1 /* -*- C++ -*- |
|
2 * src/lemon/dijkstra.h - Part of LEMON, a generic C++ optimization library |
|
3 * |
|
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
|
5 * (Egervary Combinatorial Optimization Research Group, EGRES). |
|
6 * |
|
7 * Permission to use, modify and distribute this software is granted |
|
8 * provided that this copyright notice appears in all copies. For |
|
9 * precise terms see the accompanying LICENSE file. |
|
10 * |
|
11 * This software is provided "AS IS" with no warranty of any kind, |
|
12 * express or implied, and with no claim as to its suitability for any |
|
13 * purpose. |
|
14 * |
|
15 */ |
|
16 |
|
17 #ifndef LEMON_DIJKSTRA_H |
|
18 #define LEMON_DIJKSTRA_H |
|
19 |
|
20 ///\ingroup flowalgs |
|
21 ///\file |
|
22 ///\brief Dijkstra algorithm. |
|
23 |
|
24 #include <lemon/list_graph.h> |
|
25 #include <lemon/bin_heap.h> |
|
26 #include <lemon/invalid.h> |
|
27 #include <lemon/error.h> |
|
28 #include <lemon/maps.h> |
|
29 |
|
30 namespace lemon { |
|
31 |
|
32 |
|
33 /// \addtogroup flowalgs |
|
34 /// @{ |
|
35 |
|
36 ///Default traits class of Dijkstra class. |
|
37 |
|
38 ///Default traits class of Dijkstra class. |
|
39 ///\param GR Graph type. |
|
40 ///\param LM Type of length map. |
|
41 template<class GR, class LM> |
|
42 struct DijkstraDefaultTraits |
|
43 { |
|
44 ///The graph type the algorithm runs on. |
|
45 typedef GR Graph; |
|
46 ///The type of the map that stores the edge lengths. |
|
47 |
|
48 ///The type of the map that stores the edge lengths. |
|
49 ///It must meet the \ref concept::ReadMap "ReadMap" concept. |
|
50 typedef LM LengthMap; |
|
51 //The type of the length of the edges. |
|
52 typedef typename LM::Value Value; |
|
53 ///The heap type used by Dijkstra algorithm. |
|
54 |
|
55 ///The heap type used by Dijkstra algorithm. |
|
56 /// |
|
57 ///\sa BinHeap |
|
58 ///\sa Dijkstra |
|
59 typedef BinHeap<typename Graph::Node, |
|
60 typename LM::Value, |
|
61 typename GR::template NodeMap<int>, |
|
62 std::less<Value> > Heap; |
|
63 |
|
64 ///\brief The type of the map that stores the last |
|
65 ///edges of the shortest paths. |
|
66 /// |
|
67 ///The type of the map that stores the last |
|
68 ///edges of the shortest paths. |
|
69 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
70 /// |
|
71 typedef typename Graph::template NodeMap<typename GR::Edge> PredMap; |
|
72 ///Instantiates a PredMap. |
|
73 |
|
74 ///This function instantiates a \ref PredMap. |
|
75 ///\param G is the graph, to which we would like to define the PredMap. |
|
76 ///\todo The graph alone may be insufficient for the initialization |
|
77 static PredMap *createPredMap(const GR &G) |
|
78 { |
|
79 return new PredMap(G); |
|
80 } |
|
81 ///\brief The type of the map that stores the last but one |
|
82 ///nodes of the shortest paths. |
|
83 /// |
|
84 ///The type of the map that stores the last but one |
|
85 ///nodes of the shortest paths. |
|
86 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
87 /// |
|
88 typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap; |
|
89 ///Instantiates a PredNodeMap. |
|
90 |
|
91 ///This function instantiates a \ref PredNodeMap. |
|
92 ///\param G is the graph, to which we would like to define the \ref PredNodeMap |
|
93 static PredNodeMap *createPredNodeMap(const GR &G) |
|
94 { |
|
95 return new PredNodeMap(); |
|
96 } |
|
97 |
|
98 ///The type of the map that stores whether a nodes is reached. |
|
99 |
|
100 ///The type of the map that stores whether a nodes is reached. |
|
101 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
102 ///By default it is a NullMap. |
|
103 ///\todo If it is set to a real map, Dijkstra::reached() should read this. |
|
104 ///\todo named parameter to set this type, function to read and write. |
|
105 typedef NullMap<typename Graph::Node,bool> ReachedMap; |
|
106 ///Instantiates a ReachedMap. |
|
107 |
|
108 ///This function instantiates a \ref ReachedMap. |
|
109 ///\param G is the graph, to which we would like to define the \ref ReachedMap |
|
110 static ReachedMap *createReachedMap(const GR &G) |
