COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/dijkstra.h @ 1710:f531c16dd923

Last change on this file since 1710:f531c16dd923 was 1710:f531c16dd923, checked in by Balazs Dezso, 14 years ago

Bug solved in named parameters
Simplify my Johnson algorithm

File size: 32.0 KB
Line 
1/* -*- C++ -*-
2 * 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, typename LM::Value,
60                    typename GR::template NodeMap<int>,
61                    std::less<Value> > Heap;
62
63    ///\brief The type of the map that stores the last
64    ///edges of the shortest paths.
65    ///
66    ///The type of the map that stores the last
67    ///edges of the shortest paths.
68    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
69    ///
70    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
71    ///Instantiates a PredMap.
72 
73    ///This function instantiates a \ref PredMap.
74    ///\param G is the graph, to which we would like to define the PredMap.
75    ///\todo The graph alone may be insufficient for the initialization
76    static PredMap *createPredMap(const GR &G)
77    {
78      return new PredMap(G);
79    }
80
81    ///The type of the map that stores whether a nodes is processed.
82 
83    ///The type of the map that stores whether a nodes is processed.
84    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
85    ///By default it is a NullMap.
86    ///\todo If it is set to a real map,
87    ///Dijkstra::processed() should read this.
88    ///\todo named parameter to set this type, function to read and write.
89    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
90    ///Instantiates a ProcessedMap.
91 
92    ///This function instantiates a \ref ProcessedMap.
93    ///\param g is the graph, to which
94    ///we would like to define the \ref ProcessedMap
95#ifdef DOXYGEN
96    static ProcessedMap *createProcessedMap(const GR &g)
97#else
98    static ProcessedMap *createProcessedMap(const GR &)
99#endif
100    {
101      return new ProcessedMap();
102    }
103    ///The type of the map that stores the dists of the nodes.
104 
105    ///The type of the map that stores the dists of the nodes.
106    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
107    ///
108    typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
109    ///Instantiates a DistMap.
110 
111    ///This function instantiates a \ref DistMap.
112    ///\param G is the graph, to which we would like to define the \ref DistMap
113    static DistMap *createDistMap(const GR &G)
114    {
115      return new DistMap(G);
116    }
117  };
118 
119  ///%Dijkstra algorithm class.
120 
121  /// \ingroup flowalgs
122  ///This class provides an efficient implementation of %Dijkstra algorithm.
123  ///The edge lengths are passed to the algorithm using a
124  ///\ref concept::ReadMap "ReadMap",
125  ///so it is easy to change it to any kind of length.
126  ///
127  ///The type of the length is determined by the
128  ///\ref concept::ReadMap::Value "Value" of the length map.
129  ///
130  ///It is also possible to change the underlying priority heap.
131  ///
132  ///\param GR The graph type the algorithm runs on. The default value
133  ///is \ref ListGraph. The value of GR is not used directly by
134  ///Dijkstra, it is only passed to \ref DijkstraDefaultTraits.
135  ///\param LM This read-only EdgeMap determines the lengths of the
136  ///edges. It is read once for each edge, so the map may involve in
137  ///relatively time consuming process to compute the edge length if
138  ///it is necessary. The default map type is \ref
139  ///concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>".  The value
140  ///of LM is not used directly by Dijkstra, it is only passed to \ref
141  ///DijkstraDefaultTraits.  \param TR Traits class to set
142  ///various data types used by the algorithm.  The default traits
143  ///class is \ref DijkstraDefaultTraits
144  ///"DijkstraDefaultTraits<GR,LM>".  See \ref
145  ///DijkstraDefaultTraits for the documentation of a Dijkstra traits
146  ///class.
147  ///
148  ///\author Jacint Szabo and Alpar Juttner
149  ///\todo A compare object would be nice.
150
151#ifdef DOXYGEN
152  template <typename GR,
153            typename LM,
154            typename TR>
155#else
156  template <typename GR=ListGraph,
157            typename LM=typename GR::template EdgeMap<int>,
158            typename TR=DijkstraDefaultTraits<GR,LM> >
159#endif
160  class Dijkstra {
161  public:
162    /**
163     * \brief \ref Exception for uninitialized parameters.
