1.1 --- a/src/work/alpar/dijkstra.h Sun Feb 06 20:08:25 2005 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,915 +0,0 @@
1.4 -/* -*- C++ -*-
1.5 - * src/lemon/dijkstra.h - Part of LEMON, a generic C++ optimization library
1.6 - *
1.7 - * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.8 - * (Egervary Combinatorial Optimization Research Group, EGRES).
1.9 - *
1.10 - * Permission to use, modify and distribute this software is granted
1.11 - * provided that this copyright notice appears in all copies. For
1.12 - * precise terms see the accompanying LICENSE file.
1.13 - *
1.14 - * This software is provided "AS IS" with no warranty of any kind,
1.15 - * express or implied, and with no claim as to its suitability for any
1.16 - * purpose.
1.17 - *
1.18 - */
1.19 -
1.20 -#ifndef LEMON_DIJKSTRA_H
1.21 -#define LEMON_DIJKSTRA_H
1.22 -
1.23 -///\ingroup flowalgs
1.24 -///\file
1.25 -///\brief Dijkstra algorithm.
1.26 -
1.27 -#include <lemon/list_graph.h>
1.28 -#include <lemon/bin_heap.h>
1.29 -#include <lemon/invalid.h>
1.30 -#include <lemon/error.h>
1.31 -#include <lemon/maps.h>
1.32 -
1.33 -namespace lemon {
1.34 -
1.35 -
1.36 -/// \addtogroup flowalgs
1.37 -/// @{
1.38 -
1.39 - ///Default traits class of Dijkstra class.
1.40 -
1.41 - ///Default traits class of Dijkstra class.
1.42 - ///\param GR Graph type.
1.43 - ///\param LM Type of length map.
1.44 - template<class GR, class LM>
1.45 - struct DijkstraDefaultTraits
1.46 - {
1.47 - ///The graph type the algorithm runs on.
1.48 - typedef GR Graph;
1.49 - ///The type of the map that stores the edge lengths.
1.50 -
1.51 - ///The type of the map that stores the edge lengths.
1.52 - ///It must meet the \ref concept::ReadMap "ReadMap" concept.
1.53 - typedef LM LengthMap;
1.54 - //The type of the length of the edges.
1.55 - typedef typename LM::Value Value;
1.56 - ///The heap type used by Dijkstra algorithm.
1.57 -
1.58 - ///The heap type used by Dijkstra algorithm.
1.59 - ///
1.60 - ///\sa BinHeap
1.61 - ///\sa Dijkstra
1.62 - typedef BinHeap<typename Graph::Node,
1.63 - typename LM::Value,
1.64 - typename GR::template NodeMap<int>,
1.65 - std::less<Value> > Heap;
1.66 -
1.67 - ///\brief The type of the map that stores the last
1.68 - ///edges of the shortest paths.
1.69 - ///
1.70 - ///The type of the map that stores the last
1.71 - ///edges of the shortest paths.
1.72 - ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.73 - ///
1.74 - typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
1.75 - ///Instantiates a PredMap.
1.76 -
1.77 - ///This function instantiates a \ref PredMap.
1.78 - ///\param G is the graph, to which we would like to define the PredMap.
1.79 - ///\todo The graph alone may be insufficient for the initialization
1.80 - static PredMap *createPredMap(const GR &G)
1.81 - {
1.82 - return new PredMap(G);
1.83 - }
1.84 - ///\brief The type of the map that stores the last but one
1.85 - ///nodes of the shortest paths.
1.86 - ///
1.87 - ///The type of the map that stores the last but one
1.88 - ///nodes of the shortest paths.
1.89 - ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.90 - ///
1.91 - typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
1.92 - ///Instantiates a PredNodeMap.
1.93 -
1.94 - ///This function instantiates a \ref PredNodeMap.
1.95 - ///\param G is the graph, to which we would like to define the \ref PredNodeMap
1.96 - static PredNodeMap *createPredNodeMap(const GR &G)
1.97 - {
1.98 - return new PredNodeMap();
1.99 - }
1.100 -
1.101 - ///The type of the map that stores whether a nodes is reached.
1.102 -
1.103 - ///The type of the map that stores whether a nodes is reached.
1.104 - ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.105 - ///By default it is a NullMap.
1.106 - ///\todo If it is set to a real map, Dijkstra::reached() should read this.
1.107 - ///\todo named parameter to set this type, function to read and write.
1.108 - typedef NullMap<typename Graph::Node,bool> ReachedMap;
1.109 - ///Instantiates a ReachedMap.
1.110 -
1.111 - ///This function instantiates a \ref ReachedMap.