|
111 { |
|
112 return new ReachedMap(); |
|
113 } |
|
114 ///The type of the map that stores the dists of the nodes. |
|
115 |
|
116 ///The type of the map that stores the dists of the nodes. |
|
117 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
118 /// |
|
119 typedef typename Graph::template NodeMap<typename LM::Value> DistMap; |
|
120 ///Instantiates a DistMap. |
|
121 |
|
122 ///This function instantiates a \ref DistMap. |
|
123 ///\param G is the graph, to which we would like to define the \ref DistMap |
|
124 static DistMap *createDistMap(const GR &G) |
|
125 { |
|
126 return new DistMap(G); |
|
127 } |
|
128 }; |
|
129 |
|
130 ///%Dijkstra algorithm class. |
|
131 |
|
132 ///This class provides an efficient implementation of %Dijkstra algorithm. |
|
133 ///The edge lengths are passed to the algorithm using a |
|
134 ///\ref concept::ReadMap "ReadMap", |
|
135 ///so it is easy to change it to any kind of length. |
|
136 /// |
|
137 ///The type of the length is determined by the |
|
138 ///\ref concept::ReadMap::Value "Value" of the length map. |
|
139 /// |
|
140 ///It is also possible to change the underlying priority heap. |
|
141 /// |
|
142 ///\param GR The graph type the algorithm runs on. The default value is |
|
143 ///\ref ListGraph. The value of GR is not used directly by Dijkstra, it |
|
144 ///is only passed to \ref DijkstraDefaultTraits. |
|
145 ///\param LM This read-only |
|
146 ///EdgeMap |
|
147 ///determines the |
|
148 ///lengths of the edges. It is read once for each edge, so the map |
|
149 ///may involve in relatively time consuming process to compute the edge |
|
150 ///length if it is necessary. The default map type is |
|
151 ///\ref concept::StaticGraph::EdgeMap "Graph::EdgeMap<int>". |
|
152 ///The value of LM is not used directly by Dijkstra, it |
|
153 ///is only passed to \ref DijkstraDefaultTraits. |
|
154 ///\param TR Traits class to set various data types used by the algorithm. |
|
155 ///The default traits class is |
|
156 ///\ref DijkstraDefaultTraits "DijkstraDefaultTraits<GR,LM>". |
|
157 ///See \ref DijkstraDefaultTraits for the documentation of |
|
158 ///a Dijkstra traits class. |
|
159 /// |
|
160 ///\author Jacint Szabo and Alpar Juttner |
|
161 ///\todo A compare object would be nice. |
|
162 |
|
163 #ifdef DOXYGEN |
|
164 template <typename GR, |
|
165 typename LM, |
|
166 typename TR> |
|
167 #else |
|
168 template <typename GR=ListGraph, |
|
169 typename LM=typename GR::template EdgeMap<int>, |
|
170 typename TR=DijkstraDefaultTraits<GR,LM> > |
|
171 #endif |
|
172 class Dijkstra { |
|
173 public: |
|
174 /** |
|
175 * \brief \ref Exception for uninitialized parameters. |
|
176 * |
|
177 * This error represents problems in the initialization |
|
178 * of the parameters of the algorithms. |
|
179 */ |
|
180 class UninitializedParameter : public lemon::UninitializedParameter { |
|
181 public: |
|
182 virtual const char* exceptionName() const { |
|
183 return "lemon::Dijsktra::UninitializedParameter"; |
|
184 } |
|
185 }; |
|
186 |
|
187 typedef TR Traits; |
|
188 ///The type of the underlying graph. |
|
189 typedef typename TR::Graph Graph; |
|
190 ///\e |
|
191 typedef typename Graph::Node Node; |
|
192 ///\e |
|
193 typedef typename Graph::NodeIt NodeIt; |
|
194 ///\e |
|
195 typedef typename Graph::Edge Edge; |
|
196 ///\e |
|
197 typedef typename Graph::OutEdgeIt OutEdgeIt; |
|
198 |
|
199 ///The type of the length of the edges. |
|
200 typedef typename TR::LengthMap::Value Value; |
|
201 ///The type of the map that stores the edge lengths. |
|
202 typedef typename TR::LengthMap LengthMap; |
|
203 ///\brief The type of the map that stores the last |
|
204 ///edges of the shortest paths. |
|
205 typedef typename TR::PredMap PredMap; |
|
206 ///\brief The type of the map that stores the last but one |
|
207 ///nodes of the shortest paths. |
|
208 typedef typename TR::PredNodeMap PredNodeMap; |
|
209 ///The type of the map indicating if a node is reached. |
|
210 typedef typename TR::ReachedMap ReachedMap; |
|
211 ///The type of the map that stores the dists of the nodes. |
