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/* -*- C++ -*- |
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* |
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* This file is a part of LEMON, a generic C++ optimization library |
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* |
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* Copyright (C) 2003-2008 |
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* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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* (Egervary Research Group on Combinatorial Optimization, EGRES). |
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* |
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* Permission to use, modify and distribute this software is granted |
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* provided that this copyright notice appears in all copies. For |
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* precise terms see the accompanying LICENSE file. |
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* |
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* This software is provided "AS IS" with no warranty of any kind, |
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* express or implied, and with no claim as to its suitability for any |
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* purpose. |
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* |
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*/ |
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|
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#ifndef LEMON_BELLMAN_FORD_H |
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#define LEMON_BELLMAN_FORD_H |
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|
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/// \ingroup shortest_path |
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/// \file |
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/// \brief Bellman-Ford algorithm. |
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|
26 | 26 |
#include <lemon/list_graph.h> |
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#include <lemon/bits/path_dump.h> |
28 | 28 |
#include <lemon/core.h> |
29 | 29 |
#include <lemon/error.h> |
30 | 30 |
#include <lemon/maps.h> |
31 | 31 |
#include <lemon/path.h> |
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|
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#include <limits> |
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|
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namespace lemon { |
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|
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/// \brief Default OperationTraits for the BellmanFord algorithm class. |
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/// |
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/// This operation traits class defines all computational operations |
40 | 40 |
/// and constants that are used in the Bellman-Ford algorithm. |
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/// The default implementation is based on the \c numeric_limits class. |
42 | 42 |
/// If the numeric type does not have infinity value, then the maximum |
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/// value is used as extremal infinity value. |
44 | 44 |
template < |
45 | 45 |
typename V, |
46 | 46 |
bool has_inf = std::numeric_limits<V>::has_infinity> |
47 | 47 |
struct BellmanFordDefaultOperationTraits { |
48 | 48 |
/// \e |
49 | 49 |
typedef V Value; |
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/// \brief Gives back the zero value of the type. |
51 | 51 |
static Value zero() { |
52 | 52 |
return static_cast<Value>(0); |
53 | 53 |
} |
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/// \brief Gives back the positive infinity value of the type. |
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static Value infinity() { |
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return std::numeric_limits<Value>::infinity(); |
57 | 57 |
} |
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/// \brief Gives back the sum of the given two elements. |
59 | 59 |
static Value plus(const Value& left, const Value& right) { |
60 | 60 |
return left + right; |
61 | 61 |
} |
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/// \brief Gives back \c true only if the first value is less than |
63 | 63 |
/// the second. |
64 | 64 |
static bool less(const Value& left, const Value& right) { |
65 | 65 |
return left < right; |
66 | 66 |
} |
67 | 67 |
}; |
68 | 68 |
|
69 | 69 |
template <typename V> |
70 | 70 |
struct BellmanFordDefaultOperationTraits<V, false> { |
71 | 71 |
typedef V Value; |
72 | 72 |
static Value zero() { |
73 | 73 |
return static_cast<Value>(0); |
74 | 74 |
} |
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static Value infinity() { |
76 | 76 |
return std::numeric_limits<Value>::max(); |
77 | 77 |
} |
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static Value plus(const Value& left, const Value& right) { |
79 | 79 |
if (left == infinity() || right == infinity()) return infinity(); |
80 | 80 |
return left + right; |
81 | 81 |
} |
82 | 82 |
static bool less(const Value& left, const Value& right) { |
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return left < right; |
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} |
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}; |
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|
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/// \brief Default traits class of BellmanFord class. |
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/// |
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/// Default traits class of BellmanFord class. |
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/// \param GR The type of the digraph. |
91 | 91 |
/// \param LEN The type of the length map. |
92 | 92 |
template<typename GR, typename LEN> |
93 | 93 |
struct BellmanFordDefaultTraits { |
94 | 94 |
/// The type of the digraph the algorithm runs on. |
95 | 95 |
typedef GR Digraph; |
96 | 96 |
|
97 | 97 |
/// \brief The type of the map that stores the arc lengths. |
98 | 98 |
/// |
99 | 99 |
/// The type of the map that stores the arc lengths. |
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/// It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
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typedef LEN LengthMap; |
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|
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/// The type of the arc lengths. |
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typedef typename LEN::Value Value; |
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|
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/// \brief Operation traits for Bellman-Ford algorithm. |
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/// |
108 | 108 |
/// It defines the used operations and the infinity value for the |
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/// given \c Value type. |
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/// \see BellmanFordDefaultOperationTraits |
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typedef BellmanFordDefaultOperationTraits<Value> OperationTraits; |
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|
113 | 113 |
/// \brief The type of the map that stores the last arcs of the |
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/// shortest paths. |
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/// |
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/// The type of the map that stores the last |
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/// arcs of the shortest paths. |
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/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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typedef typename GR::template NodeMap<typename GR::Arc> PredMap; |
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|
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/// \brief Instantiates a \c PredMap. |
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/// |
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/// This function instantiates a \ref PredMap. |
124 | 124 |
/// \param g is the digraph to which we would like to define the |
125 | 125 |
/// \ref PredMap. |
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static PredMap *createPredMap(const GR& g) { |
127 | 127 |
return new PredMap(g); |
128 | 128 |
} |
129 | 129 |
|
130 | 130 |
/// \brief The type of the map that stores the distances of the nodes. |
131 | 131 |
/// |
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/// The type of the map that stores the distances of the nodes. |
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/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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typedef typename GR::template NodeMap<typename LEN::Value> DistMap; |
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|
136 | 136 |
/// \brief Instantiates a \c DistMap. |
137 | 137 |
/// |
138 | 138 |
/// This function instantiates a \ref DistMap. |
139 | 139 |
/// \param g is the digraph to which we would like to define the |
140 | 140 |
/// \ref DistMap. |
141 | 141 |
static DistMap *createDistMap(const GR& g) { |
142 | 142 |
return new DistMap(g); |
143 | 143 |
} |
144 | 144 |
|
145 | 145 |
}; |
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|
147 | 147 |
/// \brief %BellmanFord algorithm class. |
148 | 148 |
/// |
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/// \ingroup shortest_path |
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/// This class provides an efficient implementation of the Bellman-Ford |
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/// algorithm. The maximum time complexity of the algorithm is |
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/// <tt>O(ne)</tt>. |
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/// |
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/// The Bellman-Ford algorithm solves the single-source shortest path |
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/// problem when the arcs can have negative lengths, but the digraph |
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/// should not contain directed cycles with negative total length. |
157 | 157 |
/// If all arc costs are non-negative, consider to use the Dijkstra |
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/// algorithm instead, since it is more efficient. |
159 | 159 |
/// |
160 | 160 |
/// The arc lengths are passed to the algorithm using a |
161 | 161 |
/// \ref concepts::ReadMap "ReadMap", so it is easy to change it to any |
162 | 162 |
/// kind of length. The type of the length values is determined by the |
163 | 163 |
/// \ref concepts::ReadMap::Value "Value" type of the length map. |
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/// |
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/// There is also a \ref bellmanFord() "function-type interface" for the |
166 | 166 |
/// Bellman-Ford algorithm, which is convenient in the simplier cases and |
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/// it can be used easier. |
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/// |
169 | 169 |
/// \tparam GR The type of the digraph the algorithm runs on. |
170 | 170 |
/// The default type is \ref ListDigraph. |
171 | 171 |
/// \tparam LEN A \ref concepts::ReadMap "readable" arc map that specifies |
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/// the lengths of the arcs. The default map type is |
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/// \ref concepts::Digraph::ArcMap "GR::ArcMap<int>". |
174 |
/// \tparam TR The traits class that defines various types used by the |
|
175 |
/// algorithm. By default, it is \ref BellmanFordDefaultTraits |
|
176 |
/// "BellmanFordDefaultTraits<GR, LEN>". |
|
177 |
/// In most cases, this parameter should not be set directly, |
|
178 |
/// consider to use the named template parameters instead. |
|
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#ifdef DOXYGEN |
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template <typename GR, typename LEN, typename TR> |
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#else |
177 | 182 |
template <typename GR=ListDigraph, |
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typename LEN=typename GR::template ArcMap<int>, |
179 | 184 |
typename TR=BellmanFordDefaultTraits<GR,LEN> > |
180 | 185 |
#endif |
181 | 186 |
class BellmanFord { |
182 | 187 |
public: |
183 | 188 |
|
184 | 189 |
///The type of the underlying digraph. |
185 | 190 |
typedef typename TR::Digraph Digraph; |
186 | 191 |
|
187 | 192 |
/// \brief The type of the arc lengths. |
188 | 193 |
typedef typename TR::LengthMap::Value Value; |
189 | 194 |
/// \brief The type of the map that stores the arc lengths. |
190 | 195 |
typedef typename TR::LengthMap LengthMap; |
191 | 196 |
/// \brief The type of the map that stores the last |
192 | 197 |
/// arcs of the shortest paths. |
193 | 198 |
typedef typename TR::PredMap PredMap; |
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/// \brief The type of the map that stores the distances of the nodes. |
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typedef typename TR::DistMap DistMap; |
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/// The type of the paths. |
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typedef PredMapPath<Digraph, PredMap> Path; |
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///\brief The \ref BellmanFordDefaultOperationTraits |
199 | 204 |
/// "operation traits class" of the algorithm. |
200 | 205 |
typedef typename TR::OperationTraits OperationTraits; |
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|
202 | 207 |
///The \ref BellmanFordDefaultTraits "traits class" of the algorithm. |
203 | 208 |
typedef TR Traits; |
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|
205 | 210 |
private: |
206 | 211 |
|
207 | 212 |
typedef typename Digraph::Node Node; |
208 | 213 |
typedef typename Digraph::NodeIt NodeIt; |
209 | 214 |
typedef typename Digraph::Arc Arc; |
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typedef typename Digraph::OutArcIt OutArcIt; |
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|
212 | 217 |
// Pointer to the underlying digraph. |
213 | 218 |
const Digraph *_gr; |
214 | 219 |
// Pointer to the length map |
215 | 220 |
const LengthMap *_length; |
216 | 221 |
// Pointer to the map of predecessors arcs. |
217 | 222 |
PredMap *_pred; |
218 | 223 |
// Indicates if _pred is locally allocated (true) or not. |
219 | 224 |
bool _local_pred; |
220 | 225 |
// Pointer to the map of distances. |
221 | 226 |
DistMap *_dist; |
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// Indicates if _dist is locally allocated (true) or not. |
223 | 228 |
bool _local_dist; |
224 | 229 |
|
225 | 230 |
typedef typename Digraph::template NodeMap<bool> MaskMap; |
226 | 231 |
MaskMap *_mask; |
227 | 232 |
|
228 | 233 |
std::vector<Node> _process; |
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|
230 | 235 |
// Creates the maps if necessary. |
231 | 236 |
void create_maps() { |
232 | 237 |
if(!_pred) { |
233 | 238 |
_local_pred = true; |
234 | 239 |
_pred = Traits::createPredMap(*_gr); |
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} |
236 | 241 |
if(!_dist) { |
237 | 242 |
_local_dist = true; |
238 | 243 |
_dist = Traits::createDistMap(*_gr); |
239 | 244 |
} |
240 | 245 |
if(!_mask) { |
241 | 246 |
_mask = new MaskMap(*_gr); |
242 | 247 |
} |
243 | 248 |
} |
244 | 249 |
|
245 | 250 |
public : |
246 | 251 |
|
247 | 252 |
typedef BellmanFord Create; |
248 | 253 |
|
249 | 254 |
/// \name Named Template Parameters |
250 | 255 |
|
251 | 256 |
///@{ |
252 | 257 |
|
253 | 258 |
template <class T> |
254 | 259 |
struct SetPredMapTraits : public Traits { |
255 | 260 |
typedef T PredMap; |
256 | 261 |
static PredMap *createPredMap(const Digraph&) { |
257 | 262 |
LEMON_ASSERT(false, "PredMap is not initialized"); |
258 | 263 |
return 0; // ignore warnings |
259 | 264 |
} |
260 | 265 |
}; |
261 | 266 |
|
262 | 267 |
/// \brief \ref named-templ-param "Named parameter" for setting |
263 | 268 |
/// \c PredMap type. |
264 | 269 |
/// |
265 | 270 |
/// \ref named-templ-param "Named parameter" for setting |
266 | 271 |
/// \c PredMap type. |
267 | 272 |
/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
268 | 273 |
template <class T> |
269 | 274 |
struct SetPredMap |
270 | 275 |
: public BellmanFord< Digraph, LengthMap, SetPredMapTraits<T> > { |
271 | 276 |
typedef BellmanFord< Digraph, LengthMap, SetPredMapTraits<T> > Create; |
272 | 277 |
}; |
273 | 278 |
|
274 | 279 |
template <class T> |
275 | 280 |
struct SetDistMapTraits : public Traits { |
276 | 281 |
typedef T DistMap; |
277 | 282 |
static DistMap *createDistMap(const Digraph&) { |
278 | 283 |
LEMON_ASSERT(false, "DistMap is not initialized"); |
279 | 284 |
return 0; // ignore warnings |
280 | 285 |
} |
281 | 286 |
}; |
282 | 287 |
|
283 | 288 |
/// \brief \ref named-templ-param "Named parameter" for setting |
284 | 289 |
/// \c DistMap type. |
285 | 290 |
/// |
286 | 291 |
/// \ref named-templ-param "Named parameter" for setting |
287 | 292 |
/// \c DistMap type. |
288 | 293 |
/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
289 | 294 |
template <class T> |
290 | 295 |
struct SetDistMap |
291 | 296 |
: public BellmanFord< Digraph, LengthMap, SetDistMapTraits<T> > { |
292 | 297 |
typedef BellmanFord< Digraph, LengthMap, SetDistMapTraits<T> > Create; |
293 | 298 |
}; |
294 | 299 |
|
295 | 300 |
template <class T> |
296 | 301 |
struct SetOperationTraitsTraits : public Traits { |
297 | 302 |
typedef T OperationTraits; |
298 | 303 |
}; |
299 | 304 |
|
300 | 305 |
/// \brief \ref named-templ-param "Named parameter" for setting |
301 | 306 |
/// \c OperationTraits type. |
302 | 307 |
/// |
303 | 308 |
/// \ref named-templ-param "Named parameter" for setting |
304 | 309 |
/// \c OperationTraits type. |
305 | 310 |
/// For more information, see \ref BellmanFordDefaultOperationTraits. |
306 | 311 |
template <class T> |
307 | 312 |
struct SetOperationTraits |
308 | 313 |
: public BellmanFord< Digraph, LengthMap, SetOperationTraitsTraits<T> > { |
309 | 314 |
typedef BellmanFord< Digraph, LengthMap, SetOperationTraitsTraits<T> > |
310 | 315 |
Create; |
311 | 316 |
}; |
312 | 317 |
|
313 | 318 |
///@} |
314 | 319 |
|
315 | 320 |
protected: |
316 | 321 |
|
317 | 322 |
BellmanFord() {} |
318 | 323 |
|
319 | 324 |
public: |
320 | 325 |
|
321 | 326 |
/// \brief Constructor. |
322 | 327 |
/// |
323 | 328 |
/// Constructor. |
324 | 329 |
/// \param g The digraph the algorithm runs on. |
325 | 330 |
/// \param length The length map used by the algorithm. |
326 | 331 |
BellmanFord(const Digraph& g, const LengthMap& length) : |
327 | 332 |
_gr(&g), _length(&length), |
328 | 333 |
_pred(0), _local_pred(false), |
329 | 334 |
_dist(0), _local_dist(false), _mask(0) {} |
330 | 335 |
|
331 | 336 |
///Destructor. |
332 | 337 |
~BellmanFord() { |
333 | 338 |
if(_local_pred) delete _pred; |
334 | 339 |
if(_local_dist) delete _dist; |
335 | 340 |
if(_mask) delete _mask; |
336 | 341 |
} |
337 | 342 |
|
338 | 343 |
/// \brief Sets the length map. |
339 | 344 |
/// |
340 | 345 |
/// Sets the length map. |
341 | 346 |
/// \return <tt>(*this)</tt> |
342 | 347 |
BellmanFord &lengthMap(const LengthMap &map) { |
343 | 348 |
_length = ↦ |
344 | 349 |
return *this; |
345 | 350 |
} |
346 | 351 |
|
347 | 352 |
/// \brief Sets the map that stores the predecessor arcs. |
348 | 353 |
/// |
349 | 354 |
/// Sets the map that stores the predecessor arcs. |
350 | 355 |
/// If you don't use this function before calling \ref run() |
351 | 356 |
/// or \ref init(), an instance will be allocated automatically. |
352 | 357 |
/// The destructor deallocates this automatically allocated map, |
353 | 358 |
/// of course. |
354 | 359 |
/// \return <tt>(*this)</tt> |
355 | 360 |
BellmanFord &predMap(PredMap &map) { |
356 | 361 |
if(_local_pred) { |
357 | 362 |
delete _pred; |
358 | 363 |
_local_pred=false; |
359 | 364 |
} |
360 | 365 |
_pred = ↦ |
361 | 366 |
return *this; |
362 | 367 |
} |
363 | 368 |
|
364 | 369 |
/// \brief Sets the map that stores the distances of the nodes. |
365 | 370 |
/// |
366 | 371 |
/// Sets the map that stores the distances of the nodes calculated |
367 | 372 |
/// by the algorithm. |
368 | 373 |
/// If you don't use this function before calling \ref run() |
369 | 374 |
/// or \ref init(), an instance will be allocated automatically. |
370 | 375 |
/// The destructor deallocates this automatically allocated map, |
371 | 376 |
/// of course. |
372 | 377 |
/// \return <tt>(*this)</tt> |
373 | 378 |
BellmanFord &distMap(DistMap &map) { |
374 | 379 |
if(_local_dist) { |
375 | 380 |
delete _dist; |
376 | 381 |
_local_dist=false; |
377 | 382 |
} |
378 | 383 |
_dist = ↦ |
379 | 384 |
return *this; |
380 | 385 |
} |
381 | 386 |
|
382 | 387 |
/// \name Execution Control |
383 | 388 |
/// The simplest way to execute the Bellman-Ford algorithm is to use |
384 | 389 |
/// one of the member functions called \ref run().\n |
385 | 390 |
/// If you need better control on the execution, you have to call |
386 | 391 |
/// \ref init() first, then you can add several source nodes |
387 | 392 |
/// with \ref addSource(). Finally the actual path computation can be |
388 | 393 |
/// performed with \ref start(), \ref checkedStart() or |
389 | 394 |
/// \ref limitedStart(). |
390 | 395 |
|
391 | 396 |
///@{ |
392 | 397 |
|
393 | 398 |
/// \brief Initializes the internal data structures. |
394 | 399 |
/// |
395 | 400 |
/// Initializes the internal data structures. The optional parameter |
396 | 401 |
/// is the initial distance of each node. |
397 | 402 |
void init(const Value value = OperationTraits::infinity()) { |
398 | 403 |
create_maps(); |
399 | 404 |
for (NodeIt it(*_gr); it != INVALID; ++it) { |
400 | 405 |
_pred->set(it, INVALID); |
401 | 406 |
_dist->set(it, value); |
402 | 407 |
} |
403 | 408 |
_process.clear(); |
404 | 409 |
if (OperationTraits::less(value, OperationTraits::infinity())) { |
405 | 410 |
for (NodeIt it(*_gr); it != INVALID; ++it) { |
406 | 411 |
_process.push_back(it); |
407 | 412 |
_mask->set(it, true); |
408 | 413 |
} |
409 | 414 |
} else { |
410 | 415 |
for (NodeIt it(*_gr); it != INVALID; ++it) { |
411 | 416 |
_mask->set(it, false); |
412 | 417 |
} |
413 | 418 |
} |
414 | 419 |
} |
415 | 420 |
|
416 | 421 |
/// \brief Adds a new source node. |
417 | 422 |
/// |
418 | 423 |
/// This function adds a new source node. The optional second parameter |
419 | 424 |
/// is the initial distance of the node. |
420 | 425 |
void addSource(Node source, Value dst = OperationTraits::zero()) { |
421 | 426 |
_dist->set(source, dst); |
422 | 427 |
if (!(*_mask)[source]) { |
423 | 428 |
_process.push_back(source); |
424 | 429 |
_mask->set(source, true); |
425 | 430 |
} |
426 | 431 |
} |
427 | 432 |
|
428 | 433 |
/// \brief Executes one round from the Bellman-Ford algorithm. |
429 | 434 |
/// |
430 | 435 |
/// If the algoritm calculated the distances in the previous round |
431 | 436 |
/// exactly for the paths of at most \c k arcs, then this function |
432 | 437 |
/// will calculate the distances exactly for the paths of at most |
433 | 438 |
/// <tt>k+1</tt> arcs. Performing \c k iterations using this function |
434 | 439 |
/// calculates the shortest path distances exactly for the paths |
435 | 440 |
/// consisting of at most \c k arcs. |
436 | 441 |
/// |
437 | 442 |
/// \warning The paths with limited arc number cannot be retrieved |
438 | 443 |
/// easily with \ref path() or \ref predArc() functions. If you also |
439 | 444 |
/// need the shortest paths and not only the distances, you should |
440 | 445 |
/// store the \ref predMap() "predecessor map" after each iteration |
441 | 446 |
/// and build the path manually. |
442 | 447 |
/// |
443 | 448 |
/// \return \c true when the algorithm have not found more shorter |
444 | 449 |
/// paths. |
445 | 450 |
/// |
446 | 451 |
/// \see ActiveIt |
447 | 452 |
bool processNextRound() { |
448 | 453 |
for (int i = 0; i < int(_process.size()); ++i) { |
449 | 454 |
_mask->set(_process[i], false); |
450 | 455 |
} |
451 | 456 |
std::vector<Node> nextProcess; |
452 | 457 |
std::vector<Value> values(_process.size()); |
453 | 458 |
for (int i = 0; i < int(_process.size()); ++i) { |
454 | 459 |
values[i] = (*_dist)[_process[i]]; |
455 | 460 |
} |
456 | 461 |
for (int i = 0; i < int(_process.size()); ++i) { |
457 | 462 |
for (OutArcIt it(*_gr, _process[i]); it != INVALID; ++it) { |
458 | 463 |
Node target = _gr->target(it); |
459 | 464 |
Value relaxed = OperationTraits::plus(values[i], (*_length)[it]); |
460 | 465 |
if (OperationTraits::less(relaxed, (*_dist)[target])) { |
461 | 466 |
_pred->set(target, it); |
462 | 467 |
_dist->set(target, relaxed); |
463 | 468 |
if (!(*_mask)[target]) { |
464 | 469 |
_mask->set(target, true); |
465 | 470 |
nextProcess.push_back(target); |
466 | 471 |
} |
467 | 472 |
} |
468 | 473 |
} |
469 | 474 |
} |
470 | 475 |
_process.swap(nextProcess); |
471 | 476 |
return _process.empty(); |
472 | 477 |
} |
473 | 478 |
|
474 | 479 |
/// \brief Executes one weak round from the Bellman-Ford algorithm. |
475 | 480 |
/// |
476 | 481 |
/// If the algorithm calculated the distances in the previous round |
477 | 482 |
/// at least for the paths of at most \c k arcs, then this function |
478 | 483 |
/// will calculate the distances at least for the paths of at most |
479 | 484 |
/// <tt>k+1</tt> arcs. |
480 | 485 |
/// This function does not make it possible to calculate the shortest |
481 | 486 |
/// path distances exactly for paths consisting of at most \c k arcs, |
482 | 487 |
/// this is why it is called weak round. |
483 | 488 |
/// |
484 | 489 |
/// \return \c true when the algorithm have not found more shorter |
485 | 490 |
/// paths. |
486 | 491 |
/// |
487 | 492 |
/// \see ActiveIt |
488 | 493 |
bool processNextWeakRound() { |
489 | 494 |
for (int i = 0; i < int(_process.size()); ++i) { |
490 | 495 |
_mask->set(_process[i], false); |
491 | 496 |
} |
492 | 497 |
std::vector<Node> nextProcess; |
493 | 498 |
for (int i = 0; i < int(_process.size()); ++i) { |
494 | 499 |
for (OutArcIt it(*_gr, _process[i]); it != INVALID; ++it) { |
495 | 500 |
Node target = _gr->target(it); |
496 | 501 |
Value relaxed = |
497 | 502 |
OperationTraits::plus((*_dist)[_process[i]], (*_length)[it]); |
498 | 503 |
if (OperationTraits::less(relaxed, (*_dist)[target])) { |
499 | 504 |
_pred->set(target, it); |
500 | 505 |
_dist->set(target, relaxed); |
501 | 506 |
if (!(*_mask)[target]) { |
502 | 507 |
_mask->set(target, true); |
503 | 508 |
nextProcess.push_back(target); |
504 | 509 |
} |
505 | 510 |
} |
506 | 511 |
} |
507 | 512 |
} |
508 | 513 |
_process.swap(nextProcess); |
509 | 514 |
return _process.empty(); |
510 | 515 |
} |
511 | 516 |
|
512 | 517 |
/// \brief Executes the algorithm. |
513 | 518 |
/// |
514 | 519 |
/// Executes the algorithm. |
515 | 520 |
/// |
516 | 521 |
/// This method runs the Bellman-Ford algorithm from the root node(s) |
517 | 522 |
/// in order to compute the shortest path to each node. |
518 | 523 |
/// |
519 | 524 |
/// The algorithm computes |
520 | 525 |
/// - the shortest path tree (forest), |
521 | 526 |
/// - the distance of each node from the root(s). |