1.112 - ///\param G is the graph, to which we would like to define the \ref ReachedMap
1.113 - static ReachedMap *createReachedMap(const GR &G)
1.114 - {
1.115 - return new ReachedMap();
1.116 - }
1.117 - ///The type of the map that stores the dists of the nodes.
1.118 -
1.119 - ///The type of the map that stores the dists of the nodes.
1.120 - ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.121 - ///
1.122 - typedef typename Graph::template NodeMap<typename LM::Value> DistMap;
1.123 - ///Instantiates a DistMap.
1.124 -
1.125 - ///This function instantiates a \ref DistMap.
1.126 - ///\param G is the graph, to which we would like to define the \ref DistMap
1.127 - static DistMap *createDistMap(const GR &G)
1.128 - {
1.129 - return new DistMap(G);
1.130 - }
1.131 - };
1.132 -
1.133 - ///%Dijkstra algorithm class.
1.134 -
1.135 - ///This class provides an efficient implementation of %Dijkstra algorithm.
1.136 - ///The edge lengths are passed to the algorithm using a
1.137 - ///\ref concept::ReadMap "ReadMap",
1.138 - ///so it is easy to change it to any kind of length.
1.139 - ///
1.140 - ///The type of the length is determined by the
1.141 - ///\ref concept::ReadMap::Value "Value" of the length map.
1.142 - ///
1.143 - ///It is also possible to change the underlying priority heap.
1.144 - ///
1.145 - ///\param GR The graph type the algorithm runs on. The default value is
1.146 - ///\ref ListGraph. The value of GR is not used directly by Dijkstra, it
1.147 - ///is only passed to \ref DijkstraDefaultTraits.
1.148 - ///\param LM This read-only
1.149 - ///EdgeMap
1.150 - ///determines the
1.151 - ///lengths of the edges. It is read once for each edge, so the map
1.152 - ///may involve in relatively time consuming process to compute the edge
1.153 - ///length if it is necessary. The default map type is
1.154 - ///\ref concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>".
1.155 - ///The value of LM is not used directly by Dijkstra, it
1.156 - ///is only passed to \ref DijkstraDefaultTraits.
1.157 - ///\param TR Traits class to set various data types used by the algorithm.
1.158 - ///The default traits class is
1.159 - ///\ref DijkstraDefaultTraits "DijkstraDefaultTraits<GR,LM>".
1.160 - ///See \ref DijkstraDefaultTraits for the documentation of
1.161 - ///a Dijkstra traits class.
1.162 - ///
1.163 - ///\author Jacint Szabo and Alpar Juttner
1.164 - ///\todo A compare object would be nice.
1.165 -
1.166 -#ifdef DOXYGEN
1.167 - template <typename GR,
1.168 - typename LM,
1.169 - typename TR>
1.170 -#else
1.171 - template <typename GR=ListGraph,
1.172 - typename LM=typename GR::template EdgeMap<int>,
1.173 - typename TR=DijkstraDefaultTraits<GR,LM> >
1.174 -#endif
1.175 - class Dijkstra {
1.176 - public:
1.177 - /**
1.178 - * \brief \ref Exception for uninitialized parameters.
1.179 - *
1.180 - * This error represents problems in the initialization
1.181 - * of the parameters of the algorithms.
1.182 - */
1.183 - class UninitializedParameter : public lemon::UninitializedParameter {
1.184 - public:
1.185 - virtual const char* exceptionName() const {
1.186 - return "lemon::Dijsktra::UninitializedParameter";
1.187 - }
1.188 - };
1.189 -
1.190 - typedef TR Traits;
1.191 - ///The type of the underlying graph.
1.192 - typedef typename TR::Graph Graph;
1.193 - ///\e
1.194 - typedef typename Graph::Node Node;
1.195 - ///\e
1.196 - typedef typename Graph::NodeIt NodeIt;
1.197 - ///\e
1.198 - typedef typename Graph::Edge Edge;
1.199 - ///\e
1.200 - typedef typename Graph::OutEdgeIt OutEdgeIt;
1.201 -
1.202 - ///The type of the length of the edges.
1.203 - typedef typename TR::LengthMap::Value Value;
1.204 - ///The type of the map that stores the edge lengths.
1.205 - typedef typename TR::LengthMap LengthMap;
1.206 - ///\brief The type of the map that stores the last
1.207 - ///edges of the shortest paths.
1.208 - typedef typename TR::PredMap PredMap;
1.209 - ///\brief The type of the map that stores the last but one
1.210 - ///nodes of the shortest paths.
1.211 - typedef typename TR::PredNodeMap PredNodeMap;
1.212 - ///The type of the map indicating if a node is reached.
1.213 - typedef typename TR::ReachedMap ReachedMap;
1.214 - ///The type of the map that stores the dists of the nodes.
1.215 - typedef typename TR::DistMap DistMap;
1.216 - ///The heap type used by the dijkstra algorithm.
