COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/dijkstra.h @ 1132:ab5c81fcc31a

Last change on this file since 1132:ab5c81fcc31a was 1132:ab5c81fcc31a, checked in by Alpar Juttner, 16 years ago

Revised dijkstra.h with several new features added.

File size: 28.3 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 NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
89    ///Instantiates a PredNodeMap.
90   
91    ///This function instantiates a \ref PredNodeMap.
92    ///\param G is the graph, to which we would like to define the \ref PredNodeMap
93    static PredNodeMap *createPredNodeMap(const GR &G)
94    {
95      return new PredNodeMap();
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 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::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 *_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 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    ///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(!_reached) {
259        local_reached = true;
260        _reached = Traits::createReachedMap(*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 DefReachedMapTraits : public Traits {
323      typedef T ReachedMap;
324      static ReachedMap *createReachedMap(const Graph &G)
325      {
326        throw UninitializedParameter();
327      }
328    };
329    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
330
331    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
332    ///
333    template <class T>
334    class DefReachedMap : public Dijkstra< Graph,
335                                        LengthMap,
336                                        DefReachedMapTraits<T> > { };
337   
338    struct DefGraphReachedMapTraits : public Traits {
339      typedef typename Graph::NodeMap<bool> ReachedMap;
340      static ReachedMap *createReachedMap(const Graph &G)
341      {
342        return new ReachedMap(G);
343      }
344    };
345    ///\brief \ref named-templ-param "Named parameter"
346    ///for setting the ReachedMap type to be Graph::NodeMap<bool>.
347    ///
348    ///\ref named-templ-param "Named parameter"
349    ///for setting the ReachedMap 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 DefReachedMapToBeDefaultMap :
353      public Dijkstra< Graph,
354                       LengthMap,
355                       DefGraphReachedMapTraits> { };
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      _reached(NULL), local_reached(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_reached) delete _reached;
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      _reached->set(v,true);
452      _dist->set(v, dst);
453      _predNode->set(v,G->source((*_pred)[v]));
454    }
455
456  public:
457    ///\name Excetution control
458    ///The simplest way to execute the algorithm is to use
459    ///\ref run().
460    ///\n
461    ///It you need more control on the execution,
462    ///first you must call \ref init(), then you can add several source nodes
463    ///with \ref addSource(). Finally \ref start() will perform the actual path
464    ///computation.
465
466    ///@{
467
468    ///Initializes the internal data structures.
469
470    ///Initializes the internal data structures.
471    ///
472    ///\todo _heap_map's type could also be in the traits class.
473    void init()
474    {
475      create_maps();
476     
477      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
478        _pred->set(u,INVALID);
479        _predNode->set(u,INVALID);
480        ///\todo *_reached is not set to false.
481        _heap_map.set(u,Heap::PRE_HEAP);
482      }
483    }
484   
485    ///Adds a new source node.
486
487    ///Adds a new source node the the priority heap.
488    ///It checks if the node has already been added to the heap.
489    ///
490    ///The optional second parameter is the initial distance of the node.
491    ///
492    ///\todo Do we really want to check it?
493    void addSource(Node s,Value dst=0)
494    {
495      source = s;
496      if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst);
497    }
498   
499    void processNode()
500    {
501      Node v=_heap.top();
502      Value oldvalue=_heap[v];
503      _heap.pop();
504      finalizeNodeData(v,oldvalue);
505     
506      for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
507        Node w=G->target(e);
508        switch(_heap.state(w)) {
509        case Heap::PRE_HEAP:
510          _heap.push(w,oldvalue+(*length)[e]);
511          _pred->set(w,e);
512//        _predNode->set(w,v);
513          break;
514        case Heap::IN_HEAP:
515          if ( oldvalue+(*length)[e] < _heap[w] ) {
516            _heap.decrease(w, oldvalue+(*length)[e]);
517            _pred->set(w,e);
518//          _predNode->set(w,v);
519          }
520          break;
521        case Heap::POST_HEAP:
522          break;
523        }
524      }
525    }
526
527    ///Executes the algorithm.
528
529    ///Executes the algorithm.
530    ///
531    ///\pre init() must be called and at least one node should be added
532    ///with addSource() before using this function.