164     *
165     * This error represents problems in the initialization
166     * of the parameters of the algorithms.
167     */
168    class UninitializedParameter : public lemon::UninitializedParameter {
169    public:
170      virtual const char* exceptionName() const {
171        return "lemon::Dijkstra::UninitializedParameter";
172      }
173    };
174
175    typedef TR Traits;
176    ///The type of the underlying graph.
177    typedef typename TR::Graph Graph;
178    ///\e
179    typedef typename Graph::Node Node;
180    ///\e
181    typedef typename Graph::NodeIt NodeIt;
182    ///\e
183    typedef typename Graph::Edge Edge;
184    ///\e
185    typedef typename Graph::OutEdgeIt OutEdgeIt;
186   
187    ///The type of the length of the edges.
188    typedef typename TR::LengthMap::Value Value;
189    ///The type of the map that stores the edge lengths.
190    typedef typename TR::LengthMap LengthMap;
191    ///\brief The type of the map that stores the last
192    ///edges of the shortest paths.
193    typedef typename TR::PredMap PredMap;
194    ///The type of the map indicating if a node is processed.
195    typedef typename TR::ProcessedMap ProcessedMap;
196    ///The type of the map that stores the dists of the nodes.
197    typedef typename TR::DistMap DistMap;
198    ///The heap type used by the dijkstra algorithm.
199    typedef typename TR::Heap Heap;
200  private:
201    /// Pointer to the underlying graph.
202    const Graph *G;
203    /// Pointer to the length map
204    const LengthMap *length;
205    ///Pointer to the map of predecessors edges.
206    PredMap *_pred;
207    ///Indicates if \ref _pred is locally allocated (\c true) or not.
208    bool local_pred;
209    ///Pointer to the map of distances.
210    DistMap *_dist;
211    ///Indicates if \ref _dist is locally allocated (\c true) or not.
212    bool local_dist;
213    ///Pointer to the map of processed status of the nodes.
214    ProcessedMap *_processed;
215    ///Indicates if \ref _processed is locally allocated (\c true) or not.
216    bool local_processed;
217
218    ///Creates the maps if necessary.
219   
220    ///\todo Error if \c G or are \c NULL. What about \c length?
221    ///\todo Better memory allocation (instead of new).
222    void create_maps()
223    {
224      if(!_pred) {
225        local_pred = true;
226        _pred = Traits::createPredMap(*G);
227      }
228      if(!_dist) {
229        local_dist = true;
230        _dist = Traits::createDistMap(*G);
231      }
232      if(!_processed) {
233        local_processed = true;
234        _processed = Traits::createProcessedMap(*G);
235      }
236    }
237   
238  public :
239
240    typedef Dijkstra Create;
241 
242    ///\name Named template parameters
243
244    ///@{
245
246    template <class T>
247    struct DefPredMapTraits : public Traits {
248      typedef T PredMap;
249      static PredMap *createPredMap(const Graph &G)
250      {
251        throw UninitializedParameter();
252      }
253    };
254    ///\ref named-templ-param "Named parameter" for setting PredMap type
255
256    ///\ref named-templ-param "Named parameter" for setting PredMap type
257    ///
258    template <class T>
259    struct DefPredMap
260      : public Dijkstra< Graph, LengthMap, DefPredMapTraits<T> > {
261      typedef Dijkstra< Graph,  LengthMap, DefPredMapTraits<T> > Create;
262    };
263   
264    template <class T>
265    struct DefDistMapTraits : public Traits {
266      typedef T DistMap;
267      static DistMap *createDistMap(const Graph &G)
268      {
269        throw UninitializedParameter();
270      }
271    };
272    ///\ref named-templ-param "Named parameter" for setting DistMap type
273
274    ///\ref named-templ-param "Named parameter" for setting DistMap type
275    ///
276    template <class T>
277    struct DefDistMap
278      : public Dijkstra< Graph, LengthMap, DefDistMapTraits<T> > {
279      typedef Dijkstra< Graph, LengthMap, DefDistMapTraits<T> > Create;
280    };
281   
282    template <class T>
283    struct DefProcessedMapTraits : public Traits {
284      typedef T ProcessedMap;
285      static ProcessedMap *createProcessedMap(const Graph &G)
286      {
287        throw UninitializedParameter();
288      }
289    };
290    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
291
292    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
293    ///
294    template <class T>
295    struct DefProcessedMap
296      : public Dijkstra< Graph, LengthMap, DefProcessedMapTraits<T> > {
297      typedef Dijkstra< Graph,  LengthMap, DefProcessedMapTraits<T> > Create;
298    };
299   
300    struct DefGraphProcessedMapTraits : public Traits {
301      typedef typename Graph::template NodeMap<bool> ProcessedMap;
302      static ProcessedMap *createProcessedMap(const Graph &G)
303      {
304        return new ProcessedMap(G);
305      }
306    };
307    ///\brief \ref named-templ-param "Named parameter"
308    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
309    ///
310    ///\ref named-templ-param "Named parameter"
311    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
312    ///If you don't set it explicitely, it will be automatically allocated.
