graph, to which we would like to define the \ref DistMap
797    static DistMap *createDistMap(const GR &G)
798    {
799      return new DistMap();
800    }
801  };
802 
803  /// Default traits used by \ref DijkstraWizard
804
805  /// To make it easier to use Dijkstra algorithm
806  ///we have created a wizard class.
807  /// This \ref DijkstraWizard class needs default traits,
808  ///as well as the \ref Dijkstra class.
809  /// The \ref DijkstraWizardBase is a class to be the default traits of the
810  /// \ref DijkstraWizard class.
811  /// \todo More named parameters are required...
812  template<class GR,class LM>
813  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>
814  {
815
816    typedef DijkstraWizardDefaultTraits<GR,LM> Base;
817  protected:
818    /// Type of the nodes in the graph.
819    typedef typename Base::Graph::Node Node;
820
821    /// Pointer to the underlying graph.
822    void *_g;
823    /// Pointer to the length map
824    void *_length;
825    ///Pointer to the map of predecessors edges.
826    void *_pred;
827//     ///Pointer to the map of predecessors nodes.
828//     void *_predNode;
829    ///Pointer to the map of distances.
830    void *_dist;
831    ///Pointer to the source node.
832    Node _source;
833
834    public:
835    /// Constructor.
836   
837    /// This constructor does not require parameters, therefore it initiates
838    /// all of the attributes to default values (0, INVALID).
839    DijkstraWizardBase() : _g(0), _length(0), _pred(0),
840//                         _predNode(0),
841                           _dist(0), _source(INVALID) {}
842
843    /// Constructor.
844   
845    /// This constructor requires some parameters,
846    /// listed in the parameters list.
847    /// Others are initiated to 0.
848    /// \param g is the initial value of  \ref _g
849    /// \param l is the initial value of  \ref _length
850    /// \param s is the initial value of  \ref _source
851    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
852      _g((void *)&g), _length((void *)&l), _pred(0),
853//       _predNode(0),
854      _dist(0), _source(s) {}
855
856  };
857 
858  /// A class to make the usage of Dijkstra algorithm easier
859
860  /// This class is created to make it easier to use Dijkstra algorithm.
861  /// It uses the functions and features of the plain \ref Dijkstra,
862  /// but it is much simpler to use it.
863  ///
864  /// Simplicity means that the way to change the types defined
865  /// in the traits class is based on functions that returns the new class
866  /// and not on templatable built-in classes.
867  /// When using the plain \ref Dijkstra
868  /// the new class with the modified type comes from
869  /// the original class by using the ::
870  /// operator. In the case of \ref DijkstraWizard only
871  /// a function have to be called and it will
872  /// return the needed class.
873  ///
874  /// It does not have own \ref run method. When its \ref run method is called
875  /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
876  /// method of it.
877  template<class TR>
878  class DijkstraWizard : public TR
879  {
880    typedef TR Base;
881
882    ///The type of the underlying graph.
883    typedef typename TR::Graph Graph;
884    //\e
885    typedef typename Graph::Node Node;
886    //\e
887    typedef typename Graph::NodeIt NodeIt;
888    //\e
889    typedef typename Graph::Edge Edge;
890    //\e
891    typedef typename Graph::OutEdgeIt OutEdgeIt;
892   
893    ///The type of the map that stores the edge lengths.
894    typedef typename TR::LengthMap LengthMap;
895    ///The type of the length of the edges.
896    typedef typename LengthMap::Value Value;
897    ///\brief The type of the map that stores the last
898    ///edges of the shortest paths.
899    typedef typename TR::PredMap PredMap;
900//     ///\brief The type of the map that stores the last but one
901//     ///nodes of the shortest paths.
902//     typedef typename TR::PredNodeMap PredNodeMap;
903    ///The type of the map that stores the dists of the nodes.
904    typedef typename TR::DistMap DistMap;
905
906    ///The heap type used by the dijkstra algorithm.
907    typedef typename TR::Heap Heap;
908public:
909    /// Constructor.
910    DijkstraWizard() : TR() {}
911
912    /// Constructor that requires parameters.
913
914    /// Constructor that requires parameters.
915    /// These parameters will be the default values for the traits class.