533    ///
534    ///This method runs the %Dijkstra algorithm from the root node(s)
535    ///in order to
536    ///compute the
537    ///shortest path to each node. The algorithm computes
538    ///- The shortest path tree.
539    ///- The distance of each node from the root(s).
540    ///
541    void start()
542    {
543      while ( !_heap.empty() ) processNode();
544    }
545   
546    ///Executes the algorithm until \c dest is reached.
547
548    ///Executes the algorithm until \c dest is reached.
549    ///
550    ///\pre init() must be called and at least one node should be added
551    ///with addSource() before using this function.
552    ///
553    ///This method runs the %Dijkstra algorithm from the root node(s)
554    ///in order to
555    ///compute the
556    ///shortest path to \c dest. The algorithm computes
557    ///- The shortest path to \c  dest.
558    ///- The distance of \c dest from the root(s).
559    ///
560    void start(Node dest)
561    {
562      while ( !_heap.empty() && _heap.top()!=dest ) processNode();
563      if ( _heap.top()==dest ) finalizeNodeData(_heap.top());
564    }
565   
566    ///Executes the algorithm until a condition is met.
567
568    ///Executes the algorithm until a condition is met.
569    ///
570    ///\pre init() must be called and at least one node should be added
571    ///with addSource() before using this function.
572    ///
573    ///\param nm must be a bool (or convertible) node map. The algorithm
574    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
575    template<class NM>
576    void start(const NM &nm)
577    {
578      while ( !_heap.empty() && !mn[_heap.top()] ) processNode();
579      if ( !_heap.empty() ) finalizeNodeData(_heap.top());
580    }
581   
582    ///Runs %Dijkstra algorithm from node \c s.
583   
584    ///This method runs the %Dijkstra algorithm from a root node \c s
585    ///in order to
586    ///compute the
587    ///shortest path to each node. The algorithm computes
588    ///- The shortest path tree.
589    ///- The distance of each node from the root.
590    ///
591    ///\note d.run(s) is just a shortcut of the following code.
592    ///\code
593    ///  d.init();
594    ///  d.addSource(s);
595    ///  d.start();
596    ///\endcode
597    void run(Node s) {
598      init();
599      addSource(s);
600      start();
601    }
602   
603    ///Finds the shortest path between \c s and \c t.
604   
605    ///Finds the shortest path between \c s and \c t.
606    ///
607    ///\return The length of the shortest s---t path if there exists one,
608    ///0 otherwise.
609    ///\note Apart from the return value, d.run(s) is
610    ///just a shortcut of the following code.
611    ///\code
612    ///  d.init();
613    ///  d.addSource(s);
614    ///  d.start(t);
615    ///\endcode
616    Value run(Node s,Node t) {
617      init();
618      addSource(s);
619      start(t);
620      return (*_pred)[t]==INVALID?0:(*_dist)[t];
621    }
622   
623    ///@}
624
625    ///\name Query Functions
626    ///The result of the %Dijkstra algorithm can be obtained using these
627    ///functions.\n
628    ///Before the use of these functions,
629    ///either run() or start() must be called.
630   
631    ///@{
632
633    ///The distance of a node from the root.
634
635    ///Returns the distance of a node from the root.
636    ///\pre \ref run() must be called before using this function.
637    ///\warning If node \c v in unreachable from the root the return value
638    ///of this funcion is undefined.
639    Value dist(Node v) const { return (*_dist)[v]; }
640
641    ///Returns the 'previous edge' of the shortest path tree.
642
643    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
644    ///i.e. it returns the last edge of a shortest path from the root to \c
645    ///v. It is \ref INVALID
646    ///if \c v is unreachable from the root or if \c v=s. The
647    ///shortest path tree used here is equal to the shortest path tree used in
648    ///\ref predNode(Node v).  \pre \ref run() must be called before using
649    ///this function.
650    ///\todo predEdge could be a better name.
651    Edge pred(Node v) const { return (*_pred)[v]; }
652
653    ///Returns the 'previous node' of the shortest path tree.
654
655    ///For a node \c v it returns the 'previous node' of the shortest path tree,
656    ///i.e. it returns the last but one node from a shortest path from the
657    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
658    ///\c v=s. The shortest path tree used here is equal to the shortest path
659    ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
660    ///using this function.