313    template <class T>
314    struct DefProcessedMapToBeDefaultMap
315      : public Dijkstra< Graph, LengthMap, DefGraphProcessedMapTraits> {
316      typedef Dijkstra< Graph, LengthMap, DefGraphProcessedMapTraits> Create;
317    };
318   
319    ///@}
320
321
322  private:
323    typename Graph::template NodeMap<int> _heap_map;
324    Heap _heap;
325  protected:
326
327    Dijkstra() {}
328
329  public:     
330   
331    ///Constructor.
332   
333    ///\param _G the graph the algorithm will run on.
334    ///\param _length the length map used by the algorithm.
335    Dijkstra(const Graph& _G, const LengthMap& _length) :
336      G(&_G), length(&_length),
337      _pred(NULL), local_pred(false),
338      _dist(NULL), local_dist(false),
339      _processed(NULL), local_processed(false),
340      _heap_map(*G,-1),_heap(_heap_map)
341    { }
342   
343    ///Destructor.
344    ~Dijkstra()
345    {
346      if(local_pred) delete _pred;
347      if(local_dist) delete _dist;
348      if(local_processed) delete _processed;
349    }
350
351    ///Sets the length map.
352
353    ///Sets the length map.
354    ///\return <tt> (*this) </tt>
355    Dijkstra &lengthMap(const LengthMap &m)
356    {
357      length = &m;
358      return *this;
359    }
360
361    ///Sets the map storing the predecessor edges.
362
363    ///Sets the map storing the predecessor edges.
364    ///If you don't use this function before calling \ref run(),
365    ///it will allocate one. The destuctor deallocates this
366    ///automatically allocated map, of course.
367    ///\return <tt> (*this) </tt>
368    Dijkstra &predMap(PredMap &m)
369    {
370      if(local_pred) {
371        delete _pred;
372        local_pred=false;
373      }
374      _pred = &m;
375      return *this;
376    }
377
378    ///Sets the map storing the distances calculated by the algorithm.
379
380    ///Sets the map storing the distances calculated by the algorithm.
381    ///If you don't use this function before calling \ref run(),
382    ///it will allocate one. The destuctor deallocates this
383    ///automatically allocated map, of course.
384    ///\return <tt> (*this) </tt>
385    Dijkstra &distMap(DistMap &m)
386    {
387      if(local_dist) {
388        delete _dist;
389        local_dist=false;
390      }
391      _dist = &m;
392      return *this;
393    }
394
395  private:
396    void finalizeNodeData(Node v,Value dst)
397    {
398      _processed->set(v,true);
399      _dist->set(v, dst);
400    }
401
402  public:
403    ///\name Execution control
404    ///The simplest way to execute the algorithm is to use
405    ///one of the member functions called \c run(...).
406    ///\n
407    ///If you need more control on the execution,
408    ///first you must call \ref init(), then you can add several source nodes
409    ///with \ref addSource().
