RhodeCode

      if(!_pred) {

        local_pred = true;

        _pred = Traits::createPredMap(*G);

      }

      if(!_dist) {

        local_dist = true;

        _dist = Traits::createDistMap(*G);

      }

      if(!_processed) {

        local_processed = true;

        _processed = Traits::createProcessedMap(*G);

      }

      if (!_heap_cross_ref) {

        local_heap_cross_ref = true;

        _heap_cross_ref = Traits::createHeapCrossRef(*G);

      }

      if (!_heap) {

        local_heap = true;

        _heap = Traits::createHeap(*_heap_cross_ref);

      }

    }

  public:

    typedef Dijkstra Create;

    ///\name Named template parameters

    ///@{

    template <class T>

    struct DefPredMapTraits : public Traits {

      typedef T PredMap;

      static PredMap *createPredMap(const Digraph &)

      {

        throw UninitializedParameter();

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///\ref PredMap type.

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\ref PredMap type.

    template <class T>

    struct DefPredMap

      : public Dijkstra< Digraph, LengthMap, DefPredMapTraits<T> > {

      typedef Dijkstra< Digraph, LengthMap, DefPredMapTraits<T> > Create;

    };

    template <class T>

    struct DefDistMapTraits : public Traits {

      typedef T DistMap;

      static DistMap *createDistMap(const Digraph &)

      {

        throw UninitializedParameter();

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///\ref DistMap type.

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\ref DistMap type.

    template <class T>

    struct DefDistMap

      : public Dijkstra< Digraph, LengthMap, DefDistMapTraits<T> > {

      typedef Dijkstra< Digraph, LengthMap, DefDistMapTraits<T> > Create;

    };

    template <class T>

    struct DefProcessedMapTraits : public Traits {

      typedef T ProcessedMap;

      static ProcessedMap *createProcessedMap(const Digraph &)

      {

        throw UninitializedParameter();

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///\ref ProcessedMap type.

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\ref ProcessedMap type.

    template <class T>

    struct DefProcessedMap

      : public Dijkstra< Digraph, LengthMap, DefProcessedMapTraits<T> > {

      typedef Dijkstra< Digraph, LengthMap, DefProcessedMapTraits<T> > Create;

    };

    struct DefDigraphProcessedMapTraits : public Traits {

      typedef typename Digraph::template NodeMap<bool> ProcessedMap;

      static ProcessedMap *createProcessedMap(const Digraph &g)

      {

        return new ProcessedMap(g);

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.

    ///If you don't set it explicitly, it will be automatically allocated.

    template <class T>

    struct DefProcessedMapToBeDefaultMap

      : public Dijkstra< Digraph, LengthMap, DefDigraphProcessedMapTraits> {

      typedef Dijkstra< Digraph, LengthMap, DefDigraphProcessedMapTraits>

      Create;

    };

    template <class H, class CR>

    struct DefHeapTraits : public Traits {

      typedef CR HeapCrossRef;

      typedef H Heap;

      static HeapCrossRef *createHeapCrossRef(const Digraph &) {

        throw UninitializedParameter();

      }

      static Heap *createHeap(HeapCrossRef &)

      {

        throw UninitializedParameter();

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///heap and cross reference type

    ///

    ///\ref named-templ-param "Named parameter" for setting heap and cross

    ///reference type.

    template <class H, class CR = typename Digraph::template NodeMap<int> >

    struct DefHeap

      : public Dijkstra< Digraph, LengthMap, DefHeapTraits<H, CR> > {

      typedef Dijkstra< Digraph, LengthMap, DefHeapTraits<H, CR> > Create;

    };

    template <class H, class CR>

    struct DefStandardHeapTraits : public Traits {

      typedef CR HeapCrossRef;

      typedef H Heap;

      static HeapCrossRef *createHeapCrossRef(const Digraph &G) {

        return new HeapCrossRef(G);

      }

      static Heap *createHeap(HeapCrossRef &R)

      {

        return new Heap(R);

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///heap and cross reference type with automatic allocation

    ///

    ///\ref named-templ-param "Named parameter" for setting heap and cross

    ///reference type. It can allocate the heap and the cross reference

    ///object if the cross reference's constructor waits for the digraph as

    ///parameter and the heap's constructor waits for the cross reference.