522 | 527 |
/// |
523 | 528 |
/// \pre init() must be called and at least one root node should be |
524 | 529 |
/// added with addSource() before using this function. |
525 | 530 |
void start() { |
526 | 531 |
int num = countNodes(*_gr) - 1; |
527 | 532 |
for (int i = 0; i < num; ++i) { |
528 | 533 |
if (processNextWeakRound()) break; |
529 | 534 |
} |
530 | 535 |
} |
531 | 536 |
|
532 | 537 |
/// \brief Executes the algorithm and checks the negative cycles. |
533 | 538 |
/// |
534 | 539 |
/// Executes the algorithm and checks the negative cycles. |
535 | 540 |
/// |
536 | 541 |
/// This method runs the Bellman-Ford algorithm from the root node(s) |
537 | 542 |
/// in order to compute the shortest path to each node and also checks |
538 | 543 |
/// if the digraph contains cycles with negative total length. |
539 | 544 |
/// |
540 | 545 |
/// The algorithm computes |
541 | 546 |
/// - the shortest path tree (forest), |
542 | 547 |
/// - the distance of each node from the root(s). |
543 | 548 |
/// |
544 | 549 |
/// \return \c false if there is a negative cycle in the digraph. |
545 | 550 |
/// |
546 | 551 |
/// \pre init() must be called and at least one root node should be |
547 | 552 |
/// added with addSource() before using this function. |
548 | 553 |
bool checkedStart() { |
549 | 554 |
int num = countNodes(*_gr); |
550 | 555 |
for (int i = 0; i < num; ++i) { |
551 | 556 |
if (processNextWeakRound()) return true; |
552 | 557 |
} |
553 | 558 |
return _process.empty(); |
554 | 559 |
} |
555 | 560 |
|
556 | 561 |
/// \brief Executes the algorithm with arc number limit. |
557 | 562 |
/// |
558 | 563 |
/// Executes the algorithm with arc number limit. |
559 | 564 |
/// |
560 | 565 |
/// This method runs the Bellman-Ford algorithm from the root node(s) |
561 | 566 |
/// in order to compute the shortest path distance for each node |
562 | 567 |
/// using only the paths consisting of at most \c num arcs. |
563 | 568 |
/// |
564 | 569 |
/// The algorithm computes |
565 | 570 |
/// - the limited distance of each node from the root(s), |
566 | 571 |
/// - the predecessor arc for each node. |
567 | 572 |
/// |
568 | 573 |
/// \warning The paths with limited arc number cannot be retrieved |
569 | 574 |
/// easily with \ref path() or \ref predArc() functions. If you also |
570 | 575 |
/// need the shortest paths and not only the distances, you should |
571 | 576 |
/// store the \ref predMap() "predecessor map" after each iteration |
572 | 577 |
/// and build the path manually. |
573 | 578 |
/// |
574 | 579 |
/// \pre init() must be called and at least one root node should be |
575 | 580 |
/// added with addSource() before using this function. |
576 | 581 |
void limitedStart(int num) { |
577 | 582 |
for (int i = 0; i < num; ++i) { |
578 | 583 |
if (processNextRound()) break; |
579 | 584 |
} |
580 | 585 |
} |
581 | 586 |
|
582 | 587 |
/// \brief Runs the algorithm from the given root node. |
583 | 588 |
/// |
584 | 589 |
/// This method runs the Bellman-Ford algorithm from the given root |
585 | 590 |
/// node \c s in order to compute the shortest path to each node. |
586 | 591 |
/// |
587 | 592 |
/// The algorithm computes |
588 | 593 |
/// - the shortest path tree (forest), |
589 | 594 |
/// - the distance of each node from the root(s). |
590 | 595 |
/// |
591 | 596 |
/// \note bf.run(s) is just a shortcut of the following code. |
592 | 597 |
/// \code |
593 | 598 |
/// bf.init(); |
594 | 599 |
/// bf.addSource(s); |
595 | 600 |
/// bf.start(); |
596 | 601 |
/// \endcode |
597 | 602 |
void run(Node s) { |
598 | 603 |
init(); |
599 | 604 |
addSource(s); |
600 | 605 |
start(); |
601 | 606 |
} |
602 | 607 |
|
603 | 608 |
/// \brief Runs the algorithm from the given root node with arc |
604 | 609 |
/// number limit. |
605 | 610 |
/// |
606 | 611 |
/// This method runs the Bellman-Ford algorithm from the given root |
607 | 612 |
/// node \c s in order to compute the shortest path distance for each |
608 | 613 |
/// node using only the paths consisting of at most \c num arcs. |
609 | 614 |
/// |
610 | 615 |
/// The algorithm computes |
611 | 616 |
/// - the limited distance of each node from the root(s), |
612 | 617 |
/// - the predecessor arc for each node. |
613 | 618 |
/// |
614 | 619 |
/// \warning The paths with limited arc number cannot be retrieved |
615 | 620 |
/// easily with \ref path() or \ref predArc() functions. If you also |
616 | 621 |
/// need the shortest paths and not only the distances, you should |
617 | 622 |
/// store the \ref predMap() "predecessor map" after each iteration |
618 | 623 |
/// and build the path manually. |
619 | 624 |
/// |
620 | 625 |
/// \note bf.run(s, num) is just a shortcut of the following code. |
621 | 626 |
/// \code |
622 | 627 |
/// bf.init(); |
623 | 628 |
/// bf.addSource(s); |
624 | 629 |
/// bf.limitedStart(num); |
625 | 630 |
/// \endcode |
626 | 631 |
void run(Node s, int num) { |
627 | 632 |
init(); |
628 | 633 |
addSource(s); |
629 | 634 |
limitedStart(num); |
630 | 635 |
} |
631 | 636 |
|
632 | 637 |
///@} |
633 | 638 |
|
634 | 639 |
/// \brief LEMON iterator for getting the active nodes. |
635 | 640 |
/// |
636 | 641 |
/// This class provides a common style LEMON iterator that traverses |
637 | 642 |
/// the active nodes of the Bellman-Ford algorithm after the last |
638 | 643 |
/// phase. These nodes should be checked in the next phase to |
639 | 644 |
/// find augmenting arcs outgoing from them. |
640 | 645 |
class ActiveIt { |
641 | 646 |
public: |
642 | 647 |
|
643 | 648 |
/// \brief Constructor. |
644 | 649 |
/// |
645 | 650 |
/// Constructor for getting the active nodes of the given BellmanFord |
646 | 651 |
/// instance. |
647 | 652 |
ActiveIt(const BellmanFord& algorithm) : _algorithm(&algorithm) |
648 | 653 |
{ |
649 | 654 |
_index = _algorithm->_process.size() - 1; |
650 | 655 |
} |
651 | 656 |
|
652 | 657 |
/// \brief Invalid constructor. |
653 | 658 |
/// |
654 | 659 |
/// Invalid constructor. |
655 | 660 |
ActiveIt(Invalid) : _algorithm(0), _index(-1) {} |
656 | 661 |
|
657 | 662 |
/// \brief Conversion to \c Node. |
658 | 663 |
/// |
659 | 664 |
/// Conversion to \c Node. |
660 | 665 |
operator Node() const { |
661 | 666 |
return _index >= 0 ? _algorithm->_process[_index] : INVALID; |
662 | 667 |
} |
663 | 668 |
|
664 | 669 |
/// \brief Increment operator. |
665 | 670 |
/// |
666 | 671 |
/// Increment operator. |
667 | 672 |
ActiveIt& operator++() { |
668 | 673 |
--_index; |
669 | 674 |
return *this; |
670 | 675 |
} |
671 | 676 |
|
672 | 677 |
bool operator==(const ActiveIt& it) const { |
673 | 678 |
return static_cast<Node>(*this) == static_cast<Node>(it); |
674 | 679 |
} |
675 | 680 |
bool operator!=(const ActiveIt& it) const { |
676 | 681 |
return static_cast<Node>(*this) != static_cast<Node>(it); |
677 | 682 |
} |
678 | 683 |
bool operator<(const ActiveIt& it) const { |
679 | 684 |
return static_cast<Node>(*this) < static_cast<Node>(it); |
680 | 685 |
} |
681 | 686 |
|
682 | 687 |
private: |
683 | 688 |
const BellmanFord* _algorithm; |
684 | 689 |
int _index; |
685 | 690 |
}; |
686 | 691 |
|
687 | 692 |
/// \name Query Functions |
688 | 693 |
/// The result of the Bellman-Ford algorithm can be obtained using these |
689 | 694 |
/// functions.\n |
690 | 695 |
/// Either \ref run() or \ref init() should be called before using them. |
691 | 696 |
|
692 | 697 |
///@{ |
693 | 698 |
|
694 | 699 |
/// \brief The shortest path to the given node. |
695 | 700 |
/// |
696 | 701 |
/// Gives back the shortest path to the given node from the root(s). |
697 | 702 |
/// |
698 | 703 |
/// \warning \c t should be reached from the root(s). |
699 | 704 |
/// |
700 | 705 |
/// \pre Either \ref run() or \ref init() must be called before |
701 | 706 |
/// using this function. |
702 | 707 |
Path path(Node t) const |
703 | 708 |
{ |
704 | 709 |
return Path(*_gr, *_pred, t); |
705 | 710 |
} |
706 | 711 |
|
707 | 712 |
/// \brief The distance of the given node from the root(s). |
708 | 713 |
/// |
709 | 714 |
/// Returns the distance of the given node from the root(s). |
710 | 715 |
/// |
711 | 716 |
/// \warning If node \c v is not reached from the root(s), then |
712 | 717 |
/// the return value of this function is undefined. |
713 | 718 |
/// |
714 | 719 |
/// \pre Either \ref run() or \ref init() must be called before |
715 | 720 |
/// using this function. |
716 | 721 |
Value dist(Node v) const { return (*_dist)[v]; } |
717 | 722 |
|
718 | 723 |
/// \brief Returns the 'previous arc' of the shortest path tree for |
719 | 724 |
/// the given node. |
720 | 725 |
/// |
721 | 726 |
/// This function returns the 'previous arc' of the shortest path |
722 | 727 |
/// tree for node \c v, i.e. it returns the last arc of a |
723 | 728 |
/// shortest path from a root to \c v. It is \c INVALID if \c v |
724 | 729 |
/// is not reached from the root(s) or if \c v is a root. |
725 | 730 |
/// |
726 | 731 |
/// The shortest path tree used here is equal to the shortest path |
727 | 732 |
/// tree used in \ref predNode() and \ref predMap(). |
728 | 733 |
/// |
729 | 734 |
/// \pre Either \ref run() or \ref init() must be called before |
730 | 735 |
/// using this function. |
731 | 736 |
Arc predArc(Node v) const { return (*_pred)[v]; } |
732 | 737 |
|
733 | 738 |
/// \brief Returns the 'previous node' of the shortest path tree for |
734 | 739 |
/// the given node. |
735 | 740 |
/// |
736 | 741 |
/// This function returns the 'previous node' of the shortest path |
737 | 742 |
/// tree for node \c v, i.e. it returns the last but one node of |
738 | 743 |
/// a shortest path from a root to \c v. It is \c INVALID if \c v |
739 | 744 |
/// is not reached from the root(s) or if \c v is a root. |
740 | 745 |
/// |
741 | 746 |
/// The shortest path tree used here is equal to the shortest path |
742 | 747 |
/// tree used in \ref predArc() and \ref predMap(). |
743 | 748 |
/// |
744 | 749 |
/// \pre Either \ref run() or \ref init() must be called before |
745 | 750 |
/// using this function. |
746 | 751 |
Node predNode(Node v) const { |
747 | 752 |
return (*_pred)[v] == INVALID ? INVALID : _gr->source((*_pred)[v]); |
748 | 753 |
} |
749 | 754 |
|
750 | 755 |
/// \brief Returns a const reference to the node map that stores the |
751 | 756 |
/// distances of the nodes. |
752 | 757 |
/// |
753 | 758 |
/// Returns a const reference to the node map that stores the distances |
754 | 759 |
/// of the nodes calculated by the algorithm. |
755 | 760 |
/// |
756 | 761 |
/// \pre Either \ref run() or \ref init() must be called before |
757 | 762 |
/// using this function. |
758 | 763 |
const DistMap &distMap() const { return *_dist;} |
759 | 764 |
|
760 | 765 |
/// \brief Returns a const reference to the node map that stores the |
761 | 766 |
/// predecessor arcs. |
762 | 767 |
/// |
763 | 768 |
/// Returns a const reference to the node map that stores the predecessor |
764 | 769 |
/// arcs, which form the shortest path tree (forest). |
765 | 770 |
/// |
766 | 771 |
/// \pre Either \ref run() or \ref init() must be called before |
767 | 772 |
/// using this function. |
768 | 773 |
const PredMap &predMap() const { return *_pred; } |
769 | 774 |
|
770 | 775 |
/// \brief Checks if a node is reached from the root(s). |
771 | 776 |
/// |
772 | 777 |
/// Returns \c true if \c v is reached from the root(s). |
773 | 778 |
/// |
774 | 779 |
/// \pre Either \ref run() or \ref init() must be called before |
775 | 780 |
/// using this function. |
776 | 781 |
bool reached(Node v) const { |
777 | 782 |
return (*_dist)[v] != OperationTraits::infinity(); |
778 | 783 |
} |
779 | 784 |
|
780 | 785 |
/// \brief Gives back a negative cycle. |
781 | 786 |
/// |
782 | 787 |
/// This function gives back a directed cycle with negative total |
783 | 788 |
/// length if the algorithm has already found one. |
784 | 789 |
/// Otherwise it gives back an empty path. |
785 | 790 |
lemon::Path<Digraph> negativeCycle() const { |
786 | 791 |
typename Digraph::template NodeMap<int> state(*_gr, -1); |
787 | 792 |
lemon::Path<Digraph> cycle; |
788 | 793 |
for (int i = 0; i < int(_process.size()); ++i) { |
789 | 794 |
if (state[_process[i]] != -1) continue; |
790 | 795 |
for (Node v = _process[i]; (*_pred)[v] != INVALID; |
791 | 796 |
v = _gr->source((*_pred)[v])) { |
792 | 797 |
if (state[v] == i) { |
793 | 798 |
cycle.addFront((*_pred)[v]); |
794 | 799 |
for (Node u = _gr->source((*_pred)[v]); u != v; |
795 | 800 |
u = _gr->source((*_pred)[u])) { |
796 | 801 |
cycle.addFront((*_pred)[u]); |
797 | 802 |
} |
798 | 803 |
return cycle; |
799 | 804 |
} |
800 | 805 |
else if (state[v] >= 0) { |
801 | 806 |
break; |
802 | 807 |
} |
803 | 808 |
state[v] = i; |
804 | 809 |
} |
805 | 810 |
} |
806 | 811 |
return cycle; |
807 | 812 |
} |
808 | 813 |
|
809 | 814 |
///@} |
810 | 815 |
}; |
811 | 816 |
|
812 | 817 |
/// \brief Default traits class of bellmanFord() function. |
813 | 818 |
/// |
814 | 819 |
/// Default traits class of bellmanFord() function. |
815 | 820 |
/// \tparam GR The type of the digraph. |
816 | 821 |
/// \tparam LEN The type of the length map. |
817 | 822 |
template <typename GR, typename LEN> |
818 | 823 |
struct BellmanFordWizardDefaultTraits { |
819 | 824 |
/// The type of the digraph the algorithm runs on. |
820 | 825 |
typedef GR Digraph; |
821 | 826 |
|
822 | 827 |
/// \brief The type of the map that stores the arc lengths. |
823 | 828 |
/// |
824 | 829 |
/// The type of the map that stores the arc lengths. |
825 | 830 |
/// It must meet the \ref concepts::ReadMap "ReadMap" concept. |
826 | 831 |
typedef LEN LengthMap; |
827 | 832 |
|
828 | 833 |
/// The type of the arc lengths. |
829 | 834 |
typedef typename LEN::Value Value; |
830 | 835 |
|
831 | 836 |
/// \brief Operation traits for Bellman-Ford algorithm. |
832 | 837 |
/// |
833 | 838 |
/// It defines the used operations and the infinity value for the |
834 | 839 |
/// given \c Value type. |
835 | 840 |
/// \see BellmanFordDefaultOperationTraits |
836 | 841 |
typedef BellmanFordDefaultOperationTraits<Value> OperationTraits; |
837 | 842 |
|
838 | 843 |
/// \brief The type of the map that stores the last |
839 | 844 |
/// arcs of the shortest paths. |
840 | 845 |
/// |
841 | 846 |
/// The type of the map that stores the last arcs of the shortest paths. |
842 | 847 |
/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
843 | 848 |
typedef typename GR::template NodeMap<typename GR::Arc> PredMap; |
844 | 849 |
|
845 | 850 |
/// \brief Instantiates a \c PredMap. |
846 | 851 |
/// |
847 | 852 |
/// This function instantiates a \ref PredMap. |
848 | 853 |
/// \param g is the digraph to which we would like to define the |
849 | 854 |
/// \ref PredMap. |
850 | 855 |
static PredMap *createPredMap(const GR &g) { |
851 | 856 |
return new PredMap(g); |
852 | 857 |
} |
853 | 858 |
|
854 | 859 |
/// \brief The type of the map that stores the distances of the nodes. |
855 | 860 |
/// |
856 | 861 |
/// The type of the map that stores the distances of the nodes. |
857 | 862 |
/// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
858 | 863 |
typedef typename GR::template NodeMap<Value> DistMap; |
859 | 864 |
|
860 | 865 |
/// \brief Instantiates a \c DistMap. |
861 | 866 |
/// |
862 | 867 |
/// This function instantiates a \ref DistMap. |
863 | 868 |
/// \param g is the digraph to which we would like to define the |
864 | 869 |
/// \ref DistMap. |
865 | 870 |
static DistMap *createDistMap(const GR &g) { |
866 | 871 |
return new DistMap(g); |
867 | 872 |
} |
868 | 873 |
|
869 | 874 |
///The type of the shortest paths. |
870 | 875 |
|
871 | 876 |
///The type of the shortest paths. |
872 | 877 |
///It must meet the \ref concepts::Path "Path" concept. |
873 | 878 |
typedef lemon::Path<Digraph> Path; |
874 | 879 |
}; |
875 | 880 |
|
876 | 881 |
/// \brief Default traits class used by BellmanFordWizard. |
877 | 882 |
/// |
878 | 883 |
/// Default traits class used by BellmanFordWizard. |
879 | 884 |
/// \tparam GR The type of the digraph. |
880 | 885 |
/// \tparam LEN The type of the length map. |
881 | 886 |
template <typename GR, typename LEN> |
882 | 887 |
class BellmanFordWizardBase |
883 | 888 |
: public BellmanFordWizardDefaultTraits<GR, LEN> { |
884 | 889 |
|
885 | 890 |
typedef BellmanFordWizardDefaultTraits<GR, LEN> Base; |
886 | 891 |
protected: |
887 | 892 |
// Type of the nodes in the digraph. |
888 | 893 |
typedef typename Base::Digraph::Node Node; |
889 | 894 |
|
890 | 895 |
// Pointer to the underlying digraph. |
891 | 896 |
void *_graph; |
892 | 897 |
// Pointer to the length map |
893 | 898 |
void *_length; |
894 | 899 |
// Pointer to the map of predecessors arcs. |
895 | 900 |
void *_pred; |
896 | 901 |
// Pointer to the map of distances. |
897 | 902 |
void *_dist; |
898 | 903 |
//Pointer to the shortest path to the target node. |
899 | 904 |
void *_path; |
900 | 905 |
//Pointer to the distance of the target node. |
901 | 906 |
void *_di; |
902 | 907 |
|
903 | 908 |
public: |
904 | 909 |
/// Constructor. |
905 | 910 |
|
906 | 911 |
/// This constructor does not require parameters, it initiates |
907 | 912 |
/// all of the attributes to default values \c 0. |
908 | 913 |
BellmanFordWizardBase() : |
909 | 914 |
_graph(0), _length(0), _pred(0), _dist(0), _path(0), _di(0) {} |
910 | 915 |
|
911 | 916 |
/// Constructor. |
912 | 917 |
|
913 | 918 |
/// This constructor requires two parameters, |
914 | 919 |
/// others are initiated to \c 0. |
915 | 920 |
/// \param gr The digraph the algorithm runs on. |
916 | 921 |
/// \param len The length map. |
917 | 922 |
BellmanFordWizardBase(const GR& gr, |
918 | 923 |
const LEN& len) : |
919 | 924 |
_graph(reinterpret_cast<void*>(const_cast<GR*>(&gr))), |
920 | 925 |
_length(reinterpret_cast<void*>(const_cast<LEN*>(&len))), |
921 | 926 |
_pred(0), _dist(0), _path(0), _di(0) {} |
922 | 927 |
|
923 | 928 |
}; |
924 | 929 |
|
925 | 930 |
/// \brief Auxiliary class for the function-type interface of the |
926 | 931 |
/// \ref BellmanFord "Bellman-Ford" algorithm. |
927 | 932 |
/// |
928 | 933 |
/// This auxiliary class is created to implement the |
929 | 934 |
/// \ref bellmanFord() "function-type interface" of the |
930 | 935 |
/// \ref BellmanFord "Bellman-Ford" algorithm. |
931 | 936 |
/// It does not have own \ref run() method, it uses the |
932 | 937 |
/// functions and features of the plain \ref BellmanFord. |
933 | 938 |
/// |
934 | 939 |
/// This class should only be used through the \ref bellmanFord() |
935 | 940 |
/// function, which makes it easier to use the algorithm. |
941 |
/// |
|
942 |
/// \tparam TR The traits class that defines various types used by the |
|
943 |
/// algorithm. |
|
936 | 944 |
template<class TR> |
937 | 945 |
class BellmanFordWizard : public TR { |
938 | 946 |
typedef TR Base; |
939 | 947 |
|
940 | 948 |
typedef typename TR::Digraph Digraph; |
941 | 949 |
|
942 | 950 |
typedef typename Digraph::Node Node; |
943 | 951 |
typedef typename Digraph::NodeIt NodeIt; |
944 | 952 |
typedef typename Digraph::Arc Arc; |
945 | 953 |
typedef typename Digraph::OutArcIt ArcIt; |
946 | 954 |
|
947 | 955 |
typedef typename TR::LengthMap LengthMap; |
948 | 956 |
typedef typename LengthMap::Value Value; |
949 | 957 |
typedef typename TR::PredMap PredMap; |
950 | 958 |
typedef typename TR::DistMap DistMap; |
951 | 959 |
typedef typename TR::Path Path; |
952 | 960 |
|
953 | 961 |
public: |
954 | 962 |
/// Constructor. |
955 | 963 |
BellmanFordWizard() : TR() {} |
956 | 964 |
|
957 | 965 |
/// \brief Constructor that requires parameters. |
958 | 966 |
/// |
959 | 967 |
/// Constructor that requires parameters. |
960 | 968 |
/// These parameters will be the default values for the traits class. |
961 | 969 |
/// \param gr The digraph the algorithm runs on. |
962 | 970 |
/// \param len The length map. |
963 | 971 |
BellmanFordWizard(const Digraph& gr, const LengthMap& len) |
964 | 972 |
: TR(gr, len) {} |
965 | 973 |
|
966 | 974 |
/// \brief Copy constructor |
967 | 975 |
BellmanFordWizard(const TR &b) : TR(b) {} |
968 | 976 |
|
969 | 977 |
~BellmanFordWizard() {} |
970 | 978 |
|
971 | 979 |
/// \brief Runs the Bellman-Ford algorithm from the given source node. |
972 | 980 |
/// |
973 | 981 |
/// This method runs the Bellman-Ford algorithm from the given source |
974 | 982 |
/// node in order to compute the shortest path to each node. |
975 | 983 |
void run(Node s) { |
976 | 984 |
BellmanFord<Digraph,LengthMap,TR> |
977 | 985 |
bf(*reinterpret_cast<const Digraph*>(Base::_graph), |
978 | 986 |
*reinterpret_cast<const LengthMap*>(Base::_length)); |
979 | 987 |
if (Base::_pred) bf.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
980 | 988 |
if (Base::_dist) bf.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
981 | 989 |
bf.run(s); |
982 | 990 |
} |
983 | 991 |
|
984 | 992 |
/// \brief Runs the Bellman-Ford algorithm to find the shortest path |
985 | 993 |
/// between \c s and \c t. |
986 | 994 |
/// |
987 | 995 |
/// This method runs the Bellman-Ford algorithm from node \c s |
988 | 996 |
/// in order to compute the shortest path to node \c t. |
989 | 997 |
/// Actually, it computes the shortest path to each node, but using |
990 | 998 |
/// this function you can retrieve the distance and the shortest path |
991 | 999 |
/// for a single target node easier. |
992 | 1000 |
/// |
993 | 1001 |
/// \return \c true if \c t is reachable form \c s. |
994 | 1002 |
bool run(Node s, Node t) { |
995 | 1003 |
BellmanFord<Digraph,LengthMap,TR> |
996 | 1004 |
bf(*reinterpret_cast<const Digraph*>(Base::_graph), |
997 | 1005 |
*reinterpret_cast<const LengthMap*>(Base::_length)); |
998 | 1006 |
if (Base::_pred) bf.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
999 | 1007 |
if (Base::_dist) bf.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
1000 | 1008 |
bf.run(s); |
1001 | 1009 |
if (Base::_path) *reinterpret_cast<Path*>(Base::_path) = bf.path(t); |
1002 | 1010 |
if (Base::_di) *reinterpret_cast<Value*>(Base::_di) = bf.dist(t); |
1003 | 1011 |
return bf.reached(t); |
1004 | 1012 |
} |
1005 | 1013 |
|
1006 | 1014 |
template<class T> |
1007 | 1015 |
struct SetPredMapBase : public Base { |
1008 | 1016 |
typedef T PredMap; |
1009 | 1017 |
static PredMap *createPredMap(const Digraph &) { return 0; }; |
1010 | 1018 |
SetPredMapBase(const TR &b) : TR(b) {} |
1011 | 1019 |
}; |
1012 | 1020 |
|
1013 | 1021 |
/// \brief \ref named-templ-param "Named parameter" for setting |
1014 | 1022 |
/// the predecessor map. |
1015 | 1023 |
/// |
1016 | 1024 |
/// \ref named-templ-param "Named parameter" for setting |
1017 | 1025 |
/// the map that stores the predecessor arcs of the nodes. |
1018 | 1026 |
template<class T> |
1019 | 1027 |
BellmanFordWizard<SetPredMapBase<T> > predMap(const T &t) { |
1020 | 1028 |
Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1021 | 1029 |
return BellmanFordWizard<SetPredMapBase<T> >(*this); |
1022 | 1030 |
} |
1023 | 1031 |
|
1024 | 1032 |
template<class T> |
1025 | 1033 |
struct SetDistMapBase : public Base { |
1026 | 1034 |
typedef T DistMap; |
1027 | 1035 |
static DistMap *createDistMap(const Digraph &) { return 0; }; |
1028 | 1036 |
SetDistMapBase(const TR &b) : TR(b) {} |
1029 | 1037 |
}; |
1030 | 1038 |
|
1031 | 1039 |
/// \brief \ref named-templ-param "Named parameter" for setting |
1032 | 1040 |
/// the distance map. |
1033 | 1041 |
/// |
1034 | 1042 |
/// \ref named-templ-param "Named parameter" for setting |
1035 | 1043 |
/// the map that stores the distances of the nodes calculated |
1036 | 1044 |
/// by the algorithm. |
1037 | 1045 |
template<class T> |
1038 | 1046 |
BellmanFordWizard<SetDistMapBase<T> > distMap(const T &t) { |
1039 | 1047 |
Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1040 | 1048 |
return BellmanFordWizard<SetDistMapBase<T> >(*this); |
1041 | 1049 |
} |
1042 | 1050 |
|
1043 | 1051 |
template<class T> |
1044 | 1052 |
struct SetPathBase : public Base { |
1045 | 1053 |
typedef T Path; |
1046 | 1054 |
SetPathBase(const TR &b) : TR(b) {} |
1047 | 1055 |
}; |
1048 | 1056 |
|
1049 | 1057 |
/// \brief \ref named-func-param "Named parameter" for getting |
1050 | 1058 |
/// the shortest path to the target node. |
1051 | 1059 |
/// |
1052 | 1060 |
/// \ref named-func-param "Named parameter" for getting |
1053 | 1061 |
/// the shortest path to the target node. |
1054 | 1062 |
template<class T> |
1055 | 1063 |
BellmanFordWizard<SetPathBase<T> > path(const T &t) |
1056 | 1064 |
{ |
1057 | 1065 |
Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1058 | 1066 |
return BellmanFordWizard<SetPathBase<T> >(*this); |
1059 | 1067 |
} |
1060 | 1068 |
|
1061 | 1069 |
/// \brief \ref named-func-param "Named parameter" for getting |
1062 | 1070 |
/// the distance of the target node. |
1063 | 1071 |
/// |
1064 | 1072 |
/// \ref named-func-param "Named parameter" for getting |
1065 | 1073 |
/// the distance of the target node. |
1066 | 1074 |
BellmanFordWizard dist(const Value &d) |
1067 | 1075 |
{ |
1068 | 1076 |
Base::_di=reinterpret_cast<void*>(const_cast<Value*>(&d)); |
1069 | 1077 |
return *this; |
1070 | 1078 |
} |
1071 | 1079 |
|
1072 | 1080 |
}; |
1073 | 1081 |
|
1074 | 1082 |
/// \brief Function type interface for the \ref BellmanFord "Bellman-Ford" |
1075 | 1083 |
/// algorithm. |
1076 | 1084 |
/// |
1077 | 1085 |
/// \ingroup shortest_path |
1078 | 1086 |
/// Function type interface for the \ref BellmanFord "Bellman-Ford" |
1079 | 1087 |
/// algorithm. |
1080 | 1088 |
/// |
1081 | 1089 |
/// This function also has several \ref named-templ-func-param |
1082 | 1090 |
/// "named parameters", they are declared as the members of class |
1083 | 1091 |
/// \ref BellmanFordWizard. |
1084 | 1092 |
/// The following examples show how to use these parameters. |
1085 | 1093 |
/// \code |
1086 | 1094 |
/// // Compute shortest path from node s to each node |
1087 | 1095 |
/// bellmanFord(g,length).predMap(preds).distMap(dists).run(s); |
1088 | 1096 |
/// |
1089 | 1097 |
/// // Compute shortest path from s to t |
1090 | 1098 |
/// bool reached = bellmanFord(g,length).path(p).dist(d).run(s,t); |
1091 | 1099 |
/// \endcode |
1092 | 1100 |
/// \warning Don't forget to put the \ref BellmanFordWizard::run() "run()" |
1093 | 1101 |
/// to the end of the parameter list. |
1094 | 1102 |
/// \sa BellmanFordWizard |
1095 | 1103 |
/// \sa BellmanFord |
1096 | 1104 |
template<typename GR, typename LEN> |
1097 | 1105 |
BellmanFordWizard<BellmanFordWizardBase<GR,LEN> > |
1098 | 1106 |
bellmanFord(const GR& digraph, |
1099 | 1107 |
const LEN& length) |
1100 | 1108 |
{ |
1101 | 1109 |
return BellmanFordWizard<BellmanFordWizardBase<GR,LEN> >(digraph, length); |
1102 | 1110 |
} |
1103 | 1111 |
|
1104 | 1112 |
} //END OF NAMESPACE LEMON |
1105 | 1113 |
|
1106 | 1114 |
#endif |
1107 | 1115 |
1 | 1 |
/* -*- mode: C++; indent-tabs-mode: nil; -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library. |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2009 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_BFS_H |
20 | 20 |
#define LEMON_BFS_H |
21 | 21 |
|
22 | 22 |
///\ingroup search |
23 | 23 |
///\file |
24 | 24 |
///\brief BFS algorithm. |
25 | 25 |
|
26 | 26 |
#include <lemon/list_graph.h> |
27 | 27 |
#include <lemon/bits/path_dump.h> |
28 | 28 |
#include <lemon/core.h> |
29 | 29 |
#include <lemon/error.h> |
30 | 30 |
#include <lemon/maps.h> |
31 | 31 |
#include <lemon/path.h> |
32 | 32 |
|
33 | 33 |
namespace lemon { |
34 | 34 |
|
35 | 35 |
///Default traits class of Bfs class. |
36 | 36 |
|
37 | 37 |
///Default traits class of Bfs class. |
38 | 38 |
///\tparam GR Digraph type. |
39 | 39 |
template<class GR> |
40 | 40 |
