COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/dijkstra.h @ 2335:27aa03cd3121

Last change on this file since 2335:27aa03cd3121 was 2335:27aa03cd3121, checked in by Balazs Dezso, 13 years ago

New path concept and path structures

TODO: BellmanFord::negativeCycle()

File size: 35.0 KB
RevLine 
[906]1/* -*- C++ -*-
2 *
[1956]3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2006
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
[1359]7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
[906]8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
[921]19#ifndef LEMON_DIJKSTRA_H
20#define LEMON_DIJKSTRA_H
[255]21
[758]22///\ingroup flowalgs
[255]23///\file
24///\brief Dijkstra algorithm.
[1283]25///
[1734]26///\todo dijkstraZero() solution should be revised.
[255]27
[953]28#include <lemon/list_graph.h>
[921]29#include <lemon/bin_heap.h>
[2335]30#include <lemon/bits/path_dump.h>
[1993]31#include <lemon/bits/invalid.h>
[1119]32#include <lemon/error.h>
33#include <lemon/maps.h>
[255]34
[2335]35
[921]36namespace lemon {
[385]37
[1734]38  template<class T> T dijkstraZero() {return 0;}
[1151]39 
[954]40  ///Default traits class of Dijkstra class.
41
42  ///Default traits class of Dijkstra class.
43  ///\param GR Graph type.
44  ///\param LM Type of length map.
[953]45  template<class GR, class LM>
46  struct DijkstraDefaultTraits
47  {
[954]48    ///The graph type the algorithm runs on.
[953]49    typedef GR Graph;
50    ///The type of the map that stores the edge lengths.
51
[1124]52    ///The type of the map that stores the edge lengths.
[2260]53    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.
[953]54    typedef LM LengthMap;
[954]55    //The type of the length of the edges.
[987]56    typedef typename LM::Value Value;
[1721]57    /// The cross reference type used by heap.
58
59    /// The cross reference type used by heap.
60    /// Usually it is \c Graph::NodeMap<int>.
61    typedef typename Graph::template NodeMap<int> HeapCrossRef;
62    ///Instantiates a HeapCrossRef.
63
64    ///This function instantiates a \ref HeapCrossRef.
65    /// \param G is the graph, to which we would like to define the
66    /// HeapCrossRef.
67    static HeapCrossRef *createHeapCrossRef(const GR &G)
68    {
69      return new HeapCrossRef(G);
70    }
71   
[954]72    ///The heap type used by Dijkstra algorithm.
[967]73
74    ///The heap type used by Dijkstra algorithm.
75    ///
76    ///\sa BinHeap
77    ///\sa Dijkstra
[2263]78    typedef BinHeap<typename LM::Value, HeapCrossRef, std::less<Value> > Heap;
[953]79
[1721]80    static Heap *createHeap(HeapCrossRef& R)
81    {
82      return new Heap(R);
83    }
84
[953]85    ///\brief The type of the map that stores the last
86    ///edges of the shortest paths.
87    ///
[1124]88    ///The type of the map that stores the last
89    ///edges of the shortest paths.
[2260]90    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[953]91    ///
[954]92    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
93    ///Instantiates a PredMap.
[953]94 
[1123]95    ///This function instantiates a \ref PredMap.
96    ///\param G is the graph, to which we would like to define the PredMap.
[1119]97    ///\todo The graph alone may be insufficient for the initialization
[954]98    static PredMap *createPredMap(const GR &G)
[953]99    {
100      return new PredMap(G);
101    }
[1119]102
[1218]103    ///The type of the map that stores whether a nodes is processed.
[1119]104 
[1218]105    ///The type of the map that stores whether a nodes is processed.
[2260]106    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[1119]107    ///By default it is a NullMap.
[1218]108    ///\todo If it is set to a real map,
109    ///Dijkstra::processed() should read this.
[1119]110    ///\todo named parameter to set this type, function to read and write.
[1218]111    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
112    ///Instantiates a ProcessedMap.
[1119]113 
[1218]114    ///This function instantiates a \ref ProcessedMap.
[1536]115    ///\param g is the graph, to which
[1218]116    ///we would like to define the \ref ProcessedMap
[1536]117#ifdef DOXYGEN
118    static ProcessedMap *createProcessedMap(const GR &g)
119#else
[1366]120    static ProcessedMap *createProcessedMap(const GR &)
[1536]121#endif
[1119]122    {
[1218]123      return new ProcessedMap();
[1119]124    }
[953]125    ///The type of the map that stores the dists of the nodes.
126 
[1124]127    ///The type of the map that stores the dists of the nodes.
[2260]128    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[953]129    ///
[987]130    typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
[954]131    ///Instantiates a DistMap.
[953]132 
[1123]133    ///This function instantiates a \ref DistMap.
134    ///\param G is the graph, to which we would like to define the \ref DistMap
[954]135    static DistMap *createDistMap(const GR &G)
[953]136    {
137      return new DistMap(G);
138    }
139  };
140 
[255]141  ///%Dijkstra algorithm class.
[1125]142 
[1151]143  /// \ingroup flowalgs
[255]144  ///This class provides an efficient implementation of %Dijkstra algorithm.
145  ///The edge lengths are passed to the algorithm using a
[2260]146  ///\ref concepts::ReadMap "ReadMap",
[255]147  ///so it is easy to change it to any kind of length.
