COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/work/alpar/dijkstra.h @ 1125:377e240b050f

Last change on this file since 1125:377e240b050f was 1125:377e240b050f, checked in by Alpar Juttner, 18 years ago

A new exception class called UninitializedParameter?.

File size: 23.4 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/dijkstra.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 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/// \addtogroup flowalgs
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 typename Graph::template NodeMap<typename GR::Node> PredNodeMap;
89    ///Instantiates a PredNodeMap.
90   
91    ///This function instantiates a \ref PredNodeMap.
92    ///\param G is the graph, to which we would like to define the \ref PredNodeMap
93    static PredNodeMap *createPredNodeMap(const GR &G)
94    {
95      return new PredNodeMap(G);
96    }
97
98    ///The type of the map that stores whether a nodes is reached.
99 
100    ///The type of the map that stores whether a nodes is reached.
101    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
102    ///By default it is a NullMap.
103    ///\todo If it is set to a real map, Dijkstra::reached() should read this.
104    ///\todo named parameter to set this type, function to read and write.
105    typedef NullMap<typename Graph::Node,bool> ReachedMap;
106    ///Instantiates a ReachedMap.
107 
108    ///This function instantiates a \ref ReachedMap.
109    ///\param G is the graph, to which we would like to define the \ref ReachedMap
110    static ReachedMap *createReachedMap(const GR &G)
111    {
112      return new ReachedMap();
113    }
114    ///The type of the map that stores the dists of the nodes.
115 
116    ///The type of the map that stores the dists of the nodes.
117    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
118    ///
119    typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
120    ///Instantiates a DistMap.
121 
122    ///This function instantiates a \ref DistMap.
123    ///\param G is the graph, to which we would like to define the \ref DistMap
124    static DistMap *createDistMap(const GR &G)
125    {
126      return new DistMap(G);
127    }
128  };
129 
130  ///%Dijkstra algorithm class.
131 
132  ///This class provides an efficient implementation of %Dijkstra algorithm.
133  ///The edge lengths are passed to the algorithm using a
134  ///\ref concept::ReadMap "ReadMap",
135  ///so it is easy to change it to any kind of length.
136  ///
137  ///The type of the length is determined by the
138  ///\ref concept::ReadMap::Value "Value" of the length map.
139  ///
140  ///It is also possible to change the underlying priority heap.
141  ///
142  ///\param GR The graph type the algorithm runs on. The default value is
143  ///\ref ListGraph. The value of GR is not used directly by Dijkstra, it
144  ///is only passed to \ref DijkstraDefaultTraits.
145  ///\param LM This read-only
146  ///EdgeMap
147  ///determines the
148  ///lengths of the edges. It is read once for each edge, so the map
149  ///may involve in relatively time consuming process to compute the edge
150  ///length if it is necessary. The default map type is
151  ///\ref concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>".
152  ///The value of LM is not used directly by Dijkstra, it
153  ///is only passed to \ref DijkstraDefaultTraits.
154  ///\param TR Traits class to set various data types used by the algorithm.
155  ///The default traits class is
156  ///\ref DijkstraDefaultTraits "DijkstraDefaultTraits<GR,LM>".
157  ///See \ref DijkstraDefaultTraits for the documentation of
158  ///a Dijkstra traits class.
159  ///
160  ///\author Jacint Szabo and Alpar Juttner
161  ///\todo We need a typedef-names should be standardized. (-:
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::Dijsktra::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 reached.
210    typedef typename TR::ReachedMap ReachedMap;
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 *pred_node;
226    ///Indicates if \ref pred_node is locally allocated (\c true) or not.
227    bool local_pred_node;
228    ///Pointer to the map of distances.
229    DistMap *distance;
230    ///Indicates if \ref distance is locally allocated (\c true) or not.
231    bool local_distance;
232    ///Pointer to the map of reached status of the nodes.
233    ReachedMap *_reached;
234    ///Indicates if \ref _reached is locally allocated (\c true) or not.
235    bool local_reached;
236
237    ///The source node of the last execution.
238    Node source;
239
240    ///Initializes the maps.
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 init_maps()
245    {
246      if(!_pred) {
247        local_pred = true;
248        _pred = Traits::createPredMap(*G);
249      }
250      if(!pred_node) {
251        local_pred_node = true;
252        pred_node = Traits::createPredNodeMap(*G);
253      }
254      if(!distance) {
255        local_distance = true;
256        distance = Traits::createDistMap(*G);
257      }
258      if(!_reached) {
259        local_reached = true;
260        _reached = Traits::createReachedMap(*G);
261      }
262    }
263   
264  public :
265 
266    template <class T>
267    struct DefPredMapTraits : public Traits {
268      typedef T PredMap;
269      ///\todo An exception should be thrown.