    template <class H, class CR = typename Digraph::template NodeMap<int> >

    struct DefStandardHeap

      : public Dijkstra< Digraph, LengthMap, DefStandardHeapTraits<H, CR> > {

      typedef Dijkstra< Digraph, LengthMap, DefStandardHeapTraits<H, CR> >

      Create;

    };

    template <class T>

    struct DefOperationTraitsTraits : public Traits {

      typedef T OperationTraits;

    };

    /// \brief \ref named-templ-param "Named parameter" for setting

    ///\ref OperationTraits type

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\ref OperationTraits type.

    template <class T>

    struct DefOperationTraits

      : public Dijkstra<Digraph, LengthMap, DefOperationTraitsTraits<T> > {

      typedef Dijkstra<Digraph, LengthMap, DefOperationTraitsTraits<T> >

      Create;

    };

    ///@}

  protected:

    Dijkstra() {}

  public:

    ///Constructor.

    ///Constructor.

    ///\param _g The digraph the algorithm runs on.

    ///\param _length The length map used by the algorithm.

    Dijkstra(const Digraph& _g, const LengthMap& _length) :

      G(&_g), length(&_length),

      _pred(NULL), local_pred(false),

      _dist(NULL), local_dist(false),

      _processed(NULL), local_processed(false),

      _heap_cross_ref(NULL), local_heap_cross_ref(false),

      _heap(NULL), local_heap(false)

    { }

    ///Destructor.

    ~Dijkstra()

    {

      if(local_pred) delete _pred;

      if(local_dist) delete _dist;

      if(local_processed) delete _processed;

      if(local_heap_cross_ref) delete _heap_cross_ref;

      if(local_heap) delete _heap;

    }

    ///Sets the length map.

    ///Sets the length map.

    ///\return <tt> (*this) </tt>

    Dijkstra &lengthMap(const LengthMap &m)

    {

      length = &m;

      return *this;

    }

    ///Sets the map that stores the predecessor arcs.

    ///Sets the map that stores the predecessor arcs.

    ///If you don't use this function before calling \ref run(),

    ///it will allocate one. The destructor deallocates this

    ///automatically allocated map, of course.

    ///\return <tt> (*this) </tt>

    Dijkstra &predMap(PredMap &m)

    {

      if(local_pred) {

        delete _pred;

        local_pred=false;

      }

      _pred = &m;

      return *this;

    }

    ///Sets the map that indicates which nodes are processed.

    ///Sets the map that indicates which nodes are processed.

    ///If you don't use this function before calling \ref run(),

    ///it will allocate one. The destructor deallocates this

    ///automatically allocated map, of course.

    ///\return <tt> (*this) </tt>

    Dijkstra &processedMap(ProcessedMap &m)

    {

      if(local_processed) {

        delete _processed;

        local_processed=false;

      }

      _processed = &m;

      return *this;

    }

    ///Sets the map that stores the distances of the nodes.

    ///Sets the map that stores the distances of the nodes calculated by the

    ///algorithm.

    ///If you don't use this function before calling \ref run(),

    ///it will allocate one. The destructor deallocates this

    ///automatically allocated map, of course.

    ///\return <tt> (*this) </tt>

    Dijkstra &distMap(DistMap &m)

    {

      if(local_dist) {

        delete _dist;

        local_dist=false;

      }

      _dist = &m;

      return *this;

    }

    ///Sets the heap and the cross reference used by algorithm.

    ///Sets the heap and the cross reference used by algorithm.

    ///If you don't use this function before calling \ref run(),

    ///it will allocate one. The destructor deallocates this

    ///automatically allocated heap and cross reference, of course.

    ///\return <tt> (*this) </tt>

    Dijkstra &heap(Heap& hp, HeapCrossRef &cr)

    {

      if(local_heap_cross_ref) {

        delete _heap_cross_ref;

        local_heap_cross_ref=false;

      }

      _heap_cross_ref = &cr;

      if(local_heap) {

        delete _heap;

        local_heap=false;

      }

      _heap = &hp;

      return *this;

    }

  private:

    void finalizeNodeData(Node v,Value dst)

    {

      _processed->set(v,true);

      _dist->set(v, dst);

    }

  public:

    ///\name Execution control

    ///The simplest way to execute the algorithm is to use one of the

    ///member functions called \ref lemon::Dijkstra::run() "run()".