struct BfsDefaultTraits |
41 | 41 |
{ |
42 | 42 |
///The type of the digraph the algorithm runs on. |
43 | 43 |
typedef GR Digraph; |
44 | 44 |
|
45 | 45 |
///\brief The type of the map that stores the predecessor |
46 | 46 |
///arcs of the shortest paths. |
47 | 47 |
/// |
48 | 48 |
///The type of the map that stores the predecessor |
49 | 49 |
///arcs of the shortest paths. |
50 | 50 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
51 | 51 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
52 | 52 |
///Instantiates a \c PredMap. |
53 | 53 |
|
54 | 54 |
///This function instantiates a \ref PredMap. |
55 | 55 |
///\param g is the digraph, to which we would like to define the |
56 | 56 |
///\ref PredMap. |
57 | 57 |
static PredMap *createPredMap(const Digraph &g) |
58 | 58 |
{ |
59 | 59 |
return new PredMap(g); |
60 | 60 |
} |
61 | 61 |
|
62 | 62 |
///The type of the map that indicates which nodes are processed. |
63 | 63 |
|
64 | 64 |
///The type of the map that indicates which nodes are processed. |
65 | 65 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
66 | 66 |
///By default, it is a NullMap. |
67 | 67 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
68 | 68 |
///Instantiates a \c ProcessedMap. |
69 | 69 |
|
70 | 70 |
///This function instantiates a \ref ProcessedMap. |
71 | 71 |
///\param g is the digraph, to which |
72 | 72 |
///we would like to define the \ref ProcessedMap |
73 | 73 |
#ifdef DOXYGEN |
74 | 74 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
75 | 75 |
#else |
76 | 76 |
static ProcessedMap *createProcessedMap(const Digraph &) |
77 | 77 |
#endif |
78 | 78 |
{ |
79 | 79 |
return new ProcessedMap(); |
80 | 80 |
} |
81 | 81 |
|
82 | 82 |
///The type of the map that indicates which nodes are reached. |
83 | 83 |
|
84 | 84 |
///The type of the map that indicates which nodes are reached. |
85 | 85 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
86 | 86 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
87 | 87 |
///Instantiates a \c ReachedMap. |
88 | 88 |
|
89 | 89 |
///This function instantiates a \ref ReachedMap. |
90 | 90 |
///\param g is the digraph, to which |
91 | 91 |
///we would like to define the \ref ReachedMap. |
92 | 92 |
static ReachedMap *createReachedMap(const Digraph &g) |
93 | 93 |
{ |
94 | 94 |
return new ReachedMap(g); |
95 | 95 |
} |
96 | 96 |
|
97 | 97 |
///The type of the map that stores the distances of the nodes. |
98 | 98 |
|
99 | 99 |
///The type of the map that stores the distances of the nodes. |
100 | 100 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
101 | 101 |
typedef typename Digraph::template NodeMap<int> DistMap; |
102 | 102 |
///Instantiates a \c DistMap. |
103 | 103 |
|
104 | 104 |
///This function instantiates a \ref DistMap. |
105 | 105 |
///\param g is the digraph, to which we would like to define the |
106 | 106 |
///\ref DistMap. |
107 | 107 |
static DistMap *createDistMap(const Digraph &g) |
108 | 108 |
{ |
109 | 109 |
return new DistMap(g); |
110 | 110 |
} |
111 | 111 |
}; |
112 | 112 |
|
113 | 113 |
///%BFS algorithm class. |
114 | 114 |
|
115 | 115 |
///\ingroup search |
116 | 116 |
///This class provides an efficient implementation of the %BFS algorithm. |
117 | 117 |
/// |
118 | 118 |
///There is also a \ref bfs() "function-type interface" for the BFS |
119 | 119 |
///algorithm, which is convenient in the simplier cases and it can be |
120 | 120 |
///used easier. |
121 | 121 |
/// |
122 | 122 |
///\tparam GR The type of the digraph the algorithm runs on. |
123 | 123 |
///The default type is \ref ListDigraph. |
124 |
///\tparam TR The traits class that defines various types used by the |
|
125 |
///algorithm. By default, it is \ref BfsDefaultTraits |
|
126 |
///"BfsDefaultTraits<GR>". |
|
127 |
///In most cases, this parameter should not be set directly, |
|
128 |
///consider to use the named template parameters instead. |
|
124 | 129 |
#ifdef DOXYGEN |
125 | 130 |
template <typename GR, |
126 | 131 |
typename TR> |
127 | 132 |
#else |
128 | 133 |
template <typename GR=ListDigraph, |
129 | 134 |
typename TR=BfsDefaultTraits<GR> > |
130 | 135 |
#endif |
131 | 136 |
class Bfs { |
132 | 137 |
public: |
133 | 138 |
|
134 | 139 |
///The type of the digraph the algorithm runs on. |
135 | 140 |
typedef typename TR::Digraph Digraph; |
136 | 141 |
|
137 | 142 |
///\brief The type of the map that stores the predecessor arcs of the |
138 | 143 |
///shortest paths. |
139 | 144 |
typedef typename TR::PredMap PredMap; |
140 | 145 |
///The type of the map that stores the distances of the nodes. |
141 | 146 |
typedef typename TR::DistMap DistMap; |
142 | 147 |
///The type of the map that indicates which nodes are reached. |
143 | 148 |
typedef typename TR::ReachedMap ReachedMap; |
144 | 149 |
///The type of the map that indicates which nodes are processed. |
145 | 150 |
typedef typename TR::ProcessedMap ProcessedMap; |
146 | 151 |
///The type of the paths. |
147 | 152 |
typedef PredMapPath<Digraph, PredMap> Path; |
148 | 153 |
|
149 | 154 |
///The \ref BfsDefaultTraits "traits class" of the algorithm. |
150 | 155 |
typedef TR Traits; |
151 | 156 |
|
152 | 157 |
private: |
153 | 158 |
|
154 | 159 |
typedef typename Digraph::Node Node; |
155 | 160 |
typedef typename Digraph::NodeIt NodeIt; |
156 | 161 |
typedef typename Digraph::Arc Arc; |
157 | 162 |
typedef typename Digraph::OutArcIt OutArcIt; |
158 | 163 |
|
159 | 164 |
//Pointer to the underlying digraph. |
160 | 165 |
const Digraph *G; |
161 | 166 |
//Pointer to the map of predecessor arcs. |
162 | 167 |
PredMap *_pred; |
163 | 168 |
//Indicates if _pred is locally allocated (true) or not. |
164 | 169 |
bool local_pred; |
165 | 170 |
//Pointer to the map of distances. |
166 | 171 |
DistMap *_dist; |
167 | 172 |
//Indicates if _dist is locally allocated (true) or not. |
168 | 173 |
bool local_dist; |
169 | 174 |
//Pointer to the map of reached status of the nodes. |
170 | 175 |
ReachedMap *_reached; |
171 | 176 |
//Indicates if _reached is locally allocated (true) or not. |
172 | 177 |
bool local_reached; |
173 | 178 |
//Pointer to the map of processed status of the nodes. |
174 | 179 |
ProcessedMap *_processed; |
175 | 180 |
//Indicates if _processed is locally allocated (true) or not. |
176 | 181 |
bool local_processed; |
177 | 182 |
|
178 | 183 |
std::vector<typename Digraph::Node> _queue; |
179 | 184 |
int _queue_head,_queue_tail,_queue_next_dist; |
180 | 185 |
int _curr_dist; |
181 | 186 |
|
182 | 187 |
//Creates the maps if necessary. |
183 | 188 |
void create_maps() |
184 | 189 |
{ |
185 | 190 |
if(!_pred) { |
186 | 191 |
local_pred = true; |
187 | 192 |
_pred = Traits::createPredMap(*G); |
188 | 193 |
} |
189 | 194 |
if(!_dist) { |
190 | 195 |
local_dist = true; |
191 | 196 |
_dist = Traits::createDistMap(*G); |
192 | 197 |
} |
193 | 198 |
if(!_reached) { |
194 | 199 |
local_reached = true; |
195 | 200 |
_reached = Traits::createReachedMap(*G); |
196 | 201 |
} |
197 | 202 |
if(!_processed) { |
198 | 203 |
local_processed = true; |
199 | 204 |
_processed = Traits::createProcessedMap(*G); |
200 | 205 |
} |
201 | 206 |
} |
202 | 207 |
|
203 | 208 |
protected: |
204 | 209 |
|
205 | 210 |
Bfs() {} |
206 | 211 |
|
207 | 212 |
public: |
208 | 213 |
|
209 | 214 |
typedef Bfs Create; |
210 | 215 |
|
211 | 216 |
///\name Named Template Parameters |
212 | 217 |
|
213 | 218 |
///@{ |
214 | 219 |
|
215 | 220 |
template <class T> |
216 | 221 |
struct SetPredMapTraits : public Traits { |
217 | 222 |
typedef T PredMap; |
218 | 223 |
static PredMap *createPredMap(const Digraph &) |
219 | 224 |
{ |
220 | 225 |
LEMON_ASSERT(false, "PredMap is not initialized"); |
221 | 226 |
return 0; // ignore warnings |
222 | 227 |
} |
223 | 228 |
}; |
224 | 229 |
///\brief \ref named-templ-param "Named parameter" for setting |
225 | 230 |
///\c PredMap type. |
226 | 231 |
/// |
227 | 232 |
///\ref named-templ-param "Named parameter" for setting |
228 | 233 |
///\c PredMap type. |
229 | 234 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
230 | 235 |
template <class T> |
231 | 236 |
struct SetPredMap : public Bfs< Digraph, SetPredMapTraits<T> > { |
232 | 237 |
typedef Bfs< Digraph, SetPredMapTraits<T> > Create; |
233 | 238 |
}; |
234 | 239 |
|
235 | 240 |
template <class T> |
236 | 241 |
struct SetDistMapTraits : public Traits { |
237 | 242 |
typedef T DistMap; |
238 | 243 |
static DistMap *createDistMap(const Digraph &) |
239 | 244 |
{ |
240 | 245 |
LEMON_ASSERT(false, "DistMap is not initialized"); |
241 | 246 |
return 0; // ignore warnings |
242 | 247 |
} |
243 | 248 |
}; |
244 | 249 |
///\brief \ref named-templ-param "Named parameter" for setting |
245 | 250 |
///\c DistMap type. |
246 | 251 |
/// |
247 | 252 |
///\ref named-templ-param "Named parameter" for setting |
248 | 253 |
///\c DistMap type. |
249 | 254 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
250 | 255 |
template <class T> |
251 | 256 |
struct SetDistMap : public Bfs< Digraph, SetDistMapTraits<T> > { |
252 | 257 |
typedef Bfs< Digraph, SetDistMapTraits<T> > Create; |
253 | 258 |
}; |
254 | 259 |
|
255 | 260 |
template <class T> |
256 | 261 |
struct SetReachedMapTraits : public Traits { |
257 | 262 |
typedef T ReachedMap; |
258 | 263 |
static ReachedMap *createReachedMap(const Digraph &) |
259 | 264 |
{ |
260 | 265 |
LEMON_ASSERT(false, "ReachedMap is not initialized"); |
261 | 266 |
return 0; // ignore warnings |
262 | 267 |
} |
263 | 268 |
}; |
264 | 269 |
///\brief \ref named-templ-param "Named parameter" for setting |
265 | 270 |
///\c ReachedMap type. |
266 | 271 |
/// |
267 | 272 |
///\ref named-templ-param "Named parameter" for setting |
268 | 273 |
///\c ReachedMap type. |
269 | 274 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
270 | 275 |
template <class T> |
271 | 276 |
struct SetReachedMap : public Bfs< Digraph, SetReachedMapTraits<T> > { |
272 | 277 |
typedef Bfs< Digraph, SetReachedMapTraits<T> > Create; |
273 | 278 |
}; |
274 | 279 |
|
275 | 280 |
template <class T> |
276 | 281 |
struct SetProcessedMapTraits : public Traits { |
277 | 282 |
typedef T ProcessedMap; |
278 | 283 |
static ProcessedMap *createProcessedMap(const Digraph &) |
279 | 284 |
{ |
280 | 285 |
LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
281 | 286 |
return 0; // ignore warnings |
282 | 287 |
} |
283 | 288 |
}; |
284 | 289 |
///\brief \ref named-templ-param "Named parameter" for setting |
285 | 290 |
///\c ProcessedMap type. |
286 | 291 |
/// |
287 | 292 |
///\ref named-templ-param "Named parameter" for setting |
288 | 293 |
///\c ProcessedMap type. |
289 | 294 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
290 | 295 |
template <class T> |
291 | 296 |
struct SetProcessedMap : public Bfs< Digraph, SetProcessedMapTraits<T> > { |
292 | 297 |
typedef Bfs< Digraph, SetProcessedMapTraits<T> > Create; |
293 | 298 |
}; |
294 | 299 |
|
295 | 300 |
struct SetStandardProcessedMapTraits : public Traits { |
296 | 301 |
typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
297 | 302 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
298 | 303 |
{ |
299 | 304 |
return new ProcessedMap(g); |
300 | 305 |
return 0; // ignore warnings |
301 | 306 |
} |
302 | 307 |
}; |
303 | 308 |
///\brief \ref named-templ-param "Named parameter" for setting |
304 | 309 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
305 | 310 |
/// |
306 | 311 |
///\ref named-templ-param "Named parameter" for setting |
307 | 312 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
308 | 313 |
///If you don't set it explicitly, it will be automatically allocated. |
309 | 314 |
struct SetStandardProcessedMap : |
310 | 315 |
public Bfs< Digraph, SetStandardProcessedMapTraits > { |
311 | 316 |
typedef Bfs< Digraph, SetStandardProcessedMapTraits > Create; |
312 | 317 |
}; |
313 | 318 |
|
314 | 319 |
///@} |
315 | 320 |
|
316 | 321 |
public: |
317 | 322 |
|
318 | 323 |
///Constructor. |
319 | 324 |
|
320 | 325 |
///Constructor. |
321 | 326 |
///\param g The digraph the algorithm runs on. |
322 | 327 |
Bfs(const Digraph &g) : |
323 | 328 |
G(&g), |
324 | 329 |
_pred(NULL), local_pred(false), |
325 | 330 |
_dist(NULL), local_dist(false), |
326 | 331 |
_reached(NULL), local_reached(false), |
327 | 332 |
_processed(NULL), local_processed(false) |
328 | 333 |
{ } |
329 | 334 |
|
330 | 335 |
///Destructor. |
331 | 336 |
~Bfs() |
332 | 337 |
{ |
333 | 338 |
if(local_pred) delete _pred; |
334 | 339 |
if(local_dist) delete _dist; |
335 | 340 |
if(local_reached) delete _reached; |
336 | 341 |
if(local_processed) delete _processed; |
337 | 342 |
} |
338 | 343 |
|
339 | 344 |
///Sets the map that stores the predecessor arcs. |
340 | 345 |
|
341 | 346 |
///Sets the map that stores the predecessor arcs. |
342 | 347 |
///If you don't use this function before calling \ref run(Node) "run()" |
343 | 348 |
///or \ref init(), an instance will be allocated automatically. |
344 | 349 |
///The destructor deallocates this automatically allocated map, |
345 | 350 |
///of course. |
346 | 351 |
///\return <tt> (*this) </tt> |
347 | 352 |
Bfs &predMap(PredMap &m) |
348 | 353 |
{ |
349 | 354 |
if(local_pred) { |
350 | 355 |
delete _pred; |
351 | 356 |
local_pred=false; |
352 | 357 |
} |
353 | 358 |
_pred = &m; |
354 | 359 |
return *this; |
355 | 360 |
} |
356 | 361 |
|
357 | 362 |
///Sets the map that indicates which nodes are reached. |
358 | 363 |
|
359 | 364 |
///Sets the map that indicates which nodes are reached. |
360 | 365 |
///If you don't use this function before calling \ref run(Node) "run()" |
361 | 366 |
///or \ref init(), an instance will be allocated automatically. |
362 | 367 |
///The destructor deallocates this automatically allocated map, |
363 | 368 |
///of course. |
364 | 369 |
///\return <tt> (*this) </tt> |
365 | 370 |
Bfs &reachedMap(ReachedMap &m) |
366 | 371 |
{ |
367 | 372 |
if(local_reached) { |
368 | 373 |
delete _reached; |
369 | 374 |
local_reached=false; |
370 | 375 |
} |
371 | 376 |
_reached = &m; |
372 | 377 |
return *this; |
373 | 378 |
} |
374 | 379 |
|
375 | 380 |
///Sets the map that indicates which nodes are processed. |
376 | 381 |
|
377 | 382 |
///Sets the map that indicates which nodes are processed. |
378 | 383 |
///If you don't use this function before calling \ref run(Node) "run()" |
379 | 384 |
///or \ref init(), an instance will be allocated automatically. |
380 | 385 |
///The destructor deallocates this automatically allocated map, |
381 | 386 |
///of course. |
382 | 387 |
///\return <tt> (*this) </tt> |
383 | 388 |
Bfs &processedMap(ProcessedMap &m) |
384 | 389 |
{ |
385 | 390 |
if(local_processed) { |
386 | 391 |
delete _processed; |
387 | 392 |
local_processed=false; |
388 | 393 |
} |
389 | 394 |
_processed = &m; |
390 | 395 |
return *this; |
391 | 396 |
} |
392 | 397 |
|
393 | 398 |
///Sets the map that stores the distances of the nodes. |
394 | 399 |
|
395 | 400 |
///Sets the map that stores the distances of the nodes calculated by |
396 | 401 |
///the algorithm. |
397 | 402 |
///If you don't use this function before calling \ref run(Node) "run()" |
398 | 403 |
///or \ref init(), an instance will be allocated automatically. |
399 | 404 |
///The destructor deallocates this automatically allocated map, |
400 | 405 |
///of course. |
401 | 406 |
///\return <tt> (*this) </tt> |
402 | 407 |
Bfs &distMap(DistMap &m) |
403 | 408 |
{ |
404 | 409 |
if(local_dist) { |
405 | 410 |
delete _dist; |
406 | 411 |
local_dist=false; |
407 | 412 |
} |
408 | 413 |
_dist = &m; |
409 | 414 |
return *this; |
410 | 415 |
} |
411 | 416 |
|
412 | 417 |
public: |
413 | 418 |
|
414 | 419 |
///\name Execution Control |
415 | 420 |
///The simplest way to execute the BFS algorithm is to use one of the |
416 | 421 |
///member functions called \ref run(Node) "run()".\n |
417 | 422 |
///If you need better control on the execution, you have to call |
418 | 423 |
///\ref init() first, then you can add several source nodes with |
419 | 424 |
///\ref addSource(). Finally the actual path computation can be |
420 | 425 |
///performed with one of the \ref start() functions. |
421 | 426 |
|
422 | 427 |
///@{ |
423 | 428 |
|
424 | 429 |
///\brief Initializes the internal data structures. |
425 | 430 |
/// |
426 | 431 |
///Initializes the internal data structures. |
427 | 432 |
void init() |
428 | 433 |
{ |
429 | 434 |
create_maps(); |
430 | 435 |
_queue.resize(countNodes(*G)); |
431 | 436 |
_queue_head=_queue_tail=0; |
432 | 437 |
_curr_dist=1; |
433 | 438 |
for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
434 | 439 |
_pred->set(u,INVALID); |
435 | 440 |
_reached->set(u,false); |
436 | 441 |
_processed->set(u,false); |
437 | 442 |
} |
438 | 443 |
} |
439 | 444 |
|
440 | 445 |
///Adds a new source node. |
441 | 446 |
|
442 | 447 |
///Adds a new source node to the set of nodes to be processed. |
443 | 448 |
/// |
444 | 449 |
void addSource(Node s) |
445 | 450 |
{ |
446 | 451 |
if(!(*_reached)[s]) |
447 | 452 |
{ |
448 | 453 |
_reached->set(s,true); |
449 | 454 |
_pred->set(s,INVALID); |
450 | 455 |
_dist->set(s,0); |
451 | 456 |
_queue[_queue_head++]=s; |
452 | 457 |
_queue_next_dist=_queue_head; |
453 | 458 |
} |
454 | 459 |
} |
455 | 460 |
|
456 | 461 |
///Processes the next node. |
457 | 462 |
|
458 | 463 |
///Processes the next node. |
459 | 464 |
/// |
460 | 465 |
///\return The processed node. |
461 | 466 |
/// |
462 | 467 |
///\pre The queue must not be empty. |
463 | 468 |
Node processNextNode() |
464 | 469 |
{ |
465 | 470 |
if(_queue_tail==_queue_next_dist) { |
466 | 471 |
_curr_dist++; |
467 | 472 |
_queue_next_dist=_queue_head; |
468 | 473 |
} |
469 | 474 |
Node n=_queue[_queue_tail++]; |
470 | 475 |
_processed->set(n,true); |
471 | 476 |
Node m; |
472 | 477 |
for(OutArcIt e(*G,n);e!=INVALID;++e) |
473 | 478 |
if(!(*_reached)[m=G->target(e)]) { |
474 | 479 |
_queue[_queue_head++]=m; |
475 | 480 |
_reached->set(m,true); |
476 | 481 |
_pred->set(m,e); |
477 | 482 |
_dist->set(m,_curr_dist); |
478 | 483 |
} |
479 | 484 |
return n; |
480 | 485 |
} |
481 | 486 |
|
482 | 487 |
///Processes the next node. |
483 | 488 |
|
484 | 489 |
///Processes the next node and checks if the given target node |
485 | 490 |
///is reached. If the target node is reachable from the processed |
486 | 491 |
///node, then the \c reach parameter will be set to \c true. |
487 | 492 |
/// |
488 | 493 |
///\param target The target node. |
489 | 494 |
///\retval reach Indicates if the target node is reached. |
490 | 495 |
///It should be initially \c false. |
491 | 496 |
/// |
492 | 497 |
///\return The processed node. |
493 | 498 |
/// |
494 | 499 |
///\pre The queue must not be empty. |
495 | 500 |
Node processNextNode(Node target, bool& reach) |
496 | 501 |
{ |
497 | 502 |
if(_queue_tail==_queue_next_dist) { |
498 | 503 |
_curr_dist++; |
499 | 504 |
_queue_next_dist=_queue_head; |
500 | 505 |
} |
501 | 506 |
Node n=_queue[_queue_tail++]; |
502 | 507 |
_processed->set(n,true); |
503 | 508 |
Node m; |
504 | 509 |
for(OutArcIt e(*G,n);e!=INVALID;++e) |
505 | 510 |
if(!(*_reached)[m=G->target(e)]) { |
506 | 511 |
_queue[_queue_head++]=m; |
507 | 512 |
_reached->set(m,true); |
... | ... |
@@ -576,1111 +581,1114 @@ |
576 | 581 |
///This method runs the %BFS algorithm from the root node(s) |
577 | 582 |
///in order to compute the shortest path to each node. |
578 | 583 |
/// |
579 | 584 |
///The algorithm computes |
580 | 585 |
///- the shortest path tree (forest), |
581 | 586 |
///- the distance of each node from the root(s). |
582 | 587 |
/// |
583 | 588 |
///\pre init() must be called and at least one root node should be |
584 | 589 |
///added with addSource() before using this function. |
585 | 590 |
/// |
586 | 591 |
///\note <tt>b.start()</tt> is just a shortcut of the following code. |
587 | 592 |
///\code |
588 | 593 |
/// while ( !b.emptyQueue() ) { |
589 | 594 |
/// b.processNextNode(); |
590 | 595 |
/// } |
591 | 596 |
///\endcode |
592 | 597 |
void start() |
593 | 598 |
{ |
594 | 599 |
while ( !emptyQueue() ) processNextNode(); |
595 | 600 |
} |
596 | 601 |
|
597 | 602 |
///Executes the algorithm until the given target node is reached. |
598 | 603 |
|
599 | 604 |
///Executes the algorithm until the given target node is reached. |
600 | 605 |
/// |
601 | 606 |
///This method runs the %BFS algorithm from the root node(s) |
602 | 607 |
///in order to compute the shortest path to \c t. |
603 | 608 |
/// |
604 | 609 |
///The algorithm computes |
605 | 610 |
///- the shortest path to \c t, |
606 | 611 |
///- the distance of \c t from the root(s). |
607 | 612 |
/// |
608 | 613 |
///\pre init() must be called and at least one root node should be |
609 | 614 |
///added with addSource() before using this function. |
610 | 615 |
/// |
611 | 616 |
///\note <tt>b.start(t)</tt> is just a shortcut of the following code. |
612 | 617 |
///\code |
613 | 618 |
/// bool reach = false; |
614 | 619 |
/// while ( !b.emptyQueue() && !reach ) { |
615 | 620 |
/// b.processNextNode(t, reach); |
616 | 621 |
/// } |
617 | 622 |
///\endcode |
618 | 623 |
void start(Node t) |
619 | 624 |
{ |
620 | 625 |
bool reach = false; |
621 | 626 |
while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
622 | 627 |
} |
623 | 628 |
|
624 | 629 |
///Executes the algorithm until a condition is met. |
625 | 630 |
|
626 | 631 |
///Executes the algorithm until a condition is met. |
627 | 632 |
/// |
628 | 633 |
///This method runs the %BFS algorithm from the root node(s) in |
629 | 634 |
///order to compute the shortest path to a node \c v with |
630 | 635 |
/// <tt>nm[v]</tt> true, if such a node can be found. |
631 | 636 |
/// |
632 | 637 |
///\param nm A \c bool (or convertible) node map. The algorithm |
633 | 638 |
///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
634 | 639 |
/// |
635 | 640 |
///\return The reached node \c v with <tt>nm[v]</tt> true or |
636 | 641 |
///\c INVALID if no such node was found. |
637 | 642 |
/// |
638 | 643 |
///\pre init() must be called and at least one root node should be |
639 | 644 |
///added with addSource() before using this function. |
640 | 645 |
/// |
641 | 646 |
///\note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
642 | 647 |
///\code |
643 | 648 |
/// Node rnode = INVALID; |
644 | 649 |
/// while ( !b.emptyQueue() && rnode == INVALID ) { |
645 | 650 |
/// b.processNextNode(nm, rnode); |
646 | 651 |
/// } |
647 | 652 |
/// return rnode; |
648 | 653 |
///\endcode |
649 | 654 |
template<class NodeBoolMap> |
650 | 655 |
Node start(const NodeBoolMap &nm) |
651 | 656 |
{ |
652 | 657 |
Node rnode = INVALID; |
653 | 658 |
while ( !emptyQueue() && rnode == INVALID ) { |
654 | 659 |
processNextNode(nm, rnode); |
655 | 660 |
} |
656 | 661 |
return rnode; |
657 | 662 |
} |
658 | 663 |
|
659 | 664 |
///Runs the algorithm from the given source node. |
660 | 665 |
|
661 | 666 |
///This method runs the %BFS algorithm from node \c s |
662 | 667 |
///in order to compute the shortest path to each node. |
663 | 668 |
/// |
664 | 669 |
///The algorithm computes |
665 | 670 |
///- the shortest path tree, |
666 | 671 |
///- the distance of each node from the root. |
667 | 672 |
/// |
668 | 673 |
///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
669 | 674 |
///\code |
670 | 675 |
/// b.init(); |
671 | 676 |
/// b.addSource(s); |
672 | 677 |
/// b.start(); |
673 | 678 |
///\endcode |
674 | 679 |
void run(Node s) { |
675 | 680 |
init(); |
676 | 681 |
addSource(s); |
677 | 682 |
start(); |
678 | 683 |
} |
679 | 684 |
|
680 | 685 |
///Finds the shortest path between \c s and \c t. |
681 | 686 |
|
682 | 687 |
///This method runs the %BFS algorithm from node \c s |
683 | 688 |
///in order to compute the shortest path to node \c t |
684 | 689 |
///(it stops searching when \c t is processed). |
685 | 690 |
/// |
686 | 691 |
///\return \c true if \c t is reachable form \c s. |
687 | 692 |
/// |
688 | 693 |
///\note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
689 | 694 |
///shortcut of the following code. |
690 | 695 |
///\code |
691 | 696 |
/// b.init(); |
692 | 697 |
/// b.addSource(s); |
693 | 698 |
/// b.start(t); |
694 | 699 |
///\endcode |
695 | 700 |
bool run(Node s,Node t) { |
696 | 701 |
init(); |
697 | 702 |
addSource(s); |
698 | 703 |
start(t); |
699 | 704 |
return reached(t); |
700 | 705 |
} |
701 | 706 |
|
702 | 707 |
///Runs the algorithm to visit all nodes in the digraph. |
703 | 708 |
|
704 | 709 |
///This method runs the %BFS algorithm in order to visit all nodes |
705 | 710 |
///in the digraph. |
706 | 711 |
/// |
707 | 712 |
///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
708 | 713 |
///\code |
709 | 714 |
/// b.init(); |
710 | 715 |
/// for (NodeIt n(gr); n != INVALID; ++n) { |
711 | 716 |
/// if (!b.reached(n)) { |
712 | 717 |
/// b.addSource(n); |
713 | 718 |
/// b.start(); |
714 | 719 |
/// } |
715 | 720 |
/// } |
716 | 721 |
///\endcode |
717 | 722 |
void run() { |
718 | 723 |
init(); |
719 | 724 |
for (NodeIt n(*G); n != INVALID; ++n) { |
720 | 725 |
if (!reached(n)) { |
721 | 726 |
addSource(n); |
722 | 727 |
start(); |
723 | 728 |
} |
724 | 729 |
} |
725 | 730 |
} |
726 | 731 |
|
727 | 732 |
///@} |
728 | 733 |
|
729 | 734 |
///\name Query Functions |
730 | 735 |
///The results of the BFS algorithm can be obtained using these |
731 | 736 |
///functions.\n |
732 | 737 |
///Either \ref run(Node) "run()" or \ref start() should be called |
733 | 738 |
///before using them. |
734 | 739 |
|
735 | 740 |
///@{ |
736 | 741 |
|
737 | 742 |
///The shortest path to the given node. |
738 | 743 |
|
739 | 744 |
///Returns the shortest path to the given node from the root(s). |
740 | 745 |
/// |
741 | 746 |
///\warning \c t should be reached from the root(s). |
742 | 747 |
/// |
743 | 748 |
///\pre Either \ref run(Node) "run()" or \ref init() |
744 | 749 |
///must be called before using this function. |
745 | 750 |
Path path(Node t) const { return Path(*G, *_pred, t); } |
746 | 751 |
|
747 | 752 |
///The distance of the given node from the root(s). |
748 | 753 |
|
749 | 754 |
///Returns the distance of the given node from the root(s). |
750 | 755 |
/// |
751 | 756 |
///\warning If node \c v is not reached from the root(s), then |
752 | 757 |
///the return value of this function is undefined. |
753 | 758 |
/// |
754 | 759 |
///\pre Either \ref run(Node) "run()" or \ref init() |
755 | 760 |
///must be called before using this function. |
756 | 761 |
int dist(Node v) const { return (*_dist)[v]; } |
757 | 762 |
|
758 | 763 |
///\brief Returns the 'previous arc' of the shortest path tree for |
759 | 764 |
///the given node. |
760 | 765 |
/// |
761 | 766 |
///This function returns the 'previous arc' of the shortest path |
762 | 767 |
///tree for the node \c v, i.e. it returns the last arc of a |
763 | 768 |
///shortest path from a root to \c v. It is \c INVALID if \c v |
764 | 769 |
///is not reached from the root(s) or if \c v is a root. |
765 | 770 |
/// |
766 | 771 |
///The shortest path tree used here is equal to the shortest path |
767 | 772 |
///tree used in \ref predNode() and \ref predMap(). |
768 | 773 |
/// |
769 | 774 |
///\pre Either \ref run(Node) "run()" or \ref init() |
770 | 775 |
///must be called before using this function. |
771 | 776 |
Arc predArc(Node v) const { return (*_pred)[v];} |
772 | 777 |
|
773 | 778 |
///\brief Returns the 'previous node' of the shortest path tree for |
774 | 779 |
///the given node. |
775 | 780 |
/// |
776 | 781 |
///This function returns the 'previous node' of the shortest path |
777 | 782 |
///tree for the node \c v, i.e. it returns the last but one node |
778 | 783 |
///of a shortest path from a root to \c v. It is \c INVALID |