410    ///Finally \ref start() will perform the actual path
411    ///computation.
412
413    ///@{
414
415    ///Initializes the internal data structures.
416
417    ///Initializes the internal data structures.
418    ///
419    ///\todo _heap_map's type could also be in the traits class.
420    ///\todo The heaps should be able to make themselves empty directly.
421    void init()
422    {
423      create_maps();
424      while(!_heap.empty()) _heap.pop();
425      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
426        _pred->set(u,INVALID);
427        _processed->set(u,false);
428        _heap_map.set(u,Heap::PRE_HEAP);
429      }
430    }
431   
432    ///Adds a new source node.
433
434    ///Adds a new source node to the priority heap.
435    ///
436    ///The optional second parameter is the initial distance of the node.
437    ///
438    ///It checks if the node has already been added to the heap and
439    ///It is pushed to the heap only if either it was not in the heap
440    ///or the shortest path found till then is longer then \c dst.
441    void addSource(Node s,Value dst=0)
442    {
443      if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst);
444      else if(_heap[s]<dst) {
445        _heap.push(s,dst);
446        _pred->set(s,INVALID);
447      }
448    }
449   
450    ///Processes the next node in the priority heap
451
452    ///Processes the next node in the priority heap.
453    ///
454    ///\return The processed node.
455    ///
456    ///\warning The priority heap must not be empty!
457    Node processNextNode()
458    {
459      Node v=_heap.top();
460      Value oldvalue=_heap[v];
461      _heap.pop();
462      finalizeNodeData(v,oldvalue);
463     
464      for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
465        Node w=G->target(e);
466        switch(_heap.state(w)) {
467        case Heap::PRE_HEAP:
468          _heap.push(w,oldvalue+(*length)[e]);
469          _pred->set(w,e);
470          break;
471        case Heap::IN_HEAP:
472          if ( oldvalue+(*length)[e] < _heap[w] ) {
473            _heap.decrease(w, oldvalue+(*length)[e]);
474            _pred->set(w,e);
475          }
476          break;
477        case Heap::POST_HEAP:
478          break;
479        }
480      }
481      return v;
482    }
483
484    ///Next node to be processed.
485   
486    ///Next node to be processed.
487    ///
488    ///\return The next node to be processed or INVALID if the priority heap
489    /// is empty.
490    Node nextNode()
491    {
492      return _heap.empty()?_heap.top():INVALID;
493    }
494 
495    ///\brief Returns \c false if there are nodes
496    ///to be processed in the priority heap
497    ///
498    ///Returns \c false if there are nodes
499    ///to be processed in the priority heap
500    bool emptyQueue() { return _heap.empty(); }
501    ///Returns the number of the nodes to be processed in the priority heap
502
503    ///Returns the number of the nodes to be processed in the priority heap
504    ///
505    int queueSize() { return _heap.size(); }
506   
507    ///Executes the algorithm.
508
509    ///Executes the algorithm.
510    ///
511    ///\pre init() must be called and at least one node should be added
512    ///with addSource() before using this function.
513    ///
514    ///This method runs the %Dijkstra algorithm from the root node(s)
515    ///in order to
516    ///compute the
517    ///shortest path to each node. The algorithm computes
518    ///- The shortest path tree.
519    ///- The distance of each node from the root(s).
520    ///
521    void start()
522    {
523      while ( !_heap.empty() ) processNextNode();
524    }
525   
526    ///Executes the algorithm until \c dest is reached.
527
528    ///Executes the algorithm until \c dest is reached.
529    ///
530    ///\pre init() must be called and at least one node should be added
531    ///with addSource() before using this function.
532    ///
533    ///This method runs the %Dijkstra algorithm from the root node(s)
534    ///in order to
535    ///compute the
536    ///shortest path to \c dest. The algorithm computes
537    ///- The shortest path to \c  dest.
538    ///- The distance of \c dest from the root(s).
539    ///
540    void start(Node dest)
541    {
542      while ( !_heap.empty() && _heap.top()!=dest ) processNextNode();
543      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
544    }
545   
546    ///Executes the algorithm until a condition is met.