    ///\n

    ///If you need more control on the execution, first you must call

    ///\ref lemon::Dijkstra::init() "init()", then you can add several

    ///source nodes with \ref lemon::Dijkstra::addSource() "addSource()".

    ///Finally \ref lemon::Dijkstra::start() "start()" will perform the

    ///actual path computation.

    ///@{

    ///Initializes the internal data structures.

    ///Initializes the internal data structures.

    ///

    void init()

    {

      create_maps();

      _heap->clear();

      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {

        _pred->set(u,INVALID);

        _processed->set(u,false);

        _heap_cross_ref->set(u,Heap::PRE_HEAP);

      }

    }

    ///Adds a new source node.

    ///Adds a new source node to the priority heap.

    ///The optional second parameter is the initial distance of the node.

    ///

    ///The function checks if the node has already been added to the heap and

    ///it is pushed to the heap only if either it was not in the heap

    ///or the shortest path found till then is shorter than \c dst.

    void addSource(Node s,Value dst=OperationTraits::zero())

    {

      if(_heap->state(s) != Heap::IN_HEAP) {

        _heap->push(s,dst);

      } else if(OperationTraits::less((*_heap)[s], dst)) {

        _heap->set(s,dst);

        _pred->set(s,INVALID);

      }

    }

    ///Processes the next node in the priority heap

    ///Processes the next node in the priority heap.

    ///

    ///\return The processed node.

    ///

    ///\warning The priority heap must not be empty.

    Node processNextNode()

    {

      Node v=_heap->top();

      Value oldvalue=_heap->prio();

      _heap->pop();

      finalizeNodeData(v,oldvalue);

      for(OutArcIt e(*G,v); e!=INVALID; ++e) {

        Node w=G->target(e);

        switch(_heap->state(w)) {

        case Heap::PRE_HEAP:

          _heap->push(w,OperationTraits::plus(oldvalue, (*length)[e]));

          _pred->set(w,e);

          break;

        case Heap::IN_HEAP:

          {

            Value newvalue = OperationTraits::plus(oldvalue, (*length)[e]);

            if ( OperationTraits::less(newvalue, (*_heap)[w]) ) {

              _heap->decrease(w, newvalue);

              _pred->set(w,e);

            }

          }

          break;

        case Heap::POST_HEAP:

          break;

        }

      }

      return v;

    }

    ///The next node to be processed.

    ///Returns the next node to be processed or \c INVALID if the

    ///priority heap is empty.

    Node nextNode() const

    {

      return !_heap->empty()?_heap->top():INVALID;

    }

    ///\brief Returns \c false if there are nodes

    ///to be processed.

    ///

    ///Returns \c false if there are nodes

    ///to be processed in the priority heap.

    bool emptyQueue() const { return _heap->empty(); }

    ///Returns the number of the nodes to be processed in the priority heap

    ///Returns the number of the nodes to be processed in the priority heap.

    ///

    int queueSize() const { return _heap->size(); }

    ///Executes the algorithm.

    ///Executes the algorithm.

    ///

    ///This method runs the %Dijkstra algorithm from the root node(s)

    ///in order to compute the shortest path to each node.

    ///

    ///The algorithm computes

    ///- the shortest path tree (forest),

    ///- the distance of each node from the root(s).

    ///

    ///\pre init() must be called and at least one root node should be

    ///added with addSource() before using this function.

    ///

    ///\note <tt>d.start()</tt> is just a shortcut of the following code.

    ///\code

    ///  while ( !d.emptyQueue() ) {

    ///    d.processNextNode();

    ///  }

    ///\endcode

    void start()

    {

      while ( !emptyQueue() ) processNextNode();

    }

    ///Executes the algorithm until the given target node is reached.

    ///Executes the algorithm until the given target node is reached.

    ///

    ///This method runs the %Dijkstra algorithm from the root node(s)

    ///in order to compute the shortest path to \c dest.

    ///

    ///The algorithm computes

    ///- the shortest path to \c dest,

    ///- the distance of \c dest from the root(s).

    ///

    ///\pre init() must be called and at least one root node should be

    ///added with addSource() before using this function.

    void start(Node dest)

    {

      while ( !_heap->empty() && _heap->top()!=dest ) processNextNode();

      if ( !_heap->empty() ) finalizeNodeData(_heap->top(),_heap->prio());

    }

    ///Executes the algorithm until a condition is met.