779 | 784 |
///if \c v is not reached from the root(s) or if \c v is a root. |
780 | 785 |
/// |
781 | 786 |
///The shortest path tree used here is equal to the shortest path |
782 | 787 |
///tree used in \ref predArc() and \ref predMap(). |
783 | 788 |
/// |
784 | 789 |
///\pre Either \ref run(Node) "run()" or \ref init() |
785 | 790 |
///must be called before using this function. |
786 | 791 |
Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
787 | 792 |
G->source((*_pred)[v]); } |
788 | 793 |
|
789 | 794 |
///\brief Returns a const reference to the node map that stores the |
790 | 795 |
/// distances of the nodes. |
791 | 796 |
/// |
792 | 797 |
///Returns a const reference to the node map that stores the distances |
793 | 798 |
///of the nodes calculated by the algorithm. |
794 | 799 |
/// |
795 | 800 |
///\pre Either \ref run(Node) "run()" or \ref init() |
796 | 801 |
///must be called before using this function. |
797 | 802 |
const DistMap &distMap() const { return *_dist;} |
798 | 803 |
|
799 | 804 |
///\brief Returns a const reference to the node map that stores the |
800 | 805 |
///predecessor arcs. |
801 | 806 |
/// |
802 | 807 |
///Returns a const reference to the node map that stores the predecessor |
803 | 808 |
///arcs, which form the shortest path tree (forest). |
804 | 809 |
/// |
805 | 810 |
///\pre Either \ref run(Node) "run()" or \ref init() |
806 | 811 |
///must be called before using this function. |
807 | 812 |
const PredMap &predMap() const { return *_pred;} |
808 | 813 |
|
809 | 814 |
///Checks if the given node is reached from the root(s). |
810 | 815 |
|
811 | 816 |
///Returns \c true if \c v is reached from the root(s). |
812 | 817 |
/// |
813 | 818 |
///\pre Either \ref run(Node) "run()" or \ref init() |
814 | 819 |
///must be called before using this function. |
815 | 820 |
bool reached(Node v) const { return (*_reached)[v]; } |
816 | 821 |
|
817 | 822 |
///@} |
818 | 823 |
}; |
819 | 824 |
|
820 | 825 |
///Default traits class of bfs() function. |
821 | 826 |
|
822 | 827 |
///Default traits class of bfs() function. |
823 | 828 |
///\tparam GR Digraph type. |
824 | 829 |
template<class GR> |
825 | 830 |
struct BfsWizardDefaultTraits |
826 | 831 |
{ |
827 | 832 |
///The type of the digraph the algorithm runs on. |
828 | 833 |
typedef GR Digraph; |
829 | 834 |
|
830 | 835 |
///\brief The type of the map that stores the predecessor |
831 | 836 |
///arcs of the shortest paths. |
832 | 837 |
/// |
833 | 838 |
///The type of the map that stores the predecessor |
834 | 839 |
///arcs of the shortest paths. |
835 | 840 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
836 | 841 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
837 | 842 |
///Instantiates a PredMap. |
838 | 843 |
|
839 | 844 |
///This function instantiates a PredMap. |
840 | 845 |
///\param g is the digraph, to which we would like to define the |
841 | 846 |
///PredMap. |
842 | 847 |
static PredMap *createPredMap(const Digraph &g) |
843 | 848 |
{ |
844 | 849 |
return new PredMap(g); |
845 | 850 |
} |
846 | 851 |
|
847 | 852 |
///The type of the map that indicates which nodes are processed. |
848 | 853 |
|
849 | 854 |
///The type of the map that indicates which nodes are processed. |
850 | 855 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
851 | 856 |
///By default, it is a NullMap. |
852 | 857 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
853 | 858 |
///Instantiates a ProcessedMap. |
854 | 859 |
|
855 | 860 |
///This function instantiates a ProcessedMap. |
856 | 861 |
///\param g is the digraph, to which |
857 | 862 |
///we would like to define the ProcessedMap. |
858 | 863 |
#ifdef DOXYGEN |
859 | 864 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
860 | 865 |
#else |
861 | 866 |
static ProcessedMap *createProcessedMap(const Digraph &) |
862 | 867 |
#endif |
863 | 868 |
{ |
864 | 869 |
return new ProcessedMap(); |
865 | 870 |
} |
866 | 871 |
|
867 | 872 |
///The type of the map that indicates which nodes are reached. |
868 | 873 |
|
869 | 874 |
///The type of the map that indicates which nodes are reached. |
870 | 875 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
871 | 876 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
872 | 877 |
///Instantiates a ReachedMap. |
873 | 878 |
|
874 | 879 |
///This function instantiates a ReachedMap. |
875 | 880 |
///\param g is the digraph, to which |
876 | 881 |
///we would like to define the ReachedMap. |
877 | 882 |
static ReachedMap *createReachedMap(const Digraph &g) |
878 | 883 |
{ |
879 | 884 |
return new ReachedMap(g); |
880 | 885 |
} |
881 | 886 |
|
882 | 887 |
///The type of the map that stores the distances of the nodes. |
883 | 888 |
|
884 | 889 |
///The type of the map that stores the distances of the nodes. |
885 | 890 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
886 | 891 |
typedef typename Digraph::template NodeMap<int> DistMap; |
887 | 892 |
///Instantiates a DistMap. |
888 | 893 |
|
889 | 894 |
///This function instantiates a DistMap. |
890 | 895 |
///\param g is the digraph, to which we would like to define |
891 | 896 |
///the DistMap |
892 | 897 |
static DistMap *createDistMap(const Digraph &g) |
893 | 898 |
{ |
894 | 899 |
return new DistMap(g); |
895 | 900 |
} |
896 | 901 |
|
897 | 902 |
///The type of the shortest paths. |
898 | 903 |
|
899 | 904 |
///The type of the shortest paths. |
900 | 905 |
///It must conform to the \ref concepts::Path "Path" concept. |
901 | 906 |
typedef lemon::Path<Digraph> Path; |
902 | 907 |
}; |
903 | 908 |
|
904 | 909 |
/// Default traits class used by BfsWizard |
905 | 910 |
|
906 | 911 |
/// Default traits class used by BfsWizard. |
907 | 912 |
/// \tparam GR The type of the digraph. |
908 | 913 |
template<class GR> |
909 | 914 |
class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
910 | 915 |
{ |
911 | 916 |
|
912 | 917 |
typedef BfsWizardDefaultTraits<GR> Base; |
913 | 918 |
protected: |
914 | 919 |
//The type of the nodes in the digraph. |
915 | 920 |
typedef typename Base::Digraph::Node Node; |
916 | 921 |
|
917 | 922 |
//Pointer to the digraph the algorithm runs on. |
918 | 923 |
void *_g; |
919 | 924 |
//Pointer to the map of reached nodes. |
920 | 925 |
void *_reached; |
921 | 926 |
//Pointer to the map of processed nodes. |
922 | 927 |
void *_processed; |
923 | 928 |
//Pointer to the map of predecessors arcs. |
924 | 929 |
void *_pred; |
925 | 930 |
//Pointer to the map of distances. |
926 | 931 |
void *_dist; |
927 | 932 |
//Pointer to the shortest path to the target node. |
928 | 933 |
void *_path; |
929 | 934 |
//Pointer to the distance of the target node. |
930 | 935 |
int *_di; |
931 | 936 |
|
932 | 937 |
public: |
933 | 938 |
/// Constructor. |
934 | 939 |
|
935 | 940 |
/// This constructor does not require parameters, it initiates |
936 | 941 |
/// all of the attributes to \c 0. |
937 | 942 |
BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
938 | 943 |
_dist(0), _path(0), _di(0) {} |
939 | 944 |
|
940 | 945 |
/// Constructor. |
941 | 946 |
|
942 | 947 |
/// This constructor requires one parameter, |
943 | 948 |
/// others are initiated to \c 0. |
944 | 949 |
/// \param g The digraph the algorithm runs on. |
945 | 950 |
BfsWizardBase(const GR &g) : |
946 | 951 |
_g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
947 | 952 |
_reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
948 | 953 |
|
949 | 954 |
}; |
950 | 955 |
|
951 | 956 |
/// Auxiliary class for the function-type interface of BFS algorithm. |
952 | 957 |
|
953 | 958 |
/// This auxiliary class is created to implement the |
954 | 959 |
/// \ref bfs() "function-type interface" of \ref Bfs algorithm. |
955 | 960 |
/// It does not have own \ref run(Node) "run()" method, it uses the |
956 | 961 |
/// functions and features of the plain \ref Bfs. |
957 | 962 |
/// |
958 | 963 |
/// This class should only be used through the \ref bfs() function, |
959 | 964 |
/// which makes it easier to use the algorithm. |
965 |
/// |
|
966 |
/// \tparam TR The traits class that defines various types used by the |
|
967 |
/// algorithm. |
|
960 | 968 |
template<class TR> |
961 | 969 |
class BfsWizard : public TR |
962 | 970 |
{ |
963 | 971 |
typedef TR Base; |
964 | 972 |
|
965 | 973 |
typedef typename TR::Digraph Digraph; |
966 | 974 |
|
967 | 975 |
typedef typename Digraph::Node Node; |
968 | 976 |
typedef typename Digraph::NodeIt NodeIt; |
969 | 977 |
typedef typename Digraph::Arc Arc; |
970 | 978 |
typedef typename Digraph::OutArcIt OutArcIt; |
971 | 979 |
|
972 | 980 |
typedef typename TR::PredMap PredMap; |
973 | 981 |
typedef typename TR::DistMap DistMap; |
974 | 982 |
typedef typename TR::ReachedMap ReachedMap; |
975 | 983 |
typedef typename TR::ProcessedMap ProcessedMap; |
976 | 984 |
typedef typename TR::Path Path; |
977 | 985 |
|
978 | 986 |
public: |
979 | 987 |
|
980 | 988 |
/// Constructor. |
981 | 989 |
BfsWizard() : TR() {} |
982 | 990 |
|
983 | 991 |
/// Constructor that requires parameters. |
984 | 992 |
|
985 | 993 |
/// Constructor that requires parameters. |
986 | 994 |
/// These parameters will be the default values for the traits class. |
987 | 995 |
/// \param g The digraph the algorithm runs on. |
988 | 996 |
BfsWizard(const Digraph &g) : |
989 | 997 |
TR(g) {} |
990 | 998 |
|
991 | 999 |
///Copy constructor |
992 | 1000 |
BfsWizard(const TR &b) : TR(b) {} |
993 | 1001 |
|
994 | 1002 |
~BfsWizard() {} |
995 | 1003 |
|
996 | 1004 |
///Runs BFS algorithm from the given source node. |
997 | 1005 |
|
998 | 1006 |
///This method runs BFS algorithm from node \c s |
999 | 1007 |
///in order to compute the shortest path to each node. |
1000 | 1008 |
void run(Node s) |
1001 | 1009 |
{ |
1002 | 1010 |
Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
1003 | 1011 |
if (Base::_pred) |
1004 | 1012 |
alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
1005 | 1013 |
if (Base::_dist) |
1006 | 1014 |
alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
1007 | 1015 |
if (Base::_reached) |
1008 | 1016 |
alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
1009 | 1017 |
if (Base::_processed) |
1010 | 1018 |
alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
1011 | 1019 |
if (s!=INVALID) |
1012 | 1020 |
alg.run(s); |
1013 | 1021 |
else |
1014 | 1022 |
alg.run(); |
1015 | 1023 |
} |
1016 | 1024 |
|
1017 | 1025 |
///Finds the shortest path between \c s and \c t. |
1018 | 1026 |
|
1019 | 1027 |
///This method runs BFS algorithm from node \c s |
1020 | 1028 |
///in order to compute the shortest path to node \c t |
1021 | 1029 |
///(it stops searching when \c t is processed). |
1022 | 1030 |
/// |
1023 | 1031 |
///\return \c true if \c t is reachable form \c s. |
1024 | 1032 |
bool run(Node s, Node t) |
1025 | 1033 |
{ |
1026 | 1034 |
Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
1027 | 1035 |
if (Base::_pred) |
1028 | 1036 |
alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
1029 | 1037 |
if (Base::_dist) |
1030 | 1038 |
alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
1031 | 1039 |
if (Base::_reached) |
1032 | 1040 |
alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
1033 | 1041 |
if (Base::_processed) |
1034 | 1042 |
alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
1035 | 1043 |
alg.run(s,t); |
1036 | 1044 |
if (Base::_path) |
1037 | 1045 |
*reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
1038 | 1046 |
if (Base::_di) |
1039 | 1047 |
*Base::_di = alg.dist(t); |
1040 | 1048 |
return alg.reached(t); |
1041 | 1049 |
} |
1042 | 1050 |
|
1043 | 1051 |
///Runs BFS algorithm to visit all nodes in the digraph. |
1044 | 1052 |
|
1045 | 1053 |
///This method runs BFS algorithm in order to visit all nodes |
1046 | 1054 |
///in the digraph. |
1047 | 1055 |
void run() |
1048 | 1056 |
{ |
1049 | 1057 |
run(INVALID); |
1050 | 1058 |
} |
1051 | 1059 |
|
1052 | 1060 |
template<class T> |
1053 | 1061 |
struct SetPredMapBase : public Base { |
1054 | 1062 |
typedef T PredMap; |
1055 | 1063 |
static PredMap *createPredMap(const Digraph &) { return 0; }; |
1056 | 1064 |
SetPredMapBase(const TR &b) : TR(b) {} |
1057 | 1065 |
}; |
1058 | 1066 |
|
1059 | 1067 |
///\brief \ref named-templ-param "Named parameter" for setting |
1060 | 1068 |
///the predecessor map. |
1061 | 1069 |
/// |
1062 | 1070 |
///\ref named-templ-param "Named parameter" function for setting |
1063 | 1071 |
///the map that stores the predecessor arcs of the nodes. |
1064 | 1072 |
template<class T> |
1065 | 1073 |
BfsWizard<SetPredMapBase<T> > predMap(const T &t) |
1066 | 1074 |
{ |
1067 | 1075 |
Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1068 | 1076 |
return BfsWizard<SetPredMapBase<T> >(*this); |
1069 | 1077 |
} |
1070 | 1078 |
|
1071 | 1079 |
template<class T> |
1072 | 1080 |
struct SetReachedMapBase : public Base { |
1073 | 1081 |
typedef T ReachedMap; |
1074 | 1082 |
static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
1075 | 1083 |
SetReachedMapBase(const TR &b) : TR(b) {} |
1076 | 1084 |
}; |
1077 | 1085 |
|
1078 | 1086 |
///\brief \ref named-templ-param "Named parameter" for setting |
1079 | 1087 |
///the reached map. |
1080 | 1088 |
/// |
1081 | 1089 |
///\ref named-templ-param "Named parameter" function for setting |
1082 | 1090 |
///the map that indicates which nodes are reached. |
1083 | 1091 |
template<class T> |
1084 | 1092 |
BfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
1085 | 1093 |
{ |
1086 | 1094 |
Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1087 | 1095 |
return BfsWizard<SetReachedMapBase<T> >(*this); |
1088 | 1096 |
} |
1089 | 1097 |
|
1090 | 1098 |
template<class T> |
1091 | 1099 |
struct SetDistMapBase : public Base { |
1092 | 1100 |
typedef T DistMap; |
1093 | 1101 |
static DistMap *createDistMap(const Digraph &) { return 0; }; |
1094 | 1102 |
SetDistMapBase(const TR &b) : TR(b) {} |
1095 | 1103 |
}; |
1096 | 1104 |
|
1097 | 1105 |
///\brief \ref named-templ-param "Named parameter" for setting |
1098 | 1106 |
///the distance map. |
1099 | 1107 |
/// |
1100 | 1108 |
///\ref named-templ-param "Named parameter" function for setting |
1101 | 1109 |
///the map that stores the distances of the nodes calculated |
1102 | 1110 |
///by the algorithm. |
1103 | 1111 |
template<class T> |
1104 | 1112 |
BfsWizard<SetDistMapBase<T> > distMap(const T &t) |
1105 | 1113 |
{ |
1106 | 1114 |
Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1107 | 1115 |
return BfsWizard<SetDistMapBase<T> >(*this); |
1108 | 1116 |
} |
1109 | 1117 |
|
1110 | 1118 |
template<class T> |
1111 | 1119 |
struct SetProcessedMapBase : public Base { |
1112 | 1120 |
typedef T ProcessedMap; |
1113 | 1121 |
static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
1114 | 1122 |
SetProcessedMapBase(const TR &b) : TR(b) {} |
1115 | 1123 |
}; |
1116 | 1124 |
|
1117 | 1125 |
///\brief \ref named-func-param "Named parameter" for setting |
1118 | 1126 |
///the processed map. |
1119 | 1127 |
/// |
1120 | 1128 |
///\ref named-templ-param "Named parameter" function for setting |
1121 | 1129 |
///the map that indicates which nodes are processed. |
1122 | 1130 |
template<class T> |
1123 | 1131 |
BfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
1124 | 1132 |
{ |
1125 | 1133 |
Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1126 | 1134 |
return BfsWizard<SetProcessedMapBase<T> >(*this); |
1127 | 1135 |
} |
1128 | 1136 |
|
1129 | 1137 |
template<class T> |
1130 | 1138 |
struct SetPathBase : public Base { |
1131 | 1139 |
typedef T Path; |
1132 | 1140 |
SetPathBase(const TR &b) : TR(b) {} |
1133 | 1141 |
}; |
1134 | 1142 |
///\brief \ref named-func-param "Named parameter" |
1135 | 1143 |
///for getting the shortest path to the target node. |
1136 | 1144 |
/// |
1137 | 1145 |
///\ref named-func-param "Named parameter" |
1138 | 1146 |
///for getting the shortest path to the target node. |
1139 | 1147 |
template<class T> |
1140 | 1148 |
BfsWizard<SetPathBase<T> > path(const T &t) |
1141 | 1149 |
{ |
1142 | 1150 |
Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1143 | 1151 |
return BfsWizard<SetPathBase<T> >(*this); |
1144 | 1152 |
} |
1145 | 1153 |
|
1146 | 1154 |
///\brief \ref named-func-param "Named parameter" |
1147 | 1155 |
///for getting the distance of the target node. |
1148 | 1156 |
/// |
1149 | 1157 |
///\ref named-func-param "Named parameter" |
1150 | 1158 |
///for getting the distance of the target node. |
1151 | 1159 |
BfsWizard dist(const int &d) |
1152 | 1160 |
{ |
1153 | 1161 |
Base::_di=const_cast<int*>(&d); |
1154 | 1162 |
return *this; |
1155 | 1163 |
} |
1156 | 1164 |
|
1157 | 1165 |
}; |
1158 | 1166 |
|
1159 | 1167 |
///Function-type interface for BFS algorithm. |
1160 | 1168 |
|
1161 | 1169 |
/// \ingroup search |
1162 | 1170 |
///Function-type interface for BFS algorithm. |
1163 | 1171 |
/// |
1164 | 1172 |
///This function also has several \ref named-func-param "named parameters", |
1165 | 1173 |
///they are declared as the members of class \ref BfsWizard. |
1166 | 1174 |
///The following examples show how to use these parameters. |
1167 | 1175 |
///\code |
1168 | 1176 |
/// // Compute shortest path from node s to each node |
1169 | 1177 |
/// bfs(g).predMap(preds).distMap(dists).run(s); |
1170 | 1178 |
/// |
1171 | 1179 |
/// // Compute shortest path from s to t |
1172 | 1180 |
/// bool reached = bfs(g).path(p).dist(d).run(s,t); |
1173 | 1181 |
///\endcode |
1174 | 1182 |
///\warning Don't forget to put the \ref BfsWizard::run(Node) "run()" |
1175 | 1183 |
///to the end of the parameter list. |
1176 | 1184 |
///\sa BfsWizard |
1177 | 1185 |
///\sa Bfs |
1178 | 1186 |
template<class GR> |
1179 | 1187 |
BfsWizard<BfsWizardBase<GR> > |
1180 | 1188 |
bfs(const GR &digraph) |
1181 | 1189 |
{ |
1182 | 1190 |
return BfsWizard<BfsWizardBase<GR> >(digraph); |
1183 | 1191 |
} |
1184 | 1192 |
|
1185 | 1193 |
#ifdef DOXYGEN |
1186 | 1194 |
/// \brief Visitor class for BFS. |
1187 | 1195 |
/// |
1188 | 1196 |
/// This class defines the interface of the BfsVisit events, and |
1189 | 1197 |
/// it could be the base of a real visitor class. |
1190 | 1198 |
template <typename GR> |
1191 | 1199 |
struct BfsVisitor { |
1192 | 1200 |
typedef GR Digraph; |
1193 | 1201 |
typedef typename Digraph::Arc Arc; |
1194 | 1202 |
typedef typename Digraph::Node Node; |
1195 | 1203 |
/// \brief Called for the source node(s) of the BFS. |
1196 | 1204 |
/// |
1197 | 1205 |
/// This function is called for the source node(s) of the BFS. |
1198 | 1206 |
void start(const Node& node) {} |
1199 | 1207 |
/// \brief Called when a node is reached first time. |
1200 | 1208 |
/// |
1201 | 1209 |
/// This function is called when a node is reached first time. |
1202 | 1210 |
void reach(const Node& node) {} |
1203 | 1211 |
/// \brief Called when a node is processed. |
1204 | 1212 |
/// |
1205 | 1213 |
/// This function is called when a node is processed. |
1206 | 1214 |
void process(const Node& node) {} |
1207 | 1215 |
/// \brief Called when an arc reaches a new node. |
1208 | 1216 |
/// |
1209 | 1217 |
/// This function is called when the BFS finds an arc whose target node |
1210 | 1218 |
/// is not reached yet. |
1211 | 1219 |
void discover(const Arc& arc) {} |
1212 | 1220 |
/// \brief Called when an arc is examined but its target node is |
1213 | 1221 |
/// already discovered. |
1214 | 1222 |
/// |
1215 | 1223 |
/// This function is called when an arc is examined but its target node is |
1216 | 1224 |
/// already discovered. |
1217 | 1225 |
void examine(const Arc& arc) {} |
1218 | 1226 |
}; |
1219 | 1227 |
#else |
1220 | 1228 |
template <typename GR> |
1221 | 1229 |
struct BfsVisitor { |
1222 | 1230 |
typedef GR Digraph; |
1223 | 1231 |
typedef typename Digraph::Arc Arc; |
1224 | 1232 |
typedef typename Digraph::Node Node; |
1225 | 1233 |
void start(const Node&) {} |
1226 | 1234 |
void reach(const Node&) {} |
1227 | 1235 |
void process(const Node&) {} |
1228 | 1236 |
void discover(const Arc&) {} |
1229 | 1237 |
void examine(const Arc&) {} |
1230 | 1238 |
|
1231 | 1239 |
template <typename _Visitor> |
1232 | 1240 |
struct Constraints { |
1233 | 1241 |
void constraints() { |
1234 | 1242 |
Arc arc; |
1235 | 1243 |
Node node; |
1236 | 1244 |
visitor.start(node); |
1237 | 1245 |
visitor.reach(node); |
1238 | 1246 |
visitor.process(node); |
1239 | 1247 |
visitor.discover(arc); |
1240 | 1248 |
visitor.examine(arc); |
1241 | 1249 |
} |
1242 | 1250 |
_Visitor& visitor; |
1243 | 1251 |
}; |
1244 | 1252 |
}; |
1245 | 1253 |
#endif |
1246 | 1254 |
|
1247 | 1255 |
/// \brief Default traits class of BfsVisit class. |
1248 | 1256 |
/// |
1249 | 1257 |
/// Default traits class of BfsVisit class. |
1250 | 1258 |
/// \tparam GR The type of the digraph the algorithm runs on. |
1251 | 1259 |
template<class GR> |
1252 | 1260 |
struct BfsVisitDefaultTraits { |
1253 | 1261 |
|
1254 | 1262 |
/// \brief The type of the digraph the algorithm runs on. |
1255 | 1263 |
typedef GR Digraph; |
1256 | 1264 |
|
1257 | 1265 |
/// \brief The type of the map that indicates which nodes are reached. |
1258 | 1266 |
/// |
1259 | 1267 |
/// The type of the map that indicates which nodes are reached. |
1260 | 1268 |
/// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
1261 | 1269 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
1262 | 1270 |
|
1263 | 1271 |
/// \brief Instantiates a ReachedMap. |
1264 | 1272 |
/// |
1265 | 1273 |
/// This function instantiates a ReachedMap. |
1266 | 1274 |
/// \param digraph is the digraph, to which |
1267 | 1275 |
/// we would like to define the ReachedMap. |
1268 | 1276 |
static ReachedMap *createReachedMap(const Digraph &digraph) { |
1269 | 1277 |
return new ReachedMap(digraph); |
1270 | 1278 |
} |
1271 | 1279 |
|
1272 | 1280 |
}; |
1273 | 1281 |
|
1274 | 1282 |
/// \ingroup search |
1275 | 1283 |
/// |
1276 | 1284 |
/// \brief BFS algorithm class with visitor interface. |
1277 | 1285 |
/// |
1278 | 1286 |
/// This class provides an efficient implementation of the BFS algorithm |
1279 | 1287 |
/// with visitor interface. |
1280 | 1288 |
/// |
1281 | 1289 |
/// The BfsVisit class provides an alternative interface to the Bfs |
1282 | 1290 |
/// class. It works with callback mechanism, the BfsVisit object calls |
1283 | 1291 |
/// the member functions of the \c Visitor class on every BFS event. |
1284 | 1292 |
/// |
1285 | 1293 |
/// This interface of the BFS algorithm should be used in special cases |
1286 | 1294 |
/// when extra actions have to be performed in connection with certain |
1287 | 1295 |
/// events of the BFS algorithm. Otherwise consider to use Bfs or bfs() |
1288 | 1296 |
/// instead. |
1289 | 1297 |
/// |
1290 | 1298 |
/// \tparam GR The type of the digraph the algorithm runs on. |
1291 | 1299 |
/// The default type is \ref ListDigraph. |
1292 | 1300 |
/// The value of GR is not used directly by \ref BfsVisit, |
1293 | 1301 |
/// it is only passed to \ref BfsVisitDefaultTraits. |
1294 | 1302 |
/// \tparam VS The Visitor type that is used by the algorithm. |
1295 | 1303 |
/// \ref BfsVisitor "BfsVisitor<GR>" is an empty visitor, which |
1296 | 1304 |
/// does not observe the BFS events. If you want to observe the BFS |
1297 | 1305 |
/// events, you should implement your own visitor class. |
1298 |
/// \tparam TR Traits class to set various data types used by the |
|
1299 |
/// algorithm. The default traits class is |
|
1300 |
/// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<GR>". |
|
1301 |
/// See \ref BfsVisitDefaultTraits for the documentation of |
|
1302 |
/// |
|
1306 |
/// \tparam TR The traits class that defines various types used by the |
|
1307 |
/// algorithm. By default, it is \ref BfsVisitDefaultTraits |
|
1308 |
/// "BfsVisitDefaultTraits<GR>". |
|
1309 |
/// In most cases, this parameter should not be set directly, |
|
1310 |
/// consider to use the named template parameters instead. |
|
1303 | 1311 |
#ifdef DOXYGEN |
1304 | 1312 |
template <typename GR, typename VS, typename TR> |
1305 | 1313 |
#else |
1306 | 1314 |
template <typename GR = ListDigraph, |
1307 | 1315 |
typename VS = BfsVisitor<GR>, |
1308 | 1316 |
typename TR = BfsVisitDefaultTraits<GR> > |
1309 | 1317 |
#endif |
1310 | 1318 |
class BfsVisit { |
1311 | 1319 |
public: |
1312 | 1320 |
|
1313 | 1321 |
///The traits class. |
1314 | 1322 |
typedef TR Traits; |
1315 | 1323 |
|
1316 | 1324 |
///The type of the digraph the algorithm runs on. |
1317 | 1325 |
typedef typename Traits::Digraph Digraph; |
1318 | 1326 |
|
1319 | 1327 |
///The visitor type used by the algorithm. |
1320 | 1328 |
typedef VS Visitor; |
1321 | 1329 |
|
1322 | 1330 |
///The type of the map that indicates which nodes are reached. |
1323 | 1331 |
typedef typename Traits::ReachedMap ReachedMap; |
1324 | 1332 |
|
1325 | 1333 |
private: |
1326 | 1334 |
|
1327 | 1335 |
typedef typename Digraph::Node Node; |
1328 | 1336 |
typedef typename Digraph::NodeIt NodeIt; |
1329 | 1337 |
typedef typename Digraph::Arc Arc; |
1330 | 1338 |
typedef typename Digraph::OutArcIt OutArcIt; |
1331 | 1339 |
|
1332 | 1340 |
//Pointer to the underlying digraph. |
1333 | 1341 |
const Digraph *_digraph; |
1334 | 1342 |
//Pointer to the visitor object. |
1335 | 1343 |
Visitor *_visitor; |
1336 | 1344 |
//Pointer to the map of reached status of the nodes. |
1337 | 1345 |
ReachedMap *_reached; |
1338 | 1346 |
//Indicates if _reached is locally allocated (true) or not. |
1339 | 1347 |
bool local_reached; |
1340 | 1348 |
|
1341 | 1349 |
std::vector<typename Digraph::Node> _list; |
1342 | 1350 |
int _list_front, _list_back; |
1343 | 1351 |
|
1344 | 1352 |
//Creates the maps if necessary. |
1345 | 1353 |
void create_maps() { |
1346 | 1354 |
if(!_reached) { |
1347 | 1355 |
local_reached = true; |
1348 | 1356 |
_reached = Traits::createReachedMap(*_digraph); |
1349 | 1357 |
} |
1350 | 1358 |
} |
1351 | 1359 |
|
1352 | 1360 |
protected: |
1353 | 1361 |
|
1354 | 1362 |
BfsVisit() {} |
1355 | 1363 |
|
1356 | 1364 |
public: |
1357 | 1365 |
|
1358 | 1366 |
typedef BfsVisit Create; |
1359 | 1367 |
|
1360 | 1368 |
/// \name Named Template Parameters |
1361 | 1369 |
|
1362 | 1370 |
///@{ |
1363 | 1371 |
template <class T> |
1364 | 1372 |
struct SetReachedMapTraits : public Traits { |
1365 | 1373 |
typedef T ReachedMap; |
1366 | 1374 |
static ReachedMap *createReachedMap(const Digraph &digraph) { |
1367 | 1375 |
LEMON_ASSERT(false, "ReachedMap is not initialized"); |
1368 | 1376 |
return 0; // ignore warnings |
1369 | 1377 |
} |
1370 | 1378 |
}; |
1371 | 1379 |
/// \brief \ref named-templ-param "Named parameter" for setting |
1372 | 1380 |
/// ReachedMap type. |
1373 | 1381 |
/// |
1374 | 1382 |
/// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
1375 | 1383 |
template <class T> |
1376 | 1384 |
struct SetReachedMap : public BfsVisit< Digraph, Visitor, |
1377 | 1385 |
SetReachedMapTraits<T> > { |
1378 | 1386 |
typedef BfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
1379 | 1387 |
}; |
1380 | 1388 |
///@} |
1381 | 1389 |
|
1382 | 1390 |
public: |
1383 | 1391 |
|
1384 | 1392 |
/// \brief Constructor. |
1385 | 1393 |
/// |
1386 | 1394 |
/// Constructor. |
1387 | 1395 |
/// |
1388 | 1396 |
/// \param digraph The digraph the algorithm runs on. |
1389 | 1397 |
/// \param visitor The visitor object of the algorithm. |
1390 | 1398 |
BfsVisit(const Digraph& digraph, Visitor& visitor) |
1391 | 1399 |
: _digraph(&digraph), _visitor(&visitor), |
1392 | 1400 |
_reached(0), local_reached(false) {} |
1393 | 1401 |
|
1394 | 1402 |
/// \brief Destructor. |
1395 | 1403 |
~BfsVisit() { |
1396 | 1404 |
if(local_reached) delete _reached; |
1397 | 1405 |
} |
1398 | 1406 |
|
1399 | 1407 |