|
212 typedef typename TR::DistMap DistMap; |
|
213 ///The heap type used by the dijkstra algorithm. |
|
214 typedef typename TR::Heap Heap; |
|
215 private: |
|
216 /// Pointer to the underlying graph. |
|
217 const Graph *G; |
|
218 /// Pointer to the length map |
|
219 const LengthMap *length; |
|
220 ///Pointer to the map of predecessors edges. |
|
221 PredMap *_pred; |
|
222 ///Indicates if \ref _pred is locally allocated (\c true) or not. |
|
223 bool local_pred; |
|
224 ///Pointer to the map of predecessors nodes. |
|
225 PredNodeMap *_predNode; |
|
226 ///Indicates if \ref _predNode is locally allocated (\c true) or not. |
|
227 bool local_predNode; |
|
228 ///Pointer to the map of distances. |
|
229 DistMap *_dist; |
|
230 ///Indicates if \ref _dist is locally allocated (\c true) or not. |
|
231 bool local_dist; |
|
232 ///Pointer to the map of reached status of the nodes. |
|
233 ReachedMap *_reached; |
|
234 ///Indicates if \ref _reached is locally allocated (\c true) or not. |
|
235 bool local_reached; |
|
236 |
|
237 ///The source node of the last execution. |
|
238 Node source; |
|
239 |
|
240 ///Creates the maps if necessary. |
|
241 |
|
242 ///\todo Error if \c G or are \c NULL. What about \c length? |
|
243 ///\todo Better memory allocation (instead of new). |
|
244 void create_maps() |
|
245 { |
|
246 if(!_pred) { |
|
247 local_pred = true; |
|
248 _pred = Traits::createPredMap(*G); |
|
249 } |
|
250 if(!_predNode) { |
|
251 local_predNode = true; |
|
252 _predNode = Traits::createPredNodeMap(*G); |
|
253 } |
|
254 if(!_dist) { |
|
255 local_dist = true; |
|
256 _dist = Traits::createDistMap(*G); |
|
257 } |
|
258 if(!_reached) { |
|
259 local_reached = true; |
|
260 _reached = Traits::createReachedMap(*G); |
|
261 } |
|
262 } |
|
263 |
|
264 public : |
|
265 |
|
266 ///\name Named template parameters |
|
267 |
|
268 ///@{ |
|
269 |
|
270 template <class T> |
|
271 struct DefPredMapTraits : public Traits { |
|
272 typedef T PredMap; |
|
273 static PredMap *createPredMap(const Graph &G) |
|
274 { |
|
275 throw UninitializedParameter(); |
|
276 } |
|
277 }; |
|
278 ///\ref named-templ-param "Named parameter" for setting PredMap type |
|
279 |
|
280 ///\ref named-templ-param "Named parameter" for setting PredMap type |
|
281 /// |
|
282 template <class T> |
|
283 class DefPredMap : public Dijkstra< Graph, |
|
284 LengthMap, |
|
285 DefPredMapTraits<T> > { }; |
|
286 |
|
287 template <class T> |
|
288 struct DefPredNodeMapTraits : public Traits { |
|
289 typedef T PredNodeMap; |
|
290 static PredNodeMap *createPredNodeMap(const Graph &G) |
|
291 { |
|
292 throw UninitializedParameter(); |
|
293 } |
|
294 }; |
|
295 ///\ref named-templ-param "Named parameter" for setting PredNodeMap type |
|
296 |
|
297 ///\ref named-templ-param "Named parameter" for setting PredNodeMap type |
|
298 /// |
|
299 template <class T> |
|
300 class DefPredNodeMap : public Dijkstra< Graph, |
|
301 LengthMap, |
|
302 DefPredNodeMapTraits<T> > { }; |
|
303 |
|
304 template <class T> |
|
305 struct DefDistMapTraits : public Traits { |
|
306 typedef T DistMap; |
|
307 static DistMap *createDistMap(const Graph &G) |
|
308 { |
|
309 throw UninitializedParameter(); |
|
310 } |
|
311 }; |
|
312 ///\ref named-templ-param "Named parameter" for setting DistMap type |
|
313 |
|
314 ///\ref named-templ-param "Named parameter" for setting DistMap type |
|
315 /// |
|
316 template <class T> |
|
317 class DefDistMap : public Dijkstra< Graph, |
|
318 LengthMap, |
|
319 DefDistMapTraits<T> > { }; |
|
320 |
|
321 template <class T> |
|
322 struct DefReachedMapTraits : public Traits { |
|
323 typedef T ReachedMap; |
|
324 static ReachedMap *createReachedMap(const Graph &G) |
|
325 { |
|
326 throw UninitializedParameter(); |
|
327 } |
|
328 }; |
|
329 ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
|
330 |
|
331 ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
|
332 /// |
|
333 template <class T> |
|
334 class DefReachedMap : public Dijkstra< Graph, |
|
335 LengthMap, |
|
336 DefReachedMapTraits<T> > { }; |
