src/hugo/dijkstra.h
changeset 695 887c551fb0aa
parent 693 80164e89dcbc
child 707 ec034cfade65
equal deleted inserted replaced
6:9cd8c9cef167 7:17373302ad14
    82     DistMap *distance;
    82     DistMap *distance;
    83     bool local_distance;
    83     bool local_distance;
    84 
    84 
    85     ///Initialize maps
    85     ///Initialize maps
    86     
    86     
    87     ///\todo Error if \c G or are \c NULL. What about \c length
    87     ///\todo Error if \c G or are \c NULL. What about \c length?
    88     ///\todo Better memory allocation (instead of new).
    88     ///\todo Better memory allocation (instead of new).
    89     void init_maps() 
    89     void init_maps() 
    90     {
    90     {
    91 //       if(!length) {
    91 //       if(!length) {
    92 // 	local_length = true;
    92 // 	local_length = true;
   194       }
   194       }
   195       distance = &m;
   195       distance = &m;
   196       return *this;
   196       return *this;
   197     }
   197     }
   198     
   198     
   199     void run(Node s);
   199   ///Runs %Dijkstra algorithm from node \c s.
   200     
       
   201     ///The distance of a node from the root.
       
   202 
       
   203     ///Returns the distance of a node from the root.
       
   204     ///\pre \ref run() must be called before using this function.
       
   205     ///\warning If node \c v in unreachable from the root the return value
       
   206     ///of this funcion is undefined.
       
   207     ValueType dist(Node v) const { return (*distance)[v]; }
       
   208 
       
   209     ///Returns the 'previous edge' of the shortest path tree.
       
   210 
       
   211     ///For a node \c v it returns the 'previous edge' of the shortest path tree,
       
   212     ///i.e. it returns the last edge from a shortest path from the root to \c
       
   213     ///v. It is \ref INVALID
       
   214     ///if \c v is unreachable from the root or if \c v=s. The
       
   215     ///shortest path tree used here is equal to the shortest path tree used in
       
   216     ///\ref predNode(Node v).  \pre \ref run() must be called before using
       
   217     ///this function.
       
   218     Edge pred(Node v) const { return (*predecessor)[v]; }
       
   219 
       
   220     ///Returns the 'previous node' of the shortest path tree.
       
   221 
       
   222     ///For a node \c v it returns the 'previous node' of the shortest path tree,
       
   223     ///i.e. it returns the last but one node from a shortest path from the
       
   224     ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
       
   225     ///\c v=s. The shortest path tree used here is equal to the shortest path
       
   226     ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
       
   227     ///using this function.
       
   228     Node predNode(Node v) const { return (*pred_node)[v]; }
       
   229     
       
   230     ///Returns a reference to the NodeMap of distances.
       
   231 
       
   232     ///Returns a reference to the NodeMap of distances. \pre \ref run() must
       
   233     ///be called before using this function.
       
   234     const DistMap &distMap() const { return *distance;}
       
   235  
       
   236     ///Returns a reference to the shortest path tree map.
       
   237 
       
   238     ///Returns a reference to the NodeMap of the edges of the
       
   239     ///shortest path tree.
       
   240     ///\pre \ref run() must be called before using this function.
       
   241     const PredMap &predMap() const { return *predecessor;}
       
   242  
       
   243     ///Returns a reference to the map of nodes of shortest paths.
       
   244 
       
   245     ///Returns a reference to the NodeMap of the last but one nodes of the
       
   246     ///shortest path tree.
       
   247     ///\pre \ref run() must be called before using this function.
       
   248     const PredNodeMap &predNodeMap() const { return *pred_node;}
       
   249 
       
   250     ///Checks if a node is reachable from the root.
       
   251 
       
   252     ///Returns \c true if \c v is reachable from the root.
       
   253     ///\warning the root node is reported to be unreached!
       
   254     ///\todo Is this what we want?
       
   255     ///\pre \ref run() must be called before using this function.
       
   256     ///
       
   257     bool reached(Node v) { return G->valid((*predecessor)[v]); }
       
   258     
       
   259   };
       
   260   
       
   261 
       
   262   // **********************************************************************
       
   263   //  IMPLEMENTATIONS
       
   264   // **********************************************************************
       
   265 
       
   266   ///Runs %Dijkstra algorithm from node the root.
       
   267 
   200 
   268   ///This method runs the %Dijkstra algorithm from a root node \c s
   201   ///This method runs the %Dijkstra algorithm from a root node \c s
   269   ///in order to
   202   ///in order to
   270   ///compute the
   203   ///compute the
   271   ///shortest path to each node. The algorithm computes
   204   ///shortest path to each node. The algorithm computes
   272   ///- The shortest path tree.
   205   ///- The shortest path tree.
   273   ///- The distance of each node from the root.
   206   ///- The distance of each node from the root.
   274   template <typename GR, typename LM,
   207     
   275 	    template<class,class,class,class> class Heap >
   208     void run(Node s) {
   276   void Dijkstra<GR,LM,Heap>::run(Node s) {
   209       
   277 
   210       init_maps();
   278     init_maps();
   211       
   279 
   212       for ( NodeIt u(*G) ; G->valid(u) ; G->next(u) ) {
   280     for ( NodeIt u(*G) ; G->valid(u) ; G->next(u) ) {
   213 	predecessor->set(u,INVALID);
   281       predecessor->set(u,INVALID);
   214 	pred_node->set(u,INVALID);
   282       pred_node->set(u,INVALID);
   215       }
   283     }
   216       
   284     
   217       typename GR::template NodeMap<int> heap_map(*G,-1);
   285     typename GR::template NodeMap<int> heap_map(*G,-1);
   218       
   286     
   219       typedef Heap<Node, ValueType, typename GR::template NodeMap<int>,
   287     typedef Heap<Node, ValueType, typename GR::template NodeMap<int>,
       