    ///Executes the algorithm until a condition is met.

    ///

    ///This method runs the %Dijkstra algorithm from the root node(s) in

    ///order to compute the shortest path to a node \c v with

    /// <tt>nm[v]</tt> true, if such a node can be found.

    ///

    ///\param nm A \c bool (or convertible) node map. The algorithm

    ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true.

    ///

    ///\return The reached node \c v with <tt>nm[v]</tt> true or

    ///\c INVALID if no such node was found.

    ///

    ///\pre init() must be called and at least one root node should be

    ///added with addSource() before using this function.

    template<class NodeBoolMap>

    Node start(const NodeBoolMap &nm)

    {

      while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode();

      if ( _heap->empty() ) return INVALID;

      finalizeNodeData(_heap->top(),_heap->prio());

      return _heap->top();

    }

    ///Runs the algorithm from the given node.

    ///This method runs the %Dijkstra algorithm from node \c s

    ///in order to compute the shortest path to each node.

    ///

    ///The algorithm computes

    ///- the shortest path tree,

    ///- the distance of each node from the root.

    ///

    ///\note <tt>d.run(s)</tt> is just a shortcut of the following code.

    ///\code

    ///  d.init();

    ///  d.addSource(s);

    ///  d.start();

    ///\endcode

    void run(Node s) {

      init();

      addSource(s);

      start();

    }

    ///Finds the shortest path between \c s and \c t.

    ///This method runs the %Dijkstra algorithm from node \c s

    ///in order to compute the shortest path to \c t.

    ///

    ///\return The length of the shortest <tt>s</tt>--<tt>t</tt> path,

    ///if \c t is reachable form \c s, \c 0 otherwise.

    ///

    ///\note Apart from the return value, <tt>d.run(s,t)</tt> is just a

    ///shortcut of the following code.

    ///\code

    ///  d.init();

    ///  d.addSource(s);

    ///  d.start(t);

    ///\endcode

    Value run(Node s,Node t) {

      init();

      addSource(s);

      start(t);

      return (*_pred)[t]==INVALID?OperationTraits::zero():(*_dist)[t];

    }

    ///@}

    ///\name Query Functions

    ///The result of the %Dijkstra algorithm can be obtained using these

    ///functions.\n

    ///Either \ref lemon::Dijkstra::run() "run()" or

    ///\ref lemon::Dijkstra::start() "start()" must be called before

    ///using them.

    ///@{

    ///The shortest path to a node.

    ///Returns the shortest path to a node.

    ///

    ///\warning \c t should be reachable from the root(s).

    ///

    ///\pre Either \ref run() or \ref start() must be called before

    ///using this function.

    Path path(Node t) const { return Path(*G, *_pred, t); }

    ///The distance of a node from the root(s).

    ///Returns the distance of a node from the root(s).

    ///

    ///\warning If node \c v is not reachable from the root(s), then

    ///the return value of this function is undefined.

    ///

    ///\pre Either \ref run() or \ref start() must be called before

    ///using this function.

    Value dist(Node v) const { return (*_dist)[v]; }

    ///Returns the 'previous arc' of the shortest path tree for a node.

    ///This function returns the 'previous arc' of the shortest path

    ///tree for the node \c v, i.e. it returns the last arc of a

    ///shortest path from the root(s) to \c v. It is \c INVALID if \c v

    ///is not reachable from the root(s) or if \c v is a root.

    ///

    ///The shortest path tree used here is equal to the shortest path

    ///tree used in \ref predNode().

    ///

    ///\pre Either \ref run() or \ref start() must be called before

    ///using this function.

    Arc predArc(Node v) const { return (*_pred)[v]; }

    ///Returns the 'previous node' of the shortest path tree for a node.

    ///This function returns the 'previous node' of the shortest path

    ///tree for the node \c v, i.e. it returns the last but one node

    ///from a shortest path from the root(s) to \c v. It is \c INVALID

    ///if \c v is not reachable from the root(s) or if \c v is a root.

    ///

    ///The shortest path tree used here is equal to the shortest path

    ///tree used in \ref predArc().

    ///

    ///\pre Either \ref run() or \ref start() must be called before

    ///using this function.