916    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
917      TR(g,l,s) {}
918
919    ///Copy constructor
920    DijkstraWizard(const TR &b) : TR(b) {}
921
922    ~DijkstraWizard() {}
923
924    ///Runs Dijkstra algorithm from a given node.
925   
926    ///Runs Dijkstra algorithm from a given node.
927    ///The node can be given by the \ref source function.
928    void run()
929    {
930      if(Base::_source==INVALID) throw UninitializedParameter();
931      Dijkstra<Graph,LengthMap,TR>
932        Dij(*(Graph*)Base::_g,*(LengthMap*)Base::_length);
933      if(Base::_pred) Dij.predMap(*(PredMap*)Base::_pred);
934//       if(Base::_predNode) Dij.predNodeMap(*(PredNodeMap*)Base::_predNode);
935      if(Base::_dist) Dij.distMap(*(DistMap*)Base::_dist);
936      Dij.run(Base::_source);
937    }
938
939    ///Runs Dijkstra algorithm from the given node.
940
941    ///Runs Dijkstra algorithm from the given node.
942    ///\param s is the given source.
943    void run(Node s)
944    {
945      Base::_source=s;
946      run();
947    }
948
949    template<class T>
950    struct DefPredMapBase : public Base {
951      typedef T PredMap;
952      static PredMap *createPredMap(const Graph &G) { return 0; };
953      DefPredMapBase(const TR &b) : TR(b) {}
954    };
955   
956    ///\brief \ref named-templ-param "Named parameter"
957    ///function for setting PredMap type
958    ///
959    /// \ref named-templ-param "Named parameter"
960    ///function for setting PredMap type
961    ///
962    template<class T>
963    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
964    {
965      Base::_pred=(void *)&t;
966      return DijkstraWizard<DefPredMapBase<T> >(*this);
967    }
968   
969
970//     template<class T>
971//     struct DefPredNodeMapBase : public Base {
972//       typedef T PredNodeMap;
973//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
974//       DefPredNodeMapBase(const TR &b) : TR(b) {}
975//     };
976   
977//     ///\brief \ref named-templ-param "Named parameter"
978//     ///function for setting PredNodeMap type
979//     ///
980//     /// \ref named-templ-param "Named parameter"
981//     ///function for setting PredNodeMap type
982//     ///
983//     template<class T>
984//     DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
985//     {
986//       Base::_predNode=(void *)&t;
987//       return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
988//     }
989   
990    template<class T>
991    struct DefDistMapBase : public Base {
992      typedef T DistMap;
993      static DistMap *createDistMap(const Graph &G) { return 0; };
994      DefDistMapBase(const TR &b) : TR(b) {}
995    };
996   
997    ///\brief \ref named-templ-param "Named parameter"
998    ///function for setting DistMap type
999    ///
1000    /// \ref named-templ-param "Named parameter"
1001    ///function for setting DistMap type
1002    ///
1003    template<class T>
1004    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
1005    {
1006      Base::_dist=(void *)&t;
1007      return DijkstraWizard<DefDistMapBase<T> >(*this);
1008    }
1009   
1010    /// Sets the source node, from which the Dijkstra algorithm runs.
1011
1012    /// Sets the source node, from which the Dijkstra algorithm runs.
1013    /// \param s is the source node.
1014    DijkstraWizard<TR> &source(Node s)
1015    {
1016      Base::_source=s;
1017      return *this;
1018    }
1019   
1020  };
1021 
1022  ///Function type interface for Dijkstra algorithm.
1023
1024  /// \ingroup flowalgs
1025  ///Function type interface for Dijkstra algorithm.
1026  ///
1027  ///This function also has several
1028  ///\ref named-templ-func-param "named parameters",
1029  ///they are declared as the members of class \ref DijkstraWizard.
1030  ///The following
1031  ///example shows how to use these parameters.
1032  ///\code
1033  ///  dijkstra(g,length,source).predMap(preds).run();
1034  ///\endcode
1035  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"
1036  ///to the end of the parameter list.
1037  ///\sa DijkstraWizard
1038  ///\sa Dijkstra
1039  template<class GR, class LM>
1040  DijkstraWizard<DijkstraWizardBase<GR,LM> >
1041  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
1042  {
1043    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
1044  }
1045
1046} //END OF NAMESPACE LEMON
1047
1048#endif
1049
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