/// \brief Sets the map that indicates which nodes are reached. |
1400 | 1408 |
/// |
1401 | 1409 |
/// Sets the map that indicates which nodes are reached. |
1402 | 1410 |
/// If you don't use this function before calling \ref run(Node) "run()" |
1403 | 1411 |
/// or \ref init(), an instance will be allocated automatically. |
1404 | 1412 |
/// The destructor deallocates this automatically allocated map, |
1405 | 1413 |
/// of course. |
1406 | 1414 |
/// \return <tt> (*this) </tt> |
1407 | 1415 |
BfsVisit &reachedMap(ReachedMap &m) { |
1408 | 1416 |
if(local_reached) { |
1409 | 1417 |
delete _reached; |
1410 | 1418 |
local_reached = false; |
1411 | 1419 |
} |
1412 | 1420 |
_reached = &m; |
1413 | 1421 |
return *this; |
1414 | 1422 |
} |
1415 | 1423 |
|
1416 | 1424 |
public: |
1417 | 1425 |
|
1418 | 1426 |
/// \name Execution Control |
1419 | 1427 |
/// The simplest way to execute the BFS algorithm is to use one of the |
1420 | 1428 |
/// member functions called \ref run(Node) "run()".\n |
1421 | 1429 |
/// If you need better control on the execution, you have to call |
1422 | 1430 |
/// \ref init() first, then you can add several source nodes with |
1423 | 1431 |
/// \ref addSource(). Finally the actual path computation can be |
1424 | 1432 |
/// performed with one of the \ref start() functions. |
1425 | 1433 |
|
1426 | 1434 |
/// @{ |
1427 | 1435 |
|
1428 | 1436 |
/// \brief Initializes the internal data structures. |
1429 | 1437 |
/// |
1430 | 1438 |
/// Initializes the internal data structures. |
1431 | 1439 |
void init() { |
1432 | 1440 |
create_maps(); |
1433 | 1441 |
_list.resize(countNodes(*_digraph)); |
1434 | 1442 |
_list_front = _list_back = -1; |
1435 | 1443 |
for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
1436 | 1444 |
_reached->set(u, false); |
1437 | 1445 |
} |
1438 | 1446 |
} |
1439 | 1447 |
|
1440 | 1448 |
/// \brief Adds a new source node. |
1441 | 1449 |
/// |
1442 | 1450 |
/// Adds a new source node to the set of nodes to be processed. |
1443 | 1451 |
void addSource(Node s) { |
1444 | 1452 |
if(!(*_reached)[s]) { |
1445 | 1453 |
_reached->set(s,true); |
1446 | 1454 |
_visitor->start(s); |
1447 | 1455 |
_visitor->reach(s); |
1448 | 1456 |
_list[++_list_back] = s; |
1449 | 1457 |
} |
1450 | 1458 |
} |
1451 | 1459 |
|
1452 | 1460 |
/// \brief Processes the next node. |
1453 | 1461 |
/// |
1454 | 1462 |
/// Processes the next node. |
1455 | 1463 |
/// |
1456 | 1464 |
/// \return The processed node. |
1457 | 1465 |
/// |
1458 | 1466 |
/// \pre The queue must not be empty. |
1459 | 1467 |
Node processNextNode() { |
1460 | 1468 |
Node n = _list[++_list_front]; |
1461 | 1469 |
_visitor->process(n); |
1462 | 1470 |
Arc e; |
1463 | 1471 |
for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
1464 | 1472 |
Node m = _digraph->target(e); |
1465 | 1473 |
if (!(*_reached)[m]) { |
1466 | 1474 |
_visitor->discover(e); |
1467 | 1475 |
_visitor->reach(m); |
1468 | 1476 |
_reached->set(m, true); |
1469 | 1477 |
_list[++_list_back] = m; |
1470 | 1478 |
} else { |
1471 | 1479 |
_visitor->examine(e); |
1472 | 1480 |
} |
1473 | 1481 |
} |
1474 | 1482 |
return n; |
1475 | 1483 |
} |
1476 | 1484 |
|
1477 | 1485 |
/// \brief Processes the next node. |
1478 | 1486 |
/// |
1479 | 1487 |
/// Processes the next node and checks if the given target node |
1480 | 1488 |
/// is reached. If the target node is reachable from the processed |
1481 | 1489 |
/// node, then the \c reach parameter will be set to \c true. |
1482 | 1490 |
/// |
1483 | 1491 |
/// \param target The target node. |
1484 | 1492 |
/// \retval reach Indicates if the target node is reached. |
1485 | 1493 |
/// It should be initially \c false. |
1486 | 1494 |
/// |
1487 | 1495 |
/// \return The processed node. |
1488 | 1496 |
/// |
1489 | 1497 |
/// \pre The queue must not be empty. |
1490 | 1498 |
Node processNextNode(Node target, bool& reach) { |
1491 | 1499 |
Node n = _list[++_list_front]; |
1492 | 1500 |
_visitor->process(n); |
1493 | 1501 |
Arc e; |
1494 | 1502 |
for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
1495 | 1503 |
Node m = _digraph->target(e); |
1496 | 1504 |
if (!(*_reached)[m]) { |
1497 | 1505 |
_visitor->discover(e); |
1498 | 1506 |
_visitor->reach(m); |
1499 | 1507 |
_reached->set(m, true); |
1500 | 1508 |
_list[++_list_back] = m; |
1501 | 1509 |
reach = reach || (target == m); |
1502 | 1510 |
} else { |
1503 | 1511 |
_visitor->examine(e); |
1504 | 1512 |
} |
1505 | 1513 |
} |
1506 | 1514 |
return n; |
1507 | 1515 |
} |
1508 | 1516 |
|
1509 | 1517 |
/// \brief Processes the next node. |
1510 | 1518 |
/// |
1511 | 1519 |
/// Processes the next node and checks if at least one of reached |
1512 | 1520 |
/// nodes has \c true value in the \c nm node map. If one node |
1513 | 1521 |
/// with \c true value is reachable from the processed node, then the |
1514 | 1522 |
/// \c rnode parameter will be set to the first of such nodes. |
1515 | 1523 |
/// |
1516 | 1524 |
/// \param nm A \c bool (or convertible) node map that indicates the |
1517 | 1525 |
/// possible targets. |
1518 | 1526 |
/// \retval rnode The reached target node. |
1519 | 1527 |
/// It should be initially \c INVALID. |
1520 | 1528 |
/// |
1521 | 1529 |
/// \return The processed node. |
1522 | 1530 |
/// |
1523 | 1531 |
/// \pre The queue must not be empty. |
1524 | 1532 |
template <typename NM> |
1525 | 1533 |
Node processNextNode(const NM& nm, Node& rnode) { |
1526 | 1534 |
Node n = _list[++_list_front]; |
1527 | 1535 |
_visitor->process(n); |
1528 | 1536 |
Arc e; |
1529 | 1537 |
for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
1530 | 1538 |
Node m = _digraph->target(e); |
1531 | 1539 |
if (!(*_reached)[m]) { |
1532 | 1540 |
_visitor->discover(e); |
1533 | 1541 |
_visitor->reach(m); |
1534 | 1542 |
_reached->set(m, true); |
1535 | 1543 |
_list[++_list_back] = m; |
1536 | 1544 |
if (nm[m] && rnode == INVALID) rnode = m; |
1537 | 1545 |
} else { |
1538 | 1546 |
_visitor->examine(e); |
1539 | 1547 |
} |
1540 | 1548 |
} |
1541 | 1549 |
return n; |
1542 | 1550 |
} |
1543 | 1551 |
|
1544 | 1552 |
/// \brief The next node to be processed. |
1545 | 1553 |
/// |
1546 | 1554 |
/// Returns the next node to be processed or \c INVALID if the queue |
1547 | 1555 |
/// is empty. |
1548 | 1556 |
Node nextNode() const { |
1549 | 1557 |
return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
1550 | 1558 |
} |
1551 | 1559 |
|
1552 | 1560 |
/// \brief Returns \c false if there are nodes |
1553 | 1561 |
/// to be processed. |
1554 | 1562 |
/// |
1555 | 1563 |
/// Returns \c false if there are nodes |
1556 | 1564 |
/// to be processed in the queue. |
1557 | 1565 |
bool emptyQueue() const { return _list_front == _list_back; } |
1558 | 1566 |
|
1559 | 1567 |
/// \brief Returns the number of the nodes to be processed. |
1560 | 1568 |
/// |
1561 | 1569 |
/// Returns the number of the nodes to be processed in the queue. |
1562 | 1570 |
int queueSize() const { return _list_back - _list_front; } |
1563 | 1571 |
|
1564 | 1572 |
/// \brief Executes the algorithm. |
1565 | 1573 |
/// |
1566 | 1574 |
/// Executes the algorithm. |
1567 | 1575 |
/// |
1568 | 1576 |
/// This method runs the %BFS algorithm from the root node(s) |
1569 | 1577 |
/// in order to compute the shortest path to each node. |
1570 | 1578 |
/// |
1571 | 1579 |
/// The algorithm computes |
1572 | 1580 |
/// - the shortest path tree (forest), |
1573 | 1581 |
/// - the distance of each node from the root(s). |
1574 | 1582 |
/// |
1575 | 1583 |
/// \pre init() must be called and at least one root node should be added |
1576 | 1584 |
/// with addSource() before using this function. |
1577 | 1585 |
/// |
1578 | 1586 |
/// \note <tt>b.start()</tt> is just a shortcut of the following code. |
1579 | 1587 |
/// \code |
1580 | 1588 |
/// while ( !b.emptyQueue() ) { |
1581 | 1589 |
/// b.processNextNode(); |
1582 | 1590 |
/// } |
1583 | 1591 |
/// \endcode |
1584 | 1592 |
void start() { |
1585 | 1593 |
while ( !emptyQueue() ) processNextNode(); |
1586 | 1594 |
} |
1587 | 1595 |
|
1588 | 1596 |
/// \brief Executes the algorithm until the given target node is reached. |
1589 | 1597 |
/// |
1590 | 1598 |
/// Executes the algorithm until the given target node is reached. |
1591 | 1599 |
/// |
1592 | 1600 |
/// This method runs the %BFS algorithm from the root node(s) |
1593 | 1601 |
/// in order to compute the shortest path to \c t. |
1594 | 1602 |
/// |
1595 | 1603 |
/// The algorithm computes |
1596 | 1604 |
/// - the shortest path to \c t, |
1597 | 1605 |
/// - the distance of \c t from the root(s). |
1598 | 1606 |
/// |
1599 | 1607 |
/// \pre init() must be called and at least one root node should be |
1600 | 1608 |
/// added with addSource() before using this function. |
1601 | 1609 |
/// |
1602 | 1610 |
/// \note <tt>b.start(t)</tt> is just a shortcut of the following code. |
1603 | 1611 |
/// \code |
1604 | 1612 |
/// bool reach = false; |
1605 | 1613 |
/// while ( !b.emptyQueue() && !reach ) { |
1606 | 1614 |
/// b.processNextNode(t, reach); |
1607 | 1615 |
/// } |
1608 | 1616 |
/// \endcode |
1609 | 1617 |
void start(Node t) { |
1610 | 1618 |
bool reach = false; |
1611 | 1619 |
while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
1612 | 1620 |
} |
1613 | 1621 |
|
1614 | 1622 |
/// \brief Executes the algorithm until a condition is met. |
1615 | 1623 |
/// |
1616 | 1624 |
/// Executes the algorithm until a condition is met. |
1617 | 1625 |
/// |
1618 | 1626 |
/// This method runs the %BFS algorithm from the root node(s) in |
1619 | 1627 |
/// order to compute the shortest path to a node \c v with |
1620 | 1628 |
/// <tt>nm[v]</tt> true, if such a node can be found. |
1621 | 1629 |
/// |
1622 | 1630 |
/// \param nm must be a bool (or convertible) node map. The |
1623 | 1631 |
/// algorithm will stop when it reaches a node \c v with |
1624 | 1632 |
/// <tt>nm[v]</tt> true. |
1625 | 1633 |
/// |
1626 | 1634 |
/// \return The reached node \c v with <tt>nm[v]</tt> true or |
1627 | 1635 |
/// \c INVALID if no such node was found. |
1628 | 1636 |
/// |
1629 | 1637 |
/// \pre init() must be called and at least one root node should be |
1630 | 1638 |
/// added with addSource() before using this function. |
1631 | 1639 |
/// |
1632 | 1640 |
/// \note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
1633 | 1641 |
/// \code |
1634 | 1642 |
/// Node rnode = INVALID; |
1635 | 1643 |
/// while ( !b.emptyQueue() && rnode == INVALID ) { |
1636 | 1644 |
/// b.processNextNode(nm, rnode); |
1637 | 1645 |
/// } |
1638 | 1646 |
/// return rnode; |
1639 | 1647 |
/// \endcode |
1640 | 1648 |
template <typename NM> |
1641 | 1649 |
Node start(const NM &nm) { |
1642 | 1650 |
Node rnode = INVALID; |
1643 | 1651 |
while ( !emptyQueue() && rnode == INVALID ) { |
1644 | 1652 |
processNextNode(nm, rnode); |
1645 | 1653 |
} |
1646 | 1654 |
return rnode; |
1647 | 1655 |
} |
1648 | 1656 |
|
1649 | 1657 |
/// \brief Runs the algorithm from the given source node. |
1650 | 1658 |
/// |
1651 | 1659 |
/// This method runs the %BFS algorithm from node \c s |
1652 | 1660 |
/// in order to compute the shortest path to each node. |
1653 | 1661 |
/// |
1654 | 1662 |
/// The algorithm computes |
1655 | 1663 |
/// - the shortest path tree, |
1656 | 1664 |
/// - the distance of each node from the root. |
1657 | 1665 |
/// |
1658 | 1666 |
/// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
1659 | 1667 |
///\code |
1660 | 1668 |
/// b.init(); |
1661 | 1669 |
/// b.addSource(s); |
1662 | 1670 |
/// b.start(); |
1663 | 1671 |
///\endcode |
1664 | 1672 |
void run(Node s) { |
1665 | 1673 |
init(); |
1666 | 1674 |
addSource(s); |
1667 | 1675 |
start(); |
1668 | 1676 |
} |
1669 | 1677 |
|
1670 | 1678 |
/// \brief Finds the shortest path between \c s and \c t. |
1671 | 1679 |
/// |
1672 | 1680 |
/// This method runs the %BFS algorithm from node \c s |
1673 | 1681 |
/// in order to compute the shortest path to node \c t |
1674 | 1682 |
/// (it stops searching when \c t is processed). |
1675 | 1683 |
/// |
1676 | 1684 |
/// \return \c true if \c t is reachable form \c s. |
1677 | 1685 |
/// |
1678 | 1686 |
/// \note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
1679 | 1687 |
/// shortcut of the following code. |
1680 | 1688 |
///\code |
1681 | 1689 |
/// b.init(); |
1682 | 1690 |
/// b.addSource(s); |
1683 | 1691 |
/// b.start(t); |
1684 | 1692 |
///\endcode |
1685 | 1693 |
bool run(Node s,Node t) { |
1686 | 1694 |
init(); |
1 | 1 |
/* -*- C++ -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2008 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_CAPACITY_SCALING_H |
20 | 20 |
#define LEMON_CAPACITY_SCALING_H |
21 | 21 |
|
22 | 22 |
/// \ingroup min_cost_flow_algs |
23 | 23 |
/// |
24 | 24 |
/// \file |
25 | 25 |
/// \brief Capacity Scaling algorithm for finding a minimum cost flow. |
26 | 26 |
|
27 | 27 |
#include <vector> |
28 | 28 |
#include <limits> |
29 | 29 |
#include <lemon/core.h> |
30 | 30 |
#include <lemon/bin_heap.h> |
31 | 31 |
|
32 | 32 |
namespace lemon { |
33 | 33 |
|
34 | 34 |
/// \brief Default traits class of CapacityScaling algorithm. |
35 | 35 |
/// |
36 | 36 |
/// Default traits class of CapacityScaling algorithm. |
37 | 37 |
/// \tparam GR Digraph type. |
38 | 38 |
/// \tparam V The number type used for flow amounts, capacity bounds |
39 | 39 |
/// and supply values. By default it is \c int. |
40 | 40 |
/// \tparam C The number type used for costs and potentials. |
41 | 41 |
/// By default it is the same as \c V. |
42 | 42 |
template <typename GR, typename V = int, typename C = V> |
43 | 43 |
struct CapacityScalingDefaultTraits |
44 | 44 |
{ |
45 | 45 |
/// The type of the digraph |
46 | 46 |
typedef GR Digraph; |
47 | 47 |
/// The type of the flow amounts, capacity bounds and supply values |
48 | 48 |
typedef V Value; |
49 | 49 |
/// The type of the arc costs |
50 | 50 |
typedef C Cost; |
51 | 51 |
|
52 | 52 |
/// \brief The type of the heap used for internal Dijkstra computations. |
53 | 53 |
/// |
54 | 54 |
/// The type of the heap used for internal Dijkstra computations. |
55 | 55 |
/// It must conform to the \ref lemon::concepts::Heap "Heap" concept, |
56 | 56 |
/// its priority type must be \c Cost and its cross reference type |
57 | 57 |
/// must be \ref RangeMap "RangeMap<int>". |
58 | 58 |
typedef BinHeap<Cost, RangeMap<int> > Heap; |
59 | 59 |
}; |
60 | 60 |
|
61 | 61 |
/// \addtogroup min_cost_flow_algs |
62 | 62 |
/// @{ |
63 | 63 |
|
64 | 64 |
/// \brief Implementation of the Capacity Scaling algorithm for |
65 | 65 |
/// finding a \ref min_cost_flow "minimum cost flow". |
66 | 66 |
/// |
67 | 67 |
/// \ref CapacityScaling implements the capacity scaling version |
68 | 68 |
/// of the successive shortest path algorithm for finding a |
69 | 69 |
/// \ref min_cost_flow "minimum cost flow" \ref amo93networkflows, |
70 | 70 |
/// \ref edmondskarp72theoretical. It is an efficient dual |
71 | 71 |
/// solution method. |
72 | 72 |
/// |
73 | 73 |
/// Most of the parameters of the problem (except for the digraph) |
74 | 74 |
/// can be given using separate functions, and the algorithm can be |
75 | 75 |
/// executed using the \ref run() function. If some parameters are not |
76 | 76 |
/// specified, then default values will be used. |
77 | 77 |
/// |
78 | 78 |
/// \tparam GR The digraph type the algorithm runs on. |
79 | 79 |
/// \tparam V The number type used for flow amounts, capacity bounds |
80 |
/// and supply values in the algorithm. By default it is \c int. |
|
80 |
/// and supply values in the algorithm. By default, it is \c int. |
|
81 | 81 |
/// \tparam C The number type used for costs and potentials in the |
82 |
/// algorithm. By default it is the same as \c V. |
|
82 |
/// algorithm. By default, it is the same as \c V. |
|
83 |
/// \tparam TR The traits class that defines various types used by the |
|
84 |
/// algorithm. By default, it is \ref CapacityScalingDefaultTraits |
|
85 |
/// "CapacityScalingDefaultTraits<GR, V, C>". |
|
86 |
/// In most cases, this parameter should not be set directly, |
|
87 |
/// consider to use the named template parameters instead. |
|
83 | 88 |
/// |
84 | 89 |
/// \warning Both number types must be signed and all input data must |
85 | 90 |
/// be integer. |
86 | 91 |
/// \warning This algorithm does not support negative costs for such |
87 | 92 |
/// arcs that have infinite upper bound. |
88 | 93 |
#ifdef DOXYGEN |
89 | 94 |
template <typename GR, typename V, typename C, typename TR> |
90 | 95 |
#else |
91 | 96 |
template < typename GR, typename V = int, typename C = V, |
92 | 97 |
typename TR = CapacityScalingDefaultTraits<GR, V, C> > |
93 | 98 |
#endif |
94 | 99 |
class CapacityScaling |
95 | 100 |
{ |
96 | 101 |
public: |
97 | 102 |
|
98 | 103 |
/// The type of the digraph |
99 | 104 |
typedef typename TR::Digraph Digraph; |
100 | 105 |
/// The type of the flow amounts, capacity bounds and supply values |
101 | 106 |
typedef typename TR::Value Value; |
102 | 107 |
/// The type of the arc costs |
103 | 108 |
typedef typename TR::Cost Cost; |
104 | 109 |
|
105 | 110 |
/// The type of the heap used for internal Dijkstra computations |
106 | 111 |
typedef typename TR::Heap Heap; |
107 | 112 |
|
108 | 113 |
/// The \ref CapacityScalingDefaultTraits "traits class" of the algorithm |
109 | 114 |
typedef TR Traits; |
110 | 115 |
|
111 | 116 |
public: |
112 | 117 |
|
113 | 118 |
/// \brief Problem type constants for the \c run() function. |
114 | 119 |
/// |
115 | 120 |
/// Enum type containing the problem type constants that can be |
116 | 121 |
/// returned by the \ref run() function of the algorithm. |
117 | 122 |
enum ProblemType { |
118 | 123 |
/// The problem has no feasible solution (flow). |
119 | 124 |
INFEASIBLE, |
120 | 125 |
/// The problem has optimal solution (i.e. it is feasible and |
121 | 126 |
/// bounded), and the algorithm has found optimal flow and node |
122 | 127 |
/// potentials (primal and dual solutions). |
123 | 128 |
OPTIMAL, |
124 | 129 |
/// The digraph contains an arc of negative cost and infinite |
125 | 130 |
/// upper bound. It means that the objective function is unbounded |
126 | 131 |
/// on that arc, however, note that it could actually be bounded |
127 | 132 |
/// over the feasible flows, but this algroithm cannot handle |
128 | 133 |
/// these cases. |
129 | 134 |
UNBOUNDED |
130 | 135 |
}; |
131 | 136 |
|
132 | 137 |
private: |
133 | 138 |
|
134 | 139 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
135 | 140 |
|
136 | 141 |
typedef std::vector<int> IntVector; |
137 | 142 |
typedef std::vector<char> BoolVector; |
138 | 143 |
typedef std::vector<Value> ValueVector; |
139 | 144 |
typedef std::vector<Cost> CostVector; |
140 | 145 |
|
141 | 146 |
private: |
142 | 147 |
|
143 | 148 |
// Data related to the underlying digraph |
144 | 149 |
const GR &_graph; |
145 | 150 |
int _node_num; |
146 | 151 |
int _arc_num; |
147 | 152 |
int _res_arc_num; |
148 | 153 |
int _root; |
149 | 154 |
|
150 | 155 |
// Parameters of the problem |
151 | 156 |
bool _have_lower; |
152 | 157 |
Value _sum_supply; |
153 | 158 |
|
154 | 159 |
// Data structures for storing the digraph |
155 | 160 |
IntNodeMap _node_id; |
156 | 161 |
IntArcMap _arc_idf; |
157 | 162 |
IntArcMap _arc_idb; |
158 | 163 |
IntVector _first_out; |
159 | 164 |
BoolVector _forward; |
160 | 165 |
IntVector _source; |
161 | 166 |
IntVector _target; |
162 | 167 |
IntVector _reverse; |
163 | 168 |
|
164 | 169 |
// Node and arc data |
165 | 170 |
ValueVector _lower; |
166 | 171 |
ValueVector _upper; |
167 | 172 |
CostVector _cost; |
168 | 173 |
ValueVector _supply; |
169 | 174 |
|
170 | 175 |
ValueVector _res_cap; |
171 | 176 |
CostVector _pi; |
172 | 177 |
ValueVector _excess; |
173 | 178 |
IntVector _excess_nodes; |
174 | 179 |
IntVector _deficit_nodes; |
175 | 180 |
|
176 | 181 |
Value _delta; |
177 | 182 |
int _factor; |
178 | 183 |
IntVector _pred; |
179 | 184 |
|
180 | 185 |
public: |
181 | 186 |
|
182 | 187 |
/// \brief Constant for infinite upper bounds (capacities). |
183 | 188 |
/// |
184 | 189 |
/// Constant for infinite upper bounds (capacities). |
185 | 190 |
/// It is \c std::numeric_limits<Value>::infinity() if available, |
186 | 191 |
/// \c std::numeric_limits<Value>::max() otherwise. |
187 | 192 |
const Value INF; |
188 | 193 |
|
189 | 194 |
private: |
190 | 195 |
|
191 | 196 |
// Special implementation of the Dijkstra algorithm for finding |
192 | 197 |
// shortest paths in the residual network of the digraph with |
193 | 198 |
// respect to the reduced arc costs and modifying the node |
194 | 199 |
// potentials according to the found distance labels. |
195 | 200 |
class ResidualDijkstra |
196 | 201 |
{ |
197 | 202 |
private: |
198 | 203 |
|
199 | 204 |
int _node_num; |
200 | 205 |
bool _geq; |
201 | 206 |
const IntVector &_first_out; |
202 | 207 |
const IntVector &_target; |
203 | 208 |
const CostVector &_cost; |
204 | 209 |
const ValueVector &_res_cap; |
205 | 210 |
const ValueVector &_excess; |
206 | 211 |
CostVector &_pi; |
207 | 212 |
IntVector &_pred; |
208 | 213 |
|
209 | 214 |
IntVector _proc_nodes; |
210 | 215 |
CostVector _dist; |
211 | 216 |
|
212 | 217 |
public: |
213 | 218 |
|
214 | 219 |
ResidualDijkstra(CapacityScaling& cs) : |
215 | 220 |
_node_num(cs._node_num), _geq(cs._sum_supply < 0), |
216 | 221 |
_first_out(cs._first_out), _target(cs._target), _cost(cs._cost), |
217 | 222 |
_res_cap(cs._res_cap), _excess(cs._excess), _pi(cs._pi), |
218 | 223 |
_pred(cs._pred), _dist(cs._node_num) |
219 | 224 |
{} |
220 | 225 |
|
221 | 226 |
int run(int s, Value delta = 1) { |
222 | 227 |
RangeMap<int> heap_cross_ref(_node_num, Heap::PRE_HEAP); |
223 | 228 |
Heap heap(heap_cross_ref); |
224 | 229 |
heap.push(s, 0); |
225 | 230 |
_pred[s] = -1; |
226 | 231 |
_proc_nodes.clear(); |
227 | 232 |
|
228 | 233 |
// Process nodes |
229 | 234 |
while (!heap.empty() && _excess[heap.top()] > -delta) { |
230 | 235 |
int u = heap.top(), v; |
231 | 236 |
Cost d = heap.prio() + _pi[u], dn; |
232 | 237 |
_dist[u] = heap.prio(); |
233 | 238 |
_proc_nodes.push_back(u); |
234 | 239 |
heap.pop(); |
235 | 240 |
|
236 | 241 |
// Traverse outgoing residual arcs |
237 | 242 |
int last_out = _geq ? _first_out[u+1] : _first_out[u+1] - 1; |
238 | 243 |
for (int a = _first_out[u]; a != last_out; ++a) { |
239 | 244 |
if (_res_cap[a] < delta) continue; |
240 | 245 |
v = _target[a]; |
241 | 246 |
switch (heap.state(v)) { |
242 | 247 |
case Heap::PRE_HEAP: |
243 | 248 |
heap.push(v, d + _cost[a] - _pi[v]); |
244 | 249 |
_pred[v] = a; |
245 | 250 |
break; |
246 | 251 |
case Heap::IN_HEAP: |
247 | 252 |
dn = d + _cost[a] - _pi[v]; |
248 | 253 |
if (dn < heap[v]) { |
249 | 254 |
heap.decrease(v, dn); |
250 | 255 |
_pred[v] = a; |
251 | 256 |
} |
252 | 257 |
break; |
253 | 258 |
case Heap::POST_HEAP: |
254 | 259 |
break; |
255 | 260 |
} |
256 | 261 |
} |
257 | 262 |
} |
258 | 263 |
if (heap.empty()) return -1; |
259 | 264 |
|
260 | 265 |
// Update potentials of processed nodes |
261 | 266 |
int t = heap.top(); |
262 | 267 |
Cost dt = heap.prio(); |
263 | 268 |
for (int i = 0; i < int(_proc_nodes.size()); ++i) { |
264 | 269 |
_pi[_proc_nodes[i]] += _dist[_proc_nodes[i]] - dt; |
265 | 270 |
} |
266 | 271 |
|
267 | 272 |
return t; |
268 | 273 |
} |
269 | 274 |
|
270 | 275 |
}; //class ResidualDijkstra |
271 | 276 |
|
272 | 277 |
public: |
273 | 278 |
|
274 | 279 |
/// \name Named Template Parameters |
275 | 280 |
/// @{ |
276 | 281 |
|
277 | 282 |
template <typename T> |
278 | 283 |
struct SetHeapTraits : public Traits { |
279 | 284 |
typedef T Heap; |
280 | 285 |
}; |
281 | 286 |
|
282 | 287 |
/// \brief \ref named-templ-param "Named parameter" for setting |
283 | 288 |
/// \c Heap type. |
284 | 289 |
/// |
285 | 290 |
/// \ref named-templ-param "Named parameter" for setting \c Heap |
286 | 291 |
/// type, which is used for internal Dijkstra computations. |
287 | 292 |
/// It must conform to the \ref lemon::concepts::Heap "Heap" concept, |
288 | 293 |
/// its priority type must be \c Cost and its cross reference type |
289 | 294 |
/// must be \ref RangeMap "RangeMap<int>". |
290 | 295 |
template <typename T> |
291 | 296 |
struct SetHeap |
292 | 297 |
: public CapacityScaling<GR, V, C, SetHeapTraits<T> > { |
293 | 298 |
typedef CapacityScaling<GR, V, C, SetHeapTraits<T> > Create; |
294 | 299 |
}; |
295 | 300 |
|
296 | 301 |
/// @} |
297 | 302 |
|
298 | 303 |
public: |
299 | 304 |
|
300 | 305 |
/// \brief Constructor. |
301 | 306 |
/// |
302 | 307 |
/// The constructor of the class. |
303 | 308 |
/// |
304 | 309 |
/// \param graph The digraph the algorithm runs on. |
305 | 310 |
CapacityScaling(const GR& graph) : |
306 | 311 |
_graph(graph), _node_id(graph), _arc_idf(graph), _arc_idb(graph), |
307 | 312 |
INF(std::numeric_limits<Value>::has_infinity ? |
308 | 313 |
std::numeric_limits<Value>::infinity() : |
309 | 314 |
std::numeric_limits<Value>::max()) |
310 | 315 |
{ |
311 | 316 |
// Check the number types |
312 | 317 |
LEMON_ASSERT(std::numeric_limits<Value>::is_signed, |
313 | 318 |
"The flow type of CapacityScaling must be signed"); |
314 | 319 |
LEMON_ASSERT(std::numeric_limits<Cost>::is_signed, |
315 | 320 |
"The cost type of CapacityScaling must be signed"); |
316 | 321 |
|
317 | 322 |
// Resize vectors |
318 | 323 |
_node_num = countNodes(_graph); |
319 | 324 |
_arc_num = countArcs(_graph); |
320 | 325 |
_res_arc_num = 2 * (_arc_num + _node_num); |
321 | 326 |
_root = _node_num; |
322 | 327 |
++_node_num; |
323 | 328 |
|
324 | 329 |
_first_out.resize(_node_num + 1); |
325 | 330 |
_forward.resize(_res_arc_num); |
326 | 331 |
_source.resize(_res_arc_num); |
327 | 332 |
_target.resize(_res_arc_num); |
328 | 333 |
_reverse.resize(_res_arc_num); |
329 | 334 |
|
330 | 335 |
_lower.resize(_res_arc_num); |
331 | 336 |
_upper.resize(_res_arc_num); |
332 | 337 |
_cost.resize(_res_arc_num); |
333 | 338 |
_supply.resize(_node_num); |
334 | 339 |
|
335 | 340 |
_res_cap.resize(_res_arc_num); |
336 | 341 |
_pi.resize(_node_num); |
337 | 342 |
_excess.resize(_node_num); |
338 | 343 |
_pred.resize(_node_num); |
339 | 344 |
|
340 | 345 |
// Copy the graph |
341 | 346 |
int i = 0, j = 0, k = 2 * _arc_num + _node_num - 1; |
342 | 347 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) { |
343 | 348 |
_node_id[n] = i; |
344 | 349 |
} |
345 | 350 |
i = 0; |
346 | 351 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) { |
347 | 352 |
_first_out[i] = j; |
348 | 353 |
for (OutArcIt a(_graph, n); a != INVALID; ++a, ++j) { |
349 | 354 |
_arc_idf[a] = j; |
350 | 355 |
_forward[j] = true; |
351 | 356 |
_source[j] = i; |
352 | 357 |
_target[j] = _node_id[_graph.runningNode(a)]; |
353 | 358 |
} |
354 | 359 |
for (InArcIt a(_graph, n); a != INVALID; ++a, ++j) { |
355 | 360 |
_arc_idb[a] = j; |
356 | 361 |
_forward[j] = false; |
357 | 362 |
_source[j] = i; |
358 | 363 |
_target[j] = _node_id[_graph.runningNode(a)]; |
359 | 364 |
} |
360 | 365 |
_forward[j] = false; |
361 | 366 |
_source[j] = i; |
362 | 367 |
_target[j] = _root; |
363 | 368 |
_reverse[j] = k; |
364 | 369 |
_forward[k] = true; |
365 | 370 |
_source[k] = _root; |
366 | 371 |
_target[k] = i; |
367 | 372 |
_reverse[k] = j; |
368 | 373 |
++j; ++k; |
369 | 374 |
} |
370 | 375 |
_first_out[i] = j; |
371 | 376 |
_first_out[_node_num] = k; |
372 | 377 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
373 | 378 |
int fi = _arc_idf[a]; |
374 | 379 |
int bi = _arc_idb[a]; |
375 | 380 |
_reverse[fi] = bi; |
376 | 381 |
_reverse[bi] = fi; |
377 | 382 |
} |
378 | 383 |
|
379 | 384 |
// Reset parameters |
380 | 385 |
reset(); |
381 | 386 |
} |
382 | 387 |
|
383 | 388 |
/// \name Parameters |
384 | 389 |