|
337 |
|
338 struct DefGraphReachedMapTraits : public Traits { |
|
339 typedef typename Graph::NodeMap<bool> ReachedMap; |
|
340 static ReachedMap *createReachedMap(const Graph &G) |
|
341 { |
|
342 return new ReachedMap(G); |
|
343 } |
|
344 }; |
|
345 ///\brief \ref named-templ-param "Named parameter" |
|
346 ///for setting the ReachedMap type to be Graph::NodeMap<bool>. |
|
347 /// |
|
348 ///\ref named-templ-param "Named parameter" |
|
349 ///for setting the ReachedMap type to be Graph::NodeMap<bool>. |
|
350 ///If you don't set it explicitely, it will be automatically allocated. |
|
351 template <class T> |
|
352 class DefReachedMapToBeDefaultMap : |
|
353 public Dijkstra< Graph, |
|
354 LengthMap, |
|
355 DefGraphReachedMapTraits> { }; |
|
356 |
|
357 ///@} |
|
358 |
|
359 |
|
360 private: |
|
361 typename Graph::template NodeMap<int> _heap_map; |
|
362 Heap _heap; |
|
363 public: |
|
364 |
|
365 ///Constructor. |
|
366 |
|
367 ///\param _G the graph the algorithm will run on. |
|
368 ///\param _length the length map used by the algorithm. |
|
369 Dijkstra(const Graph& _G, const LengthMap& _length) : |
|
370 G(&_G), length(&_length), |
|
371 _pred(NULL), local_pred(false), |
|
372 _predNode(NULL), local_predNode(false), |
|
373 _dist(NULL), local_dist(false), |
|
374 _reached(NULL), local_reached(false), |
|
375 _heap_map(*G,-1),_heap(_heap_map) |
|
376 { } |
|
377 |
|
378 ///Destructor. |
|
379 ~Dijkstra() |
|
380 { |
|
381 if(local_pred) delete _pred; |
|
382 if(local_predNode) delete _predNode; |
|
383 if(local_dist) delete _dist; |
|
384 if(local_reached) delete _reached; |
|
385 } |
|
386 |
|
387 ///Sets the length map. |
|
388 |
|
389 ///Sets the length map. |
|
390 ///\return <tt> (*this) </tt> |
|
391 Dijkstra &lengthMap(const LengthMap &m) |
|
392 { |
|
393 length = &m; |
|
394 return *this; |
|
395 } |
|
396 |
|
397 ///Sets the map storing the predecessor edges. |
|
398 |
|
399 ///Sets the map storing the predecessor edges. |
|
400 ///If you don't use this function before calling \ref run(), |
|
401 ///it will allocate one. The destuctor deallocates this |
|
402 ///automatically allocated map, of course. |
|
403 ///\return <tt> (*this) </tt> |
|
404 Dijkstra &predMap(PredMap &m) |
|
405 { |
|
406 if(local_pred) { |
|
407 delete _pred; |
|
408 local_pred=false; |
|
409 } |
|
410 _pred = &m; |
|
411 return *this; |
|
412 } |
|
413 |
|
414 ///Sets the map storing the predecessor nodes. |
|
415 |
|
416 ///Sets the map storing the predecessor nodes. |
|
417 ///If you don't use this function before calling \ref run(), |
|
418 ///it will allocate one. The destuctor deallocates this |
|
419 ///automatically allocated map, of course. |
|
420 ///\return <tt> (*this) </tt> |
|
421 Dijkstra &predNodeMap(PredNodeMap &m) |
|
422 { |
|
423 if(local_predNode) { |
|
424 delete _predNode; |
|
425 local_predNode=false; |
|
426 } |
|
427 _predNode = &m; |
|
428 return *this; |
|
429 } |
|
430 |
|
431 ///Sets the map storing the distances calculated by the algorithm. |
|
432 |
|
433 ///Sets the map storing the distances calculated by the algorithm. |
|
434 ///If you don't use this function before calling \ref run(), |
|
435 ///it will allocate one. The destuctor deallocates this |
|
436 ///automatically allocated map, of course. |
|
437 ///\return <tt> (*this) </tt> |
|
438 Dijkstra &distMap(DistMap &m) |
|
439 { |
|
440 if(local_dist) { |
|
441 delete _dist; |
|
442 local_dist=false; |
|
443 } |
|
444 _dist = &m; |
|
445 return *this; |
|
446 } |
|
447 |
|
448 private: |
|
449 void finalizeNodeData(Node v,Value dst) |
|
450 { |
|
451 _reached->set(v,true); |
|
452 _dist->set(v, dst); |
|
453 _predNode->set(v,G->source((*_pred)[v])); |
|
454 } |
|
455 |
|
456 public: |
|
457 ///\name Excetution control |
|
458 ///The simplest way to execute the algorithm is to use |
|
459 ///\ref run(). |
|
460 ///\n |
|
461 ///It you need more control on the execution, |
|
462 ///first you must call \ref init(), then you can add several source nodes |
|
463 ///with \ref addSource(). Finally \ref start() will perform the actual path |