148  ///
[880]149  ///The type of the length is determined by the
[2260]150  ///\ref concepts::ReadMap::Value "Value" of the length map.
[255]151  ///
152  ///It is also possible to change the underlying priority heap.
153  ///
[1218]154  ///\param GR The graph type the algorithm runs on. The default value
155  ///is \ref ListGraph. The value of GR is not used directly by
156  ///Dijkstra, it is only passed to \ref DijkstraDefaultTraits.
157  ///\param LM This read-only EdgeMap determines the lengths of the
158  ///edges. It is read once for each edge, so the map may involve in
159  ///relatively time consuming process to compute the edge length if
160  ///it is necessary. The default map type is \ref
[2260]161  ///concepts::Graph::EdgeMap "Graph::EdgeMap<int>".  The value
[1218]162  ///of LM is not used directly by Dijkstra, it is only passed to \ref
163  ///DijkstraDefaultTraits.  \param TR Traits class to set
164  ///various data types used by the algorithm.  The default traits
165  ///class is \ref DijkstraDefaultTraits
166  ///"DijkstraDefaultTraits<GR,LM>".  See \ref
167  ///DijkstraDefaultTraits for the documentation of a Dijkstra traits
168  ///class.
[456]169  ///
[689]170  ///\author Jacint Szabo and Alpar Juttner
[584]171
[255]172#ifdef DOXYGEN
[584]173  template <typename GR,
174            typename LM,
[953]175            typename TR>
[255]176#else
[953]177  template <typename GR=ListGraph,
[584]178            typename LM=typename GR::template EdgeMap<int>,
[953]179            typename TR=DijkstraDefaultTraits<GR,LM> >
[255]180#endif
[1116]181  class Dijkstra {
[255]182  public:
[1125]183    /**
184     * \brief \ref Exception for uninitialized parameters.
185     *
186     * This error represents problems in the initialization
187     * of the parameters of the algorithms.
188     */
189    class UninitializedParameter : public lemon::UninitializedParameter {
190    public:
[2151]191      virtual const char* what() const throw() {
[1218]192        return "lemon::Dijkstra::UninitializedParameter";
[1125]193      }
194    };
[1119]195
[953]196    typedef TR Traits;
[584]197    ///The type of the underlying graph.
[954]198    typedef typename TR::Graph Graph;
[911]199    ///\e
[255]200    typedef typename Graph::Node Node;
[911]201    ///\e
[255]202    typedef typename Graph::NodeIt NodeIt;
[911]203    ///\e
[255]204    typedef typename Graph::Edge Edge;
[911]205    ///\e
[255]206    typedef typename Graph::OutEdgeIt OutEdgeIt;
207   
[584]208    ///The type of the length of the edges.
[987]209    typedef typename TR::LengthMap::Value Value;
[693]210    ///The type of the map that stores the edge lengths.
[954]211    typedef typename TR::LengthMap LengthMap;
[693]212    ///\brief The type of the map that stores the last
[584]213    ///edges of the shortest paths.
[953]214    typedef typename TR::PredMap PredMap;
[1218]215    ///The type of the map indicating if a node is processed.
216    typedef typename TR::ProcessedMap ProcessedMap;
[693]217    ///The type of the map that stores the dists of the nodes.
[953]218    typedef typename TR::DistMap DistMap;
[1721]219    ///The cross reference type used for the current heap.
220    typedef typename TR::HeapCrossRef HeapCrossRef;
[953]221    ///The heap type used by the dijkstra algorithm.
222    typedef typename TR::Heap Heap;
[255]223  private:
[802]224    /// Pointer to the underlying graph.
[688]225    const Graph *G;
[802]226    /// Pointer to the length map
[954]227    const LengthMap *length;
[802]228    ///Pointer to the map of predecessors edges.
[1119]229    PredMap *_pred;
230    ///Indicates if \ref _pred is locally allocated (\c true) or not.
231    bool local_pred;
[802]232    ///Pointer to the map of distances.
[1130]233    DistMap *_dist;
234    ///Indicates if \ref _dist is locally allocated (\c true) or not.
235    bool local_dist;
[1218]236    ///Pointer to the map of processed status of the nodes.
237    ProcessedMap *_processed;
238    ///Indicates if \ref _processed is locally allocated (\c true) or not.
239    bool local_processed;
[1721]240    ///Pointer to the heap cross references.
241    HeapCrossRef *_heap_cross_ref;
242    ///Indicates if \ref _heap_cross_ref is locally allocated (\c true) or not.
243    bool local_heap_cross_ref;
244    ///Pointer to the heap.
245    Heap *_heap;
246    ///Indicates if \ref _heap is locally allocated (\c true) or not.
247    bool local_heap;
[688]248
[1128]249    ///Creates the maps if necessary.
[688]250   
251    ///\todo Better memory allocation (instead of new).