270      ///
271      static PredMap *createPredMap(const Graph &G)
272      {
273        throw UninitializedData();
274      }
275    };
276    ///\ref named-templ-param "Named parameter" for setting PredMap type
277
278    ///\ref named-templ-param "Named parameter" for setting PredMap type
279    ///
280    template <class T>
281    class DefPredMap : public Dijkstra< Graph,
282                                        LengthMap,
283                                        DefPredMapTraits<T> > { };
284   
285    template <class T>
286    struct DefPredNodeMapTraits : public Traits {
287      typedef T PredNodeMap;
288      ///\todo An exception should be thrown.
289      ///
290      static PredNodeMap *createPredNodeMap(const Graph &G)
291      {
292        throw UninitializedData();
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      ///\todo An exception should be thrown.
308      ///
309      static DistMap *createDistMap(const Graph &G)
310      {
311        throw UninitializedData();
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    ///Constructor.
324   
325    ///\param _G the graph the algorithm will run on.
326    ///\param _length the length map used by the algorithm.
327    Dijkstra(const Graph& _G, const LengthMap& _length) :
328      G(&_G), length(&_length),
329      _pred(NULL), local_pred(false),
330      pred_node(NULL), local_pred_node(false),
331      distance(NULL), local_distance(false),
332      _reached(NULL), local_reached(false)
333    { }
334   
335    ///Destructor.
336    ~Dijkstra()
337    {
338      if(local_pred) delete _pred;
339      if(local_pred_node) delete pred_node;
340      if(local_distance) delete distance;
341      if(local_reached) delete _reached;
342    }
343
344    ///Sets the length map.
345
346    ///Sets the length map.
347    ///\return <tt> (*this) </tt>
348    Dijkstra &lengthMap(const LengthMap &m)
349    {
350      length = &m;
351      return *this;
352    }
353
354    ///Sets the map storing the predecessor edges.
355
356    ///Sets the map storing the predecessor edges.
357    ///If you don't use this function before calling \ref run(),
358    ///it will allocate one. The destuctor deallocates this
359    ///automatically allocated map, of course.
360    ///\return <tt> (*this) </tt>
361    Dijkstra &predMap(PredMap &m)
362    {
363      if(local_pred) {
364        delete _pred;
365        local_pred=false;
366      }
367      _pred = &m;
368      return *this;
369    }
370
371    ///Sets the map storing the predecessor nodes.
372
373    ///Sets the map storing the predecessor nodes.
374    ///If you don't use this function before calling \ref run(),
375    ///it will allocate one. The destuctor deallocates this
376    ///automatically allocated map, of course.
377    ///\return <tt> (*this) </tt>
378    Dijkstra &predNodeMap(PredNodeMap &m)
379    {
380      if(local_pred_node) {
381        delete pred_node;
382        local_pred_node=false;
383      }
384      pred_node = &m;
385      return *this;
386    }
387
388    ///Sets the map storing the distances calculated by the algorithm.
389
390    ///Sets the map storing the distances calculated by the algorithm.
391    ///If you don't use this function before calling \ref run(),
392    ///it will allocate one. The destuctor deallocates this
393    ///automatically allocated map, of course.
394    ///\return <tt> (*this) </tt>
395    Dijkstra &distMap(DistMap &m)
396    {
397      if(local_distance) {
398        delete distance;
399        local_distance=false;
400      }
401      distance = &m;
402      return *this;
403    }
404   
405  ///Runs %Dijkstra algorithm from node \c s.
406
407  ///This method runs the %Dijkstra algorithm from a root node \c s
408  ///in order to
409  ///compute the
410  ///shortest path to each node. The algorithm computes
411  ///- The shortest path tree.
412  ///- The distance of each node from the root.
413  ///\todo heap_map's type could also be in the traits class.
414    void run(Node s) {
415     
416      init_maps();
417     
418      source = s;
419     
420      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
421        _pred->set(u,INVALID);
422        pred_node->set(u,INVALID);
423        ///\todo *_reached is not set to false.
424      }
425     
426      typename Graph::template NodeMap<int> heap_map(*G,-1);
427     
428      Heap heap(heap_map);
429     
430      heap.push(s,0);
431     
432      while ( !heap.empty() ) {
433       
434        Node v=heap.top();
435        _reached->set(v,true);
436        Value oldvalue=heap[v];
437        heap.pop();
438        distance->set(v, oldvalue);
439       
440       
441        for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
442          Node w=G->target(e);
443          switch(heap.state(w)) {
444          case Heap::PRE_HEAP:
445            heap.push(w,oldvalue+(*length)[e]);
446            _pred->set(w,e);
447            pred_node->set(w,v);
448            break;
449          case Heap::IN_HEAP:
450            if ( oldvalue+(*length)[e] < heap[w] ) {
451              heap.decrease(w, oldvalue+(*length)[e]);
452              _pred->set(w,e);
453              pred_node->set(w,v);
454            }
455            break;
456          case Heap::POST_HEAP:
457            break;
458          }
459        }
460      }
461    }
462   
463    ///The distance of a node from the root.