    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:

                                  G->source((*_pred)[v]); }

    ///\brief Returns a const reference to the node map that stores the

    ///distances of the nodes.

    ///

    ///Returns a const reference to the node map that stores the distances

    ///of the nodes calculated by the algorithm.

    ///

    ///\pre Either \ref run() or \ref init()

    ///must be called before using this function.

    const DistMap &distMap() const { return *_dist;}

    ///\brief Returns a const reference to the node map that stores the

    ///predecessor arcs.

    ///

    ///Returns a const reference to the node map that stores the predecessor

    ///arcs, which form the shortest path tree.

    ///

    ///\pre Either \ref run() or \ref init()

    ///must be called before using this function.

    const PredMap &predMap() const { return *_pred;}

    ///Checks if a node is reachable from the root(s).

    ///Returns \c true if \c v is reachable from the root(s).

    ///\pre Either \ref run() or \ref start()

    ///must be called before using this function.

    bool reached(Node v) const { return (*_heap_cross_ref)[v] !=

                                        Heap::PRE_HEAP; }

    ///Checks if a node is processed.

    ///Returns \c true if \c v is processed, i.e. the shortest

    ///path to \c v has already found.

    ///\pre Either \ref run() or \ref start()

    ///must be called before using this function.

    bool processed(Node v) const { return (*_heap_cross_ref)[v] ==

                                          Heap::POST_HEAP; }

    ///The current distance of a node from the root(s).

    ///Returns the current distance of a node from the root(s).

    ///It may be decreased in the following processes.

    ///\pre \c v should be reached but not processed.

    Value currentDist(Node v) const { return (*_heap)[v]; }

    ///@}

  };

  ///Default traits class of dijkstra() function.

  ///Default traits class of dijkstra() function.

  ///\tparam GR The type of the digraph.

  ///\tparam LM The type of the length map.

  template<class GR, class LM>

  struct DijkstraWizardDefaultTraits

  {

    ///The type of the digraph the algorithm runs on.

    typedef GR Digraph;

    ///The type of the map that stores the arc lengths.

    ///The type of the map that stores the arc lengths.

    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.

    typedef LM LengthMap;

    ///The type of the length of the arcs.

    typedef typename LM::Value Value;

    /// Operation traits for Dijkstra algorithm.

    /// This class defines the operations that are used in the algorithm.

    /// \see DijkstraDefaultOperationTraits

    typedef DijkstraDefaultOperationTraits<Value> OperationTraits;

    /// The cross reference type used by the heap.

    /// The cross reference type used by the heap.

    /// Usually it is \c Digraph::NodeMap<int>.

    typedef typename Digraph::template NodeMap<int> HeapCrossRef;

    ///Instantiates a \ref HeapCrossRef.

    ///This function instantiates a \ref HeapCrossRef.

    /// \param g is the digraph, to which we would like to define the

    /// HeapCrossRef.

    /// \todo The digraph alone may be insufficient for the initialization

    static HeapCrossRef *createHeapCrossRef(const Digraph &g)

    {

      return new HeapCrossRef(g);

    }

    ///The heap type used by the Dijkstra algorithm.

    ///The heap type used by the Dijkstra algorithm.

    ///

    ///\sa BinHeap

    ///\sa Dijkstra

    typedef BinHeap<Value, typename Digraph::template NodeMap<int>,

                    std::less<Value> > Heap;

    ///Instantiates a \ref Heap.

    ///This function instantiates a \ref Heap.

    /// \param r is the HeapCrossRef which is used.

    static Heap *createHeap(HeapCrossRef& r)

    {

      return new Heap(r);

    }

    ///\brief The type of the map that stores the predecessor

    ///arcs of the shortest paths.

    ///

    ///The type of the map that stores the predecessor

    ///arcs of the shortest paths.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef NullMap <typename Digraph::Node,typename Digraph::Arc> PredMap;

    ///Instantiates a \ref PredMap.

    ///This function instantiates a \ref PredMap.

    ///\param g is the digraph, to which we would like to define the

    ///\ref PredMap.

    ///\todo The digraph alone may be insufficient to initialize

#ifdef DOXYGEN

    static PredMap *createPredMap(const Digraph &g)

#else

    static PredMap *createPredMap(const Digraph &)

#endif

    {

      return new PredMap();

    }

    ///The type of the map that indicates which nodes are processed.