   288       std::less<ValueType> > 
   220       std::less<ValueType> > 
   289       HeapType;
   221       HeapType;
   290     
   222       
   291     HeapType heap(heap_map);
   223       HeapType heap(heap_map);
   292     
   224       
   293     heap.push(s,0); 
   225       heap.push(s,0); 
   294     
   226       
   295       while ( !heap.empty() ) {
   227       while ( !heap.empty() ) {
   296 	
   228 	
   297 	Node v=heap.top(); 
   229 	Node v=heap.top(); 
   298 	ValueType oldvalue=heap[v];
   230 	ValueType oldvalue=heap[v];
   299 	heap.pop();
   231 	heap.pop();
   300 	distance->set(v, oldvalue);
   232 	distance->set(v, oldvalue);
   301 	
   233 	
   302 	  
   234 	
   303 	for(OutEdgeIt e(*G,v); G->valid(e); G->next(e)) {
   235 	for(OutEdgeIt e(*G,v); G->valid(e); G->next(e)) {
   304 	  Node w=G->bNode(e); 
   236 	  Node w=G->bNode(e); 
   305 	  
   237 	  
   306 	  switch(heap.state(w)) {
   238 	  switch(heap.state(w)) {
   307 	  case HeapType::PRE_HEAP:
   239 	  case HeapType::PRE_HEAP:
   319 	  case HeapType::POST_HEAP:
   251 	  case HeapType::POST_HEAP:
   320 	    break;
   252 	    break;
   321 	  }
   253 	  }
   322 	}
   254 	}
   323       }
   255       }
   324   }
   256     }
       
   257     
       
   258     ///The distance of a node from the root.
       
   259 
       
   260     ///Returns the distance of a node from the root.
       
   261     ///\pre \ref run() must be called before using this function.
       
   262     ///\warning If node \c v in unreachable from the root the return value
       
   263     ///of this funcion is undefined.
       
   264     ValueType dist(Node v) const { return (*distance)[v]; }
       
   265 
       
   266     ///Returns the 'previous edge' of the shortest path tree.
       
   267 
       
   268     ///For a node \c v it returns the 'previous edge' of the shortest path tree,
       
   269     ///i.e. it returns the last edge from a shortest path from the root to \c
       
   270     ///v. It is \ref INVALID
       
   271     ///if \c v is unreachable from the root or if \c v=s. The
       
   272     ///shortest path tree used here is equal to the shortest path tree used in
       
   273     ///\ref predNode(Node v).  \pre \ref run() must be called before using
       
   274     ///this function.
       
   275     Edge pred(Node v) const { return (*predecessor)[v]; }
       
   276 
       
   277     ///Returns the 'previous node' of the shortest path tree.
       
   278 
       
   279     ///For a node \c v it returns the 'previous node' of the shortest path tree,
       
   280     ///i.e. it returns the last but one node from a shortest path from the
       
   281     ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
       
   282     ///\c v=s. The shortest path tree used here is equal to the shortest path
       
   283     ///tree used in \ref pred(Node v).  \pre \ref run() must be called before
       
   284     ///using this function.
       
   285     Node predNode(Node v) const { return (*pred_node)[v]; }
       
   286     
       
   287     ///Returns a reference to the NodeMap of distances.
       
   288 
       
   289     ///Returns a reference to the NodeMap of distances. \pre \ref run() must
       
   290     ///be called before using this function.
       
   291     const DistMap &distMap() const { return *distance;}
       
   292  
       
   293     ///Returns a reference to the shortest path tree map.
       
   294 
       
   295     ///Returns a reference to the NodeMap of the edges of the
       
   296     ///shortest path tree.
       
   297     ///\pre \ref run() must be called before using this function.
       
   298     const PredMap &predMap() const { return *predecessor;}
       
   299  
       
   300     ///Returns a reference to the map of nodes of shortest paths.
       
   301 
       
   302     ///Returns a reference to the NodeMap of the last but one nodes of the
       
   303     ///shortest path tree.
       
   304     ///\pre \ref run() must be called before using this function.
       
   305     const PredNodeMap &predNodeMap() const { return *pred_node;}
       
   306 
       
   307     ///Checks if a node is reachable from the root.
       
   308 
       
   309     ///Returns \c true if \c v is reachable from the root.
       
   310     ///\warning the root node is reported to be unreached!
       
   311     ///\todo Is this what we want?
       
   312     ///\pre \ref run() must be called before using this function.
       
   313     ///
       
   314     bool reached(Node v) { return G->valid((*predecessor)[v]); }
       
   315     
       
   316   };
       
   317   
       
   318 
       
   319   // **********************************************************************
       
   320   //  IMPLEMENTATIONS
       
   321   // **********************************************************************
   325 
   322 
   326 /// @}
   323 /// @}
   327   
   324   
   328 } //END OF NAMESPACE HUGO
   325 } //END OF NAMESPACE HUGO
   329 
   326