464
465    ///Returns the distance of a node from the root.
466    ///\pre \ref run() must be called before using this function.
467    ///\warning If node \c v in unreachable from the root the return value
468    ///of this funcion is undefined.
469    Value dist(Node v) const { return (*distance)[v]; }
470
471    ///Returns the 'previous edge' of the shortest path tree.
472
473    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
474    ///i.e. it returns the last edge of a shortest path from the root to \c
475    ///v. It is \ref INVALID
476    ///if \c v is unreachable from the root or if \c v=s. The
477    ///shortest path tree used here is equal to the shortest path tree used in
478    ///\ref predNode(Node v).  \pre \ref run() must be called before using
479    ///this function.
480    ///\todo predEdge could be a better name.
481    Edge pred(Node v) const { return (*_pred)[v]; }
482
483    ///Returns the 'previous node' of the shortest path tree.
484
485    ///For a node \c v it returns the 'previous node' of the shortest path tree,
486    ///i.e. it returns the last but one node from a shortest path from the
487    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
488    ///\c v=s. The shortest path tree used here is equal to the shortest path
489    ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
490    ///using this function.
491    Node predNode(Node v) const { return (*pred_node)[v]; }
492   
493    ///Returns a reference to the NodeMap of distances.
494
495    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
496    ///be called before using this function.
497    const DistMap &distMap() const { return *distance;}
498 
499    ///Returns a reference to the shortest path tree map.
500
501    ///Returns a reference to the NodeMap of the edges of the
502    ///shortest path tree.
503    ///\pre \ref run() must be called before using this function.
504    const PredMap &predMap() const { return *_pred;}
505 
506    ///Returns a reference to the map of nodes of shortest paths.
507
508    ///Returns a reference to the NodeMap of the last but one nodes of the
509    ///shortest path tree.
510    ///\pre \ref run() must be called before using this function.
511    const PredNodeMap &predNodeMap() const { return *pred_node;}
512
513    ///Checks if a node is reachable from the root.
514
515    ///Returns \c true if \c v is reachable from the root.
516    ///\note The root node is reported to be reached!
517    ///\pre \ref run() must be called before using this function.
518    ///
519    bool reached(Node v) { return v==source || (*_pred)[v]!=INVALID; }
520   
521  };
522
523  /// Default traits used by \ref DijkstraWizard
524
525  /// To make it easier to use Dijkstra algorithm we have created a wizard class.
526  /// This \ref DijkstraWizard class needs default traits, as well as the \ref Dijkstra class.
527  /// The \ref DijkstraWizardBase is a class to be the default traits of the
528  /// \ref DijkstraWizard class.
529  template<class GR,class LM>
530  class DijkstraWizardBase : public DijkstraDefaultTraits<GR,LM>
531  {
532
533    typedef DijkstraDefaultTraits<GR,LM> Base;
534  protected:
535    /// Pointer to the underlying graph.
536    void *_g;
537    /// Pointer to the length map
538    void *_length;
539    ///Pointer to the map of predecessors edges.
540    void *_pred;
541    ///Pointer to the map of predecessors nodes.
542    void *_predNode;
543    ///Pointer to the map of distances.
544    void *_dist;
545    ///Pointer to the source node.
546    void *_source;
547
548    /// Type of the nodes in the graph.
549    typedef typename Base::Graph::Node Node;
550
551    public:
552    /// Constructor.
553   
554    /// This constructor does not require parameters, therefore it initiates
555    /// all of the attributes to default values (0, INVALID).
556    DijkstraWizardBase() : _g(0), _length(0), _pred(0), _predNode(0),
557                       _dist(0), _source(INVALID) {}
558
559    /// Constructor.
560   
561    /// This constructor requires some parameters, listed in the parameters list.
562    /// Others are initiated to 0.
563    /// \param g is the initial value of  \ref _g
564    /// \param l is the initial value of  \ref _length
565    /// \param s is the initial value of  \ref _source
566    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
567      _g((void *)&g), _length((void *)&l), _pred(0), _predNode(0),
568                  _dist(0), _source((void *)&s) {}
569
570  };
571 
572  /// A class to make easier the usage of Dijkstra algorithm
573
574  /// This class is created to make it easier to use Dijkstra algorithm.
575  /// It uses the functions and features of the plain \ref Dijkstra,
576  /// but it is much more simple to use it.
577  ///
578  /// Simplicity means that the way to change the types defined
579  /// in the traits class is based on functions that returns the new class
580  /// and not on templatable built-in classes. When using the plain \ref Dijkstra
581  /// the new class with the modified type comes from the original class by using the ::
582  /// operator. In the case of \ref DijkstraWizard only a function have to be called and it will
583  /// return the needed class.