[1128]252    void create_maps()
[688]253    {
[1119]254      if(!_pred) {
255        local_pred = true;
256        _pred = Traits::createPredMap(*G);
[688]257      }
[1130]258      if(!_dist) {
259        local_dist = true;
260        _dist = Traits::createDistMap(*G);
[688]261      }
[1218]262      if(!_processed) {
263        local_processed = true;
264        _processed = Traits::createProcessedMap(*G);
[1119]265      }
[1721]266      if (!_heap_cross_ref) {
267        local_heap_cross_ref = true;
268        _heap_cross_ref = Traits::createHeapCrossRef(*G);
269      }
270      if (!_heap) {
271        local_heap = true;
272        _heap = Traits::createHeap(*_heap_cross_ref);
273      }
[688]274    }
[255]275   
276  public :
[1710]277
278    typedef Dijkstra Create;
[1116]279 
[1128]280    ///\name Named template parameters
281
282    ///@{
283
[953]284    template <class T>
[1116]285    struct DefPredMapTraits : public Traits {
[953]286      typedef T PredMap;
[2010]287      static PredMap *createPredMap(const Graph &)
[953]288      {
[1126]289        throw UninitializedParameter();
[953]290      }
291    };
[954]292    ///\ref named-templ-param "Named parameter" for setting PredMap type
293
294    ///\ref named-templ-param "Named parameter" for setting PredMap type
[1043]295    ///
[953]296    template <class T>
[1709]297    struct DefPredMap
298      : public Dijkstra< Graph, LengthMap, DefPredMapTraits<T> > {
299      typedef Dijkstra< Graph,  LengthMap, DefPredMapTraits<T> > Create;
300    };
[953]301   
302    template <class T>
[1116]303    struct DefDistMapTraits : public Traits {
[953]304      typedef T DistMap;
[2010]305      static DistMap *createDistMap(const Graph &)
[953]306      {
[1126]307        throw UninitializedParameter();
[953]308      }
309    };
[954]310    ///\ref named-templ-param "Named parameter" for setting DistMap type
311
312    ///\ref named-templ-param "Named parameter" for setting DistMap type
[1043]313    ///
[953]314    template <class T>
[1709]315    struct DefDistMap
316      : public Dijkstra< Graph, LengthMap, DefDistMapTraits<T> > {
317      typedef Dijkstra< Graph, LengthMap, DefDistMapTraits<T> > Create;
318    };
[953]319   
[1128]320    template <class T>
[1218]321    struct DefProcessedMapTraits : public Traits {
322      typedef T ProcessedMap;
323      static ProcessedMap *createProcessedMap(const Graph &G)
[1128]324      {
325        throw UninitializedParameter();
326      }
327    };
[1218]328    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
[1128]329
[1218]330    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
[1128]331    ///
332    template <class T>
[1709]333    struct DefProcessedMap
334      : public Dijkstra< Graph, LengthMap, DefProcessedMapTraits<T> > {
335      typedef Dijkstra< Graph,  LengthMap, DefProcessedMapTraits<T> > Create;
336    };
[1128]337   
[1218]338    struct DefGraphProcessedMapTraits : public Traits {
339      typedef typename Graph::template NodeMap<bool> ProcessedMap;
340      static ProcessedMap *createProcessedMap(const Graph &G)
[1128]341      {
[1218]342        return new ProcessedMap(G);
[1128]343      }
344    };
345    ///\brief \ref named-templ-param "Named parameter"
[1218]346    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
[1128]347    ///
348    ///\ref named-templ-param "Named parameter"
[1218]349    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
[1128]350    ///If you don't set it explicitely, it will be automatically allocated.
351    template <class T>
[1709]352    struct DefProcessedMapToBeDefaultMap
353      : public Dijkstra< Graph, LengthMap, DefGraphProcessedMapTraits> {
354      typedef Dijkstra< Graph, LengthMap, DefGraphProcessedMapTraits> Create;
355    };
[1721]356
357    template <class H, class CR>
358    struct DefHeapTraits : public Traits {
359      typedef CR HeapCrossRef;
360      typedef H Heap;
[1741]361      static HeapCrossRef *createHeapCrossRef(const Graph &) {
362        throw UninitializedParameter();
[1721]363      }
[1741]364      static Heap *createHeap(HeapCrossRef &)
[1721]365      {
[1741]366        throw UninitializedParameter();
[1721]367      }
368    };
[2230]369    ///\brief \ref named-templ-param "Named parameter" for setting
370    ///heap and cross reference type
371    ///
[1721]372    ///\ref named-templ-param "Named parameter" for setting heap and cross
373    ///reference type
374    ///
375    template <class H, class CR = typename Graph::template NodeMap<int> >
376    struct DefHeap
377      : public Dijkstra< Graph, LengthMap, DefHeapTraits<H, CR> > {
378      typedef Dijkstra< Graph,  LengthMap, DefHeapTraits<H, CR> > Create;
379    };
[1741]380
381    template <class H, class CR>
382    struct DefStandardHeapTraits : public Traits {
383      typedef CR HeapCrossRef;
384      typedef H Heap;
385      static HeapCrossRef *createHeapCrossRef(const Graph &G) {
386        return new HeapCrossRef(G);
387      }
388      static Heap *createHeap(HeapCrossRef &R)
389      {
390        return new Heap(R);
391      }
392    };
[2230]393    ///\brief \ref named-templ-param "Named parameter" for setting
394    ///heap and cross reference type with automatic allocation
395    ///
[1741]396    ///\ref named-templ-param "Named parameter" for setting heap and cross
397    ///reference type. It can allocate the heap and the cross reference
398    ///object if the cross reference's constructor waits for the graph as
399    ///parameter and the heap's constructor waits for the cross reference.
