[Lemon-commits] [lemon_svn] alpar: r1529 - hugo/trunk/src/work/alpar
Lemon SVN
svn at lemon.cs.elte.hu
Mon Nov 6 20:46:03 CET 2006
Author: alpar
Date: Sun Feb 6 21:00:56 2005
New Revision: 1529
Modified:
hugo/trunk/src/work/alpar/dijkstra.h
Log:
- PredNodeMap is a NullMap by default
- Execution with stop condition
- Find shortest path between two nodes
Modified: hugo/trunk/src/work/alpar/dijkstra.h
==============================================================================
--- hugo/trunk/src/work/alpar/dijkstra.h (original)
+++ hugo/trunk/src/work/alpar/dijkstra.h Sun Feb 6 21:00:56 2005
@@ -85,14 +85,14 @@
///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.
@@ -222,13 +222,13 @@
///Indicates if \ref _pred is locally allocated (\c true) or not.
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;
///Indicates if \ref _reached is locally allocated (\c true) or not.
@@ -247,13 +247,13 @@
local_pred = true;
_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) {
local_reached = true;
@@ -369,8 +369,8 @@
Dijkstra(const Graph& _G, const LengthMap& _length) :
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)
{ }
@@ -379,8 +379,8 @@
~Dijkstra()
{
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;
}
@@ -420,11 +420,11 @@
///\return <tt> (*this) </tt>
Dijkstra &predNodeMap(PredNodeMap &m)
{
- if(local_pred_node) {
- delete pred_node;
- local_pred_node=false;
+ if(local_predNode) {
+ delete _predNode;
+ local_predNode=false;
}
- pred_node = &m;
+ _predNode = &m;
return *this;
}
@@ -437,14 +437,23 @@
///\return <tt> (*this) </tt>
Dijkstra &distMap(DistMap &m)
{
- if(local_distance) {
- delete distance;
- local_distance=false;
+ if(local_dist) {
+ delete _dist;
+ 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().
@@ -467,7 +476,7 @@
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);
}
@@ -490,10 +499,9 @@
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);
@@ -501,13 +509,13 @@
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:
@@ -516,12 +524,12 @@
}
}
- ///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
- ///with addSource().
+ ///\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)
///in order to
@@ -535,12 +543,12 @@
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
- ///with addSource().
+ ///\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)
///in order to
@@ -551,7 +559,24 @@
///
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.
@@ -575,6 +600,26 @@
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
@@ -591,7 +636,7 @@
///\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.
@@ -613,13 +658,14 @@
///\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.
@@ -633,7 +679,7 @@
///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.
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