    ///The type of the map that indicates which nodes are processed.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    ///By default it is a NullMap.

    ///\todo If it is set to a real map,

    ///Dijkstra::processed() should read this.

    ///\todo named parameter to set this type, function to read and write.

    typedef NullMap<typename Digraph::Node,bool> ProcessedMap;

    ///Instantiates a \ref ProcessedMap.

    ///This function instantiates a \ref ProcessedMap.

    ///\param g is the digraph, to which

    ///we would like to define the \ref ProcessedMap.

#ifdef DOXYGEN

    static ProcessedMap *createProcessedMap(const Digraph &g)

#else

    static ProcessedMap *createProcessedMap(const Digraph &)

#endif

    {

      return new ProcessedMap();

    }

    ///The type of the map that stores the distances of the nodes.

    ///The type of the map that stores the distances of the nodes.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef NullMap<typename Digraph::Node,Value> DistMap;

    ///Instantiates a \ref DistMap.

    ///This function instantiates a \ref DistMap.

    ///\param g is the digraph, to which we would like to define

    ///the \ref DistMap

#ifdef DOXYGEN

    static DistMap *createDistMap(const Digraph &g)

#else

    static DistMap *createDistMap(const Digraph &)

#endif

    {

      return new DistMap();

    }

  };

  /// Default traits class used by \ref DijkstraWizard

  /// To make it easier to use Dijkstra algorithm

  /// we have created a wizard class.

  /// This \ref DijkstraWizard class needs default traits,

  /// as well as the \ref Dijkstra class.

  /// The \ref DijkstraWizardBase is a class to be the default traits of the

  /// \ref DijkstraWizard class.

  /// \todo More named parameters are required...

  template<class GR,class LM>

  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>

  {

    typedef DijkstraWizardDefaultTraits<GR,LM> Base;

  protected:

    //The type of the nodes in the digraph.

    typedef typename Base::Digraph::Node Node;

    //Pointer to the digraph the algorithm runs on.

    void *_g;

    //Pointer to the length map

    void *_length;

    //Pointer to the map of predecessors arcs.

    void *_pred;

    //Pointer to the map of distances.

    void *_dist;

    //Pointer to the source node.

    Node _source;

  public:

    /// Constructor.

    /// This constructor does not require parameters, therefore it initiates

    /// all of the attributes to default values (0, INVALID).

                           _dist(0), _source(INVALID) {}

    /// Constructor.

    /// This constructor requires some parameters,

    /// listed in the parameters list.

    /// Others are initiated to 0.

    /// \param g The digraph the algorithm runs on.

    /// \param l The length map.

    /// \param s The source node.

    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :

      _g(reinterpret_cast<void*>(const_cast<GR*>(&g))),

      _length(reinterpret_cast<void*>(const_cast<LM*>(&l))),

  };

  /// Auxiliary class for the function type interface of Dijkstra algorithm.

  /// This auxiliary class is created to implement the function type

  /// interface of \ref Dijkstra algorithm. It uses the functions and features

  /// of the plain \ref Dijkstra, but it is much simpler to use it.

  /// It should only be used through the \ref dijkstra() function, which makes

  /// it easier to use the algorithm.

  ///

  /// Simplicity means that the way to change the types defined

  /// in the traits class is based on functions that returns the new class

  /// and not on templatable built-in classes.

  /// When using the plain \ref Dijkstra

  /// the new class with the modified type comes from

  /// the original class by using the ::

  /// operator. In the case of \ref DijkstraWizard only

  /// a function have to be called, and it will

  /// return the needed class.

  ///

  /// It does not have own \ref run() method. When its \ref run() method

  /// is called, it initiates a plain \ref Dijkstra object, and calls the

  /// \ref Dijkstra::run() method of it.

  template<class TR>

  class DijkstraWizard : public TR

  {

    typedef TR Base;

    ///The type of the digraph the algorithm runs on.

    typedef typename TR::Digraph Digraph;

    typedef typename Digraph::Node Node;

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::OutArcIt OutArcIt;

    ///The type of the map that stores the arc lengths.

    typedef typename TR::LengthMap LengthMap;

    ///The type of the length of the arcs.

    typedef typename LengthMap::Value Value;

    ///\brief The type of the map that stores the predecessor

    ///arcs of the shortest paths.

    typedef typename TR::PredMap PredMap;

    ///The type of the map that stores the distances of the nodes.

    typedef typename TR::DistMap DistMap;

    ///The type of the map that indicates which nodes are processed.

    typedef typename TR::ProcessedMap ProcessedMap;

    ///The heap type used by the dijkstra algorithm.

    typedef typename TR::Heap Heap;

  public:

    /// Constructor.

