lemon-0.x: comparison src/work/alpar/dijkstra.h

equal deleted inserted replaced

-:bf1533bdc053
+:64907c0a845e
 ///
 ///The type of the map that stores the last but one
 ///nodes of the shortest paths.
 ///It must meet the \ref concept::WriteMap "WriteMap" concept.
 ///
-typedef typename Graph::template NodeMap<typename GR::Node> PredNodeMap;
+typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
 ///Instantiates a PredNodeMap.
 ///This function instantiates a \ref PredNodeMap.
 ///\param G is the graph, to which we would like to define the \ref PredNodeMap
 static PredNodeMap *createPredNodeMap(const GR &G)
 {
-return new PredNodeMap(G);
+return new PredNodeMap();
 }
 ///The type of the map that stores whether a nodes is reached.
 ///The type of the map that stores whether a nodes is reached.
 ///Pointer to the map of predecessors edges.
 PredMap *_pred;
 ///Indicates if \ref _pred is locally allocated (\c true) or not.
 bool local_pred;
 ///Pointer to the map of predecessors nodes.
-PredNodeMap *pred_node;
+PredNodeMap *_predNode;
-///Indicates if \ref pred_node is locally allocated (\c true) or not.
+///Indicates if \ref _predNode is locally allocated (\c true) or not.
-bool local_pred_node;
+bool local_predNode;
 ///Pointer to the map of distances.
-DistMap *distance;
+DistMap *_dist;
-///Indicates if \ref distance is locally allocated (\c true) or not.
+///Indicates if \ref _dist is locally allocated (\c true) or not.
-bool local_distance;
+bool local_dist;
 ///Pointer to the map of reached status of the nodes.
 ReachedMap *_reached;
 ///Indicates if \ref _reached is locally allocated (\c true) or not.
 bool local_reached;
 {
 if(!_pred) {
 	local_pred = true;
 	_pred = Traits::createPredMap(*G);
 }
-if(!pred_node) {
+if(!_predNode) {
-	local_pred_node = true;
+	local_predNode = true;
-	pred_node = Traits::createPredNodeMap(*G);
+	_predNode = Traits::createPredNodeMap(*G);
 }
-if(!distance) {
+if(!_dist) {
-	local_distance = true;
+	local_dist = true;
-	distance = Traits::createDistMap(*G);
+	_dist = Traits::createDistMap(*G);
 }
 if(!_reached) {
 	local_reached = true;
 	_reached = Traits::createReachedMap(*G);
 }
 ///\param _G the graph the algorithm will run on.
 ///\param _length the length map used by the algorithm.
 Dijkstra(const Graph& _G, const LengthMap& _length) :
 G(&_G), length(&_length),
 _pred(NULL), local_pred(false),
-pred_node(NULL), local_pred_node(false),
+_predNode(NULL), local_predNode(false),
-distance(NULL), local_distance(false),
+_dist(NULL), local_dist(false),
 _reached(NULL), local_reached(false),
 _heap_map(*G,-1),_heap(_heap_map)
 { }
 ///Destructor.
 ~Dijkstra()
 {
 if(local_pred) delete _pred;
-if(local_pred_node) delete pred_node;
+if(local_predNode) delete _predNode;
-if(local_distance) delete distance;
+if(local_dist) delete _dist;
 if(local_reached) delete _reached;
 }
 ///Sets the length map.
 ///it will allocate one. The destuctor deallocates this
 ///automatically allocated map, of course.
 ///\return <tt> (*this) </tt>
 Dijkstra &predNodeMap(PredNodeMap &m)
 {
-if(local_pred_node) {
+if(local_predNode) {
-	delete pred_node;
+	delete _predNode;
-	local_pred_node=false;
+	local_predNode=false;
 }
-pred_node = &m;
+_predNode = &m;
 return *this;
 }
 ///Sets the map storing the distances calculated by the algorithm.
 ///it will allocate one. The destuctor deallocates this
 ///automatically allocated map, of course.
 ///\return <tt> (*this) </tt>
 Dijkstra &distMap(DistMap &m)
 {
-if(local_distance) {
+if(local_dist) {
-	delete distance;
+	delete _dist;
-	local_distance=false;
+	local_dist=false;
 }
-distance = &m;
+_dist = &m;
 return *this;
 }
+private:
+void finalizeNodeData(Node v,Value dst)
+{
+_reached->set(v,true);
+_dist->set(v, dst);
+_predNode->set(v,G->source((*_pred)[v]));
+}
+public:
 ///\name Excetution control
 ///The simplest way to execute the algorithm is to use
 ///\ref run().
 ///\n
 ///It you need more control on the execution,
 {
 create_maps();
 for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
 	_pred->set(u,INVALID);
-	pred_node->set(u,INVALID);
+	_predNode->set(u,INVALID);
 	///\todo *_reached is not set to false.
 	_heap_map.set(u,Heap::PRE_HEAP);
 }
 }
 }
 void processNode()
 {
 Node v=_heap.top();
-_reached->set(v,true);
 Value oldvalue=_heap[v];
 _heap.pop();
-distance->set(v, oldvalue);
+finalizeNodeData(v,oldvalue);
 for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
 	Node w=G->target(e);
 	switch(_heap.state(w)) {
 	case Heap::PRE_HEAP:
 	  _heap.push(w,oldvalue+(*length)[e]);
 	  _pred->set(w,e);
-	  pred_node->set(w,v);
+//  	  _predNode->set(w,v);
 	  break;