400    template <class H, class CR = typename Graph::template NodeMap<int> >
401    struct DefStandardHeap
402      : public Dijkstra< Graph, LengthMap, DefStandardHeapTraits<H, CR> > {
403      typedef Dijkstra< Graph,  LengthMap, DefStandardHeapTraits<H, CR> >
404      Create;
405    };
[1128]406   
407    ///@}
408
409
[1710]410  protected:
411
412    Dijkstra() {}
413
[1128]414  public:     
415   
[802]416    ///Constructor.
[255]417   
[802]418    ///\param _G the graph the algorithm will run on.
419    ///\param _length the length map used by the algorithm.
[954]420    Dijkstra(const Graph& _G, const LengthMap& _length) :
[688]421      G(&_G), length(&_length),
[1119]422      _pred(NULL), local_pred(false),
[1130]423      _dist(NULL), local_dist(false),
[1218]424      _processed(NULL), local_processed(false),
[1721]425      _heap_cross_ref(NULL), local_heap_cross_ref(false),
426      _heap(NULL), local_heap(false)
[688]427    { }
428   
[802]429    ///Destructor.
[688]430    ~Dijkstra()
431    {
[1119]432      if(local_pred) delete _pred;
[1130]433      if(local_dist) delete _dist;
[1218]434      if(local_processed) delete _processed;
[1721]435      if(local_heap_cross_ref) delete _heap_cross_ref;
436      if(local_heap) delete _heap;
[688]437    }
438
439    ///Sets the length map.
440
441    ///Sets the length map.
442    ///\return <tt> (*this) </tt>
[1116]443    Dijkstra &lengthMap(const LengthMap &m)
[688]444    {
445      length = &m;
446      return *this;
447    }
448
449    ///Sets the map storing the predecessor edges.
450
451    ///Sets the map storing the predecessor edges.
452    ///If you don't use this function before calling \ref run(),
453    ///it will allocate one. The destuctor deallocates this
454    ///automatically allocated map, of course.
455    ///\return <tt> (*this) </tt>
[1116]456    Dijkstra &predMap(PredMap &m)
[688]457    {
[1119]458      if(local_pred) {
459        delete _pred;
460        local_pred=false;
[688]461      }
[1119]462      _pred = &m;
[688]463      return *this;
464    }
465
466    ///Sets the map storing the distances calculated by the algorithm.
467
468    ///Sets the map storing the distances calculated by the algorithm.
469    ///If you don't use this function before calling \ref run(),
470    ///it will allocate one. The destuctor deallocates this
471    ///automatically allocated map, of course.
472    ///\return <tt> (*this) </tt>
[1116]473    Dijkstra &distMap(DistMap &m)
[688]474    {
[1130]475      if(local_dist) {
476        delete _dist;
477        local_dist=false;
[688]478      }
[1130]479      _dist = &m;
[688]480      return *this;
481    }
[694]482
[1741]483    ///Sets the heap and the cross reference used by algorithm.
484
485    ///Sets the heap and the cross reference used by algorithm.
486    ///If you don't use this function before calling \ref run(),
487    ///it will allocate one. The destuctor deallocates this
[1981]488    ///automatically allocated heap and cross reference, of course.
[1741]489    ///\return <tt> (*this) </tt>
490    Dijkstra &heap(Heap& heap, HeapCrossRef &crossRef)
491    {
492      if(local_heap_cross_ref) {
493        delete _heap_cross_ref;
494        local_heap_cross_ref=false;
495      }
496      _heap_cross_ref = &crossRef;
497      if(local_heap) {
498        delete _heap;
499        local_heap=false;
500      }
501      _heap = &heap;
502      return *this;
503    }
504
[1130]505  private:
506    void finalizeNodeData(Node v,Value dst)
507    {
[1218]508      _processed->set(v,true);
[1130]509      _dist->set(v, dst);
510    }
511
512  public:
[1218]513    ///\name Execution control
[1128]514    ///The simplest way to execute the algorithm is to use
[1156]515    ///one of the member functions called \c run(...).
[1128]516    ///\n
[1218]517    ///If you need more control on the execution,
[1128]518    ///first you must call \ref init(), then you can add several source nodes
[1218]519    ///with \ref addSource().
520    ///Finally \ref start() will perform the actual path
[1128]521    ///computation.
522
523    ///@{
524
525    ///Initializes the internal data structures.
526
527    ///Initializes the internal data structures.
528    ///
529    void init()
530    {
531      create_maps();
[1721]532      _heap->clear();
[774]533      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
[1119]534        _pred->set(u,INVALID);
[1218]535        _processed->set(u,false);
[1721]536        _heap_cross_ref->set(u,Heap::PRE_HEAP);
[694]537      }
[1128]538    }
539   
540    ///Adds a new source node.
541
[1155]542    ///Adds a new source node to the priority heap.
[1128]543    ///
544    ///The optional second parameter is the initial distance of the node.
545    ///
[1155]546    ///It checks if the node has already been added to the heap and
[1988]547    ///it is pushed to the heap only if either it was not in the heap
548    ///or the shortest path found till then is shorter than \c dst.
[1734]549    void addSource(Node s,Value dst=dijkstraZero<Value>())
[1128]550    {
[1721]551      if(_heap->state(s) != Heap::IN_HEAP) {
552        _heap->push(s,dst);
553      } else if((*_heap)[s]<dst) {
[1988]554        _heap->set(s,dst);
[1155]555        _pred->set(s,INVALID);
556      }
[1128]557    }
558   
[1155]559    ///Processes the next node in the priority heap
560
561    ///Processes the next node in the priority heap.
562    ///
[1516]563    ///\return The processed node.