|
464 ///computation. |
|
465 |
|
466 ///@{ |
|
467 |
|
468 ///Initializes the internal data structures. |
|
469 |
|
470 ///Initializes the internal data structures. |
|
471 /// |
|
472 ///\todo _heap_map's type could also be in the traits class. |
|
473 void init() |
|
474 { |
|
475 create_maps(); |
|
476 |
|
477 for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
|
478 _pred->set(u,INVALID); |
|
479 _predNode->set(u,INVALID); |
|
480 ///\todo *_reached is not set to false. |
|
481 _heap_map.set(u,Heap::PRE_HEAP); |
|
482 } |
|
483 } |
|
484 |
|
485 ///Adds a new source node. |
|
486 |
|
487 ///Adds a new source node the the priority heap. |
|
488 ///It checks if the node has already been added to the heap. |
|
489 /// |
|
490 ///The optional second parameter is the initial distance of the node. |
|
491 /// |
|
492 ///\todo Do we really want to check it? |
|
493 void addSource(Node s,Value dst=0) |
|
494 { |
|
495 source = s; |
|
496 if(_heap.state(s) != Heap::IN_HEAP) _heap.push(s,dst); |
|
497 } |
|
498 |
|
499 void processNode() |
|
500 { |
|
501 Node v=_heap.top(); |
|
502 Value oldvalue=_heap[v]; |
|
503 _heap.pop(); |
|
504 finalizeNodeData(v,oldvalue); |
|
505 |
|
506 for(OutEdgeIt e(*G,v); e!=INVALID; ++e) { |
|
507 Node w=G->target(e); |
|
508 switch(_heap.state(w)) { |
|
509 case Heap::PRE_HEAP: |
|
510 _heap.push(w,oldvalue+(*length)[e]); |
|
511 _pred->set(w,e); |
|
512 // _predNode->set(w,v); |
|
513 break; |
|
514 case Heap::IN_HEAP: |
|
515 if ( oldvalue+(*length)[e] < _heap[w] ) { |
|
516 _heap.decrease(w, oldvalue+(*length)[e]); |
|
517 _pred->set(w,e); |
|
518 // _predNode->set(w,v); |
|
519 } |
|
520 break; |
|
521 case Heap::POST_HEAP: |
|
522 break; |
|
523 } |
|
524 } |
|
525 } |
|
526 |
|
527 ///Executes the algorithm. |
|
528 |
|
529 ///Executes the algorithm. |
|
530 /// |
|
531 ///\pre init() must be called and at least one node should be added |
|
532 ///with addSource() before using this function. |
|
533 /// |
|
534 ///This method runs the %Dijkstra algorithm from the root node(s) |
|
535 ///in order to |
|
536 ///compute the |
|
537 ///shortest path to each node. The algorithm computes |
|
538 ///- The shortest path tree. |
|
539 ///- The distance of each node from the root(s). |
|
540 /// |
|
541 void start() |
|
542 { |
|
543 while ( !_heap.empty() ) processNode(); |
|
544 } |
|
545 |
|
546 ///Executes the algorithm until \c dest is reached. |
|
547 |
|
548 ///Executes the algorithm until \c dest is reached. |
|
549 /// |
|
550 ///\pre init() must be called and at least one node should be added |
|
551 ///with addSource() before using this function. |
|
552 /// |
|
553 ///This method runs the %Dijkstra algorithm from the root node(s) |
|
554 ///in order to |
|
555 ///compute the |
|
556 ///shortest path to \c dest. The algorithm computes |
|
557 ///- The shortest path to \c dest. |
|
558 ///- The distance of \c dest from the root(s). |
|
559 /// |
|
560 void start(Node dest) |
|
561 { |
|
562 while ( !_heap.empty() && _heap.top()!=dest ) processNode(); |
|
563 if ( _heap.top()==dest ) finalizeNodeData(_heap.top()); |
|
564 } |
|
565 |
|
566 ///Executes the algorithm until a condition is met. |
|
567 |
|
568 ///Executes the algorithm until a condition is met. |
|
569 /// |
|
570 ///\pre init() must be called and at least one node should be added |
|
571 ///with addSource() before using this function. |
|
572 /// |
|
573 ///\param nm must be a bool (or convertible) node map. The algorithm |
|
574 ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>. |
|
575 template<class NM> |
|
576 void start(const NM &nm) |
|
577 { |
|
578 while ( !_heap.empty() && !mn[_heap.top()] ) processNode(); |
|
579 if ( !_heap.empty() ) finalizeNodeData(_heap.top()); |
|
580 } |
|
581 |
|
582 ///Runs %Dijkstra algorithm from node \c s. |
|
583 |
|
584 ///This method runs the %Dijkstra algorithm from a root node \c s |
|
585 ///in order to |
|
586 ///compute the |
|
587 ///shortest path to each node. The algorithm computes |
|
588 ///- The shortest path tree. |
|