 	case Heap::IN_HEAP:
 	  if ( oldvalue+(*length)[e] < _heap[w] ) {
 	    _heap.decrease(w, oldvalue+(*length)[e]);
 	    _pred->set(w,e);
-	    pred_node->set(w,v);
+// 	    _predNode->set(w,v);
 	  }
 	  break;
 	case Heap::POST_HEAP:
 	  break;
 	}
 }
 }
-///Starts the execution of the algorithm.
+///Executes the algorithm.
-///Starts the execution of the algorithm.
+///Executes the algorithm.
 ///
-///\pre init() must be called before and at least one node should be added
+///\pre init() must be called and at least one node should be added
-///with addSource().
+///with addSource() before using this function.
 ///
 ///This method runs the %Dijkstra algorithm from the root node(s)
 ///in order to
 ///compute the
 ///shortest path to each node. The algorithm computes
 void start()
 {
 while ( !_heap.empty() ) processNode();
 }
-///Starts the execution of the algorithm until \c dest is reached.
+///Executes the algorithm until \c dest is reached.
-///Starts the execution of the algorithm until \c dest is reached.
+///Executes the algorithm until \c dest is reached.
 ///
-///\pre init() must be called before and at least one node should be added
+///\pre init() must be called and at least one node should be added
-///with addSource().
+///with addSource() before using this function.
 ///
 ///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).
 ///
 void start(Node dest)
 {
-while ( !_heap.empty() && _heap.top()!=dest) processNode();
+while ( !_heap.empty() && _heap.top()!=dest ) processNode();
+if ( _heap.top()==dest ) finalizeNodeData(_heap.top());
+}
+///Executes the algorithm until a condition is met.
+///Executes the algorithm until a condition is met.
+///
+///\pre init() must be called and at least one node should be added
+///with addSource() before using this function.
+///
+///\param nm must be a bool (or convertible) node map. The algorithm
+///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
+template<class NM>
+void start(const NM &nm)
+{
+while ( !_heap.empty() && !mn[_heap.top()] ) processNode();
+if ( !_heap.empty() ) finalizeNodeData(_heap.top());
 }
 ///Runs %Dijkstra algorithm from node \c s.
 ///This method runs the %Dijkstra algorithm from a root node \c s
 init();
 addSource(s);
 start();
 }
+///Finds the shortest path between \c s and \c t.
+///Finds the shortest path between \c s and \c t.
+///
+///\return The length of the shortest s---t path if there exists one,
+///0 otherwise.
+///\note Apart from the return value, d.run(s) 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?0:(*_dist)[t];
+}
 ///@}
 ///\name Query Functions
 ///The result of the %Dijkstra algorithm can be obtained using these
 ///functions.\n
 ///Returns the distance of a node from the root.
 ///\pre \ref run() must be called before using this function.
 ///\warning If node \c v in unreachable from the root the return value
 ///of this funcion is undefined.
-Value dist(Node v) const { return (*distance)[v]; }
+Value dist(Node v) const { return (*_dist)[v]; }
 ///Returns the 'previous edge' of the shortest path tree.
 ///For a node \c v it returns the 'previous edge' of the shortest path tree,
 ///i.e. it returns the last edge of a shortest path from the root to \c
 ///i.e. it returns the last but one node from a shortest path from the
 ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
 ///\c v=s. The shortest path tree used here is equal to the shortest path
 ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
 ///using this function.
-Node predNode(Node v) const { return (*pred_node)[v]; }
+Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
+				  G->source((*_pred)[v]); }
 ///Returns a reference to the NodeMap of distances.
 ///Returns a reference to the NodeMap of distances. \pre \ref run() must
 ///be called before using this function.
-const DistMap &distMap() const { return *distance;}
+const DistMap &distMap() const { return *_dist;}
 ///Returns a reference to the shortest path tree map.
 ///Returns a reference to the NodeMap of the edges of the
 ///shortest path tree.
 ///Returns a reference to the map of nodes of shortest paths.
 ///Returns a reference to the NodeMap of the last but one nodes of the
 ///shortest path tree.
 ///\pre \ref run() must be called before using this function.
-const PredNodeMap &predNodeMap() const { return *pred_node;}
+const PredNodeMap &predNodeMap() const { return *_predNode;}
 ///Checks if a node is reachable from the root.
 ///Returns \c true if \c v is reachable from the root.
 ///\warning If the algorithm is started from multiple nodes,

changeset 1131	425731cb66de
parent 1128	6a347310d4c2