661    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
662                                  G->source((*_pred)[v]); }
663   
664    ///Returns a reference to the NodeMap of distances.
665
666    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
667    ///be called before using this function.
668    const DistMap &distMap() const { return *_dist;}
669 
670    ///Returns a reference to the shortest path tree map.
671
672    ///Returns a reference to the NodeMap of the edges of the
673    ///shortest path tree.
674    ///\pre \ref run() must be called before using this function.
675    const PredMap &predMap() const { return *_pred;}
676 
677    ///Returns a reference to the map of nodes of shortest paths.
678
679    ///Returns a reference to the NodeMap of the last but one nodes of the
680    ///shortest path tree.
681    ///\pre \ref run() must be called before using this function.
682    const PredNodeMap &predNodeMap() const { return *_predNode;}
683
684    ///Checks if a node is reachable from the root.
685
686    ///Returns \c true if \c v is reachable from the root.
687    ///\warning If the algorithm is started from multiple nodes,
688    ///this function may give false result for the source nodes.
689    ///\pre \ref run() must be called before using this function.
690    ///
691    bool reached(Node v) { return v==source || (*_pred)[v]!=INVALID; }
692   
693    ///@}
694  };
695
696  /// Default traits used by \ref DijkstraWizard
697
698  /// To make it easier to use Dijkstra algorithm we have created a wizard class.
699  /// This \ref DijkstraWizard class needs default traits, as well as the \ref Dijkstra class.
700  /// The \ref DijkstraWizardBase is a class to be the default traits of the
701  /// \ref DijkstraWizard class.
702  template<class GR,class LM>
703  class DijkstraWizardBase : public DijkstraDefaultTraits<GR,LM>
704  {
705
706    typedef DijkstraDefaultTraits<GR,LM> Base;
707  protected:
708    /// Pointer to the underlying graph.
709    void *_g;
710    /// Pointer to the length map
711    void *_length;
712    ///Pointer to the map of predecessors edges.
713    void *_pred;
714    ///Pointer to the map of predecessors nodes.
715    void *_predNode;
716    ///Pointer to the map of distances.
717    void *_dist;
718    ///Pointer to the source node.
719    void *_source;
720
721    /// Type of the nodes in the graph.
722    typedef typename Base::Graph::Node Node;
723
724    public:
725    /// Constructor.
726   
727    /// This constructor does not require parameters, therefore it initiates
728    /// all of the attributes to default values (0, INVALID).
729    DijkstraWizardBase() : _g(0), _length(0), _pred(0), _predNode(0),
730                       _dist(0), _source(INVALID) {}
731
732    /// Constructor.
733   
734    /// This constructor requires some parameters, listed in the parameters list.
735    /// Others are initiated to 0.
736    /// \param g is the initial value of  \ref _g
737    /// \param l is the initial value of  \ref _length
738    /// \param s is the initial value of  \ref _source
739    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
740      _g((void *)&g), _length((void *)&l), _pred(0), _predNode(0),
741                  _dist(0), _source((void *)&s) {}
742
743  };
744 
745  /// A class to make easier the usage of Dijkstra algorithm
746
747  /// This class is created to make it easier to use Dijkstra algorithm.
748  /// It uses the functions and features of the plain \ref Dijkstra,
749  /// but it is much more simple to use it.
750  ///
751  /// Simplicity means that the way to change the types defined
752  /// in the traits class is based on functions that returns the new class
753  /// and not on templatable built-in classes. When using the plain \ref Dijkstra
754  /// the new class with the modified type comes from the original class by using the ::
755  /// operator. In the case of \ref DijkstraWizard only a function have to be called and it will
756  /// return the needed class.
757  ///
758  /// It does not have own \ref run method. When its \ref run method is called
759  /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
760  /// method of it.
761  template<class TR>
762  class DijkstraWizard : public TR
763  {
764    typedef TR Base;
765
766    ///The type of the underlying graph.
767    typedef typename TR::Graph Graph;
768    //\e
769    typedef typename Graph::Node Node;
770    //\e
771    typedef typename Graph::NodeIt NodeIt;
772    //\e
773    typedef typename Graph::Edge Edge;
774    //\e
775    typedef typename Graph::OutEdgeIt OutEdgeIt;
776   
777    ///The type of the map that stores the edge lengths.