589 ///- The distance of each node from the root. |
|
590 /// |
|
591 ///\note d.run(s) is just a shortcut of the following code. |
|
592 ///\code |
|
593 /// d.init(); |
|
594 /// d.addSource(s); |
|
595 /// d.start(); |
|
596 ///\endcode |
|
597 void run(Node s) { |
|
598 init(); |
|
599 addSource(s); |
|
600 start(); |
|
601 } |
|
602 |
|
603 ///Finds the shortest path between \c s and \c t. |
|
604 |
|
605 ///Finds the shortest path between \c s and \c t. |
|
606 /// |
|
607 ///\return The length of the shortest s---t path if there exists one, |
|
608 ///0 otherwise. |
|
609 ///\note Apart from the return value, d.run(s) is |
|
610 ///just a shortcut of the following code. |
|
611 ///\code |
|
612 /// d.init(); |
|
613 /// d.addSource(s); |
|
614 /// d.start(t); |
|
615 ///\endcode |
|
616 Value run(Node s,Node t) { |
|
617 init(); |
|
618 addSource(s); |
|
619 start(t); |
|
620 return (*_pred)[t]==INVALID?0:(*_dist)[t]; |
|
621 } |
|
622 |
|
623 ///@} |
|
624 |
|
625 ///\name Query Functions |
|
626 ///The result of the %Dijkstra algorithm can be obtained using these |
|
627 ///functions.\n |
|
628 ///Before the use of these functions, |
|
629 ///either run() or start() must be called. |
|
630 |
|
631 ///@{ |
|
632 |
|
633 ///The distance of a node from the root. |
|
634 |
|
635 ///Returns the distance of a node from the root. |
|
636 ///\pre \ref run() must be called before using this function. |
|
637 ///\warning If node \c v in unreachable from the root the return value |
|
638 ///of this funcion is undefined. |
|
639 Value dist(Node v) const { return (*_dist)[v]; } |
|
640 |
|
641 ///Returns the 'previous edge' of the shortest path tree. |
|
642 |
|
643 ///For a node \c v it returns the 'previous edge' of the shortest path tree, |
|
644 ///i.e. it returns the last edge of a shortest path from the root to \c |
|
645 ///v. It is \ref INVALID |
|
646 ///if \c v is unreachable from the root or if \c v=s. The |
|
647 ///shortest path tree used here is equal to the shortest path tree used in |
|
648 ///\ref predNode(Node v). \pre \ref run() must be called before using |
|
649 ///this function. |
|
650 ///\todo predEdge could be a better name. |
|
651 Edge pred(Node v) const { return (*_pred)[v]; } |
|
652 |
|
653 ///Returns the 'previous node' of the shortest path tree. |
|
654 |
|
655 ///For a node \c v it returns the 'previous node' of the shortest path tree, |
|
656 ///i.e. it returns the last but one node from a shortest path from the |
|
657 ///root to \c /v. It is INVALID if \c v is unreachable from the root or if |
|
658 ///\c v=s. The shortest path tree used here is equal to the shortest path |
|
659 ///tree used in \ref pred(Node v). \pre \ref run() must be called before |
|
660 ///using this function. |
|
661 Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
|
662 G->source((*_pred)[v]); } |
|
663 |
|
664 ///Returns a reference to the NodeMap of distances. |
|
665 |
|
666 ///Returns a reference to the NodeMap of distances. \pre \ref run() must |
|
667 ///be called before using this function. |
|
668 const DistMap &distMap() const { return *_dist;} |
|
669 |
|
670 ///Returns a reference to the shortest path tree map. |
|
671 |
|
672 ///Returns a reference to the NodeMap of the edges of the |
|
673 ///shortest path tree. |
|
674 ///\pre \ref run() must be called before using this function. |
|
675 const PredMap &predMap() const { return *_pred;} |
|
676 |
|
677 ///Returns a reference to the map of nodes of shortest paths. |
|
678 |
|
679 ///Returns a reference to the NodeMap of the last but one nodes of the |
|
680 ///shortest path tree. |
|
681 ///\pre \ref run() must be called before using this function. |
|
682 const PredNodeMap &predNodeMap() const { return *_predNode;} |
|
683 |
|
684 ///Checks if a node is reachable from the root. |
|
685 |
|
686 ///Returns \c true if \c v is reachable from the root. |
|
687 ///\warning If the algorithm is started from multiple nodes, |
|
688 ///this function may give false result for the source nodes. |
|
689 ///\pre \ref run() must be called before using this function. |
|
690 /// |