564    ///
[1155]565    ///\warning The priority heap must not be empty!
[1516]566    Node processNextNode()
[1128]567    {
[1721]568      Node v=_heap->top();
569      Value oldvalue=_heap->prio();
570      _heap->pop();
[1130]571      finalizeNodeData(v,oldvalue);
[694]572     
[1128]573      for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
574        Node w=G->target(e);
[1721]575        switch(_heap->state(w)) {
[1128]576        case Heap::PRE_HEAP:
[1721]577          _heap->push(w,oldvalue+(*length)[e]);
[1128]578          _pred->set(w,e);
579          break;
580        case Heap::IN_HEAP:
[1721]581          if ( oldvalue+(*length)[e] < (*_heap)[w] ) {
582            _heap->decrease(w, oldvalue+(*length)[e]);
[1119]583            _pred->set(w,e);
[694]584          }
[1128]585          break;
586        case Heap::POST_HEAP:
587          break;
[694]588        }
589      }
[1516]590      return v;
[694]591    }
[1128]592
[1665]593    ///Next node to be processed.
594   
595    ///Next node to be processed.
596    ///
597    ///\return The next node to be processed or INVALID if the priority heap
598    /// is empty.
[1694]599    Node nextNode()
[1665]600    {
[1721]601      return _heap->empty()?_heap->top():INVALID;
[1665]602    }
603 
[1218]604    ///\brief Returns \c false if there are nodes
605    ///to be processed in the priority heap
[1155]606    ///
[1218]607    ///Returns \c false if there are nodes
608    ///to be processed in the priority heap
[1721]609    bool emptyQueue() { return _heap->empty(); }
[1155]610    ///Returns the number of the nodes to be processed in the priority heap
611
612    ///Returns the number of the nodes to be processed in the priority heap
613    ///
[1721]614    int queueSize() { return _heap->size(); }
[1155]615   
[1130]616    ///Executes the algorithm.
[1128]617
[1130]618    ///Executes the algorithm.
[1128]619    ///
[1130]620    ///\pre init() must be called and at least one node should be added
621    ///with addSource() before using this function.
[1128]622    ///
623    ///This method runs the %Dijkstra algorithm from the root node(s)
624    ///in order to
625    ///compute the
626    ///shortest path to each node. The algorithm computes
627    ///- The shortest path tree.
628    ///- The distance of each node from the root(s).
629    ///
630    void start()
631    {
[1721]632      while ( !_heap->empty() ) processNextNode();
[1128]633    }
[255]634   
[1130]635    ///Executes the algorithm until \c dest is reached.
[1128]636
[1130]637    ///Executes the algorithm until \c dest is reached.
[1128]638    ///
[1130]639    ///\pre init() must be called and at least one node should be added
640    ///with addSource() before using this function.
[1128]641    ///
642    ///This method runs the %Dijkstra algorithm from the root node(s)
643    ///in order to
644    ///compute the
645    ///shortest path to \c dest. The algorithm computes
646    ///- The shortest path to \c  dest.
647    ///- The distance of \c dest from the root(s).
648    ///
649    void start(Node dest)
650    {
[1721]651      while ( !_heap->empty() && _heap->top()!=dest ) processNextNode();
652      if ( !_heap->empty() ) finalizeNodeData(_heap->top(),_heap->prio());
[1130]653    }
654   
655    ///Executes the algorithm until a condition is met.
656
657    ///Executes the algorithm until a condition is met.
658    ///
659    ///\pre init() must be called and at least one node should be added
660    ///with addSource() before using this function.
661    ///
662    ///\param nm must be a bool (or convertible) node map. The algorithm
663    ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
[1345]664    template<class NodeBoolMap>
665    void start(const NodeBoolMap &nm)
[1130]666    {
[1721]667      while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode();
668      if ( !_heap->empty() ) finalizeNodeData(_heap->top(),_heap->prio());
[1128]669    }
670   
671    ///Runs %Dijkstra algorithm from node \c s.
672   
673    ///This method runs the %Dijkstra algorithm from a root node \c s
674    ///in order to
675    ///compute the
676    ///shortest path to each node. The algorithm computes
677    ///- The shortest path tree.
678    ///- The distance of each node from the root.
679    ///
680    ///\note d.run(s) is just a shortcut of the following code.
681    ///\code
682    ///  d.init();
683    ///  d.addSource(s);
684    ///  d.start();
685    ///\endcode
686    void run(Node s) {
687      init();
688      addSource(s);
689      start();
690    }
691   
[1130]692    ///Finds the shortest path between \c s and \c t.
693   
694    ///Finds the shortest path between \c s and \c t.
695    ///
696    ///\return The length of the shortest s---t path if there exists one,
697    ///0 otherwise.
698    ///\note Apart from the return value, d.run(s) is
699    ///just a shortcut of the following code.
700    ///\code
701    ///  d.init();
702    ///  d.addSource(s);
703    ///  d.start(t);
704    ///\endcode
705    Value run(Node s,Node t) {
706      init();
707      addSource(s);
708      start(t);
[1734]709      return (*_pred)[t]==INVALID?dijkstraZero<Value>():(*_dist)[t];
[1130]710    }
711   
[1128]712    ///@}
713
714    ///\name Query Functions
715    ///The result of the %Dijkstra algorithm can be obtained using these
716    ///functions.\n
717    ///Before the use of these functions,
718    ///either run() or start() must be called.