1.217 - typedef typename TR::Heap Heap;
1.218 - private:
1.219 - /// Pointer to the underlying graph.
1.220 - const Graph *G;
1.221 - /// Pointer to the length map
1.222 - const LengthMap *length;
1.223 - ///Pointer to the map of predecessors edges.
1.224 - PredMap *_pred;
1.225 - ///Indicates if \ref _pred is locally allocated (\c true) or not.
1.226 - bool local_pred;
1.227 - ///Pointer to the map of predecessors nodes.
1.228 - PredNodeMap *_predNode;
1.229 - ///Indicates if \ref _predNode is locally allocated (\c true) or not.
1.230 - bool local_predNode;
1.231 - ///Pointer to the map of distances.
1.232 - DistMap *_dist;
1.233 - ///Indicates if \ref _dist is locally allocated (\c true) or not.
1.234 - bool local_dist;
1.235 - ///Pointer to the map of reached status of the nodes.
1.236 - ReachedMap *_reached;
1.237 - ///Indicates if \ref _reached is locally allocated (\c true) or not.
1.238 - bool local_reached;
1.239 -
1.240 - ///The source node of the last execution.
1.241 - Node source;
1.242 -
1.243 - ///Creates the maps if necessary.
1.244 -
1.245 - ///\todo Error if \c G or are \c NULL. What about \c length?
1.246 - ///\todo Better memory allocation (instead of new).
1.247 - void create_maps()
1.248 - {
1.249 - if(!_pred) {
1.250 - local_pred = true;
1.251 - _pred = Traits::createPredMap(*G);
1.252 - }
1.253 - if(!_predNode) {
1.254 - local_predNode = true;
1.255 - _predNode = Traits::createPredNodeMap(*G);
1.256 - }
1.257 - if(!_dist) {
1.258 - local_dist = true;
1.259 - _dist = Traits::createDistMap(*G);
1.260 - }
1.261 - if(!_reached) {
1.262 - local_reached = true;
1.263 - _reached = Traits::createReachedMap(*G);
1.264 - }
1.265 - }
1.266 -
1.267 - public :
1.268 -
1.269 - ///\name Named template parameters
1.270 -
1.271 - ///@{
1.272 -
1.273 - template <class T>
1.274 - struct DefPredMapTraits : public Traits {
1.275 - typedef T PredMap;
1.276 - static PredMap *createPredMap(const Graph &G)
1.277 - {
1.278 - throw UninitializedParameter();
1.279 - }
1.280 - };
1.281 - ///\ref named-templ-param "Named parameter" for setting PredMap type
1.282 -
1.283 - ///\ref named-templ-param "Named parameter" for setting PredMap type
1.284 - ///
1.285 - template <class T>
1.286 - class DefPredMap : public Dijkstra< Graph,
1.287 - LengthMap,
1.288 - DefPredMapTraits<T> > { };
1.289 -
1.290 - template <class T>
1.291 - struct DefPredNodeMapTraits : public Traits {
1.292 - typedef T PredNodeMap;
1.293 - static PredNodeMap *createPredNodeMap(const Graph &G)
1.294 - {
1.295 - throw UninitializedParameter();
1.296 - }
1.297 - };
1.298 - ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
1.299 -
1.300 - ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
1.301 - ///
1.302 - template <class T>
1.303 - class DefPredNodeMap : public Dijkstra< Graph,
1.304 - LengthMap,
1.305 - DefPredNodeMapTraits<T> > { };
1.306 -
1.307 - template <class T>
1.308 - struct DefDistMapTraits : public Traits {
1.309 - typedef T DistMap;
1.310 - static DistMap *createDistMap(const Graph &G)
1.311 - {
1.312 - throw UninitializedParameter();
1.313 - }
1.314 - };
1.315 - ///\ref named-templ-param "Named parameter" for setting DistMap type
1.316 -
1.317 - ///\ref named-templ-param "Named parameter" for setting DistMap type
1.318 - ///
1.319 - template <class T>
1.320 - class DefDistMap : public Dijkstra< Graph,
1.321 - LengthMap,
1.322 - DefDistMapTraits<T> > { };
1.323 -
1.324 - template <class T>
1.325 - struct DefReachedMapTraits : public Traits {
1.326 - typedef T ReachedMap;
1.327 - static ReachedMap *createReachedMap(const Graph &G)
1.328 - {
1.329 - throw UninitializedParameter();
1.330 - }
1.331 - };
1.332 - ///\ref named-templ-param "Named parameter" for setting ReachedMap type
1.333 -
1.334 - ///\ref named-templ-param "Named parameter" for setting ReachedMap type
1.335 - ///
1.336 - template <class T>
1.337 - class DefReachedMap : public Dijkstra< Graph,
1.338 - LengthMap,
1.339 - DefReachedMapTraits<T> > { };
1.340 -
1.341 - struct DefGraphReachedMapTraits : public Traits {
1.342 - typedef typename Graph::NodeMap<bool> ReachedMap;
1.343 - static ReachedMap *createReachedMap(const Graph &G)
1.344 - {
1.345 - return new ReachedMap(G);
1.346 - }
1.347 - };
1.348 - ///\brief \ref named-templ-param "Named parameter"
1.349 - ///for setting the ReachedMap type to be Graph::NodeMap<bool>.