/// The parameters of the algorithm can be specified using these |
385 | 390 |
/// functions. |
386 | 391 |
|
387 | 392 |
/// @{ |
388 | 393 |
|
389 | 394 |
/// \brief Set the lower bounds on the arcs. |
390 | 395 |
/// |
391 | 396 |
/// This function sets the lower bounds on the arcs. |
392 | 397 |
/// If it is not used before calling \ref run(), the lower bounds |
393 | 398 |
/// will be set to zero on all arcs. |
394 | 399 |
/// |
395 | 400 |
/// \param map An arc map storing the lower bounds. |
396 | 401 |
/// Its \c Value type must be convertible to the \c Value type |
397 | 402 |
/// of the algorithm. |
398 | 403 |
/// |
399 | 404 |
/// \return <tt>(*this)</tt> |
400 | 405 |
template <typename LowerMap> |
401 | 406 |
CapacityScaling& lowerMap(const LowerMap& map) { |
402 | 407 |
_have_lower = true; |
403 | 408 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
404 | 409 |
_lower[_arc_idf[a]] = map[a]; |
405 | 410 |
_lower[_arc_idb[a]] = map[a]; |
406 | 411 |
} |
407 | 412 |
return *this; |
408 | 413 |
} |
409 | 414 |
|
410 | 415 |
/// \brief Set the upper bounds (capacities) on the arcs. |
411 | 416 |
/// |
412 | 417 |
/// This function sets the upper bounds (capacities) on the arcs. |
413 | 418 |
/// If it is not used before calling \ref run(), the upper bounds |
414 | 419 |
/// will be set to \ref INF on all arcs (i.e. the flow value will be |
415 | 420 |
/// unbounded from above). |
416 | 421 |
/// |
417 | 422 |
/// \param map An arc map storing the upper bounds. |
418 | 423 |
/// Its \c Value type must be convertible to the \c Value type |
419 | 424 |
/// of the algorithm. |
420 | 425 |
/// |
421 | 426 |
/// \return <tt>(*this)</tt> |
422 | 427 |
template<typename UpperMap> |
423 | 428 |
CapacityScaling& upperMap(const UpperMap& map) { |
424 | 429 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
425 | 430 |
_upper[_arc_idf[a]] = map[a]; |
426 | 431 |
} |
427 | 432 |
return *this; |
428 | 433 |
} |
429 | 434 |
|
430 | 435 |
/// \brief Set the costs of the arcs. |
431 | 436 |
/// |
432 | 437 |
/// This function sets the costs of the arcs. |
433 | 438 |
/// If it is not used before calling \ref run(), the costs |
434 | 439 |
/// will be set to \c 1 on all arcs. |
435 | 440 |
/// |
436 | 441 |
/// \param map An arc map storing the costs. |
437 | 442 |
/// Its \c Value type must be convertible to the \c Cost type |
438 | 443 |
/// of the algorithm. |
439 | 444 |
/// |
440 | 445 |
/// \return <tt>(*this)</tt> |
441 | 446 |
template<typename CostMap> |
442 | 447 |
CapacityScaling& costMap(const CostMap& map) { |
443 | 448 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
444 | 449 |
_cost[_arc_idf[a]] = map[a]; |
445 | 450 |
_cost[_arc_idb[a]] = -map[a]; |
446 | 451 |
} |
447 | 452 |
return *this; |
448 | 453 |
} |
449 | 454 |
|
450 | 455 |
/// \brief Set the supply values of the nodes. |
451 | 456 |
/// |
452 | 457 |
/// This function sets the supply values of the nodes. |
453 | 458 |
/// If neither this function nor \ref stSupply() is used before |
454 | 459 |
/// calling \ref run(), the supply of each node will be set to zero. |
455 | 460 |
/// |
456 | 461 |
/// \param map A node map storing the supply values. |
457 | 462 |
/// Its \c Value type must be convertible to the \c Value type |
458 | 463 |
/// of the algorithm. |
459 | 464 |
/// |
460 | 465 |
/// \return <tt>(*this)</tt> |
461 | 466 |
template<typename SupplyMap> |
462 | 467 |
CapacityScaling& supplyMap(const SupplyMap& map) { |
463 | 468 |
for (NodeIt n(_graph); n != INVALID; ++n) { |
464 | 469 |
_supply[_node_id[n]] = map[n]; |
465 | 470 |
} |
466 | 471 |
return *this; |
1 | 1 |
/* -*- mode: C++; indent-tabs-mode: nil; -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library. |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2009 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_CIRCULATION_H |
20 | 20 |
#define LEMON_CIRCULATION_H |
21 | 21 |
|
22 | 22 |
#include <lemon/tolerance.h> |
23 | 23 |
#include <lemon/elevator.h> |
24 | 24 |
#include <limits> |
25 | 25 |
|
26 | 26 |
///\ingroup max_flow |
27 | 27 |
///\file |
28 | 28 |
///\brief Push-relabel algorithm for finding a feasible circulation. |
29 | 29 |
/// |
30 | 30 |
namespace lemon { |
31 | 31 |
|
32 | 32 |
/// \brief Default traits class of Circulation class. |
33 | 33 |
/// |
34 | 34 |
/// Default traits class of Circulation class. |
35 | 35 |
/// |
36 | 36 |
/// \tparam GR Type of the digraph the algorithm runs on. |
37 | 37 |
/// \tparam LM The type of the lower bound map. |
38 | 38 |
/// \tparam UM The type of the upper bound (capacity) map. |
39 | 39 |
/// \tparam SM The type of the supply map. |
40 | 40 |
template <typename GR, typename LM, |
41 | 41 |
typename UM, typename SM> |
42 | 42 |
struct CirculationDefaultTraits { |
43 | 43 |
|
44 | 44 |
/// \brief The type of the digraph the algorithm runs on. |
45 | 45 |
typedef GR Digraph; |
46 | 46 |
|
47 | 47 |
/// \brief The type of the lower bound map. |
48 | 48 |
/// |
49 | 49 |
/// The type of the map that stores the lower bounds on the arcs. |
50 | 50 |
/// It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
51 | 51 |
typedef LM LowerMap; |
52 | 52 |
|
53 | 53 |
/// \brief The type of the upper bound (capacity) map. |
54 | 54 |
/// |
55 | 55 |
/// The type of the map that stores the upper bounds (capacities) |
56 | 56 |
/// on the arcs. |
57 | 57 |
/// It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
58 | 58 |
typedef UM UpperMap; |
59 | 59 |
|
60 | 60 |
/// \brief The type of supply map. |
61 | 61 |
/// |
62 | 62 |
/// The type of the map that stores the signed supply values of the |
63 | 63 |
/// nodes. |
64 | 64 |
/// It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
65 | 65 |
typedef SM SupplyMap; |
66 | 66 |
|
67 | 67 |
/// \brief The type of the flow and supply values. |
68 | 68 |
typedef typename SupplyMap::Value Value; |
69 | 69 |
|
70 | 70 |
/// \brief The type of the map that stores the flow values. |
71 | 71 |
/// |
72 | 72 |
/// The type of the map that stores the flow values. |
73 | 73 |
/// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" |
74 | 74 |
/// concept. |
75 | 75 |
#ifdef DOXYGEN |
76 | 76 |
typedef GR::ArcMap<Value> FlowMap; |
77 | 77 |
#else |
78 | 78 |
typedef typename Digraph::template ArcMap<Value> FlowMap; |
79 | 79 |
#endif |
80 | 80 |
|
81 | 81 |
/// \brief Instantiates a FlowMap. |
82 | 82 |
/// |
83 | 83 |
/// This function instantiates a \ref FlowMap. |
84 | 84 |
/// \param digraph The digraph for which we would like to define |
85 | 85 |
/// the flow map. |
86 | 86 |
static FlowMap* createFlowMap(const Digraph& digraph) { |
87 | 87 |
return new FlowMap(digraph); |
88 | 88 |
} |
89 | 89 |
|
90 | 90 |
/// \brief The elevator type used by the algorithm. |
91 | 91 |
/// |
92 | 92 |
/// The elevator type used by the algorithm. |
93 | 93 |
/// |
94 | 94 |
/// \sa Elevator, LinkedElevator |
95 | 95 |
#ifdef DOXYGEN |
96 | 96 |
typedef lemon::Elevator<GR, GR::Node> Elevator; |
97 | 97 |
#else |
98 | 98 |
typedef lemon::Elevator<Digraph, typename Digraph::Node> Elevator; |
99 | 99 |
#endif |
100 | 100 |
|
101 | 101 |
/// \brief Instantiates an Elevator. |
102 | 102 |
/// |
103 | 103 |
/// This function instantiates an \ref Elevator. |
104 | 104 |
/// \param digraph The digraph for which we would like to define |
105 | 105 |
/// the elevator. |
106 | 106 |
/// \param max_level The maximum level of the elevator. |
107 | 107 |
static Elevator* createElevator(const Digraph& digraph, int max_level) { |
108 | 108 |
return new Elevator(digraph, max_level); |
109 | 109 |
} |
110 | 110 |
|
111 | 111 |
/// \brief The tolerance used by the algorithm |
112 | 112 |
/// |
113 | 113 |
/// The tolerance used by the algorithm to handle inexact computation. |
114 | 114 |
typedef lemon::Tolerance<Value> Tolerance; |
115 | 115 |
|
116 | 116 |
}; |
117 | 117 |
|
118 | 118 |
/** |
119 | 119 |
\brief Push-relabel algorithm for the network circulation problem. |
120 | 120 |
|
121 | 121 |
\ingroup max_flow |
122 | 122 |
This class implements a push-relabel algorithm for the \e network |
123 | 123 |
\e circulation problem. |
124 | 124 |
It is to find a feasible circulation when lower and upper bounds |
125 | 125 |
are given for the flow values on the arcs and lower bounds are |
126 | 126 |
given for the difference between the outgoing and incoming flow |
127 | 127 |
at the nodes. |
128 | 128 |
|
129 | 129 |
The exact formulation of this problem is the following. |
130 | 130 |
Let \f$G=(V,A)\f$ be a digraph, \f$lower: A\rightarrow\mathbf{R}\f$ |
131 | 131 |
\f$upper: A\rightarrow\mathbf{R}\cup\{\infty\}\f$ denote the lower and |
132 | 132 |
upper bounds on the arcs, for which \f$lower(uv) \leq upper(uv)\f$ |
133 | 133 |
holds for all \f$uv\in A\f$, and \f$sup: V\rightarrow\mathbf{R}\f$ |
134 | 134 |
denotes the signed supply values of the nodes. |
135 | 135 |
If \f$sup(u)>0\f$, then \f$u\f$ is a supply node with \f$sup(u)\f$ |
136 | 136 |
supply, if \f$sup(u)<0\f$, then \f$u\f$ is a demand node with |
137 | 137 |
\f$-sup(u)\f$ demand. |
138 | 138 |
A feasible circulation is an \f$f: A\rightarrow\mathbf{R}\f$ |
139 | 139 |
solution of the following problem. |
140 | 140 |
|
141 | 141 |
\f[ \sum_{uv\in A} f(uv) - \sum_{vu\in A} f(vu) |
142 | 142 |
\geq sup(u) \quad \forall u\in V, \f] |
143 | 143 |
\f[ lower(uv) \leq f(uv) \leq upper(uv) \quad \forall uv\in A. \f] |
144 | 144 |
|
145 | 145 |
The sum of the supply values, i.e. \f$\sum_{u\in V} sup(u)\f$ must be |
146 | 146 |
zero or negative in order to have a feasible solution (since the sum |
147 | 147 |
of the expressions on the left-hand side of the inequalities is zero). |
148 | 148 |
It means that the total demand must be greater or equal to the total |
149 | 149 |
supply and all the supplies have to be carried out from the supply nodes, |
150 | 150 |
but there could be demands that are not satisfied. |
151 | 151 |
If \f$\sum_{u\in V} sup(u)\f$ is zero, then all the supply/demand |
152 | 152 |
constraints have to be satisfied with equality, i.e. all demands |
153 | 153 |
have to be satisfied and all supplies have to be used. |
154 | 154 |
|
155 | 155 |
If you need the opposite inequalities in the supply/demand constraints |
156 | 156 |
(i.e. the total demand is less than the total supply and all the demands |
157 | 157 |
have to be satisfied while there could be supplies that are not used), |
158 | 158 |
then you could easily transform the problem to the above form by reversing |
159 | 159 |
the direction of the arcs and taking the negative of the supply values |
160 | 160 |
(e.g. using \ref ReverseDigraph and \ref NegMap adaptors). |
161 | 161 |
|
162 | 162 |
This algorithm either calculates a feasible circulation, or provides |
163 | 163 |
a \ref barrier() "barrier", which prooves that a feasible soultion |
164 | 164 |
cannot exist. |
165 | 165 |
|
166 | 166 |
Note that this algorithm also provides a feasible solution for the |
167 | 167 |
\ref min_cost_flow "minimum cost flow problem". |
168 | 168 |
|
169 | 169 |
\tparam GR The type of the digraph the algorithm runs on. |
170 | 170 |
\tparam LM The type of the lower bound map. The default |
171 | 171 |
map type is \ref concepts::Digraph::ArcMap "GR::ArcMap<int>". |
172 | 172 |
\tparam UM The type of the upper bound (capacity) map. |
173 | 173 |
The default map type is \c LM. |
174 | 174 |
\tparam SM The type of the supply map. The default map type is |
175 | 175 |
\ref concepts::Digraph::NodeMap "GR::NodeMap<UM::Value>". |
176 |
\tparam TR The traits class that defines various types used by the |
|
177 |
algorithm. By default, it is \ref CirculationDefaultTraits |
|
178 |
"CirculationDefaultTraits<GR, LM, UM, SM>". |
|
179 |
In most cases, this parameter should not be set directly, |
|
180 |
consider to use the named template parameters instead. |
|
176 | 181 |
*/ |
177 | 182 |
#ifdef DOXYGEN |
178 | 183 |
template< typename GR, |
179 | 184 |
typename LM, |
180 | 185 |
typename UM, |
181 | 186 |
typename SM, |
182 | 187 |
typename TR > |
183 | 188 |
#else |
184 | 189 |
template< typename GR, |
185 | 190 |
typename LM = typename GR::template ArcMap<int>, |
186 | 191 |
typename UM = LM, |
187 | 192 |
typename SM = typename GR::template NodeMap<typename UM::Value>, |
188 | 193 |
typename TR = CirculationDefaultTraits<GR, LM, UM, SM> > |
189 | 194 |
#endif |
190 | 195 |
class Circulation { |
191 | 196 |
public: |
192 | 197 |
|
193 | 198 |
///The \ref CirculationDefaultTraits "traits class" of the algorithm. |
194 | 199 |
typedef TR Traits; |
195 | 200 |
///The type of the digraph the algorithm runs on. |
196 | 201 |
typedef typename Traits::Digraph Digraph; |
197 | 202 |
///The type of the flow and supply values. |
198 | 203 |
typedef typename Traits::Value Value; |
199 | 204 |
|
200 | 205 |
///The type of the lower bound map. |
201 | 206 |
typedef typename Traits::LowerMap LowerMap; |
202 | 207 |
///The type of the upper bound (capacity) map. |
203 | 208 |
typedef typename Traits::UpperMap UpperMap; |
204 | 209 |
///The type of the supply map. |
205 | 210 |
typedef typename Traits::SupplyMap SupplyMap; |
206 | 211 |
///The type of the flow map. |
207 | 212 |
typedef typename Traits::FlowMap FlowMap; |
208 | 213 |
|
209 | 214 |
///The type of the elevator. |
210 | 215 |
typedef typename Traits::Elevator Elevator; |
211 | 216 |
///The type of the tolerance. |
212 | 217 |
typedef typename Traits::Tolerance Tolerance; |
213 | 218 |
|
214 | 219 |
private: |
215 | 220 |
|
216 | 221 |
TEMPLATE_DIGRAPH_TYPEDEFS(Digraph); |
217 | 222 |
|
218 | 223 |
const Digraph &_g; |
219 | 224 |
int _node_num; |
220 | 225 |
|
221 | 226 |
const LowerMap *_lo; |
222 | 227 |
const UpperMap *_up; |
223 | 228 |
const SupplyMap *_supply; |
224 | 229 |
|
225 | 230 |
FlowMap *_flow; |
226 | 231 |
bool _local_flow; |
227 | 232 |
|
228 | 233 |
Elevator* _level; |
229 | 234 |
bool _local_level; |
230 | 235 |
|
231 | 236 |
typedef typename Digraph::template NodeMap<Value> ExcessMap; |
232 | 237 |
ExcessMap* _excess; |
233 | 238 |
|
234 | 239 |
Tolerance _tol; |
235 | 240 |
int _el; |
236 | 241 |
|
237 | 242 |
public: |
238 | 243 |
|
239 | 244 |
typedef Circulation Create; |
240 | 245 |
|
241 | 246 |
///\name Named Template Parameters |
242 | 247 |
|
243 | 248 |
///@{ |
244 | 249 |
|
245 | 250 |
template <typename T> |
246 | 251 |
struct SetFlowMapTraits : public Traits { |
247 | 252 |
typedef T FlowMap; |
248 | 253 |
static FlowMap *createFlowMap(const Digraph&) { |
249 | 254 |
LEMON_ASSERT(false, "FlowMap is not initialized"); |
250 | 255 |
return 0; // ignore warnings |
251 | 256 |
} |
252 | 257 |
}; |
253 | 258 |
|
254 | 259 |
/// \brief \ref named-templ-param "Named parameter" for setting |
255 | 260 |
/// FlowMap type |
256 | 261 |
/// |
257 | 262 |
/// \ref named-templ-param "Named parameter" for setting FlowMap |
258 | 263 |
/// type. |
259 | 264 |
template <typename T> |
260 | 265 |
struct SetFlowMap |
261 | 266 |
: public Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
262 | 267 |
SetFlowMapTraits<T> > { |
263 | 268 |
typedef Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
264 | 269 |
SetFlowMapTraits<T> > Create; |
265 | 270 |
}; |
266 | 271 |
|
267 | 272 |
template <typename T> |
268 | 273 |
struct SetElevatorTraits : public Traits { |
269 | 274 |
typedef T Elevator; |
270 | 275 |
static Elevator *createElevator(const Digraph&, int) { |
271 | 276 |
LEMON_ASSERT(false, "Elevator is not initialized"); |
272 | 277 |
return 0; // ignore warnings |
273 | 278 |
} |
274 | 279 |
}; |
275 | 280 |
|
276 | 281 |
/// \brief \ref named-templ-param "Named parameter" for setting |
277 | 282 |
/// Elevator type |
278 | 283 |
/// |
279 | 284 |
/// \ref named-templ-param "Named parameter" for setting Elevator |
280 | 285 |
/// type. If this named parameter is used, then an external |
281 | 286 |
/// elevator object must be passed to the algorithm using the |
282 | 287 |
/// \ref elevator(Elevator&) "elevator()" function before calling |
283 | 288 |
/// \ref run() or \ref init(). |
284 | 289 |
/// \sa SetStandardElevator |
285 | 290 |
template <typename T> |
286 | 291 |
struct SetElevator |
287 | 292 |
: public Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
288 | 293 |
SetElevatorTraits<T> > { |
289 | 294 |
typedef Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
290 | 295 |
SetElevatorTraits<T> > Create; |
291 | 296 |
}; |
292 | 297 |
|
293 | 298 |
template <typename T> |
294 | 299 |
struct SetStandardElevatorTraits : public Traits { |
295 | 300 |
typedef T Elevator; |
296 | 301 |
static Elevator *createElevator(const Digraph& digraph, int max_level) { |
297 | 302 |
return new Elevator(digraph, max_level); |
298 | 303 |
} |
299 | 304 |
}; |
300 | 305 |
|
301 | 306 |
/// \brief \ref named-templ-param "Named parameter" for setting |
302 | 307 |
/// Elevator type with automatic allocation |
303 | 308 |
/// |
304 | 309 |
/// \ref named-templ-param "Named parameter" for setting Elevator |
305 | 310 |
/// type with automatic allocation. |
306 | 311 |
/// The Elevator should have standard constructor interface to be |
307 | 312 |
/// able to automatically created by the algorithm (i.e. the |
308 | 313 |
/// digraph and the maximum level should be passed to it). |
309 | 314 |
/// However, an external elevator object could also be passed to the |
310 | 315 |
/// algorithm with the \ref elevator(Elevator&) "elevator()" function |
311 | 316 |
/// before calling \ref run() or \ref init(). |
312 | 317 |
/// \sa SetElevator |
313 | 318 |
template <typename T> |
314 | 319 |
struct SetStandardElevator |
315 | 320 |
: public Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
316 | 321 |
SetStandardElevatorTraits<T> > { |
317 | 322 |
typedef Circulation<Digraph, LowerMap, UpperMap, SupplyMap, |
318 | 323 |
SetStandardElevatorTraits<T> > Create; |
319 | 324 |
}; |
320 | 325 |
|
321 | 326 |
/// @} |
322 | 327 |
|
323 | 328 |
protected: |
324 | 329 |
|
325 | 330 |
Circulation() {} |
326 | 331 |
|
327 | 332 |
public: |
328 | 333 |
|
329 | 334 |
/// Constructor. |
330 | 335 |
|
331 | 336 |
/// The constructor of the class. |
332 | 337 |
/// |
333 | 338 |
/// \param graph The digraph the algorithm runs on. |
334 | 339 |
/// \param lower The lower bounds for the flow values on the arcs. |
335 | 340 |
/// \param upper The upper bounds (capacities) for the flow values |
336 | 341 |
/// on the arcs. |
337 | 342 |
/// \param supply The signed supply values of the nodes. |
338 | 343 |
Circulation(const Digraph &graph, const LowerMap &lower, |
339 | 344 |
const UpperMap &upper, const SupplyMap &supply) |
340 | 345 |
: _g(graph), _lo(&lower), _up(&upper), _supply(&supply), |
341 | 346 |
_flow(NULL), _local_flow(false), _level(NULL), _local_level(false), |
342 | 347 |
_excess(NULL) {} |
343 | 348 |
|
344 | 349 |
/// Destructor. |
345 | 350 |
~Circulation() { |
346 | 351 |
destroyStructures(); |
347 | 352 |
} |
348 | 353 |
|
349 | 354 |
|
350 | 355 |
private: |
351 | 356 |
|
352 | 357 |
bool checkBoundMaps() { |
353 | 358 |
for (ArcIt e(_g);e!=INVALID;++e) { |
354 | 359 |
if (_tol.less((*_up)[e], (*_lo)[e])) return false; |
355 | 360 |
} |
356 | 361 |
return true; |
357 | 362 |
} |
358 | 363 |
|
359 | 364 |
void createStructures() { |
360 | 365 |
_node_num = _el = countNodes(_g); |
361 | 366 |
|
362 | 367 |
if (!_flow) { |
363 | 368 |
_flow = Traits::createFlowMap(_g); |
364 | 369 |
_local_flow = true; |
365 | 370 |
} |
366 | 371 |
if (!_level) { |
367 | 372 |
_level = Traits::createElevator(_g, _node_num); |
368 | 373 |
_local_level = true; |
369 | 374 |
} |
370 | 375 |
if (!_excess) { |
371 | 376 |
_excess = new ExcessMap(_g); |
372 | 377 |
} |
373 | 378 |
} |
374 | 379 |
|
375 | 380 |
void destroyStructures() { |
376 | 381 |
if (_local_flow) { |
377 | 382 |
delete _flow; |
378 | 383 |
} |
379 | 384 |
if (_local_level) { |
380 | 385 |
delete _level; |
381 | 386 |
} |
382 | 387 |
if (_excess) { |
383 | 388 |
delete _excess; |
384 | 389 |
} |
385 | 390 |
} |
386 | 391 |
|
387 | 392 |
public: |
388 | 393 |
|
389 | 394 |
/// Sets the lower bound map. |
390 | 395 |
|
391 | 396 |
/// Sets the lower bound map. |
392 | 397 |
/// \return <tt>(*this)</tt> |
393 | 398 |
Circulation& lowerMap(const LowerMap& map) { |
394 | 399 |
_lo = ↦ |
395 | 400 |
return *this; |
396 | 401 |
} |
397 | 402 |
|
398 | 403 |
/// Sets the upper bound (capacity) map. |
399 | 404 |
|
400 | 405 |
/// Sets the upper bound (capacity) map. |
401 | 406 |
/// \return <tt>(*this)</tt> |
402 | 407 |
Circulation& upperMap(const UpperMap& map) { |
403 | 408 |
_up = ↦ |
404 | 409 |
return *this; |
405 | 410 |
} |
406 | 411 |
|
407 | 412 |
/// Sets the supply map. |
408 | 413 |
|
409 | 414 |
/// Sets the supply map. |
410 | 415 |
/// \return <tt>(*this)</tt> |
411 | 416 |
Circulation& supplyMap(const SupplyMap& map) { |
412 | 417 |
_supply = ↦ |
413 | 418 |
return *this; |
414 | 419 |
} |
415 | 420 |
|
416 | 421 |
/// \brief Sets the flow map. |
417 | 422 |
/// |
418 | 423 |
/// Sets the flow map. |
419 | 424 |
/// If you don't use this function before calling \ref run() or |
420 | 425 |
/// \ref init(), an instance will be allocated automatically. |
421 | 426 |
/// The destructor deallocates this automatically allocated map, |
422 | 427 |
/// of course. |
423 | 428 |
/// \return <tt>(*this)</tt> |
424 | 429 |
Circulation& flowMap(FlowMap& map) { |
425 | 430 |
if (_local_flow) { |
426 | 431 |
delete _flow; |
427 | 432 |
_local_flow = false; |
428 | 433 |
} |
429 | 434 |
_flow = ↦ |
430 | 435 |
return *this; |
431 | 436 |
} |
432 | 437 |
|
433 | 438 |
/// \brief Sets the elevator used by algorithm. |
434 | 439 |
/// |
435 | 440 |
/// Sets the elevator used by algorithm. |
436 | 441 |
/// If you don't use this function before calling \ref run() or |
437 | 442 |
/// \ref init(), an instance will be allocated automatically. |
438 | 443 |
/// The destructor deallocates this automatically allocated elevator, |
439 | 444 |
/// of course. |
440 | 445 |
/// \return <tt>(*this)</tt> |
441 | 446 |
Circulation& elevator(Elevator& elevator) { |
442 | 447 |
if (_local_level) { |
443 | 448 |
delete _level; |
444 | 449 |
_local_level = false; |
445 | 450 |
} |
446 | 451 |
_level = &elevator; |
447 | 452 |
return *this; |
448 | 453 |
} |
449 | 454 |
|
450 | 455 |
/// \brief Returns a const reference to the elevator. |
451 | 456 |
/// |
452 | 457 |
/// Returns a const reference to the elevator. |
453 | 458 |
/// |
454 | 459 |
/// \pre Either \ref run() or \ref init() must be called before |
455 | 460 |
/// using this function. |
456 | 461 |
const Elevator& elevator() const { |
457 | 462 |
return *_level; |
458 | 463 |
} |
459 | 464 |
|
460 | 465 |
/// \brief Sets the tolerance used by the algorithm. |
461 | 466 |
/// |
462 | 467 |
/// Sets the tolerance object used by the algorithm. |
463 | 468 |
/// \return <tt>(*this)</tt> |
464 | 469 |
Circulation& tolerance(const Tolerance& tolerance) { |
465 | 470 |
_tol = tolerance; |
466 | 471 |
return *this; |
467 | 472 |
} |
468 | 473 |
|
469 | 474 |
/// \brief Returns a const reference to the tolerance. |
470 | 475 |
/// |
471 | 476 |
/// Returns a const reference to the tolerance object used by |
472 | 477 |
/// the algorithm. |
473 | 478 |
const Tolerance& tolerance() const { |
474 | 479 |
return _tol; |
475 | 480 |
} |
476 | 481 |
|
477 | 482 |
/// \name Execution Control |
478 | 483 |
/// The simplest way to execute the algorithm is to call \ref run().\n |
479 | 484 |
/// If you need better control on the initial solution or the execution, |
480 | 485 |
/// you have to call one of the \ref init() functions first, then |
481 | 486 |
/// the \ref start() function. |
482 | 487 |
|
483 | 488 |
///@{ |
484 | 489 |
|
485 | 490 |
/// Initializes the internal data structures. |
486 | 491 |
|
487 | 492 |
/// Initializes the internal data structures and sets all flow values |
488 | 493 |
/// to the lower bound. |
489 | 494 |
void init() |
490 | 495 |
{ |
491 | 496 |
LEMON_DEBUG(checkBoundMaps(), |
492 | 497 |
"Upper bounds must be greater or equal to the lower bounds"); |
493 | 498 |
|
494 | 499 |
createStructures(); |
495 | 500 |
|
496 | 501 |
for(NodeIt n(_g);n!=INVALID;++n) { |
497 | 502 |
(*_excess)[n] = (*_supply)[n]; |
498 | 503 |
} |
499 | 504 |
|
500 | 505 |
for (ArcIt e(_g);e!=INVALID;++e) { |
501 | 506 |
_flow->set(e, (*_lo)[e]); |
502 | 507 |
(*_excess)[_g.target(e)] += (*_flow)[e]; |
503 | 508 |
(*_excess)[_g.source(e)] -= (*_flow)[e]; |
504 | 509 |
} |
505 | 510 |
|
506 | 511 |
// global relabeling tested, but in general case it provides |
507 | 512 |
// worse performance for random digraphs |
508 | 513 |
_level->initStart(); |
509 | 514 |
for(NodeIt n(_g);n!=INVALID;++n) |
510 | 515 |
_level->initAddItem(n); |
511 | 516 |
_level->initFinish(); |
512 | 517 |
for(NodeIt n(_g);n!=INVALID;++n) |
513 | 518 |
if(_tol.positive((*_excess)[n])) |
514 | 519 |
_level->activate(n); |
515 | 520 |
} |
516 | 521 |
|
517 | 522 |
/// Initializes the internal data structures using a greedy approach. |
518 | 523 |
|
519 | 524 |
/// Initializes the internal data structures using a greedy approach |
520 | 525 |
/// to construct the initial solution. |
521 | 526 |
void greedyInit() |
522 | 527 |
{ |
523 | 528 |
LEMON_DEBUG(checkBoundMaps(), |
524 | 529 |
"Upper bounds must be greater or equal to the lower bounds"); |
525 | 530 |
|
526 | 531 |
createStructures(); |
527 | 532 |
|
528 | 533 |
for(NodeIt n(_g);n!=INVALID;++n) { |
529 | 534 |
(*_excess)[n] = (*_supply)[n]; |
530 | 535 |
} |
531 | 536 |
|
532 | 537 |
for (ArcIt e(_g);e!=INVALID;++e) { |
533 | 538 |
if (!_tol.less(-(*_excess)[_g.target(e)], (*_up)[e])) { |
534 | 539 |
_flow->set(e, (*_up)[e]); |
535 | 540 |
(*_excess)[_g.target(e)] += (*_up)[e]; |
536 | 541 |
(*_excess)[_g.source(e)] -= (*_up)[e]; |
537 | 542 |
} else if (_tol.less(-(*_excess)[_g.target(e)], (*_lo)[e])) { |
538 | 543 |
_flow->set(e, (*_lo)[e]); |
539 | 544 |
(*_excess)[_g.target(e)] += (*_lo)[e]; |
540 | 545 |
(*_excess)[_g.source(e)] -= (*_lo)[e]; |
541 | 546 |
} else { |
542 | 547 |
Value fc = -(*_excess)[_g.target(e)]; |
543 | 548 |
_flow->set(e, fc); |
544 | 549 |
(*_excess)[_g.target(e)] = 0; |
545 | 550 |
(*_excess)[_g.source(e)] -= fc; |
546 | 551 |
} |
547 | 552 |
} |
548 | 553 |
|
549 | 554 |
_level->initStart(); |
550 | 555 |
for(NodeIt n(_g);n!=INVALID;++n) |
551 | 556 |
_level->initAddItem(n); |
552 | 557 |
_level->initFinish(); |
553 | 558 |
for(NodeIt n(_g);n!=INVALID;++n) |
554 | 559 |
if(_tol.positive((*_excess)[n])) |
555 | 560 |
_level->activate(n); |
556 | 561 |
} |
557 | 562 |
|
558 | 563 |
///Executes the algorithm |
559 | 564 |
1 | 1 |
/* -*- C++ -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2008 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_COST_SCALING_H |
20 | 20 |
#define LEMON_COST_SCALING_H |
21 | 21 |
|
22 | 22 |
/// \ingroup min_cost_flow_algs |
23 | 23 |
/// \file |
24 | 24 |
/// \brief Cost scaling algorithm for finding a minimum cost flow. |
25 | 25 |
|
26 | 26 |
#include <vector> |
27 | 27 |
#include <deque> |
28 | 28 |
#include <limits> |
29 | 29 |
|
30 | 30 |
#include <lemon/core.h> |
31 | 31 |
#include <lemon/maps.h> |
32 | 32 |
#include <lemon/math.h> |
33 | 33 |
#include <lemon/static_graph.h> |
34 | 34 |
#include <lemon/circulation.h> |
35 | 35 |
#include <lemon/bellman_ford.h> |
36 | 36 |
|
37 | 37 |
namespace lemon { |
38 | 38 |
|
39 | 39 |
/// \brief Default traits class of CostScaling algorithm. |
40 | 40 |
/// |
41 | 41 |
/// Default traits class of CostScaling algorithm. |
42 | 42 |
/// \tparam GR Digraph type. |
43 | 43 |
/// \tparam V The number type used for flow amounts, capacity bounds |