719   
720    ///@{
721
[2335]722    typedef PredMapPath<Graph, PredMap> Path;
723
724    ///Gives back the shortest path.
[1283]725   
[2335]726    ///Gives back the shortest path.
727    ///\pre The \c t should be reachable from the source.
728    Path path(Node t)
[1283]729    {
[2335]730      return Path(*G, *_pred, t);
[1283]731    }
[2335]732
[385]733    ///The distance of a node from the root.
[255]734
[385]735    ///Returns the distance of a node from the root.
[255]736    ///\pre \ref run() must be called before using this function.
[385]737    ///\warning If node \c v in unreachable from the root the return value
[255]738    ///of this funcion is undefined.
[1130]739    Value dist(Node v) const { return (*_dist)[v]; }
[373]740
[584]741    ///Returns the 'previous edge' of the shortest path tree.
[255]742
[584]743    ///For a node \c v it returns the 'previous edge' of the shortest path tree,
[785]744    ///i.e. it returns the last edge of a shortest path from the root to \c
[688]745    ///v. It is \ref INVALID
746    ///if \c v is unreachable from the root or if \c v=s. The
[385]747    ///shortest path tree used here is equal to the shortest path tree used in
[1631]748    ///\ref predNode().  \pre \ref run() must be called before using
[385]749    ///this function.
[1763]750    Edge predEdge(Node v) const { return (*_pred)[v]; }
[373]751
[584]752    ///Returns the 'previous node' of the shortest path tree.
[255]753
[584]754    ///For a node \c v it returns the 'previous node' of the shortest path tree,
[385]755    ///i.e. it returns the last but one node from a shortest path from the
756    ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
757    ///\c v=s. The shortest path tree used here is equal to the shortest path
[1763]758    ///tree used in \ref predEdge().  \pre \ref run() must be called before
[385]759    ///using this function.
[1130]760    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
761                                  G->source((*_pred)[v]); }
[255]762   
763    ///Returns a reference to the NodeMap of distances.
764
[385]765    ///Returns a reference to the NodeMap of distances. \pre \ref run() must
766    ///be called before using this function.
[1130]767    const DistMap &distMap() const { return *_dist;}
[385]768 
[255]769    ///Returns a reference to the shortest path tree map.
770
771    ///Returns a reference to the NodeMap of the edges of the
772    ///shortest path tree.
773    ///\pre \ref run() must be called before using this function.
[1119]774    const PredMap &predMap() const { return *_pred;}
[385]775 
776    ///Checks if a node is reachable from the root.
[255]777
[385]778    ///Returns \c true if \c v is reachable from the root.
[1218]779    ///\warning The source nodes are inditated as unreached.
[255]780    ///\pre \ref run() must be called before using this function.
[385]781    ///
[1721]782    bool reached(Node v) { return (*_heap_cross_ref)[v] != Heap::PRE_HEAP; }
[1734]783
784    ///Checks if a node is processed.
785
786    ///Returns \c true if \c v is processed, i.e. the shortest
787    ///path to \c v has already found.
788    ///\pre \ref run() must be called before using this function.
789    ///
790    bool processed(Node v) { return (*_heap_cross_ref)[v] == Heap::POST_HEAP; }
[255]791   
[1128]792    ///@}
[255]793  };
[953]794
[1218]795
796
797
798 
799  ///Default traits class of Dijkstra function.
800
801  ///Default traits class of Dijkstra function.
802  ///\param GR Graph type.
803  ///\param LM Type of length map.
804  template<class GR, class LM>
805  struct DijkstraWizardDefaultTraits
806  {
807    ///The graph type the algorithm runs on.
808    typedef GR Graph;
809    ///The type of the map that stores the edge lengths.
810
811    ///The type of the map that stores the edge lengths.
[2260]812    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.
[1218]813    typedef LM LengthMap;
814    //The type of the length of the edges.
815    typedef typename LM::Value Value;
816    ///The heap type used by Dijkstra algorithm.
817
[1721]818    /// The cross reference type used by heap.
819
820    /// The cross reference type used by heap.
821    /// Usually it is \c Graph::NodeMap<int>.
822    typedef typename Graph::template NodeMap<int> HeapCrossRef;
823    ///Instantiates a HeapCrossRef.
824
825    ///This function instantiates a \ref HeapCrossRef.
826    /// \param G is the graph, to which we would like to define the
827    /// HeapCrossRef.
828    /// \todo The graph alone may be insufficient for the initialization
829    static HeapCrossRef *createHeapCrossRef(const GR &G)
830    {
831      return new HeapCrossRef(G);
832    }
833   
834    ///The heap type used by Dijkstra algorithm.
835
[1218]836    ///The heap type used by Dijkstra algorithm.
837    ///
838    ///\sa BinHeap
839    ///\sa Dijkstra
[2263]840    typedef BinHeap<typename LM::Value, typename GR::template NodeMap<int>,
[1218]841                    std::less<Value> > Heap;
842
[1721]843    static Heap *createHeap(HeapCrossRef& R)
844    {
845      return new Heap(R);
846    }
847
[1218]848    ///\brief The type of the map that stores the last
849    ///edges of the shortest paths.
850    ///
851    ///The type of the map that stores the last
852    ///edges of the shortest paths.
[2260]853    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[1218]854    ///
855    typedef NullMap <typename GR::Node,typename GR::Edge> PredMap;
856    ///Instantiates a PredMap.