1.350 - ///
1.351 - ///\ref named-templ-param "Named parameter"
1.352 - ///for setting the ReachedMap type to be Graph::NodeMap<bool>.
1.353 - ///If you don't set it explicitely, it will be automatically allocated.
1.354 - template <class T>
1.355 - class DefReachedMapToBeDefaultMap :
1.356 - public Dijkstra< Graph,
1.357 - LengthMap,
1.358 - DefGraphReachedMapTraits> { };
1.359 -
1.360 - ///@}
1.361 -
1.362 -
1.363 - private:
1.364 - typename Graph::template NodeMap<int> _heap_map;
1.365 - Heap _heap;
1.366 - public:
1.367 -
1.368 - ///Constructor.
1.369 -
1.370 - ///\param _G the graph the algorithm will run on.
1.371 - ///\param _length the length map used by the algorithm.
1.372 - Dijkstra(const Graph& _G, const LengthMap& _length) :
1.373 - G(&_G), length(&_length),
1.374 - _pred(NULL), local_pred(false),
1.375 - _predNode(NULL), local_predNode(false),
1.376 - _dist(NULL), local_dist(false),
1.377 - _reached(NULL), local_reached(false),
1.378 - _heap_map(*G,-1),_heap(_heap_map)
1.379 - { }
1.380 -
1.381 - ///Destructor.
1.382 - ~Dijkstra()
1.383 - {
1.384 - if(local_pred) delete _pred;
1.385 - if(local_predNode) delete _predNode;
1.386 - if(local_dist) delete _dist;
1.387 - if(local_reached) delete _reached;
1.388 - }
1.389 -
1.390 - ///Sets the length map.
1.391 -
1.392 - ///Sets the length map.
1.393 - ///\return <tt> (*this) </tt>
1.394 - Dijkstra &lengthMap(const LengthMap &m)
1.395 - {
1.396 - length = &m;
1.397 - return *this;
1.398 - }
1.399 -
1.400 - ///Sets the map storing the predecessor edges.
1.401 -
1.402 - ///Sets the map storing the predecessor edges.
1.403 - ///If you don't use this function before calling \ref run(),
1.404 - ///it will allocate one. The destuctor deallocates this
1.405 - ///automatically allocated map, of course.
1.406 - ///\return <tt> (*this) </tt>
1.407 - Dijkstra &predMap(PredMap &m)
1.408 - {
1.409 - if(local_pred) {
1.410 - delete _pred;
1.411 - local_pred=false;
1.412 - }
1.413 - _pred = &m;
1.414 - return *this;
1.415 - }
1.416 -
1.417 - ///Sets the map storing the predecessor nodes.
1.418 -
1.419 - ///Sets the map storing the predecessor nodes.
1.420 - ///If you don't use this function before calling \ref run(),
1.421 - ///it will allocate one. The destuctor deallocates this
1.422 - ///automatically allocated map, of course.
1.423 - ///\return <tt> (*this) </tt>
1.424 - Dijkstra &predNodeMap(PredNodeMap &m)
1.425 - {
1.426 - if(local_predNode) {
1.427 - delete _predNode;
1.428 - local_predNode=false;
1.429 - }
1.430 - _predNode = &m;
1.431 - return *this;
1.432 - }
1.433 -
1.434 - ///Sets the map storing the distances calculated by the algorithm.
1.435 -
1.436 - ///Sets the map storing the distances calculated by the algorithm.
1.437 - ///If you don't use this function before calling \ref run(),
1.438 - ///it will allocate one. The destuctor deallocates this
1.439 - ///automatically allocated map, of course.
1.440 - ///\return <tt> (*this) </tt>
1.441 - Dijkstra &distMap(DistMap &m)
1.442 - {
1.443 - if(local_dist) {
1.444 - delete _dist;
1.445 - local_dist=false;
1.446 - }
1.447 - _dist = &m;
1.448 - return *this;
1.449 - }
1.450 -
1.451 - private:
1.452 - void finalizeNodeData(Node v,Value dst)
1.453 - {
1.454 - _reached->set(v,true);
1.455 - _dist->set(v, dst);
1.456 - _predNode->set(v,G->source((*_pred)[v]));
1.457 - }
1.458 -
1.459 - public:
1.460 - ///\name Excetution control
1.461 - ///The simplest way to execute the algorithm is to use
1.462 - ///\ref run().