584  ///
585  /// It does not have own \ref run method. When its \ref run method is called
586  /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
587  /// method of it.
588  template<class TR>
589  class DijkstraWizard : public TR
590  {
591    typedef TR Base;
592
593    ///The type of the underlying graph.
594    typedef typename TR::Graph Graph;
595    //\e
596    typedef typename Graph::Node Node;
597    //\e
598    typedef typename Graph::NodeIt NodeIt;
599    //\e
600    typedef typename Graph::Edge Edge;
601    //\e
602    typedef typename Graph::OutEdgeIt OutEdgeIt;
603   
604    ///The type of the map that stores the edge lengths.
605    typedef typename TR::LengthMap LengthMap;
606    ///The type of the length of the edges.
607    typedef typename LengthMap::Value Value;
608    ///\brief The type of the map that stores the last
609    ///edges of the shortest paths.
610    typedef typename TR::PredMap PredMap;
611    ///\brief The type of the map that stores the last but one
612    ///nodes of the shortest paths.
613    typedef typename TR::PredNodeMap PredNodeMap;
614    ///The type of the map that stores the dists of the nodes.
615    typedef typename TR::DistMap DistMap;
616
617    ///The heap type used by the dijkstra algorithm.
618    typedef typename TR::Heap Heap;
619public:
620    /// Constructor.
621    DijkstraWizard() : TR() {}
622
623    /// Constructor that requires parameters.
624
625    /// Constructor that requires parameters.
626    /// These parameters will be the default values for the traits class.
627    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
628      TR(g,l,s) {}
629
630    ///Copy constructor
631    DijkstraWizard(const TR &b) : TR(b) {}
632
633    ~DijkstraWizard() {}
634
635    ///Runs Dijkstra algorithm from a given node.
636   
637    ///Runs Dijkstra algorithm from a given node.
638    ///The node can be given by the \ref source function.
639    void run()
640    {
641      if(_source==0) throw UninitializedData();
642      Dijkstra<Graph,LengthMap,TR> Dij(*(Graph*)_g,*(LengthMap*)_length);
643      if(_pred) Dij.predMap(*(PredMap*)_pred);
644      if(_predNode) Dij.predNodeMap(*(PredNodeMap*)_predNode);
645      if(_dist) Dij.distMap(*(DistMap*)_dist);
646      Dij.run(*(Node*)_source);
647    }
648
649    ///Runs Dijkstra algorithm from the given node.
650
651    ///Runs Dijkstra algorithm from the given node.
652    ///\param s is the given source.
653    void run(Node s)
654    {
655      _source=(void *)&s;
656      run();
657    }
658
659    template<class T>
660    struct DefPredMapBase : public Base {
661      typedef T PredMap;
662      static PredMap *createPredMap(const Graph &G) { return 0; };
663      DefPredMapBase(const Base &b) : Base(b) {}
664    };
665   
666    /// \ref named-templ-param "Named parameter" function for setting PredMap type
667
668    /// \ref named-templ-param "Named parameter" function for setting PredMap type
669    ///
670    template<class T>
671    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
672    {
673      _pred=(void *)&t;
674      return DijkstraWizard<DefPredMapBase<T> >(*this);
675    }
676   
677
678    template<class T>
679    struct DefPredNodeMapBase : public Base {
680      typedef T PredNodeMap;
681      static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
682      DefPredNodeMapBase(const Base &b) : Base(b) {}
683    };
684   
685    /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
686
687    /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
688    ///
689    template<class T>
690    DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
691    {
692      _predNode=(void *)&t;
693      return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
694    }
695   
696    template<class T>
697    struct DefDistMapBase : public Base {
698      typedef T DistMap;
699      static DistMap *createDistMap(const Graph &G) { return 0; };
700      DefDistMapBase(const Base &b) : Base(b) {}
701    };
702   
703    /// \ref named-templ-param "Named parameter" function for setting DistMap type
704
705    /// \ref named-templ-param "Named parameter" function for setting DistMap type
706    ///
707    template<class T>
708    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
709    {
710      _dist=(void *)&t;
711      return DijkstraWizard<DefDistMapBase<T> >(*this);
712    }
713   
714    /// Sets the source node, from which the Dijkstra algorithm runs.
715
716    /// Sets the source node, from which the Dijkstra algorithm runs.
717    /// \param s is the source node.
718    DijkstraWizard<TR> &source(Node s)
719    {
720      source=(void *)&s;
721      return *this;
722    }
723   
724  };
725 
726  ///\e
727
728  ///\todo Please document...
729  ///
730  template<class GR, class LM>
731  DijkstraWizard<DijkstraWizardBase<GR,LM> >
732  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
733  {
734    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
735  }
736
737/// @}
738 
739} //END OF NAMESPACE LEMON
740
741#endif
742
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