857 
858    ///This function instantiates a \ref PredMap.
[1536]859    ///\param g is the graph, to which we would like to define the PredMap.
[1218]860    ///\todo The graph alone may be insufficient for the initialization
[1536]861#ifdef DOXYGEN
862    static PredMap *createPredMap(const GR &g)
863#else
[1367]864    static PredMap *createPredMap(const GR &)
[1536]865#endif
[1218]866    {
867      return new PredMap();
868    }
869    ///The type of the map that stores whether a nodes is processed.
870 
871    ///The type of the map that stores whether a nodes is processed.
[2260]872    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[1218]873    ///By default it is a NullMap.
874    ///\todo If it is set to a real map,
875    ///Dijkstra::processed() should read this.
876    ///\todo named parameter to set this type, function to read and write.
877    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
878    ///Instantiates a ProcessedMap.
879 
880    ///This function instantiates a \ref ProcessedMap.
[1536]881    ///\param g is the graph, to which
[1218]882    ///we would like to define the \ref ProcessedMap
[1536]883#ifdef DOXYGEN
884    static ProcessedMap *createProcessedMap(const GR &g)
885#else
[1367]886    static ProcessedMap *createProcessedMap(const GR &)
[1536]887#endif
[1218]888    {
889      return new ProcessedMap();
890    }
891    ///The type of the map that stores the dists of the nodes.
892 
893    ///The type of the map that stores the dists of the nodes.
[2260]894    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
[1218]895    ///
896    typedef NullMap<typename Graph::Node,typename LM::Value> DistMap;
897    ///Instantiates a DistMap.
898 
899    ///This function instantiates a \ref DistMap.
[1536]900    ///\param g is the graph, to which we would like to define the \ref DistMap
901#ifdef DOXYGEN
902    static DistMap *createDistMap(const GR &g)
903#else
[1367]904    static DistMap *createDistMap(const GR &)
[1536]905#endif
[1218]906    {
907      return new DistMap();
908    }
909  };
910 
[1123]911  /// Default traits used by \ref DijkstraWizard
912
[1151]913  /// To make it easier to use Dijkstra algorithm
914  ///we have created a wizard class.
915  /// This \ref DijkstraWizard class needs default traits,
916  ///as well as the \ref Dijkstra class.
[1123]917  /// The \ref DijkstraWizardBase is a class to be the default traits of the
918  /// \ref DijkstraWizard class.
[1220]919  /// \todo More named parameters are required...
[1116]920  template<class GR,class LM>
[1218]921  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>
[1116]922  {
923
[1218]924    typedef DijkstraWizardDefaultTraits<GR,LM> Base;
[1116]925  protected:
[1201]926    /// Type of the nodes in the graph.
927    typedef typename Base::Graph::Node Node;
928
[1116]929    /// Pointer to the underlying graph.
930    void *_g;
931    /// Pointer to the length map
932    void *_length;
933    ///Pointer to the map of predecessors edges.
934    void *_pred;
935    ///Pointer to the map of distances.
936    void *_dist;
937    ///Pointer to the source node.
[1201]938    Node _source;
[1116]939
940    public:
[1123]941    /// Constructor.
942   
943    /// This constructor does not require parameters, therefore it initiates
944    /// all of the attributes to default values (0, INVALID).
[1218]945    DijkstraWizardBase() : _g(0), _length(0), _pred(0),
946                           _dist(0), _source(INVALID) {}
[1116]947
[1123]948    /// Constructor.
949   
[1156]950    /// This constructor requires some parameters,
951    /// listed in the parameters list.
[1123]952    /// Others are initiated to 0.
953    /// \param g is the initial value of  \ref _g
954    /// \param l is the initial value of  \ref _length
955    /// \param s is the initial value of  \ref _source
[1116]956    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
[1218]957      _g((void *)&g), _length((void *)&l), _pred(0),
958      _dist(0), _source(s) {}
[1116]959
960  };
961 
[1229]962  /// A class to make the usage of Dijkstra algorithm easier
[953]963
[1123]964  /// This class is created to make it easier to use Dijkstra algorithm.
965  /// It uses the functions and features of the plain \ref Dijkstra,
[1151]966  /// but it is much simpler to use it.
[953]967  ///
[1123]968  /// Simplicity means that the way to change the types defined
969  /// in the traits class is based on functions that returns the new class
[1151]970  /// and not on templatable built-in classes.
971  /// When using the plain \ref Dijkstra
972  /// the new class with the modified type comes from
973  /// the original class by using the ::
974  /// operator. In the case of \ref DijkstraWizard only
975  /// a function have to be called and it will
[1123]976  /// return the needed class.
977  ///
978  /// It does not have own \ref run method. When its \ref run method is called
[1721]979  /// it initiates a plain \ref Dijkstra class, and calls the \ref
980  /// Dijkstra::run method of it.
[953]981  template<class TR>
[1116]982  class DijkstraWizard : public TR
[953]983  {
[1116]984    typedef TR Base;
[953]985
[1123]986    ///The type of the underlying graph.
[953]987    typedef typename TR::Graph Graph;
[1119]988    //\e
[953]989    typedef typename Graph::Node Node;
[1119]990    //\e
[953]991    typedef typename Graph::NodeIt NodeIt;
[1119]992    //\e
[953]993    typedef typename Graph::Edge Edge;
[1119]994    //\e
[953]995    typedef typename Graph::OutEdgeIt OutEdgeIt;
996   
[1123]997    ///The type of the map that stores the edge lengths.