1.463 - ///\n
1.464 - ///It you need more control on the execution,
1.465 - ///first you must call \ref init(), then you can add several source nodes
1.466 - ///with \ref addSource(). Finally \ref start() will perform the actual path
1.467 - ///computation.
1.468 -
1.469 - ///@{
1.470 -
1.471 - ///Initializes the internal data structures.
1.472 -
1.473 - ///Initializes the internal data structures.
1.474 - ///
1.475 - ///\todo _heap_map's type could also be in the traits class.
1.476 - void init()
1.477 - {
1.478 - create_maps();
1.479 -
1.480 - for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
1.481 - _pred->set(u,INVALID);
1.482 - _predNode->set(u,INVALID);
1.483 - ///\todo *_reached is not set to false.
1.484 - _heap_map.set(u,Heap::PRE_HEAP);
1.485 - }
1.486 - }
1.487 -
1.488 - ///Adds a new source node.
1.489 -
1.490 - ///Adds a new source node the the priority heap.
1.491 - ///It checks if the node has already been added to the heap.
1.492 - ///
1.493 - ///The optional second parameter is the initial distance of the node.
1.494 - ///
1.495 - ///\todo Do we really want to check it?
1.496 - void addSource(Node s,Value dst=0)
1.497 - {
1.498 - source = s;
1.499 - if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst);
1.500 - }
1.501 -
1.502 - void processNode()
1.503 - {
1.504 - Node v=_heap.top();
1.505 - Value oldvalue=_heap[v];
1.506 - _heap.pop();
1.507 - finalizeNodeData(v,oldvalue);
1.508 -
1.509 - for(OutEdgeIt e(*G,v); e!=INVALID; ++e) {
1.510 - Node w=G->target(e);
1.511 - switch(_heap.state(w)) {
1.512 - case Heap::PRE_HEAP:
1.513 - _heap.push(w,oldvalue+(*length)[e]);
1.514 - _pred->set(w,e);
1.515 -// _predNode->set(w,v);
1.516 - break;
1.517 - case Heap::IN_HEAP:
1.518 - if ( oldvalue+(*length)[e] < _heap[w] ) {
1.519 - _heap.decrease(w, oldvalue+(*length)[e]);
1.520 - _pred->set(w,e);
1.521 -// _predNode->set(w,v);
1.522 - }
1.523 - break;
1.524 - case Heap::POST_HEAP:
1.525 - break;
1.526 - }
1.527 - }
1.528 - }
1.529 -
1.530 - ///Executes the algorithm.
1.531 -
1.532 - ///Executes the algorithm.
1.533 - ///
1.534 - ///\pre init() must be called and at least one node should be added
1.535 - ///with addSource() before using this function.
1.536 - ///
1.537 - ///This method runs the %Dijkstra algorithm from the root node(s)
1.538 - ///in order to
1.539 - ///compute the
1.540 - ///shortest path to each node. The algorithm computes
1.541 - ///- The shortest path tree.
1.542 - ///- The distance of each node from the root(s).
1.543 - ///
1.544 - void start()
1.545 - {
1.546 - while ( !_heap.empty() ) processNode();
1.547 - }
1.548 -
1.549 - ///Executes the algorithm until \c dest is reached.
1.550 -
1.551 - ///Executes the algorithm until \c dest is reached.
1.552 - ///
1.553 - ///\pre init() must be called and at least one node should be added
1.554 - ///with addSource() before using this function.
1.555 - ///
1.556 - ///This method runs the %Dijkstra algorithm from the root node(s)
1.557 - ///in order to
1.558 - ///compute the
1.559 - ///shortest path to \c dest. The algorithm computes
1.560 - ///- The shortest path to \c dest.
1.561 - ///- The distance of \c dest from the root(s).
1.562 - ///
1.563 - void start(Node dest)
1.564 - {
1.565 - while ( !_heap.empty() && _heap.top()!=dest ) processNode();
1.566 - if ( _heap.top()==dest ) finalizeNodeData(_heap.top());
1.567 - }
1.568 -
1.569 - ///Executes the algorithm until a condition is met.
1.570 -
1.571 - ///Executes the algorithm until a condition is met.
1.572 - ///
1.573 - ///\pre init() must be called and at least one node should be added
1.574 - ///with addSource() before using this function.