547
548    ///Executes the algorithm until a condition is met.
549    ///
550    ///\pre init() must be called and at least one node should be added
551    ///with addSource() before using this function.
552    ///
553    ///\param nm must be a bool (or convertible) node map. The algorithm
554    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
555    template<class NodeBoolMap>
556    void start(const NodeBoolMap &nm)
557    {
558      while ( !_heap.empty() && !nm[_heap.top()] ) processNextNode();
559      if ( !_heap.empty() ) finalizeNodeData(_heap.top(),_heap.prio());
560    }
561   
562    ///Runs %Dijkstra algorithm from node \c s.
563   
564    ///This method runs the %Dijkstra algorithm from a root node \c s
565    ///in order to
566    ///compute the
567    ///shortest path to each node. The algorithm computes
568    ///- The shortest path tree.
569    ///- The distance of each node from the root.
570    ///
571    ///\note d.run(s) is just a shortcut of the following code.
572    ///\code
573    ///  d.init();
574    ///  d.addSource(s);
575    ///  d.start();
576    ///\endcode
577    void run(Node s) {
578      init();
579      addSource(s);
580      start();
581    }
582   
583    ///Finds the shortest path between \c s and \c t.
584   
585    ///Finds the shortest path between \c s and \c t.
586    ///
587    ///\return The length of the shortest s---t path if there exists one,
588    ///0 otherwise.
589    ///\note Apart from the return value, d.run(s) is
590    ///just a shortcut of the following code.
591    ///\code
592    ///  d.init();
593    ///  d.addSource(s);
594    ///  d.start(t);
595    ///\endcode
596    Value run(Node s,Node t) {
597      init();
598      addSource(s);
599      start(t);
600      return (*_pred)[t]==INVALID?0:(*_dist)[t];
601    }
602   
603    ///@}
604
605    ///\name Query Functions
606    ///The result of the %Dijkstra algorithm can be obtained using these
607    ///functions.\n
608    ///Before the use of these functions,
609    ///either run() or start() must be called.
610   
611    ///@{
612
613    ///Copies the shortest path to \c t into \c p
614   
615    ///This function copies the shortest path to \c t into \c p.
616    ///If it \c t is a source itself or unreachable, then it does not
617    ///alter \c p.
618    ///\todo Is it the right way to handle unreachable nodes?
619    ///\return Returns \c true if a path to \c t was actually copied to \c p,
620    ///\c false otherwise.
621    ///\sa DirPath
622    template<class P>
623    bool getPath(P &p,Node t)
624    {
625      if(reached(t)) {
626        p.clear();
627        typename P::Builder b(p);
628        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
629          b.pushFront(pred(t));
630        b.commit();
631        return true;
632      }
633      return false;
634    }
635         
636    ///The distance of a node from the root.
637
638    ///Returns the distance of a node from the root.
639    ///\pre \ref run() must be called before using this function.
640    ///\warning If node \c v in unreachable from the root the return value
641    ///of this funcion is undefined.
642    Value dist(Node v) const { return (*_dist)[v]; }
643
644    ///Returns the 'previous edge' of the shortest path tree.
645
646    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
647    ///i.e. it returns the last edge of a shortest path from the root to \c
648    ///v. It is \ref INVALID
649    ///if \c v is unreachable from the root or if \c v=s. The
650    ///shortest path tree used here is equal to the shortest path tree used in
651    ///\ref predNode().  \pre \ref run() must be called before using
652    ///this function.
653    ///\todo predEdge could be a better name.
654    Edge pred(Node v) const { return (*_pred)[v]; }
655
656    ///Returns the 'previous node' of the shortest path tree.
657
658    ///For a node \c v it returns the 'previous node' of the shortest path tree,
659    ///i.e. it returns the last but one node from a shortest path from the
660    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
661    ///\c v=s. The shortest path tree used here is equal to the shortest path
662    ///tree used in \ref pred().  \pre \ref run() must be called before
663    ///using this function.
664    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
665                                  G->source((*_pred)[v]); }
666   
667    ///Returns a reference to the NodeMap of distances.