44 | 44 |
/// and supply values. By default it is \c int. |
45 | 45 |
/// \tparam C The number type used for costs and potentials. |
46 | 46 |
/// By default it is the same as \c V. |
47 | 47 |
#ifdef DOXYGEN |
48 | 48 |
template <typename GR, typename V = int, typename C = V> |
49 | 49 |
#else |
50 | 50 |
template < typename GR, typename V = int, typename C = V, |
51 | 51 |
bool integer = std::numeric_limits<C>::is_integer > |
52 | 52 |
#endif |
53 | 53 |
struct CostScalingDefaultTraits |
54 | 54 |
{ |
55 | 55 |
/// The type of the digraph |
56 | 56 |
typedef GR Digraph; |
57 | 57 |
/// The type of the flow amounts, capacity bounds and supply values |
58 | 58 |
typedef V Value; |
59 | 59 |
/// The type of the arc costs |
60 | 60 |
typedef C Cost; |
61 | 61 |
|
62 | 62 |
/// \brief The large cost type used for internal computations |
63 | 63 |
/// |
64 | 64 |
/// The large cost type used for internal computations. |
65 | 65 |
/// It is \c long \c long if the \c Cost type is integer, |
66 | 66 |
/// otherwise it is \c double. |
67 | 67 |
/// \c Cost must be convertible to \c LargeCost. |
68 | 68 |
typedef double LargeCost; |
69 | 69 |
}; |
70 | 70 |
|
71 | 71 |
// Default traits class for integer cost types |
72 | 72 |
template <typename GR, typename V, typename C> |
73 | 73 |
struct CostScalingDefaultTraits<GR, V, C, true> |
74 | 74 |
{ |
75 | 75 |
typedef GR Digraph; |
76 | 76 |
typedef V Value; |
77 | 77 |
typedef C Cost; |
78 | 78 |
#ifdef LEMON_HAVE_LONG_LONG |
79 | 79 |
typedef long long LargeCost; |
80 | 80 |
#else |
81 | 81 |
typedef long LargeCost; |
82 | 82 |
#endif |
83 | 83 |
}; |
84 | 84 |
|
85 | 85 |
|
86 | 86 |
/// \addtogroup min_cost_flow_algs |
87 | 87 |
/// @{ |
88 | 88 |
|
89 | 89 |
/// \brief Implementation of the Cost Scaling algorithm for |
90 | 90 |
/// finding a \ref min_cost_flow "minimum cost flow". |
91 | 91 |
/// |
92 | 92 |
/// \ref CostScaling implements a cost scaling algorithm that performs |
93 | 93 |
/// push/augment and relabel operations for finding a \ref min_cost_flow |
94 | 94 |
/// "minimum cost flow" \ref amo93networkflows, \ref goldberg90approximation, |
95 | 95 |
/// \ref goldberg97efficient, \ref bunnagel98efficient. |
96 | 96 |
/// It is a highly efficient primal-dual solution method, which |
97 | 97 |
/// can be viewed as the generalization of the \ref Preflow |
98 | 98 |
/// "preflow push-relabel" algorithm for the maximum flow problem. |
99 | 99 |
/// |
100 | 100 |
/// Most of the parameters of the problem (except for the digraph) |
101 | 101 |
/// can be given using separate functions, and the algorithm can be |
102 | 102 |
/// executed using the \ref run() function. If some parameters are not |
103 | 103 |
/// specified, then default values will be used. |
104 | 104 |
/// |
105 | 105 |
/// \tparam GR The digraph type the algorithm runs on. |
106 | 106 |
/// \tparam V The number type used for flow amounts, capacity bounds |
107 |
/// and supply values in the algorithm. By default it is \c int. |
|
107 |
/// and supply values in the algorithm. By default, it is \c int. |
|
108 | 108 |
/// \tparam C The number type used for costs and potentials in the |
109 |
/// algorithm. By default it is the same as \c V. |
|
109 |
/// algorithm. By default, it is the same as \c V. |
|
110 |
/// \tparam TR The traits class that defines various types used by the |
|
111 |
/// algorithm. By default, it is \ref CostScalingDefaultTraits |
|
112 |
/// "CostScalingDefaultTraits<GR, V, C>". |
|
113 |
/// In most cases, this parameter should not be set directly, |
|
114 |
/// consider to use the named template parameters instead. |
|
110 | 115 |
/// |
111 | 116 |
/// \warning Both number types must be signed and all input data must |
112 | 117 |
/// be integer. |
113 | 118 |
/// \warning This algorithm does not support negative costs for such |
114 | 119 |
/// arcs that have infinite upper bound. |
115 | 120 |
/// |
116 | 121 |
/// \note %CostScaling provides three different internal methods, |
117 | 122 |
/// from which the most efficient one is used by default. |
118 | 123 |
/// For more information, see \ref Method. |
119 | 124 |
#ifdef DOXYGEN |
120 | 125 |
template <typename GR, typename V, typename C, typename TR> |
121 | 126 |
#else |
122 | 127 |
template < typename GR, typename V = int, typename C = V, |
123 | 128 |
typename TR = CostScalingDefaultTraits<GR, V, C> > |
124 | 129 |
#endif |
125 | 130 |
class CostScaling |
126 | 131 |
{ |
127 | 132 |
public: |
128 | 133 |
|
129 | 134 |
/// The type of the digraph |
130 | 135 |
typedef typename TR::Digraph Digraph; |
131 | 136 |
/// The type of the flow amounts, capacity bounds and supply values |
132 | 137 |
typedef typename TR::Value Value; |
133 | 138 |
/// The type of the arc costs |
134 | 139 |
typedef typename TR::Cost Cost; |
135 | 140 |
|
136 | 141 |
/// \brief The large cost type |
137 | 142 |
/// |
138 | 143 |
/// The large cost type used for internal computations. |
139 |
/// Using the \ref CostScalingDefaultTraits "default traits class", |
|
140 |
/// it is \c long \c long if the \c Cost type is integer, |
|
144 |
/// By default, it is \c long \c long if the \c Cost type is integer, |
|
141 | 145 |
/// otherwise it is \c double. |
142 | 146 |
typedef typename TR::LargeCost LargeCost; |
143 | 147 |
|
144 | 148 |
/// The \ref CostScalingDefaultTraits "traits class" of the algorithm |
145 | 149 |
typedef TR Traits; |
146 | 150 |
|
147 | 151 |
public: |
148 | 152 |
|
149 | 153 |
/// \brief Problem type constants for the \c run() function. |
150 | 154 |
/// |
151 | 155 |
/// Enum type containing the problem type constants that can be |
152 | 156 |
/// returned by the \ref run() function of the algorithm. |
153 | 157 |
enum ProblemType { |
154 | 158 |
/// The problem has no feasible solution (flow). |
155 | 159 |
INFEASIBLE, |
156 | 160 |
/// The problem has optimal solution (i.e. it is feasible and |
157 | 161 |
/// bounded), and the algorithm has found optimal flow and node |
158 | 162 |
/// potentials (primal and dual solutions). |
159 | 163 |
OPTIMAL, |
160 | 164 |
/// The digraph contains an arc of negative cost and infinite |
161 | 165 |
/// upper bound. It means that the objective function is unbounded |
162 | 166 |
/// on that arc, however, note that it could actually be bounded |
163 | 167 |
/// over the feasible flows, but this algroithm cannot handle |
164 | 168 |
/// these cases. |
165 | 169 |
UNBOUNDED |
166 | 170 |
}; |
167 | 171 |
|
168 | 172 |
/// \brief Constants for selecting the internal method. |
169 | 173 |
/// |
170 | 174 |
/// Enum type containing constants for selecting the internal method |
171 | 175 |
/// for the \ref run() function. |
172 | 176 |
/// |
173 | 177 |
/// \ref CostScaling provides three internal methods that differ mainly |
174 | 178 |
/// in their base operations, which are used in conjunction with the |
175 | 179 |
/// relabel operation. |
176 | 180 |
/// By default, the so called \ref PARTIAL_AUGMENT |
177 | 181 |
/// "Partial Augment-Relabel" method is used, which proved to be |
178 | 182 |
/// the most efficient and the most robust on various test inputs. |
179 | 183 |
/// However, the other methods can be selected using the \ref run() |
180 | 184 |
/// function with the proper parameter. |
181 | 185 |
enum Method { |
182 | 186 |
/// Local push operations are used, i.e. flow is moved only on one |
183 | 187 |
/// admissible arc at once. |
184 | 188 |
PUSH, |
185 | 189 |
/// Augment operations are used, i.e. flow is moved on admissible |
186 | 190 |
/// paths from a node with excess to a node with deficit. |
187 | 191 |
AUGMENT, |
188 | 192 |
/// Partial augment operations are used, i.e. flow is moved on |
189 | 193 |
/// admissible paths started from a node with excess, but the |
190 | 194 |
/// lengths of these paths are limited. This method can be viewed |
191 | 195 |
/// as a combined version of the previous two operations. |
192 | 196 |
PARTIAL_AUGMENT |
193 | 197 |
}; |
194 | 198 |
|
195 | 199 |
private: |
196 | 200 |
|
197 | 201 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
198 | 202 |
|
199 | 203 |
typedef std::vector<int> IntVector; |
200 | 204 |
typedef std::vector<char> BoolVector; |
201 | 205 |
typedef std::vector<Value> ValueVector; |
202 | 206 |
typedef std::vector<Cost> CostVector; |
203 | 207 |
typedef std::vector<LargeCost> LargeCostVector; |
204 | 208 |
|
205 | 209 |
private: |
206 | 210 |
|
207 | 211 |
template <typename KT, typename VT> |
208 | 212 |
class StaticVectorMap { |
209 | 213 |
public: |
210 | 214 |
typedef KT Key; |
211 | 215 |
typedef VT Value; |
212 | 216 |
|
213 | 217 |
StaticVectorMap(std::vector<Value>& v) : _v(v) {} |
214 | 218 |
|
215 | 219 |
const Value& operator[](const Key& key) const { |
216 | 220 |
return _v[StaticDigraph::id(key)]; |
217 | 221 |
} |
218 | 222 |
|
219 | 223 |
Value& operator[](const Key& key) { |
220 | 224 |
return _v[StaticDigraph::id(key)]; |
221 | 225 |
} |
222 | 226 |
|
223 | 227 |
void set(const Key& key, const Value& val) { |
224 | 228 |
_v[StaticDigraph::id(key)] = val; |
225 | 229 |
} |
226 | 230 |
|
227 | 231 |
private: |
228 | 232 |
std::vector<Value>& _v; |
229 | 233 |
}; |
230 | 234 |
|
231 | 235 |
typedef StaticVectorMap<StaticDigraph::Node, LargeCost> LargeCostNodeMap; |
232 | 236 |
typedef StaticVectorMap<StaticDigraph::Arc, LargeCost> LargeCostArcMap; |
233 | 237 |
|
234 | 238 |
private: |
235 | 239 |
|
236 | 240 |
// Data related to the underlying digraph |
237 | 241 |
const GR &_graph; |
238 | 242 |
int _node_num; |
239 | 243 |
int _arc_num; |
240 | 244 |
int _res_node_num; |
241 | 245 |
int _res_arc_num; |
242 | 246 |
int _root; |
243 | 247 |
|
244 | 248 |
// Parameters of the problem |
245 | 249 |
bool _have_lower; |
246 | 250 |
Value _sum_supply; |
247 | 251 |
|
248 | 252 |
// Data structures for storing the digraph |
249 | 253 |
IntNodeMap _node_id; |
250 | 254 |
IntArcMap _arc_idf; |
251 | 255 |
IntArcMap _arc_idb; |
252 | 256 |
IntVector _first_out; |
253 | 257 |
BoolVector _forward; |
254 | 258 |
IntVector _source; |
255 | 259 |
IntVector _target; |
256 | 260 |
IntVector _reverse; |
257 | 261 |
|
258 | 262 |
// Node and arc data |
259 | 263 |
ValueVector _lower; |
260 | 264 |
ValueVector _upper; |
261 | 265 |
CostVector _scost; |
262 | 266 |
ValueVector _supply; |
263 | 267 |
|
264 | 268 |
ValueVector _res_cap; |
265 | 269 |
LargeCostVector _cost; |
266 | 270 |
LargeCostVector _pi; |
267 | 271 |
ValueVector _excess; |
268 | 272 |
IntVector _next_out; |
269 | 273 |
std::deque<int> _active_nodes; |
270 | 274 |
|
271 | 275 |
// Data for scaling |
272 | 276 |
LargeCost _epsilon; |
273 | 277 |
int _alpha; |
274 | 278 |
|
275 | 279 |
// Data for a StaticDigraph structure |
276 | 280 |
typedef std::pair<int, int> IntPair; |
277 | 281 |
StaticDigraph _sgr; |
278 | 282 |
std::vector<IntPair> _arc_vec; |
279 | 283 |
std::vector<LargeCost> _cost_vec; |
280 | 284 |
LargeCostArcMap _cost_map; |
281 | 285 |
LargeCostNodeMap _pi_map; |
282 | 286 |
|
283 | 287 |
public: |
284 | 288 |
|
285 | 289 |
/// \brief Constant for infinite upper bounds (capacities). |
286 | 290 |
/// |
287 | 291 |
/// Constant for infinite upper bounds (capacities). |
288 | 292 |
/// It is \c std::numeric_limits<Value>::infinity() if available, |
289 | 293 |
/// \c std::numeric_limits<Value>::max() otherwise. |
290 | 294 |
const Value INF; |
291 | 295 |
|
292 | 296 |
public: |
293 | 297 |
|
294 | 298 |
/// \name Named Template Parameters |
295 | 299 |
/// @{ |
296 | 300 |
|
297 | 301 |
template <typename T> |
298 | 302 |
struct SetLargeCostTraits : public Traits { |
299 | 303 |
typedef T LargeCost; |
300 | 304 |
}; |
301 | 305 |
|
302 | 306 |
/// \brief \ref named-templ-param "Named parameter" for setting |
303 | 307 |
/// \c LargeCost type. |
304 | 308 |
/// |
305 | 309 |
/// \ref named-templ-param "Named parameter" for setting \c LargeCost |
306 | 310 |
/// type, which is used for internal computations in the algorithm. |
307 | 311 |
/// \c Cost must be convertible to \c LargeCost. |
308 | 312 |
template <typename T> |
309 | 313 |
struct SetLargeCost |
310 | 314 |
: public CostScaling<GR, V, C, SetLargeCostTraits<T> > { |
311 | 315 |
typedef CostScaling<GR, V, C, SetLargeCostTraits<T> > Create; |
312 | 316 |
}; |
313 | 317 |
|
314 | 318 |
/// @} |
315 | 319 |
|
316 | 320 |
public: |
317 | 321 |
|
318 | 322 |
/// \brief Constructor. |
319 | 323 |
/// |
320 | 324 |
/// The constructor of the class. |
321 | 325 |
/// |
322 | 326 |
/// \param graph The digraph the algorithm runs on. |
323 | 327 |
CostScaling(const GR& graph) : |
324 | 328 |
_graph(graph), _node_id(graph), _arc_idf(graph), _arc_idb(graph), |
325 | 329 |
_cost_map(_cost_vec), _pi_map(_pi), |
326 | 330 |
INF(std::numeric_limits<Value>::has_infinity ? |
327 | 331 |
std::numeric_limits<Value>::infinity() : |
328 | 332 |
std::numeric_limits<Value>::max()) |
329 | 333 |
{ |
330 | 334 |
// Check the number types |
331 | 335 |
LEMON_ASSERT(std::numeric_limits<Value>::is_signed, |
332 | 336 |
"The flow type of CostScaling must be signed"); |
333 | 337 |
LEMON_ASSERT(std::numeric_limits<Cost>::is_signed, |
334 | 338 |
"The cost type of CostScaling must be signed"); |
335 | 339 |
|
336 | 340 |
// Resize vectors |
337 | 341 |
_node_num = countNodes(_graph); |
338 | 342 |
_arc_num = countArcs(_graph); |
339 | 343 |
_res_node_num = _node_num + 1; |
340 | 344 |
_res_arc_num = 2 * (_arc_num + _node_num); |
341 | 345 |
_root = _node_num; |
342 | 346 |
|
343 | 347 |
_first_out.resize(_res_node_num + 1); |
344 | 348 |
_forward.resize(_res_arc_num); |
345 | 349 |
_source.resize(_res_arc_num); |
346 | 350 |
_target.resize(_res_arc_num); |
347 | 351 |
_reverse.resize(_res_arc_num); |
348 | 352 |
|
349 | 353 |
_lower.resize(_res_arc_num); |
350 | 354 |
_upper.resize(_res_arc_num); |
351 | 355 |
_scost.resize(_res_arc_num); |
352 | 356 |
_supply.resize(_res_node_num); |
353 | 357 |
|
354 | 358 |
_res_cap.resize(_res_arc_num); |
355 | 359 |
_cost.resize(_res_arc_num); |
356 | 360 |
_pi.resize(_res_node_num); |
357 | 361 |
_excess.resize(_res_node_num); |
358 | 362 |
_next_out.resize(_res_node_num); |
359 | 363 |
|
360 | 364 |
_arc_vec.reserve(_res_arc_num); |
361 | 365 |
_cost_vec.reserve(_res_arc_num); |
362 | 366 |
|
363 | 367 |
// Copy the graph |
364 | 368 |
int i = 0, j = 0, k = 2 * _arc_num + _node_num; |
365 | 369 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) { |
366 | 370 |
_node_id[n] = i; |
367 | 371 |
} |
368 | 372 |
i = 0; |
369 | 373 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) { |
370 | 374 |
_first_out[i] = j; |
371 | 375 |
for (OutArcIt a(_graph, n); a != INVALID; ++a, ++j) { |
372 | 376 |
_arc_idf[a] = j; |
373 | 377 |
_forward[j] = true; |
374 | 378 |
_source[j] = i; |
375 | 379 |
_target[j] = _node_id[_graph.runningNode(a)]; |
376 | 380 |
} |
377 | 381 |
for (InArcIt a(_graph, n); a != INVALID; ++a, ++j) { |
378 | 382 |
_arc_idb[a] = j; |
379 | 383 |
_forward[j] = false; |
380 | 384 |
_source[j] = i; |
381 | 385 |
_target[j] = _node_id[_graph.runningNode(a)]; |
382 | 386 |
} |
383 | 387 |
_forward[j] = false; |
384 | 388 |
_source[j] = i; |
385 | 389 |
_target[j] = _root; |
386 | 390 |
_reverse[j] = k; |
387 | 391 |
_forward[k] = true; |
388 | 392 |
_source[k] = _root; |
389 | 393 |
_target[k] = i; |
390 | 394 |
_reverse[k] = j; |
391 | 395 |
++j; ++k; |
392 | 396 |
} |
393 | 397 |
_first_out[i] = j; |
394 | 398 |
_first_out[_res_node_num] = k; |
395 | 399 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
396 | 400 |
int fi = _arc_idf[a]; |
397 | 401 |
int bi = _arc_idb[a]; |
398 | 402 |
_reverse[fi] = bi; |
399 | 403 |
_reverse[bi] = fi; |
400 | 404 |
} |
401 | 405 |
|
402 | 406 |
// Reset parameters |
403 | 407 |
reset(); |
404 | 408 |
} |
405 | 409 |
|
406 | 410 |
/// \name Parameters |
407 | 411 |
/// The parameters of the algorithm can be specified using these |
408 | 412 |
/// functions. |
409 | 413 |
|
410 | 414 |
/// @{ |
411 | 415 |
|
412 | 416 |
/// \brief Set the lower bounds on the arcs. |
413 | 417 |
/// |
414 | 418 |
/// This function sets the lower bounds on the arcs. |
415 | 419 |
/// If it is not used before calling \ref run(), the lower bounds |
416 | 420 |
/// will be set to zero on all arcs. |
417 | 421 |
/// |
418 | 422 |
/// \param map An arc map storing the lower bounds. |
419 | 423 |
/// Its \c Value type must be convertible to the \c Value type |
420 | 424 |
/// of the algorithm. |
421 | 425 |
/// |
422 | 426 |
/// \return <tt>(*this)</tt> |
423 | 427 |
template <typename LowerMap> |
424 | 428 |
CostScaling& lowerMap(const LowerMap& map) { |
425 | 429 |
_have_lower = true; |
426 | 430 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
427 | 431 |
_lower[_arc_idf[a]] = map[a]; |
428 | 432 |
_lower[_arc_idb[a]] = map[a]; |
429 | 433 |
} |
430 | 434 |
return *this; |
431 | 435 |
} |
432 | 436 |
|
433 | 437 |
/// \brief Set the upper bounds (capacities) on the arcs. |
434 | 438 |
/// |
435 | 439 |
/// This function sets the upper bounds (capacities) on the arcs. |
436 | 440 |
/// If it is not used before calling \ref run(), the upper bounds |
437 | 441 |
/// will be set to \ref INF on all arcs (i.e. the flow value will be |
438 | 442 |
/// unbounded from above). |
439 | 443 |
/// |
440 | 444 |
/// \param map An arc map storing the upper bounds. |
441 | 445 |
/// Its \c Value type must be convertible to the \c Value type |
442 | 446 |
/// of the algorithm. |
443 | 447 |
/// |
444 | 448 |
/// \return <tt>(*this)</tt> |
445 | 449 |
template<typename UpperMap> |
446 | 450 |
CostScaling& upperMap(const UpperMap& map) { |
447 | 451 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
448 | 452 |
_upper[_arc_idf[a]] = map[a]; |
449 | 453 |
} |
450 | 454 |
return *this; |
451 | 455 |
} |
452 | 456 |
|
453 | 457 |
/// \brief Set the costs of the arcs. |
454 | 458 |
/// |
455 | 459 |
/// This function sets the costs of the arcs. |
456 | 460 |
/// If it is not used before calling \ref run(), the costs |
457 | 461 |
/// will be set to \c 1 on all arcs. |
458 | 462 |
/// |
459 | 463 |
/// \param map An arc map storing the costs. |
460 | 464 |
/// Its \c Value type must be convertible to the \c Cost type |
461 | 465 |
/// of the algorithm. |
462 | 466 |
/// |
463 | 467 |
/// \return <tt>(*this)</tt> |
464 | 468 |
template<typename CostMap> |
465 | 469 |
CostScaling& costMap(const CostMap& map) { |
466 | 470 |
for (ArcIt a(_graph); a != INVALID; ++a) { |
467 | 471 |
_scost[_arc_idf[a]] = map[a]; |
468 | 472 |
_scost[_arc_idb[a]] = -map[a]; |
469 | 473 |
} |
470 | 474 |
return *this; |
471 | 475 |
} |
472 | 476 |
|
473 | 477 |
/// \brief Set the supply values of the nodes. |
474 | 478 |
/// |
475 | 479 |
/// This function sets the supply values of the nodes. |
476 | 480 |
/// If neither this function nor \ref stSupply() is used before |
477 | 481 |
/// calling \ref run(), the supply of each node will be set to zero. |
478 | 482 |
/// |
479 | 483 |
/// \param map A node map storing the supply values. |
480 | 484 |
/// Its \c Value type must be convertible to the \c Value type |
481 | 485 |
/// of the algorithm. |
482 | 486 |
/// |
483 | 487 |
/// \return <tt>(*this)</tt> |
484 | 488 |
template<typename SupplyMap> |
485 | 489 |
CostScaling& supplyMap(const SupplyMap& map) { |
486 | 490 |
for (NodeIt n(_graph); n != INVALID; ++n) { |
487 | 491 |
_supply[_node_id[n]] = map[n]; |
488 | 492 |
} |
489 | 493 |
return *this; |
490 | 494 |
} |
491 | 495 |
|
492 | 496 |
/// \brief Set single source and target nodes and a supply value. |
493 | 497 |
/// |
494 | 498 |
/// This function sets a single source node and a single target node |
495 | 499 |
/// and the required flow value. |
496 | 500 |
/// If neither this function nor \ref supplyMap() is used before |
497 | 501 |
/// calling \ref run(), the supply of each node will be set to zero. |
498 | 502 |
/// |
499 | 503 |
/// Using this function has the same effect as using \ref supplyMap() |
500 | 504 |
/// with such a map in which \c k is assigned to \c s, \c -k is |
501 | 505 |
/// assigned to \c t and all other nodes have zero supply value. |
502 | 506 |
/// |
503 | 507 |
/// \param s The source node. |
504 | 508 |
/// \param t The target node. |
505 | 509 |
/// \param k The required amount of flow from node \c s to node \c t |
506 | 510 |
/// (i.e. the supply of \c s and the demand of \c t). |
507 | 511 |
/// |
508 | 512 |
/// \return <tt>(*this)</tt> |
509 | 513 |
CostScaling& stSupply(const Node& s, const Node& t, Value k) { |
510 | 514 |
for (int i = 0; i != _res_node_num; ++i) { |
511 | 515 |
_supply[i] = 0; |
512 | 516 |
} |
513 | 517 |
_supply[_node_id[s]] = k; |
514 | 518 |
_supply[_node_id[t]] = -k; |
515 | 519 |
return *this; |
516 | 520 |
} |
517 | 521 |
|
518 | 522 |
/// @} |
519 | 523 |
|
520 | 524 |
/// \name Execution control |
521 | 525 |
/// The algorithm can be executed using \ref run(). |
522 | 526 |
|
523 | 527 |
/// @{ |
524 | 528 |
1 | 1 |
/* -*- mode: C++; indent-tabs-mode: nil; -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library. |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2009 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_DFS_H |
20 | 20 |
#define LEMON_DFS_H |
21 | 21 |
|
22 | 22 |
///\ingroup search |
23 | 23 |
///\file |
24 | 24 |
///\brief DFS algorithm. |
25 | 25 |
|
26 | 26 |
#include <lemon/list_graph.h> |
27 | 27 |
#include <lemon/bits/path_dump.h> |
28 | 28 |
#include <lemon/core.h> |
29 | 29 |
#include <lemon/error.h> |
30 | 30 |
#include <lemon/maps.h> |
31 | 31 |
#include <lemon/path.h> |
32 | 32 |
|
33 | 33 |
namespace lemon { |
34 | 34 |
|
35 | 35 |
///Default traits class of Dfs class. |
36 | 36 |
|
37 | 37 |
///Default traits class of Dfs class. |
38 | 38 |
///\tparam GR Digraph type. |
39 | 39 |
template<class GR> |
40 | 40 |
struct DfsDefaultTraits |
41 | 41 |
{ |
42 | 42 |
///The type of the digraph the algorithm runs on. |
43 | 43 |
typedef GR Digraph; |
44 | 44 |
|
45 | 45 |
///\brief The type of the map that stores the predecessor |
46 | 46 |
///arcs of the %DFS paths. |
47 | 47 |
/// |
48 | 48 |
///The type of the map that stores the predecessor |
49 | 49 |
///arcs of the %DFS paths. |
50 | 50 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
51 | 51 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
52 | 52 |
///Instantiates a \c PredMap. |
53 | 53 |
|
54 | 54 |
///This function instantiates a \ref PredMap. |
55 | 55 |
///\param g is the digraph, to which we would like to define the |
56 | 56 |
///\ref PredMap. |
57 | 57 |
static PredMap *createPredMap(const Digraph &g) |
58 | 58 |
{ |
59 | 59 |
return new PredMap(g); |
60 | 60 |
} |
61 | 61 |
|
62 | 62 |
///The type of the map that indicates which nodes are processed. |
63 | 63 |
|
64 | 64 |
///The type of the map that indicates which nodes are processed. |
65 | 65 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
66 | 66 |
///By default, it is a NullMap. |
67 | 67 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
68 | 68 |
///Instantiates a \c ProcessedMap. |
69 | 69 |
|
70 | 70 |
///This function instantiates a \ref ProcessedMap. |
71 | 71 |
///\param g is the digraph, to which |
72 | 72 |
///we would like to define the \ref ProcessedMap. |
73 | 73 |
#ifdef DOXYGEN |
74 | 74 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
75 | 75 |
#else |
76 | 76 |
static ProcessedMap *createProcessedMap(const Digraph &) |
77 | 77 |
#endif |
78 | 78 |
{ |
79 | 79 |
return new ProcessedMap(); |
80 | 80 |
} |
81 | 81 |
|
82 | 82 |
///The type of the map that indicates which nodes are reached. |
83 | 83 |
|
84 | 84 |
///The type of the map that indicates which nodes are reached. |
85 | 85 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
86 | 86 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
87 | 87 |
///Instantiates a \c ReachedMap. |
88 | 88 |
|
89 | 89 |
///This function instantiates a \ref ReachedMap. |
90 | 90 |
///\param g is the digraph, to which |
91 | 91 |
///we would like to define the \ref ReachedMap. |
92 | 92 |
static ReachedMap *createReachedMap(const Digraph &g) |
93 | 93 |
{ |
94 | 94 |
return new ReachedMap(g); |
95 | 95 |
} |
96 | 96 |
|
97 | 97 |
///The type of the map that stores the distances of the nodes. |
98 | 98 |
|
99 | 99 |
///The type of the map that stores the distances of the nodes. |
100 | 100 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
101 | 101 |
typedef typename Digraph::template NodeMap<int> DistMap; |
102 | 102 |
///Instantiates a \c DistMap. |
103 | 103 |
|
104 | 104 |
///This function instantiates a \ref DistMap. |
105 | 105 |
///\param g is the digraph, to which we would like to define the |
106 | 106 |
///\ref DistMap. |
107 | 107 |
static DistMap *createDistMap(const Digraph &g) |
108 | 108 |
{ |
109 | 109 |
return new DistMap(g); |
110 | 110 |
} |
111 | 111 |
}; |
112 | 112 |
|
113 | 113 |
///%DFS algorithm class. |
114 | 114 |
|
115 | 115 |
///\ingroup search |
116 | 116 |
///This class provides an efficient implementation of the %DFS algorithm. |
117 | 117 |
/// |
118 | 118 |
///There is also a \ref dfs() "function-type interface" for the DFS |
119 | 119 |
///algorithm, which is convenient in the simplier cases and it can be |
120 | 120 |
///used easier. |
121 | 121 |
/// |
122 | 122 |
///\tparam GR The type of the digraph the algorithm runs on. |
123 | 123 |
///The default type is \ref ListDigraph. |
124 |
///\tparam TR The traits class that defines various types used by the |
|
125 |
///algorithm. By default, it is \ref DfsDefaultTraits |
|
126 |
///"DfsDefaultTraits<GR>". |
|
127 |
///In most cases, this parameter should not be set directly, |
|
128 |
///consider to use the named template parameters instead. |
|
124 | 129 |
#ifdef DOXYGEN |
125 | 130 |
template <typename GR, |
126 | 131 |
typename TR> |
127 | 132 |
#else |
128 | 133 |
template <typename GR=ListDigraph, |
129 | 134 |
typename TR=DfsDefaultTraits<GR> > |
130 | 135 |
#endif |
131 | 136 |
class Dfs { |
132 | 137 |
public: |
133 | 138 |
|
134 | 139 |
///The type of the digraph the algorithm runs on. |
135 | 140 |
typedef typename TR::Digraph Digraph; |
136 | 141 |
|
137 | 142 |
///\brief The type of the map that stores the predecessor arcs of the |
138 | 143 |
///DFS paths. |
139 | 144 |
typedef typename TR::PredMap PredMap; |
140 | 145 |
///The type of the map that stores the distances of the nodes. |
141 | 146 |
typedef typename TR::DistMap DistMap; |
142 | 147 |
///The type of the map that indicates which nodes are reached. |
143 | 148 |
typedef typename TR::ReachedMap ReachedMap; |
144 | 149 |
///The type of the map that indicates which nodes are processed. |
145 | 150 |
typedef typename TR::ProcessedMap ProcessedMap; |
146 | 151 |
///The type of the paths. |
147 | 152 |
typedef PredMapPath<Digraph, PredMap> Path; |
148 | 153 |
|
149 | 154 |
///The \ref DfsDefaultTraits "traits class" of the algorithm. |
150 | 155 |
typedef TR Traits; |
151 | 156 |
|
152 | 157 |
private: |
153 | 158 |
|
154 | 159 |
typedef typename Digraph::Node Node; |
155 | 160 |
typedef typename Digraph::NodeIt NodeIt; |
156 | 161 |
typedef typename Digraph::Arc Arc; |
157 | 162 |
typedef typename Digraph::OutArcIt OutArcIt; |
158 | 163 |
|
159 | 164 |
//Pointer to the underlying digraph. |
160 | 165 |
const Digraph *G; |
161 | 166 |
//Pointer to the map of predecessor arcs. |
162 | 167 |
PredMap *_pred; |
163 | 168 |
//Indicates if _pred is locally allocated (true) or not. |
164 | 169 |
bool local_pred; |
165 | 170 |
//Pointer to the map of distances. |
166 | 171 |
DistMap *_dist; |
167 | 172 |
//Indicates if _dist is locally allocated (true) or not. |
168 | 173 |