1.575 - ///
1.576 - ///\param nm must be a bool (or convertible) node map. The algorithm
1.577 - ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
1.578 - template<class NM>
1.579 - void start(const NM &nm)
1.580 - {
1.581 - while ( !_heap.empty() && !mn[_heap.top()] ) processNode();
1.582 - if ( !_heap.empty() ) finalizeNodeData(_heap.top());
1.583 - }
1.584 -
1.585 - ///Runs %Dijkstra algorithm from node \c s.
1.586 -
1.587 - ///This method runs the %Dijkstra algorithm from a root node \c s
1.588 - ///in order to
1.589 - ///compute the
1.590 - ///shortest path to each node. The algorithm computes
1.591 - ///- The shortest path tree.
1.592 - ///- The distance of each node from the root.
1.593 - ///
1.594 - ///\note d.run(s) is just a shortcut of the following code.
1.595 - ///\code
1.596 - /// d.init();
1.597 - /// d.addSource(s);
1.598 - /// d.start();
1.599 - ///\endcode
1.600 - void run(Node s) {
1.601 - init();
1.602 - addSource(s);
1.603 - start();
1.604 - }
1.605 -
1.606 - ///Finds the shortest path between \c s and \c t.
1.607 -
1.608 - ///Finds the shortest path between \c s and \c t.
1.609 - ///
1.610 - ///\return The length of the shortest s---t path if there exists one,
1.611 - ///0 otherwise.
1.612 - ///\note Apart from the return value, d.run(s) is
1.613 - ///just a shortcut of the following code.
1.614 - ///\code
1.615 - /// d.init();
1.616 - /// d.addSource(s);
1.617 - /// d.start(t);
1.618 - ///\endcode
1.619 - Value run(Node s,Node t) {
1.620 - init();
1.621 - addSource(s);
1.622 - start(t);
1.623 - return (*_pred)[t]==INVALID?0:(*_dist)[t];
1.624 - }
1.625 -
1.626 - ///@}
1.627 -
1.628 - ///\name Query Functions
1.629 - ///The result of the %Dijkstra algorithm can be obtained using these
1.630 - ///functions.\n
1.631 - ///Before the use of these functions,
1.632 - ///either run() or start() must be called.
1.633 -
1.634 - ///@{
1.635 -
1.636 - ///The distance of a node from the root.
1.637 -
1.638 - ///Returns the distance of a node from the root.
1.639 - ///\pre \ref run() must be called before using this function.
1.640 - ///\warning If node \c v in unreachable from the root the return value
1.641 - ///of this funcion is undefined.
1.642 - Value dist(Node v) const { return (*_dist)[v]; }
1.643 -
1.644 - ///Returns the 'previous edge' of the shortest path tree.
1.645 -
1.646 - ///For a node \c v it returns the 'previous edge' of the shortest path tree,
1.647 - ///i.e. it returns the last edge of a shortest path from the root to \c
1.648 - ///v. It is \ref INVALID
1.649 - ///if \c v is unreachable from the root or if \c v=s. The
1.650 - ///shortest path tree used here is equal to the shortest path tree used in
1.651 - ///\ref predNode(Node v). \pre \ref run() must be called before using
1.652 - ///this function.
1.653 - ///\todo predEdge could be a better name.
1.654 - Edge pred(Node v) const { return (*_pred)[v]; }
1.655 -
1.656 - ///Returns the 'previous node' of the shortest path tree.
1.657 -
1.658 - ///For a node \c v it returns the 'previous node' of the shortest path tree,
1.659 - ///i.e. it returns the last but one node from a shortest path from the
1.660 - ///root to \c /v. It is INVALID if \c v is unreachable from the root or if
1.661 - ///\c v=s. The shortest path tree used here is equal to the shortest path
1.662 - ///tree used in \ref pred(Node v). \pre \ref run() must be called before
1.663 - ///using this function.
1.664 - Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
1.665 - G->source((*_pred)[v]); }
1.666 -
1.667 - ///Returns a reference to the NodeMap of distances.
1.668 -
1.669 - ///Returns a reference to the NodeMap of distances. \pre \ref run() must
1.670 - ///be called before using this function.
1.671 - const DistMap &distMap() const { return *_dist;}
1.672 -
1.673 - ///Returns a reference to the shortest path tree map.
1.674 -
1.675 - ///Returns a reference to the NodeMap of the edges of the
1.676 - ///shortest path tree.
1.677 - ///\pre \ref run() must be called before using this function.
1.678 - const PredMap &predMap() const { return *_pred;}
1.679 -
1.680 - ///Returns a reference to the map of nodes of shortest paths.
1.681 -
1.682 - ///Returns a reference to the NodeMap of the last but one nodes of the
1.683 - ///shortest path tree.
1.684 - ///\pre \ref run() must be called before using this function.
1.685 - const PredNodeMap &predNodeMap() const { return *_predNode;}
1.686 -
1.687 - ///Checks if a node is reachable from the root.