668
669    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
670    ///be called before using this function.
671    const DistMap &distMap() const { return *_dist;}
672 
673    ///Returns a reference to the shortest path tree map.
674
675    ///Returns a reference to the NodeMap of the edges of the
676    ///shortest path tree.
677    ///\pre \ref run() must be called before using this function.
678    const PredMap &predMap() const { return *_pred;}
679 
680    ///Checks if a node is reachable from the root.
681
682    ///Returns \c true if \c v is reachable from the root.
683    ///\warning The source nodes are inditated as unreached.
684    ///\pre \ref run() must be called before using this function.
685    ///
686    bool reached(Node v) { return _heap_map[v]!=Heap::PRE_HEAP; }
687   
688    ///@}
689  };
690
691
692
693
694 
695  ///Default traits class of Dijkstra function.
696
697  ///Default traits class of Dijkstra function.
698  ///\param GR Graph type.
699  ///\param LM Type of length map.
700  template<class GR, class LM>
701  struct DijkstraWizardDefaultTraits
702  {
703    ///The graph type the algorithm runs on.
704    typedef GR Graph;
705    ///The type of the map that stores the edge lengths.
706
707    ///The type of the map that stores the edge lengths.
708    ///It must meet the \ref concept::ReadMap "ReadMap" concept.
709    typedef LM LengthMap;
710    //The type of the length of the edges.
711    typedef typename LM::Value Value;
712    ///The heap type used by Dijkstra algorithm.
713
714    ///The heap type used by Dijkstra algorithm.
715    ///
716    ///\sa BinHeap
717    ///\sa Dijkstra
718    typedef BinHeap<typename Graph::Node,
719                    typename LM::Value,
720                    typename GR::template NodeMap<int>,
721                    std::less<Value> > Heap;
722
723    ///\brief The type of the map that stores the last
724    ///edges of the shortest paths.
725    ///
726    ///The type of the map that stores the last
727    ///edges of the shortest paths.
728    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
729    ///
730    typedef NullMap <typename GR::Node,typename GR::Edge> PredMap;
731    ///Instantiates a PredMap.
732 
733    ///This function instantiates a \ref PredMap.
734    ///\param g is the graph, to which we would like to define the PredMap.
735    ///\todo The graph alone may be insufficient for the initialization
736#ifdef DOXYGEN
737    static PredMap *createPredMap(const GR &g)
738#else
739    static PredMap *createPredMap(const GR &)
740#endif
741    {
742      return new PredMap();
743    }
744    ///The type of the map that stores whether a nodes is processed.
745 
746    ///The type of the map that stores whether a nodes is processed.
747    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
748    ///By default it is a NullMap.
749    ///\todo If it is set to a real map,
750    ///Dijkstra::processed() should read this.
751    ///\todo named parameter to set this type, function to read and write.
752    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
753    ///Instantiates a ProcessedMap.
754 
755    ///This function instantiates a \ref ProcessedMap.
756    ///\param g is the graph, to which
757    ///we would like to define the \ref ProcessedMap
758#ifdef DOXYGEN
759    static ProcessedMap *createProcessedMap(const GR &g)
760#else
761    static ProcessedMap *createProcessedMap(const GR &)
762#endif
763    {
764      return new ProcessedMap();
765    }
766    ///The type of the map that stores the dists of the nodes.
767 
768    ///The type of the map that stores the dists of the nodes.
769    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
770    ///
771    typedef NullMap<typename Graph::Node,typename LM::Value> DistMap;
772    ///Instantiates a DistMap.
773 
774    ///This function instantiates a \ref DistMap.
775    ///\param g is the graph, to which we would like to define the \ref DistMap
776#ifdef DOXYGEN
777    static DistMap *createDistMap(const GR &g)
778#else
779    static DistMap *createDistMap(const GR &)
780#endif
781    {
782      return new DistMap();
783    }
784  };
785 
786  /// Default traits used by \ref DijkstraWizard
787
788  /// To make it easier to use Dijkstra algorithm
789  ///we have created a wizard class.
