Changeset 1130:47ef467ccf70 in lemon-0.x for src/work

Timestamp:

02/06/05 21:00:56 (19 years ago)

Author:

Alpar Juttner

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@1529

Message:

• PredNodeMap? is a NullMap? by default
• Execution with stop condition
• Find shortest path between two nodes

File:

• src/work/alpar/dijkstra.h (modified) (20 diffs)

src/work/alpar/dijkstra.h

@@ -86 +86 @@
     ///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.
     
@@ -93 +93 @@
     static PredNodeMap *createPredNodeMap(const GR &G)
     {
-      return new PredNodeMap(G);
+      return new PredNodeMap();
     }
 
@@ -223 +223 @@
     bool local_pred;
     ///Pointer to the map of predecessors nodes.
-    PredNodeMap *pred_node;
-    ///Indicates if \ref pred_node is locally allocated (\c true) or not.
-    bool local_pred_node;
+    PredNodeMap *_predNode;
+    ///Indicates if \ref _predNode is locally allocated (\c true) or not.
+    bool local_predNode;
     ///Pointer to the map of distances.
-    DistMap *distance;
-    ///Indicates if \ref distance is locally allocated (\c true) or not.
-    bool local_distance;
+    DistMap *_dist;
+    ///Indicates if \ref _dist is locally allocated (\c true) or not.
+    bool local_dist;
     ///Pointer to the map of reached status of the nodes.
     ReachedMap *_reached;
@@ -248 +248 @@
         _pred = Traits::createPredMap(*G);
       }
-      if(!pred_node) {
-        local_pred_node = true;
-        pred_node = Traits::createPredNodeMap(*G);
-      }
-      if(!distance) {
-        local_distance = true;
-        distance = Traits::createDistMap(*G);
+      if(!_predNode) {
+        local_predNode = true;
+        _predNode = Traits::createPredNodeMap(*G);
+      }
+      if(!_dist) {
+        local_dist = true;
+        _dist = Traits::createDistMap(*G);
       }
       if(!_reached) {
@@ -370 +370 @@
       G(&_G), length(&_length),
       _pred(NULL), local_pred(false),
-      pred_node(NULL), local_pred_node(false),
-      distance(NULL), local_distance(false),
+      _predNode(NULL), local_predNode(false),
+      _dist(NULL), local_dist(false),
       _reached(NULL), local_reached(false),
       _heap_map(*G,-1),_heap(_heap_map)
@@ -380 +380 @@
     {
       if(local_pred) delete _pred;
-      if(local_pred_node) delete pred_node;
-      if(local_distance) delete distance;
+      if(local_predNode) delete _predNode;
+      if(local_dist) delete _dist;
       if(local_reached) delete _reached;
     }
@@ -421 +421 @@
     Dijkstra &predNodeMap(PredNodeMap &m) 
     {
-      if(local_pred_node) {
-        delete pred_node;
-        local_pred_node=false;
-      }
-      pred_node = &m;
+      if(local_predNode) {
+        delete _predNode;
+        local_predNode=false;
+      }
+      _predNode = &m;
       return *this;
     }
@@ -438 +438 @@
     Dijkstra &distMap(DistMap &m) 
     {
-      if(local_distance) {
-        delete distance;
-        local_distance=false;
-      }
-      distance = &m;
+      if(local_dist) {
+        delete _dist;
+        local_dist=false;
+      }
+      _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
@@ -468 +477 @@
       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);
@@ -491 +500 @@
     {
       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) {
@@ -502 +510 @@
           _heap.push(w,oldvalue+(*length)[e]); 
           _pred->set(w,e);
-          pred_node->set(w,v);
+//        _predNode->set(w,v);
           break;
         case Heap::IN_HEAP:
@@ -508 +516 @@
             _heap.decrease(w, oldvalue+(*length)[e]); 
             _pred->set(w,e);
-            pred_node->set(w,v);
+//          _predNode->set(w,v);
           }
           break;
@@ -517 +525 @@
     }
 
-    ///Starts the execution of the algorithm.
-
-    ///Starts the execution of the algorithm.
-    ///
-    ///\pre init() must be called before and at least one node should be added
-    ///with addSource().
+    ///Executes the algorithm.
+
+    ///Executes the algorithm.
+    ///
+    ///\pre init() must be called and at least one node should be added
+    ///with addSource() before using this function.
     ///
     ///This method runs the %Dijkstra algorithm from the root node(s)
@@ -536 +544 @@
     }
     
-    ///Starts the execution of the algorithm until \c dest is reached.
-
-    ///Starts the execution of the algorithm until \c dest is reached.
-    ///
-    ///\pre init() must be called before and at least one node should be added
-    ///with addSource().
+    ///Executes the algorithm until \c dest is reached.
+
+    ///Executes the algorithm until \c dest is reached.
+    ///
+    ///\pre init() must be called and at least one node should be added
+    ///with addSource() before using this function.
     ///
     ///This method runs the %Dijkstra algorithm from the root node(s)
@@ -552 +560 @@
     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());
     }
     
@@ -576 +601 @@
     }
     
+    ///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];
+    }
+    
     ///@}
 
@@ -592 +637 @@
     ///\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.
@@ -614 +659 @@
     ///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.
@@ -620 +666 @@
     ///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.
@@ -634 +680 @@
     ///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.