|
691 bool reached(Node v) { return v==source || (*_pred)[v]!=INVALID; } |
|
692 |
|
693 ///@} |
|
694 }; |
|
695 |
|
696 /// Default traits used by \ref DijkstraWizard |
|
697 |
|
698 /// To make it easier to use Dijkstra algorithm we have created a wizard class. |
|
699 /// This \ref DijkstraWizard class needs default traits, as well as the \ref Dijkstra class. |
|
700 /// The \ref DijkstraWizardBase is a class to be the default traits of the |
|
701 /// \ref DijkstraWizard class. |
|
702 template<class GR,class LM> |
|
703 class DijkstraWizardBase : public DijkstraDefaultTraits<GR,LM> |
|
704 { |
|
705 |
|
706 typedef DijkstraDefaultTraits<GR,LM> Base; |
|
707 protected: |
|
708 /// Pointer to the underlying graph. |
|
709 void *_g; |
|
710 /// Pointer to the length map |
|
711 void *_length; |
|
712 ///Pointer to the map of predecessors edges. |
|
713 void *_pred; |
|
714 ///Pointer to the map of predecessors nodes. |
|
715 void *_predNode; |
|
716 ///Pointer to the map of distances. |
|
717 void *_dist; |
|
718 ///Pointer to the source node. |
|
719 void *_source; |
|
720 |
|
721 /// Type of the nodes in the graph. |
|
722 typedef typename Base::Graph::Node Node; |
|
723 |
|
724 public: |
|
725 /// Constructor. |
|
726 |
|
727 /// This constructor does not require parameters, therefore it initiates |
|
728 /// all of the attributes to default values (0, INVALID). |
|
729 DijkstraWizardBase() : _g(0), _length(0), _pred(0), _predNode(0), |
|
730 _dist(0), _source(INVALID) {} |
|
731 |
|
732 /// Constructor. |
|
733 |
|
734 /// This constructor requires some parameters, listed in the parameters list. |
|
735 /// Others are initiated to 0. |
|
736 /// \param g is the initial value of \ref _g |
|
737 /// \param l is the initial value of \ref _length |
|
738 /// \param s is the initial value of \ref _source |
|
739 DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) : |
|
740 _g((void *)&g), _length((void *)&l), _pred(0), _predNode(0), |
|
741 _dist(0), _source((void *)&s) {} |
|
742 |
|
743 }; |
|
744 |
|
745 /// A class to make easier the usage of Dijkstra algorithm |
|
746 |
|
747 /// This class is created to make it easier to use Dijkstra algorithm. |
|
748 /// It uses the functions and features of the plain \ref Dijkstra, |
|
749 /// but it is much more simple to use it. |
|
750 /// |
|
751 /// Simplicity means that the way to change the types defined |
|
752 /// in the traits class is based on functions that returns the new class |
|
753 /// and not on templatable built-in classes. When using the plain \ref Dijkstra |
|
754 /// the new class with the modified type comes from the original class by using the :: |
|
755 /// operator. In the case of \ref DijkstraWizard only a function have to be called and it will |
|
756 /// return the needed class. |
|
757 /// |
|
758 /// It does not have own \ref run method. When its \ref run method is called |
|
759 /// it initiates a plain \ref Dijkstra class, and calls the \ref Dijkstra::run |
|
760 /// method of it. |
|
761 template<class TR> |
|
762 class DijkstraWizard : public TR |
|
763 { |
|
764 typedef TR Base; |
|
765 |
|
766 ///The type of the underlying graph. |
|
767 typedef typename TR::Graph Graph; |
|
768 //\e |
|
769 typedef typename Graph::Node Node; |
|
770 //\e |
|
771 typedef typename Graph::NodeIt NodeIt; |
|
772 //\e |
|
773 typedef typename Graph::Edge Edge; |
|
774 //\e |
|
775 typedef typename Graph::OutEdgeIt OutEdgeIt; |
|
776 |
|
777 ///The type of the map that stores the edge lengths. |
|
778 typedef typename TR::LengthMap LengthMap; |
|
779 ///The type of the length of the edges. |
|
780 typedef typename LengthMap::Value Value; |
|
781 ///\brief The type of the map that stores the last |
|
782 ///edges of the shortest paths. |
|
783 typedef typename TR::PredMap PredMap; |
|
784 ///\brief The type of the map that stores the last but one |
|
785 ///nodes of the shortest paths. |
|
786 typedef typename TR::PredNodeMap PredNodeMap; |
|
787 ///The type of the map that stores the dists of the nodes. |
|
788 typedef typename TR::DistMap DistMap; |