790  /// This \ref DijkstraWizard class needs default traits,
791  ///as well as the \ref Dijkstra class.
792  /// The \ref DijkstraWizardBase is a class to be the default traits of the
793  /// \ref DijkstraWizard class.
794  /// \todo More named parameters are required...
795  template<class GR,class LM>
796  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>
797  {
798
799    typedef DijkstraWizardDefaultTraits<GR,LM> Base;
800  protected:
801    /// Type of the nodes in the graph.
802    typedef typename Base::Graph::Node Node;
803
804    /// Pointer to the underlying graph.
805    void *_g;
806    /// Pointer to the length map
807    void *_length;
808    ///Pointer to the map of predecessors edges.
809    void *_pred;
810//     ///Pointer to the map of predecessors nodes.
811//     void *_predNode;
812    ///Pointer to the map of distances.
813    void *_dist;
814    ///Pointer to the source node.
815    Node _source;
816
817    public:
818    /// Constructor.
819   
820    /// This constructor does not require parameters, therefore it initiates
821    /// all of the attributes to default values (0, INVALID).
822    DijkstraWizardBase() : _g(0), _length(0), _pred(0),
823//                         _predNode(0),
824                           _dist(0), _source(INVALID) {}
825
826    /// Constructor.
827   
828    /// This constructor requires some parameters,
829    /// listed in the parameters list.
830    /// Others are initiated to 0.
831    /// \param g is the initial value of  \ref _g
832    /// \param l is the initial value of  \ref _length
833    /// \param s is the initial value of  \ref _source
834    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
835      _g((void *)&g), _length((void *)&l), _pred(0),
836//       _predNode(0),
837      _dist(0), _source(s) {}
838
839  };
840 
841  /// A class to make the usage of Dijkstra algorithm easier
842
843  /// This class is created to make it easier to use Dijkstra algorithm.
844  /// It uses the functions and features of the plain \ref Dijkstra,
845  /// but it is much simpler to use it.
846  ///
847  /// Simplicity means that the way to change the types defined
848  /// in the traits class is based on functions that returns the new class
849  /// and not on templatable built-in classes.
850  /// When using the plain \ref Dijkstra
851  /// the new class with the modified type comes from
852  /// the original class by using the ::
853  /// operator. In the case of \ref DijkstraWizard only
854  /// a function have to be called and it will
855  /// return the needed class.
856  ///
857  /// It does not have own \ref run method. When its \ref run method is called
858  /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
859  /// method of it.
860  template<class TR>
861  class DijkstraWizard : public TR
862  {
863    typedef TR Base;
864
865    ///The type of the underlying graph.
866    typedef typename TR::Graph Graph;
867    //\e
868    typedef typename Graph::Node Node;
869    //\e
870    typedef typename Graph::NodeIt NodeIt;
871    //\e
872    typedef typename Graph::Edge Edge;
873    //\e
874    typedef typename Graph::OutEdgeIt OutEdgeIt;
875   
876    ///The type of the map that stores the edge lengths.
877    typedef typename TR::LengthMap LengthMap;
878    ///The type of the length of the edges.
879    typedef typename LengthMap::Value Value;
880    ///\brief The type of the map that stores the last
881    ///edges of the shortest paths.
882    typedef typename TR::PredMap PredMap;
883//     ///\brief The type of the map that stores the last but one
884//     ///nodes of the shortest paths.
885//     typedef typename TR::PredNodeMap PredNodeMap;
886    ///The type of the map that stores the dists of the nodes.
887    typedef typename TR::DistMap DistMap;
888
889    ///The heap type used by the dijkstra algorithm.
890    typedef typename TR::Heap Heap;
891public:
892    /// Constructor.
893    DijkstraWizard() : TR() {}
894
895    /// Constructor that requires parameters.
896
897    /// Constructor that requires parameters.
898    /// These parameters will be the default values for the traits class.
899    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
900      TR(g,l,s) {}
901
902    ///Copy constructor
903    DijkstraWizard(const TR &b) : TR(b) {}
904
905    ~DijkstraWizard() {}
906
907    ///Runs Dijkstra algorithm from a given node.