[953]998    typedef typename TR::LengthMap LengthMap;
[1123]999    ///The type of the length of the edges.
[987]1000    typedef typename LengthMap::Value Value;
[1123]1001    ///\brief The type of the map that stores the last
1002    ///edges of the shortest paths.
[953]1003    typedef typename TR::PredMap PredMap;
[1123]1004    ///The type of the map that stores the dists of the nodes.
[953]1005    typedef typename TR::DistMap DistMap;
[1123]1006    ///The heap type used by the dijkstra algorithm.
[953]1007    typedef typename TR::Heap Heap;
[2269]1008  public:
[1123]1009    /// Constructor.
[1116]1010    DijkstraWizard() : TR() {}
[953]1011
[1123]1012    /// Constructor that requires parameters.
[1124]1013
1014    /// Constructor that requires parameters.
[1123]1015    /// These parameters will be the default values for the traits class.
[1116]1016    DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
1017      TR(g,l,s) {}
[953]1018
[1123]1019    ///Copy constructor
[1116]1020    DijkstraWizard(const TR &b) : TR(b) {}
[953]1021
[1116]1022    ~DijkstraWizard() {}
1023
[1123]1024    ///Runs Dijkstra algorithm from a given node.
1025   
1026    ///Runs Dijkstra algorithm from a given node.
1027    ///The node can be given by the \ref source function.
[1116]1028    void run()
[953]1029    {
[1201]1030      if(Base::_source==INVALID) throw UninitializedParameter();
[1193]1031      Dijkstra<Graph,LengthMap,TR>
[1345]1032        dij(*(Graph*)Base::_g,*(LengthMap*)Base::_length);
1033      if(Base::_pred) dij.predMap(*(PredMap*)Base::_pred);
1034      if(Base::_dist) dij.distMap(*(DistMap*)Base::_dist);
1035      dij.run(Base::_source);
[1116]1036    }
1037
[1124]1038    ///Runs Dijkstra algorithm from the given node.
[1123]1039
[1124]1040    ///Runs Dijkstra algorithm from the given node.
[1123]1041    ///\param s is the given source.
[1116]1042    void run(Node s)
1043    {
[1201]1044      Base::_source=s;
[1116]1045      run();
[953]1046    }
1047
1048    template<class T>
[1116]1049    struct DefPredMapBase : public Base {
1050      typedef T PredMap;
[1367]1051      static PredMap *createPredMap(const Graph &) { return 0; };
[1236]1052      DefPredMapBase(const TR &b) : TR(b) {}
[1116]1053    };
[953]1054   
[1156]1055    ///\brief \ref named-templ-param "Named parameter"
1056    ///function for setting PredMap type
1057    ///
1058    /// \ref named-templ-param "Named parameter"
1059    ///function for setting PredMap type
[1124]1060    ///
[953]1061    template<class T>
[1116]1062    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
[953]1063    {
[1193]1064      Base::_pred=(void *)&t;
[1116]1065      return DijkstraWizard<DefPredMapBase<T> >(*this);
[953]1066    }
1067   
[1116]1068    template<class T>
1069    struct DefDistMapBase : public Base {
1070      typedef T DistMap;
[1367]1071      static DistMap *createDistMap(const Graph &) { return 0; };
[1236]1072      DefDistMapBase(const TR &b) : TR(b) {}
[1116]1073    };
[953]1074   
[1156]1075    ///\brief \ref named-templ-param "Named parameter"
1076    ///function for setting DistMap type
1077    ///
1078    /// \ref named-templ-param "Named parameter"
1079    ///function for setting DistMap type
[1124]1080    ///
[953]1081    template<class T>
[1116]1082    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
[953]1083    {
[1193]1084      Base::_dist=(void *)&t;
[1116]1085      return DijkstraWizard<DefDistMapBase<T> >(*this);
[953]1086    }
[1117]1087   
[1123]1088    /// Sets the source node, from which the Dijkstra algorithm runs.
1089
1090    /// Sets the source node, from which the Dijkstra algorithm runs.
1091    /// \param s is the source node.
[1117]1092    DijkstraWizard<TR> &source(Node s)
[953]1093    {
[1201]1094      Base::_source=s;
[953]1095      return *this;
1096    }
1097   
1098  };
[255]1099 
[1218]1100  ///Function type interface for Dijkstra algorithm.
[953]1101
[1151]1102  /// \ingroup flowalgs
[1218]1103  ///Function type interface for Dijkstra algorithm.
[953]1104  ///
[1218]1105  ///This function also has several
1106  ///\ref named-templ-func-param "named parameters",
1107  ///they are declared as the members of class \ref DijkstraWizard.
1108  ///The following
1109  ///example shows how to use these parameters.
1110  ///\code
1111  ///  dijkstra(g,length,source).predMap(preds).run();
1112  ///\endcode
1113  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"
1114  ///to the end of the parameter list.
1115  ///\sa DijkstraWizard
1116  ///\sa Dijkstra
[953]1117  template<class GR, class LM>
[1116]1118  DijkstraWizard<DijkstraWizardBase<GR,LM> >
1119  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
[953]1120  {
[1116]1121    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
[953]1122  }
1123
[921]1124} //END OF NAMESPACE LEMON
[255]1125
1126#endif
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