1.688 -
1.689 - ///Returns \c true if \c v is reachable from the root.
1.690 - ///\warning If the algorithm is started from multiple nodes,
1.691 - ///this function may give false result for the source nodes.
1.692 - ///\pre \ref run() must be called before using this function.
1.693 - ///
1.694 - bool reached(Node v) { return v==source || (*_pred)[v]!=INVALID; }
1.695 -
1.696 - ///@}
1.697 - };
1.698 -
1.699 - /// Default traits used by \ref DijkstraWizard
1.700 -
1.701 - /// To make it easier to use Dijkstra algorithm we have created a wizard class.
1.702 - /// This \ref DijkstraWizard class needs default traits, as well as the \ref Dijkstra class.
1.703 - /// The \ref DijkstraWizardBase is a class to be the default traits of the
1.704 - /// \ref DijkstraWizard class.
1.705 - template<class GR,class LM>
1.706 - class DijkstraWizardBase : public DijkstraDefaultTraits<GR,LM>
1.707 - {
1.708 -
1.709 - typedef DijkstraDefaultTraits<GR,LM> Base;
1.710 - protected:
1.711 - /// Pointer to the underlying graph.
1.712 - void *_g;
1.713 - /// Pointer to the length map
1.714 - void *_length;
1.715 - ///Pointer to the map of predecessors edges.
1.716 - void *_pred;
1.717 - ///Pointer to the map of predecessors nodes.
1.718 - void *_predNode;
1.719 - ///Pointer to the map of distances.
1.720 - void *_dist;
1.721 - ///Pointer to the source node.
1.722 - void *_source;
1.723 -
1.724 - /// Type of the nodes in the graph.
1.725 - typedef typename Base::Graph::Node Node;
1.726 -
1.727 - public:
1.728 - /// Constructor.
1.729 -
1.730 - /// This constructor does not require parameters, therefore it initiates
1.731 - /// all of the attributes to default values (0, INVALID).
1.732 - DijkstraWizardBase() : _g(0), _length(0), _pred(0), _predNode(0),
1.733 - _dist(0), _source(INVALID) {}
1.734 -
1.735 - /// Constructor.
1.736 -
1.737 - /// This constructor requires some parameters, listed in the parameters list.
1.738 - /// Others are initiated to 0.
1.739 - /// \param g is the initial value of \ref _g
1.740 - /// \param l is the initial value of \ref _length
1.741 - /// \param s is the initial value of \ref _source
1.742 - DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
1.743 - _g((void *)&g), _length((void *)&l), _pred(0), _predNode(0),
1.744 - _dist(0), _source((void *)&s) {}
1.745 -
1.746 - };
1.747 -
1.748 - /// A class to make easier the usage of Dijkstra algorithm
1.749 -
1.750 - /// This class is created to make it easier to use Dijkstra algorithm.
1.751 - /// It uses the functions and features of the plain \ref Dijkstra,
1.752 - /// but it is much more simple to use it.
1.753 - ///
1.754 - /// Simplicity means that the way to change the types defined
1.755 - /// in the traits class is based on functions that returns the new class
1.756 - /// and not on templatable built-in classes. When using the plain \ref Dijkstra
1.757 - /// the new class with the modified type comes from the original class by using the ::
1.758 - /// operator. In the case of \ref DijkstraWizard only a function have to be called and it will
1.759 - /// return the needed class.
1.760 - ///
1.761 - /// It does not have own \ref run method. When its \ref run method is called
1.762 - /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run
1.763 - /// method of it.
1.764 - template<class TR>
1.765 - class DijkstraWizard : public TR
1.766 - {
1.767 - typedef TR Base;
1.768 -
1.769 - ///The type of the underlying graph.
1.770 - typedef typename TR::Graph Graph;
1.771 - //\e
1.772 - typedef typename Graph::Node Node;
1.773 - //\e
1.774 - typedef typename Graph::NodeIt NodeIt;
1.775 - //\e
1.776 - typedef typename Graph::Edge Edge;
1.777 - //\e
1.778 - typedef typename Graph::OutEdgeIt OutEdgeIt;
1.779 -
1.780 - ///The type of the map that stores the edge lengths.
1.781 - typedef typename TR::LengthMap LengthMap;
1.782 - ///The type of the length of the edges.
1.783 - typedef typename LengthMap::Value Value;
1.784 - ///\brief The type of the map that stores the last
1.785 - ///edges of the shortest paths.
1.786 - typedef typename TR::PredMap PredMap;
1.787 - ///\brief The type of the map that stores the last but one
1.788 - ///nodes of the shortest paths.
1.789 - typedef typename TR::PredNodeMap PredNodeMap;
1.790 - ///The type of the map that stores the dists of the nodes.