|
789 |
|
790 ///The heap type used by the dijkstra algorithm. |
|
791 typedef typename TR::Heap Heap; |
|
792 public: |
|
793 /// Constructor. |
|
794 DijkstraWizard() : TR() {} |
|
795 |
|
796 /// Constructor that requires parameters. |
|
797 |
|
798 /// Constructor that requires parameters. |
|
799 /// These parameters will be the default values for the traits class. |
|
800 DijkstraWizard(const Graph &g,const LengthMap &l, Node s=INVALID) : |
|
801 TR(g,l,s) {} |
|
802 |
|
803 ///Copy constructor |
|
804 DijkstraWizard(const TR &b) : TR(b) {} |
|
805 |
|
806 ~DijkstraWizard() {} |
|
807 |
|
808 ///Runs Dijkstra algorithm from a given node. |
|
809 |
|
810 ///Runs Dijkstra algorithm from a given node. |
|
811 ///The node can be given by the \ref source function. |
|
812 void run() |
|
813 { |
|
814 if(_source==0) throw UninitializedParameter(); |
|
815 Dijkstra<Graph,LengthMap,TR> Dij(*(Graph*)_g,*(LengthMap*)_length); |
|
816 if(_pred) Dij.predMap(*(PredMap*)_pred); |
|
817 if(_predNode) Dij.predNodeMap(*(PredNodeMap*)_predNode); |
|
818 if(_dist) Dij.distMap(*(DistMap*)_dist); |
|
819 Dij.run(*(Node*)_source); |
|
820 } |
|
821 |
|
822 ///Runs Dijkstra algorithm from the given node. |
|
823 |
|
824 ///Runs Dijkstra algorithm from the given node. |
|
825 ///\param s is the given source. |
|
826 void run(Node s) |
|
827 { |
|
828 _source=(void *)&s; |
|
829 run(); |
|
830 } |
|
831 |
|
832 template<class T> |
|
833 struct DefPredMapBase : public Base { |
|
834 typedef T PredMap; |
|
835 static PredMap *createPredMap(const Graph &G) { return 0; }; |
|
836 DefPredMapBase(const Base &b) : Base(b) {} |
|
837 }; |
|
838 |
|
839 /// \ref named-templ-param "Named parameter" function for setting PredMap type |
|
840 |
|
841 /// \ref named-templ-param "Named parameter" function for setting PredMap type |
|
842 /// |
|
843 template<class T> |
|
844 DijkstraWizard<DefPredMapBase<T> > predMap(const T &t) |
|
845 { |
|
846 _pred=(void *)&t; |
|
847 return DijkstraWizard<DefPredMapBase<T> >(*this); |
|
848 } |
|
849 |
|
850 |
|
851 template<class T> |
|
852 struct DefPredNodeMapBase : public Base { |
|
853 typedef T PredNodeMap; |
|
854 static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; }; |
|
855 DefPredNodeMapBase(const Base &b) : Base(b) {} |
|
856 }; |
|
857 |
|
858 /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type |
|
859 |
|
860 /// \ref named-templ-param "Named parameter" function for setting PredNodeMap type |
|
861 /// |
|
862 template<class T> |
|
863 DijkstraWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t) |
|
864 { |
|
865 _predNode=(void *)&t; |
|
866 return DijkstraWizard<DefPredNodeMapBase<T> >(*this); |
|
867 } |
|
868 |
|
869 template<class T> |
|
870 struct DefDistMapBase : public Base { |
|
871 typedef T DistMap; |
|
872 static DistMap *createDistMap(const Graph &G) { return 0; }; |
|
873 DefDistMapBase(const Base &b) : Base(b) {} |
|
874 }; |
|
875 |
|
876 /// \ref named-templ-param "Named parameter" function for setting DistMap type |
|
877 |
|
878 /// \ref named-templ-param "Named parameter" function for setting DistMap type |
|
879 /// |
|
880 template<class T> |
|
881 DijkstraWizard<DefDistMapBase<T> > distMap(const T &t) |
|
882 { |
|
883 _dist=(void *)&t; |
|
884 return DijkstraWizard<DefDistMapBase<T> >(*this); |
|
885 } |
|
886 |
|
887 /// Sets the source node, from which the Dijkstra algorithm runs. |
|
888 |
|
889 /// Sets the source node, from which the Dijkstra algorithm runs. |
|
890 /// \param s is the source node. |
|
891 DijkstraWizard<TR> &source(Node s) |
|
892 { |
|
893 source=(void *)&s; |
|
894 return *this; |
|
895 } |
|
896 |
|
897 }; |
|
898 |
|
899 ///\e |
|
900 |
|
901 ///\todo Please document... |
|
902 /// |
|
903 template<class GR, class LM> |
|
904 DijkstraWizard<DijkstraWizardBase<GR,LM> > |
|
905 dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID) |
|
906 { |
|
907 return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s); |
|
908 } |
|
909 |
|
910 /// @} |
|
911 |
|
912 } //END OF NAMESPACE LEMON |
|
913 |
|
914 #endif |
|
915 |
|