778    typedef typename TR::LengthMap LengthMap;
779    ///The type of the length of the edges.
780    typedef typename LengthMap::Value Value;
781    ///\brief The type of the map that stores the last
782    ///edges of the shortest paths.
783    typedef typename TR::PredMap PredMap;
784    ///\brief The type of the map that stores the last but one
785    ///nodes of the shortest paths.
786    typedef typename TR::PredNodeMap PredNodeMap;
787    ///The type of the map that stores the dists of the nodes.
788    typedef typename TR::DistMap DistMap;
789
790    ///The heap type used by the dijkstra algorithm.
791    typedef typename TR::Heap Heap;
792public:
793    /// Constructor.
794    DijkstraWizard() : TR() {}
795
796    /// Constructor that requires parameters.
797
798    /// Constructor that requires parameters.
799    /// These parameters will be the default values for the traits class.
800    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
801      TR(g,l,s) {}
802
803    ///Copy constructor
804    DijkstraWizard(const TR &b) : TR(b) {}
805
806    ~DijkstraWizard() {}
807
808    ///Runs Dijkstra algorithm from a given node.
809   
810    ///Runs Dijkstra algorithm from a given node.
811    ///The node can be given by the \ref source function.
812    void run()
813    {
814      if(_source==0) throw UninitializedParameter();
815      Dijkstra<Graph,LengthMap,TR> Dij(*(Graph*)_g,*(LengthMap*)_length);
816      if(_pred) Dij.predMap(*(PredMap*)_pred);
817      if(_predNode) Dij.predNodeMap(*(PredNodeMap*)_predNode);
818      if(_dist) Dij.distMap(*(DistMap*)_dist);
819      Dij.run(*(Node*)_source);
820    }
821
822    ///Runs Dijkstra algorithm from the given node.
823
824    ///Runs Dijkstra algorithm from the given node.
825    ///\param s is the given source.
826    void run(Node s)
827    {
828      _source=(void *)&s;
829      run();
830    }
831
832    template<class T>
833    struct DefPredMapBase : public Base {
834      typedef T PredMap;
835      static PredMap *createPredMap(const Graph &G) { return 0; };
836      DefPredMapBase(const Base &b) : Base(b) {}
837    };
838   
839    /// \ref named-templ-param "Named parameter" function for setting PredMap type
840
841    /// \ref named-templ-param "Named parameter" function for setting PredMap type
842    ///
843    template<class T>
844    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
845    {
846      _pred=(void *)&t;
847      return DijkstraWizard<DefPredMapBase<T> >(*this);
848    }
849   
850
851    template<class T>
852    struct DefPredNodeMapBase : public Base {
853      typedef T PredNodeMap;
854      static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
855      DefPredNodeMapBase(const Base &b) : Base(b) {}
856    };
857   
858    /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
859
860    /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
861    ///
862    template<class T>
863    DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
864    {
865      _predNode=(void *)&t;
866      return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
867    }
868   
869    template<class T>
870    struct DefDistMapBase : public Base {
871      typedef T DistMap;
872      static DistMap *createDistMap(const Graph &G) { return 0; };
873      DefDistMapBase(const Base &b) : Base(b) {}
874    };
875   
876    /// \ref named-templ-param "Named parameter" function for setting DistMap type
877
878    /// \ref named-templ-param "Named parameter" function for setting DistMap type
879    ///
880    template<class T>
881    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
882    {
883      _dist=(void *)&t;
884      return DijkstraWizard<DefDistMapBase<T> >(*this);
885    }
886   
887    /// Sets the source node, from which the Dijkstra algorithm runs.
888
889    /// Sets the source node, from which the Dijkstra algorithm runs.
890    /// \param s is the source node.
891    DijkstraWizard<TR> &source(Node s)
892    {
893      source=(void *)&s;
894      return *this;
895    }
896   
897  };
898 
899  ///\e
900
901  ///\todo Please document...
902  ///
903  template<class GR, class LM>
904  DijkstraWizard<DijkstraWizardBase<GR,LM> >
905  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
906  {
907    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
908  }
909
910/// @}
911 
912} //END OF NAMESPACE LEMON
913
914#endif
915
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