908   
909    ///Runs Dijkstra algorithm from a given node.
910    ///The node can be given by the \ref source function.
911    void run()
912    {
913      if(Base::_source==INVALID) throw UninitializedParameter();
914      Dijkstra<Graph,LengthMap,TR>
915        dij(*(Graph*)Base::_g,*(LengthMap*)Base::_length);
916      if(Base::_pred) dij.predMap(*(PredMap*)Base::_pred);
917//       if(Base::_predNode) Dij.predNodeMap(*(PredNodeMap*)Base::_predNode);
918      if(Base::_dist) dij.distMap(*(DistMap*)Base::_dist);
919      dij.run(Base::_source);
920    }
921
922    ///Runs Dijkstra algorithm from the given node.
923
924    ///Runs Dijkstra algorithm from the given node.
925    ///\param s is the given source.
926    void run(Node s)
927    {
928      Base::_source=s;
929      run();
930    }
931
932    template<class T>
933    struct DefPredMapBase : public Base {
934      typedef T PredMap;
935      static PredMap *createPredMap(const Graph &) { return 0; };
936      DefPredMapBase(const TR &b) : TR(b) {}
937    };
938   
939    ///\brief \ref named-templ-param "Named parameter"
940    ///function for setting PredMap type
941    ///
942    /// \ref named-templ-param "Named parameter"
943    ///function for setting PredMap type
944    ///
945    template<class T>
946    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
947    {
948      Base::_pred=(void *)&t;
949      return DijkstraWizard<DefPredMapBase<T> >(*this);
950    }
951   
952
953//     template<class T>
954//     struct DefPredNodeMapBase : public Base {
955//       typedef T PredNodeMap;
956//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
957//       DefPredNodeMapBase(const TR &b) : TR(b) {}
958//     };
959   
960//     ///\brief \ref named-templ-param "Named parameter"
961//     ///function for setting PredNodeMap type
962//     ///
963//     /// \ref named-templ-param "Named parameter"
964//     ///function for setting PredNodeMap type
965//     ///
966//     template<class T>
967//     DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
968//     {
969//       Base::_predNode=(void *)&t;
970//       return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
971//     }
972   
973    template<class T>
974    struct DefDistMapBase : public Base {
975      typedef T DistMap;
976      static DistMap *createDistMap(const Graph &) { return 0; };
977      DefDistMapBase(const TR &b) : TR(b) {}
978    };
979   
980    ///\brief \ref named-templ-param "Named parameter"
981    ///function for setting DistMap type
982    ///
983    /// \ref named-templ-param "Named parameter"
984    ///function for setting DistMap type
985    ///
986    template<class T>
987    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
988    {
989      Base::_dist=(void *)&t;
990      return DijkstraWizard<DefDistMapBase<T> >(*this);
991    }
992   
993    /// Sets the source node, from which the Dijkstra algorithm runs.
994
995    /// Sets the source node, from which the Dijkstra algorithm runs.
996    /// \param s is the source node.
997    DijkstraWizard<TR> &source(Node s)
998    {
999      Base::_source=s;
1000      return *this;
1001    }
1002   
1003  };
1004 
1005  ///Function type interface for Dijkstra algorithm.
1006
1007  /// \ingroup flowalgs
1008  ///Function type interface for Dijkstra algorithm.
1009  ///
1010  ///This function also has several
1011  ///\ref named-templ-func-param "named parameters",
1012  ///they are declared as the members of class \ref DijkstraWizard.
1013  ///The following
1014  ///example shows how to use these parameters.
1015  ///\code
1016  ///  dijkstra(g,length,source).predMap(preds).run();
1017  ///\endcode
1018  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"
1019  ///to the end of the parameter list.
1020  ///\sa DijkstraWizard
1021  ///\sa Dijkstra
1022  template<class GR, class LM>
1023  DijkstraWizard<DijkstraWizardBase<GR,LM> >
1024  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
1025  {
1026    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
1027  }
1028
1029} //END OF NAMESPACE LEMON
1030
1031#endif
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