1.791 - typedef typename TR::DistMap DistMap;
1.792 -
1.793 - ///The heap type used by the dijkstra algorithm.
1.794 - typedef typename TR::Heap Heap;
1.795 -public:
1.796 - /// Constructor.
1.797 - DijkstraWizard() : TR() {}
1.798 -
1.799 - /// Constructor that requires parameters.
1.800 -
1.801 - /// Constructor that requires parameters.
1.802 - /// These parameters will be the default values for the traits class.
1.803 - DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) :
1.804 - TR(g,l,s) {}
1.805 -
1.806 - ///Copy constructor
1.807 - DijkstraWizard(const TR &b) : TR(b) {}
1.808 -
1.809 - ~DijkstraWizard() {}
1.810 -
1.811 - ///Runs Dijkstra algorithm from a given node.
1.812 -
1.813 - ///Runs Dijkstra algorithm from a given node.
1.814 - ///The node can be given by the \ref source function.
1.815 - void run()
1.816 - {
1.817 - if(_source==0) throw UninitializedParameter();
1.818 - Dijkstra<Graph,LengthMap,TR> Dij(*(Graph*)_g,*(LengthMap*)_length);
1.819 - if(_pred) Dij.predMap(*(PredMap*)_pred);
1.820 - if(_predNode) Dij.predNodeMap(*(PredNodeMap*)_predNode);
1.821 - if(_dist) Dij.distMap(*(DistMap*)_dist);
1.822 - Dij.run(*(Node*)_source);
1.823 - }
1.824 -
1.825 - ///Runs Dijkstra algorithm from the given node.
1.826 -
1.827 - ///Runs Dijkstra algorithm from the given node.
1.828 - ///\param s is the given source.
1.829 - void run(Node s)
1.830 - {
1.831 - _source=(void *)&s;
1.832 - run();
1.833 - }
1.834 -
1.835 - template<class T>
1.836 - struct DefPredMapBase : public Base {
1.837 - typedef T PredMap;
1.838 - static PredMap *createPredMap(const Graph &G) { return 0; };
1.839 - DefPredMapBase(const Base &b) : Base(b) {}
1.840 - };
1.841 -
1.842 - /// \ref named-templ-param "Named parameter" function for setting PredMap type
1.843 -
1.844 - /// \ref named-templ-param "Named parameter" function for setting PredMap type
1.845 - ///
1.846 - template<class T>
1.847 - DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
1.848 - {
1.849 - _pred=(void *)&t;
1.850 - return DijkstraWizard<DefPredMapBase<T> >(*this);
1.851 - }
1.852 -
1.853 -
1.854 - template<class T>
1.855 - struct DefPredNodeMapBase : public Base {
1.856 - typedef T PredNodeMap;
1.857 - static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1.858 - DefPredNodeMapBase(const Base &b) : Base(b) {}
1.859 - };
1.860 -
1.861 - /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
1.862 -
1.863 - /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type
1.864 - ///
1.865 - template<class T>
1.866 - DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1.867 - {
1.868 - _predNode=(void *)&t;
1.869 - return DijkstraWizard<DefPredNodeMapBase<T> >(*this);
1.870 - }
1.871 -
1.872 - template<class T>
1.873 - struct DefDistMapBase : public Base {
1.874 - typedef T DistMap;
1.875 - static DistMap *createDistMap(const Graph &G) { return 0; };
1.876 - DefDistMapBase(const Base &b) : Base(b) {}
1.877 - };
1.878 -
1.879 - /// \ref named-templ-param "Named parameter" function for setting DistMap type
1.880 -
1.881 - /// \ref named-templ-param "Named parameter" function for setting DistMap type
1.882 - ///
1.883 - template<class T>
1.884 - DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
1.885 - {
1.886 - _dist=(void *)&t;
1.887 - return DijkstraWizard<DefDistMapBase<T> >(*this);
1.888 - }
1.889 -
1.890 - /// Sets the source node, from which the Dijkstra algorithm runs.
1.891 -
1.892 - /// Sets the source node, from which the Dijkstra algorithm runs.
1.893 - /// \param s is the source node.
1.894 - DijkstraWizard<TR> &source(Node s)
1.895 - {
1.896 - source=(void *)&s;
1.897 - return *this;
1.898 - }
1.899 -
1.900 - };
1.901 -
1.902 - ///\e
1.903 -
1.904 - ///\todo Please document...
1.905 - ///
1.906 - template<class GR, class LM>
1.907 - DijkstraWizard<DijkstraWizardBase<GR,LM> >
1.908 - dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
1.909 - {
1.910 - return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
1.911 - }
1.912 -
1.913 -/// @}
1.914 -
1.915 -} //END OF NAMESPACE LEMON
1.916 -
1.917 -#endif
1.918 -