    DijkstraWizard() : TR() {}

    /// Constructor that requires parameters.

    /// Constructor that requires parameters.

    /// These parameters will be the default values for the traits class.

    DijkstraWizard(const Digraph &g,const LengthMap &l, Node s=INVALID) :

      TR(g,l,s) {}

    ///Copy constructor

    DijkstraWizard(const TR &b) : TR(b) {}

    ~DijkstraWizard() {}

    ///Runs Dijkstra algorithm from a source node.

    ///Runs Dijkstra algorithm from a source node.

    ///The node can be given with the \ref source() function.

    void run()

    {

      if(Base::_source==INVALID) throw UninitializedParameter();

      Dijkstra<Digraph,LengthMap,TR>

        dij(*reinterpret_cast<const Digraph*>(Base::_g),

            *reinterpret_cast<const LengthMap*>(Base::_length));

      dij.run(Base::_source);

    }

    ///Runs Dijkstra algorithm from the given node.

    ///Runs Dijkstra algorithm from the given node.

    ///\param s is the given source.

    void run(Node s)

    {

      Base::_source=s;

      run();

    }

    /// Sets the source node, from which the Dijkstra algorithm runs.

    /// Sets the source node, from which the Dijkstra algorithm runs.

    /// \param s is the source node.

    DijkstraWizard<TR> &source(Node s)

    {

      Base::_source=s;

      return *this;

    }

    template<class T>

    struct DefPredMapBase : public Base {

      typedef T PredMap;

      static PredMap *createPredMap(const Digraph &) { return 0; };

      DefPredMapBase(const TR &b) : TR(b) {}

    };

    ///\brief \ref named-templ-param "Named parameter"

    ///for setting \ref PredMap object.

    ///

    ///\ref named-templ-param "Named parameter"

    ///for setting \ref PredMap object.

    template<class T>

    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)

    {

      Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));

      return DijkstraWizard<DefPredMapBase<T> >(*this);

    }

    template<class T>

    struct DefProcessedMapBase : public Base {

      typedef T ProcessedMap;

      static ProcessedMap *createProcessedMap(const Digraph &) { return 0; };

      DefProcessedMapBase(const TR &b) : TR(b) {}

    };

    ///\brief \ref named-templ-param "Named parameter"

    ///for setting \ref ProcessedMap object.

    ///

    /// \ref named-templ-param "Named parameter"

    ///for setting \ref ProcessedMap object.

    template<class T>

    DijkstraWizard<DefProcessedMapBase<T> > processedMap(const T &t)

    {

      Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t));

      return DijkstraWizard<DefProcessedMapBase<T> >(*this);

    }

    template<class T>

    struct DefDistMapBase : public Base {

      typedef T DistMap;

      static DistMap *createDistMap(const Digraph &) { return 0; };

      DefDistMapBase(const TR &b) : TR(b) {}

    };

    ///\brief \ref named-templ-param "Named parameter"

    ///for setting \ref DistMap object.

    ///

    ///\ref named-templ-param "Named parameter"

    ///for setting \ref DistMap object.

    template<class T>

    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)

    {

      Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));

      return DijkstraWizard<DefDistMapBase<T> >(*this);

    }

  };

  ///Function type interface for Dijkstra algorithm.

  /// \ingroup shortest_path

  ///Function type interface for Dijkstra algorithm.

  ///

  ///This function also has several

  ///\ref named-templ-func-param "named parameters",

  ///they are declared as the members of class \ref DijkstraWizard.

  ///The following

  ///example shows how to use these parameters.

  ///\code

  ///  dijkstra(g,length,source).predMap(preds).run();

  ///\endcode

  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"

  ///to the end of the parameter list.

  ///\sa DijkstraWizard

  ///\sa Dijkstra

  template<class GR, class LM>

  DijkstraWizard<DijkstraWizardBase<GR,LM> >

  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)

  {

    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);

  }

} //END OF NAMESPACE LEMON

#endif