bool local_dist; |
169 | 174 |
//Pointer to the map of reached status of the nodes. |
170 | 175 |
ReachedMap *_reached; |
171 | 176 |
//Indicates if _reached is locally allocated (true) or not. |
172 | 177 |
bool local_reached; |
173 | 178 |
//Pointer to the map of processed status of the nodes. |
174 | 179 |
ProcessedMap *_processed; |
175 | 180 |
//Indicates if _processed is locally allocated (true) or not. |
176 | 181 |
bool local_processed; |
177 | 182 |
|
178 | 183 |
std::vector<typename Digraph::OutArcIt> _stack; |
179 | 184 |
int _stack_head; |
180 | 185 |
|
181 | 186 |
//Creates the maps if necessary. |
182 | 187 |
void create_maps() |
183 | 188 |
{ |
184 | 189 |
if(!_pred) { |
185 | 190 |
local_pred = true; |
186 | 191 |
_pred = Traits::createPredMap(*G); |
187 | 192 |
} |
188 | 193 |
if(!_dist) { |
189 | 194 |
local_dist = true; |
190 | 195 |
_dist = Traits::createDistMap(*G); |
191 | 196 |
} |
192 | 197 |
if(!_reached) { |
193 | 198 |
local_reached = true; |
194 | 199 |
_reached = Traits::createReachedMap(*G); |
195 | 200 |
} |
196 | 201 |
if(!_processed) { |
197 | 202 |
local_processed = true; |
198 | 203 |
_processed = Traits::createProcessedMap(*G); |
199 | 204 |
} |
200 | 205 |
} |
201 | 206 |
|
202 | 207 |
protected: |
203 | 208 |
|
204 | 209 |
Dfs() {} |
205 | 210 |
|
206 | 211 |
public: |
207 | 212 |
|
208 | 213 |
typedef Dfs Create; |
209 | 214 |
|
210 | 215 |
///\name Named Template Parameters |
211 | 216 |
|
212 | 217 |
///@{ |
213 | 218 |
|
214 | 219 |
template <class T> |
215 | 220 |
struct SetPredMapTraits : public Traits { |
216 | 221 |
typedef T PredMap; |
217 | 222 |
static PredMap *createPredMap(const Digraph &) |
218 | 223 |
{ |
219 | 224 |
LEMON_ASSERT(false, "PredMap is not initialized"); |
220 | 225 |
return 0; // ignore warnings |
221 | 226 |
} |
222 | 227 |
}; |
223 | 228 |
///\brief \ref named-templ-param "Named parameter" for setting |
224 | 229 |
///\c PredMap type. |
225 | 230 |
/// |
226 | 231 |
///\ref named-templ-param "Named parameter" for setting |
227 | 232 |
///\c PredMap type. |
228 | 233 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
229 | 234 |
template <class T> |
230 | 235 |
struct SetPredMap : public Dfs<Digraph, SetPredMapTraits<T> > { |
231 | 236 |
typedef Dfs<Digraph, SetPredMapTraits<T> > Create; |
232 | 237 |
}; |
233 | 238 |
|
234 | 239 |
template <class T> |
235 | 240 |
struct SetDistMapTraits : public Traits { |
236 | 241 |
typedef T DistMap; |
237 | 242 |
static DistMap *createDistMap(const Digraph &) |
238 | 243 |
{ |
239 | 244 |
LEMON_ASSERT(false, "DistMap is not initialized"); |
240 | 245 |
return 0; // ignore warnings |
241 | 246 |
} |
242 | 247 |
}; |
243 | 248 |
///\brief \ref named-templ-param "Named parameter" for setting |
244 | 249 |
///\c DistMap type. |
245 | 250 |
/// |
246 | 251 |
///\ref named-templ-param "Named parameter" for setting |
247 | 252 |
///\c DistMap type. |
248 | 253 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
249 | 254 |
template <class T> |
250 | 255 |
struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
251 | 256 |
typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
252 | 257 |
}; |
253 | 258 |
|
254 | 259 |
template <class T> |
255 | 260 |
struct SetReachedMapTraits : public Traits { |
256 | 261 |
typedef T ReachedMap; |
257 | 262 |
static ReachedMap *createReachedMap(const Digraph &) |
258 | 263 |
{ |
259 | 264 |
LEMON_ASSERT(false, "ReachedMap is not initialized"); |
260 | 265 |
return 0; // ignore warnings |
261 | 266 |
} |
262 | 267 |
}; |
263 | 268 |
///\brief \ref named-templ-param "Named parameter" for setting |
264 | 269 |
///\c ReachedMap type. |
265 | 270 |
/// |
266 | 271 |
///\ref named-templ-param "Named parameter" for setting |
267 | 272 |
///\c ReachedMap type. |
268 | 273 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
269 | 274 |
template <class T> |
270 | 275 |
struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
271 | 276 |
typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
272 | 277 |
}; |
273 | 278 |
|
274 | 279 |
template <class T> |
275 | 280 |
struct SetProcessedMapTraits : public Traits { |
276 | 281 |
typedef T ProcessedMap; |
277 | 282 |
static ProcessedMap *createProcessedMap(const Digraph &) |
278 | 283 |
{ |
279 | 284 |
LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
280 | 285 |
return 0; // ignore warnings |
281 | 286 |
} |
282 | 287 |
}; |
283 | 288 |
///\brief \ref named-templ-param "Named parameter" for setting |
284 | 289 |
///\c ProcessedMap type. |
285 | 290 |
/// |
286 | 291 |
///\ref named-templ-param "Named parameter" for setting |
287 | 292 |
///\c ProcessedMap type. |
288 | 293 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
289 | 294 |
template <class T> |
290 | 295 |
struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
291 | 296 |
typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
292 | 297 |
}; |
293 | 298 |
|
294 | 299 |
struct SetStandardProcessedMapTraits : public Traits { |
295 | 300 |
typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
296 | 301 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
297 | 302 |
{ |
298 | 303 |
return new ProcessedMap(g); |
299 | 304 |
} |
300 | 305 |
}; |
301 | 306 |
///\brief \ref named-templ-param "Named parameter" for setting |
302 | 307 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
303 | 308 |
/// |
304 | 309 |
///\ref named-templ-param "Named parameter" for setting |
305 | 310 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
306 | 311 |
///If you don't set it explicitly, it will be automatically allocated. |
307 | 312 |
struct SetStandardProcessedMap : |
308 | 313 |
public Dfs< Digraph, SetStandardProcessedMapTraits > { |
309 | 314 |
typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
310 | 315 |
}; |
311 | 316 |
|
312 | 317 |
///@} |
313 | 318 |
|
314 | 319 |
public: |
315 | 320 |
|
316 | 321 |
///Constructor. |
317 | 322 |
|
318 | 323 |
///Constructor. |
319 | 324 |
///\param g The digraph the algorithm runs on. |
320 | 325 |
Dfs(const Digraph &g) : |
321 | 326 |
G(&g), |
322 | 327 |
_pred(NULL), local_pred(false), |
323 | 328 |
_dist(NULL), local_dist(false), |
324 | 329 |
_reached(NULL), local_reached(false), |
325 | 330 |
_processed(NULL), local_processed(false) |
326 | 331 |
{ } |
327 | 332 |
|
328 | 333 |
///Destructor. |
329 | 334 |
~Dfs() |
330 | 335 |
{ |
331 | 336 |
if(local_pred) delete _pred; |
332 | 337 |
if(local_dist) delete _dist; |
333 | 338 |
if(local_reached) delete _reached; |
334 | 339 |
if(local_processed) delete _processed; |
335 | 340 |
} |
336 | 341 |
|
337 | 342 |
///Sets the map that stores the predecessor arcs. |
338 | 343 |
|
339 | 344 |
///Sets the map that stores the predecessor arcs. |
340 | 345 |
///If you don't use this function before calling \ref run(Node) "run()" |
341 | 346 |
///or \ref init(), an instance will be allocated automatically. |
342 | 347 |
///The destructor deallocates this automatically allocated map, |
343 | 348 |
///of course. |
344 | 349 |
///\return <tt> (*this) </tt> |
345 | 350 |
Dfs &predMap(PredMap &m) |
346 | 351 |
{ |
347 | 352 |
if(local_pred) { |
348 | 353 |
delete _pred; |
349 | 354 |
local_pred=false; |
350 | 355 |
} |
351 | 356 |
_pred = &m; |
352 | 357 |
return *this; |
353 | 358 |
} |
354 | 359 |
|
355 | 360 |
///Sets the map that indicates which nodes are reached. |
356 | 361 |
|
357 | 362 |
///Sets the map that indicates which nodes are reached. |
358 | 363 |
///If you don't use this function before calling \ref run(Node) "run()" |
359 | 364 |
///or \ref init(), an instance will be allocated automatically. |
360 | 365 |
///The destructor deallocates this automatically allocated map, |
361 | 366 |
///of course. |
362 | 367 |
///\return <tt> (*this) </tt> |
363 | 368 |
Dfs &reachedMap(ReachedMap &m) |
364 | 369 |
{ |
365 | 370 |
if(local_reached) { |
366 | 371 |
delete _reached; |
367 | 372 |
local_reached=false; |
368 | 373 |
} |
369 | 374 |
_reached = &m; |
370 | 375 |
return *this; |
371 | 376 |
} |
372 | 377 |
|
373 | 378 |
///Sets the map that indicates which nodes are processed. |
374 | 379 |
|
375 | 380 |
///Sets the map that indicates which nodes are processed. |
376 | 381 |
///If you don't use this function before calling \ref run(Node) "run()" |
377 | 382 |
///or \ref init(), an instance will be allocated automatically. |
378 | 383 |
///The destructor deallocates this automatically allocated map, |
379 | 384 |
///of course. |
380 | 385 |
///\return <tt> (*this) </tt> |
381 | 386 |
Dfs &processedMap(ProcessedMap &m) |
382 | 387 |
{ |
383 | 388 |
if(local_processed) { |
384 | 389 |
delete _processed; |
385 | 390 |
local_processed=false; |
386 | 391 |
} |
387 | 392 |
_processed = &m; |
388 | 393 |
return *this; |
389 | 394 |
} |
390 | 395 |
|
391 | 396 |
///Sets the map that stores the distances of the nodes. |
392 | 397 |
|
393 | 398 |
///Sets the map that stores the distances of the nodes calculated by |
394 | 399 |
///the algorithm. |
395 | 400 |
///If you don't use this function before calling \ref run(Node) "run()" |
396 | 401 |
///or \ref init(), an instance will be allocated automatically. |
397 | 402 |
///The destructor deallocates this automatically allocated map, |
398 | 403 |
///of course. |
399 | 404 |
///\return <tt> (*this) </tt> |
400 | 405 |
Dfs &distMap(DistMap &m) |
401 | 406 |
{ |
402 | 407 |
if(local_dist) { |
403 | 408 |
delete _dist; |
404 | 409 |
local_dist=false; |
405 | 410 |
} |
406 | 411 |
_dist = &m; |
407 | 412 |
return *this; |
408 | 413 |
} |
409 | 414 |
|
410 | 415 |
public: |
411 | 416 |
|
412 | 417 |
///\name Execution Control |
413 | 418 |
///The simplest way to execute the DFS algorithm is to use one of the |
414 | 419 |
///member functions called \ref run(Node) "run()".\n |
415 | 420 |
///If you need better control on the execution, you have to call |
416 | 421 |
///\ref init() first, then you can add a source node with \ref addSource() |
417 | 422 |
///and perform the actual computation with \ref start(). |
418 | 423 |
///This procedure can be repeated if there are nodes that have not |
419 | 424 |
///been reached. |
420 | 425 |
|
421 | 426 |
///@{ |
422 | 427 |
|
423 | 428 |
///\brief Initializes the internal data structures. |
424 | 429 |
/// |
425 | 430 |
///Initializes the internal data structures. |
426 | 431 |
void init() |
427 | 432 |
{ |
428 | 433 |
create_maps(); |
429 | 434 |
_stack.resize(countNodes(*G)); |
430 | 435 |
_stack_head=-1; |
431 | 436 |
for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
432 | 437 |
_pred->set(u,INVALID); |
433 | 438 |
_reached->set(u,false); |
434 | 439 |
_processed->set(u,false); |
435 | 440 |
} |
436 | 441 |
} |
437 | 442 |
|
438 | 443 |
///Adds a new source node. |
439 | 444 |
|
440 | 445 |
///Adds a new source node to the set of nodes to be processed. |
441 | 446 |
/// |
442 | 447 |
///\pre The stack must be empty. Otherwise the algorithm gives |
443 | 448 |
///wrong results. (One of the outgoing arcs of all the source nodes |
444 | 449 |
///except for the last one will not be visited and distances will |
445 | 450 |
///also be wrong.) |
446 | 451 |
void addSource(Node s) |
447 | 452 |
{ |
448 | 453 |
LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
449 | 454 |
if(!(*_reached)[s]) |
450 | 455 |
{ |
451 | 456 |
_reached->set(s,true); |
452 | 457 |
_pred->set(s,INVALID); |
453 | 458 |
OutArcIt e(*G,s); |
454 | 459 |
if(e!=INVALID) { |
455 | 460 |
_stack[++_stack_head]=e; |
456 | 461 |
_dist->set(s,_stack_head); |
457 | 462 |
} |
458 | 463 |
else { |
459 | 464 |
_processed->set(s,true); |
460 | 465 |
_dist->set(s,0); |
461 | 466 |
} |
462 | 467 |
} |
463 | 468 |
} |
464 | 469 |
|
465 | 470 |
///Processes the next arc. |
466 | 471 |
|
467 | 472 |
///Processes the next arc. |
468 | 473 |
/// |
469 | 474 |
///\return The processed arc. |
470 | 475 |
/// |
471 | 476 |
///\pre The stack must not be empty. |
472 | 477 |
Arc processNextArc() |
473 | 478 |
{ |
474 | 479 |
Node m; |
475 | 480 |
Arc e=_stack[_stack_head]; |
476 | 481 |
if(!(*_reached)[m=G->target(e)]) { |
477 | 482 |
_pred->set(m,e); |
478 | 483 |
_reached->set(m,true); |
479 | 484 |
++_stack_head; |
480 | 485 |
_stack[_stack_head] = OutArcIt(*G, m); |
481 | 486 |
_dist->set(m,_stack_head); |
482 | 487 |
} |
483 | 488 |
else { |
484 | 489 |
m=G->source(e); |
485 | 490 |
++_stack[_stack_head]; |
486 | 491 |
} |
487 | 492 |
while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
488 | 493 |
_processed->set(m,true); |
489 | 494 |
--_stack_head; |
490 | 495 |
if(_stack_head>=0) { |
491 | 496 |
m=G->source(_stack[_stack_head]); |
492 | 497 |
++_stack[_stack_head]; |
493 | 498 |
} |
494 | 499 |
} |
495 | 500 |
return e; |
496 | 501 |
} |
497 | 502 |
|
498 | 503 |
///Next arc to be processed. |
499 | 504 |
|
500 | 505 |
///Next arc to be processed. |
501 | 506 |
/// |
502 | 507 |
///\return The next arc to be processed or \c INVALID if the stack |
503 | 508 |
///is empty. |
504 | 509 |
OutArcIt nextArc() const |
505 | 510 |
{ |
506 | 511 |
return _stack_head>=0?_stack[_stack_head]:INVALID; |
507 | 512 |
} |
508 | 513 |
|
509 | 514 |
///Returns \c false if there are nodes to be processed. |
510 | 515 |
|
511 | 516 |
///Returns \c false if there are nodes to be processed |
512 | 517 |
///in the queue (stack). |
513 | 518 |
bool emptyQueue() const { return _stack_head<0; } |
514 | 519 |
|
515 | 520 |
///Returns the number of the nodes to be processed. |
516 | 521 |
|
517 | 522 |
///Returns the number of the nodes to be processed |
518 | 523 |
///in the queue (stack). |
519 | 524 |
int queueSize() const { return _stack_head+1; } |
520 | 525 |
|
521 | 526 |
///Executes the algorithm. |
522 | 527 |
|
523 | 528 |
///Executes the algorithm. |
524 | 529 |
/// |
525 | 530 |
///This method runs the %DFS algorithm from the root node |
526 | 531 |
///in order to compute the DFS path to each node. |
527 | 532 |
/// |
528 | 533 |
/// The algorithm computes |
529 | 534 |
///- the %DFS tree, |
530 | 535 |
///- the distance of each node from the root in the %DFS tree. |
531 | 536 |
/// |
532 | 537 |
///\pre init() must be called and a root node should be |
533 | 538 |
///added with addSource() before using this function. |
534 | 539 |
/// |
535 | 540 |
///\note <tt>d.start()</tt> is just a shortcut of the following code. |
536 | 541 |
///\code |
537 | 542 |
/// while ( !d.emptyQueue() ) { |
538 | 543 |
/// d.processNextArc(); |
539 | 544 |
/// } |
540 | 545 |
///\endcode |
541 | 546 |
void start() |
542 | 547 |
{ |
543 | 548 |
while ( !emptyQueue() ) processNextArc(); |
544 | 549 |
} |
545 | 550 |
|
546 | 551 |
///Executes the algorithm until the given target node is reached. |
547 | 552 |
|
548 | 553 |
///Executes the algorithm until the given target node is reached. |
549 | 554 |
/// |
550 | 555 |
///This method runs the %DFS algorithm from the root node |
551 | 556 |
///in order to compute the DFS path to \c t. |
552 | 557 |
/// |
553 | 558 |
///The algorithm computes |
554 | 559 |
///- the %DFS path to \c t, |
555 | 560 |
///- the distance of \c t from the root in the %DFS tree. |
556 | 561 |
/// |
557 | 562 |
///\pre init() must be called and a root node should be |
558 | 563 |
///added with addSource() before using this function. |
559 | 564 |
void start(Node t) |
560 | 565 |
{ |
561 | 566 |
while ( !emptyQueue() && G->target(_stack[_stack_head])!=t ) |
562 | 567 |
processNextArc(); |
563 | 568 |
} |
564 | 569 |
|
565 | 570 |
///Executes the algorithm until a condition is met. |
566 | 571 |
|
567 | 572 |
///Executes the algorithm until a condition is met. |
568 | 573 |
/// |
569 | 574 |
///This method runs the %DFS algorithm from the root node |
570 | 575 |
///until an arc \c a with <tt>am[a]</tt> true is found. |
571 | 576 |
/// |
572 | 577 |
///\param am A \c bool (or convertible) arc map. The algorithm |
573 | 578 |
///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
574 | 579 |
/// |
575 | 580 |
///\return The reached arc \c a with <tt>am[a]</tt> true or |
576 | 581 |
///\c INVALID if no such arc was found. |
577 | 582 |
/// |
578 | 583 |
///\pre init() must be called and a root node should be |
579 | 584 |
///added with addSource() before using this function. |
580 | 585 |
/// |
581 | 586 |
///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
582 | 587 |
///not a node map. |
583 | 588 |
template<class ArcBoolMap> |
584 | 589 |
Arc start(const ArcBoolMap &am) |
585 | 590 |
{ |
586 | 591 |
while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
587 | 592 |
processNextArc(); |
588 | 593 |
return emptyQueue() ? INVALID : _stack[_stack_head]; |
589 | 594 |
} |
590 | 595 |
|
591 | 596 |
///Runs the algorithm from the given source node. |
592 | 597 |
|
593 | 598 |
///This method runs the %DFS algorithm from node \c s |
594 | 599 |
///in order to compute the DFS path to each node. |
595 | 600 |
/// |
596 | 601 |
///The algorithm computes |
597 | 602 |
///- the %DFS tree, |
598 | 603 |
///- the distance of each node from the root in the %DFS tree. |
599 | 604 |
/// |
600 | 605 |
///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
601 | 606 |
///\code |
602 | 607 |
/// d.init(); |
603 | 608 |
/// d.addSource(s); |
604 | 609 |
/// d.start(); |
605 | 610 |
///\endcode |
606 | 611 |
void run(Node s) { |
607 | 612 |
init(); |
608 | 613 |
addSource(s); |
609 | 614 |
start(); |
610 | 615 |
} |
611 | 616 |
|
612 | 617 |
///Finds the %DFS path between \c s and \c t. |
613 | 618 |
|
614 | 619 |
///This method runs the %DFS algorithm from node \c s |
615 | 620 |
///in order to compute the DFS path to node \c t |
616 | 621 |
///(it stops searching when \c t is processed) |
617 | 622 |
/// |
618 | 623 |
///\return \c true if \c t is reachable form \c s. |
619 | 624 |
/// |
620 | 625 |
///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
621 | 626 |
///just a shortcut of the following code. |
622 | 627 |
///\code |
623 | 628 |
/// d.init(); |
624 | 629 |
/// d.addSource(s); |
625 | 630 |
/// d.start(t); |
626 | 631 |
///\endcode |
627 | 632 |
bool run(Node s,Node t) { |
628 | 633 |
init(); |
629 | 634 |
addSource(s); |
630 | 635 |
start(t); |
631 | 636 |
return reached(t); |
632 | 637 |
} |
633 | 638 |
|
634 | 639 |
///Runs the algorithm to visit all nodes in the digraph. |
635 | 640 |
|
636 | 641 |
///This method runs the %DFS algorithm in order to visit all nodes |
637 | 642 |
///in the digraph. |
638 | 643 |
/// |
639 | 644 |
///\note <tt>d.run()</tt> is just a shortcut of the following code. |
640 | 645 |
///\code |
641 | 646 |
/// d.init(); |
642 | 647 |
/// for (NodeIt n(digraph); n != INVALID; ++n) { |
643 | 648 |
/// if (!d.reached(n)) { |
644 | 649 |
/// d.addSource(n); |
645 | 650 |
/// d.start(); |
646 | 651 |
/// } |
647 | 652 |
/// } |
648 | 653 |
///\endcode |
649 | 654 |
void run() { |
650 | 655 |
init(); |
651 | 656 |
for (NodeIt it(*G); it != INVALID; ++it) { |
652 | 657 |
if (!reached(it)) { |
653 | 658 |
addSource(it); |
654 | 659 |
start(); |
655 | 660 |
} |
656 | 661 |
} |
657 | 662 |
} |
658 | 663 |
|
659 | 664 |
///@} |
660 | 665 |
|
661 | 666 |
///\name Query Functions |
662 | 667 |
///The results of the DFS algorithm can be obtained using these |
663 | 668 |
///functions.\n |
664 | 669 |
///Either \ref run(Node) "run()" or \ref start() should be called |
665 | 670 |
///before using them. |
666 | 671 |
|
667 | 672 |
///@{ |
668 | 673 |
|
669 | 674 |
///The DFS path to the given node. |
670 | 675 |
|
671 | 676 |
///Returns the DFS path to the given node from the root(s). |
672 | 677 |
/// |
673 | 678 |
///\warning \c t should be reached from the root(s). |
674 | 679 |
/// |
675 | 680 |
///\pre Either \ref run(Node) "run()" or \ref init() |
676 | 681 |
///must be called before using this function. |
677 | 682 |
Path path(Node t) const { return Path(*G, *_pred, t); } |
678 | 683 |
|
679 | 684 |
///The distance of the given node from the root(s). |
680 | 685 |
|
681 | 686 |
///Returns the distance of the given node from the root(s). |
682 | 687 |
/// |
683 | 688 |
///\warning If node \c v is not reached from the root(s), then |
684 | 689 |
///the return value of this function is undefined. |
685 | 690 |
/// |
686 | 691 |
///\pre Either \ref run(Node) "run()" or \ref init() |
687 | 692 |
///must be called before using this function. |
688 | 693 |
int dist(Node v) const { return (*_dist)[v]; } |
689 | 694 |
|
690 | 695 |
///Returns the 'previous arc' of the %DFS tree for the given node. |
691 | 696 |
|
692 | 697 |
///This function returns the 'previous arc' of the %DFS tree for the |
693 | 698 |
///node \c v, i.e. it returns the last arc of a %DFS path from a |
694 | 699 |
///root to \c v. It is \c INVALID if \c v is not reached from the |
695 | 700 |
///root(s) or if \c v is a root. |
696 | 701 |
/// |
697 | 702 |
///The %DFS tree used here is equal to the %DFS tree used in |
698 | 703 |
///\ref predNode() and \ref predMap(). |
699 | 704 |
/// |
700 | 705 |
///\pre Either \ref run(Node) "run()" or \ref init() |
701 | 706 |
///must be called before using this function. |
702 | 707 |
Arc predArc(Node v) const { return (*_pred)[v];} |
703 | 708 |
|
704 | 709 |
///Returns the 'previous node' of the %DFS tree for the given node. |
705 | 710 |
|
706 | 711 |
///This function returns the 'previous node' of the %DFS |
707 | 712 |
///tree for the node \c v, i.e. it returns the last but one node |
708 | 713 |
///of a %DFS path from a root to \c v. It is \c INVALID |
709 | 714 |
///if \c v is not reached from the root(s) or if \c v is a root. |
710 | 715 |
/// |
711 | 716 |
///The %DFS tree used here is equal to the %DFS tree used in |
712 | 717 |
///\ref predArc() and \ref predMap(). |
713 | 718 |
/// |
714 | 719 |
///\pre Either \ref run(Node) "run()" or \ref init() |
715 | 720 |
///must be called before using this function. |
716 | 721 |
Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
717 | 722 |
G->source((*_pred)[v]); } |
718 | 723 |
|
719 | 724 |
///\brief Returns a const reference to the node map that stores the |
720 | 725 |
///distances of the nodes. |
721 | 726 |
/// |
722 | 727 |
///Returns a const reference to the node map that stores the |
723 | 728 |
///distances of the nodes calculated by the algorithm. |
724 | 729 |
/// |
725 | 730 |
///\pre Either \ref run(Node) "run()" or \ref init() |
726 | 731 |
///must be called before using this function. |
727 | 732 |
const DistMap &distMap() const { return *_dist;} |
728 | 733 |
|
729 | 734 |
///\brief Returns a const reference to the node map that stores the |
730 | 735 |
///predecessor arcs. |
731 | 736 |
/// |
732 | 737 |
///Returns a const reference to the node map that stores the predecessor |
733 | 738 |
///arcs, which form the DFS tree (forest). |
734 | 739 |
/// |
735 | 740 |
///\pre Either \ref run(Node) "run()" or \ref init() |
736 | 741 |
///must be called before using this function. |
737 | 742 |
const PredMap &predMap() const { return *_pred;} |
738 | 743 |
|
739 | 744 |
///Checks if the given node. node is reached from the root(s). |
740 | 745 |
|
741 | 746 |
///Returns \c true if \c v is reached from the root(s). |
742 | 747 |
/// |
743 | 748 |
///\pre Either \ref run(Node) "run()" or \ref init() |
744 | 749 |
///must be called before using this function. |
745 | 750 |
bool reached(Node v) const { return (*_reached)[v]; } |
746 | 751 |
|
747 | 752 |
///@} |
748 | 753 |
}; |
749 | 754 |
|
750 | 755 |
///Default traits class of dfs() function. |
751 | 756 |
|
752 | 757 |
///Default traits class of dfs() function. |
753 | 758 |
///\tparam GR Digraph type. |
754 | 759 |
template<class GR> |
755 | 760 |
struct DfsWizardDefaultTraits |
756 | 761 |
{ |
757 | 762 |
///The type of the digraph the algorithm runs on. |
758 | 763 |
typedef GR Digraph; |
759 | 764 |
|
760 | 765 |
///\brief The type of the map that stores the predecessor |
761 | 766 |
///arcs of the %DFS paths. |
762 | 767 |
/// |
763 | 768 |
///The type of the map that stores the predecessor |
764 | 769 |
///arcs of the %DFS paths. |
765 | 770 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
766 | 771 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
767 | 772 |
///Instantiates a PredMap. |
768 | 773 |
|
769 | 774 |
///This function instantiates a PredMap. |
770 | 775 |
///\param g is the digraph, to which we would like to define the |
771 | 776 |
///PredMap. |
772 | 777 |
static PredMap *createPredMap(const Digraph &g) |
773 | 778 |
{ |
774 | 779 |
return new PredMap(g); |
775 | 780 |
} |
776 | 781 |
|
777 | 782 |
///The type of the map that indicates which nodes are processed. |
778 | 783 |
|
779 | 784 |
///The type of the map that indicates which nodes are processed. |
780 | 785 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
781 | 786 |
///By default, it is a NullMap. |
782 | 787 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
783 | 788 |
///Instantiates a ProcessedMap. |
784 | 789 |
|
785 | 790 |
///This function instantiates a ProcessedMap. |
786 | 791 |
///\param g is the digraph, to which |
787 | 792 |
///we would like to define the ProcessedMap. |
788 | 793 |
#ifdef DOXYGEN |
789 | 794 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
790 | 795 |
#else |
791 | 796 |
static ProcessedMap *createProcessedMap(const Digraph &) |
792 | 797 |
#endif |
793 | 798 |
{ |
794 | 799 |
return new ProcessedMap(); |
795 | 800 |
} |
796 | 801 |
|
797 | 802 |
///The type of the map that indicates which nodes are reached. |
798 | 803 |
|
799 | 804 |
///The type of the map that indicates which nodes are reached. |
800 | 805 |
///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
801 | 806 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
802 | 807 |
///Instantiates a ReachedMap. |
803 | 808 |
|
804 | 809 |
///This function instantiates a ReachedMap. |
805 | 810 |
///\param g is the digraph, to which |
806 | 811 |
///we would like to define the ReachedMap. |
807 | 812 |
static ReachedMap *createReachedMap(const Digraph &g) |
808 | 813 |
{ |
809 | 814 |
return new ReachedMap(g); |
810 | 815 |
} |
811 | 816 |
|
812 | 817 |
///The type of the map that stores the distances of the nodes. |
813 | 818 |
|
814 | 819 |
///The type of the map that stores the distances of the nodes. |
815 | 820 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
816 | 821 |
typedef typename Digraph::template NodeMap<int> DistMap; |
817 | 822 |
///Instantiates a DistMap. |
818 | 823 |
|
819 | 824 |
///This function instantiates a DistMap. |
820 | 825 |
///\param g is the digraph, to which we would like to define |
821 | 826 |
///the DistMap |
822 | 827 |
static DistMap *createDistMap(const Digraph &g) |
823 | 828 |
{ |
824 | 829 |
return new DistMap(g); |
825 | 830 |
} |
826 | 831 |
|
827 | 832 |
///The type of the DFS paths. |
828 | 833 |
|
829 | 834 |
///The type of the DFS paths. |
830 | 835 |
///It must conform to the \ref concepts::Path "Path" concept. |
831 | 836 |
typedef lemon::Path<Digraph> Path; |
832 | 837 |
}; |
833 | 838 |
|
834 | 839 |
/// Default traits class used by DfsWizard |
835 | 840 |
|
836 | 841 |
/// Default traits class used by DfsWizard. |
837 | 842 |
/// \tparam GR The type of the digraph. |
838 | 843 |
template<class GR> |
839 | 844 |
class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
840 | 845 |
{ |
841 | 846 |
|
842 | 847 |
typedef DfsWizardDefaultTraits<GR> Base; |
843 | 848 |
protected: |
844 | 849 |
//The type of the nodes in the digraph. |
845 | 850 |
typedef typename Base::Digraph::Node Node; |
846 | 851 |
|
847 | 852 |
//Pointer to the digraph the algorithm runs on. |
848 | 853 |
void *_g; |
849 | 854 |
//Pointer to the map of reached nodes. |
850 | 855 |
void *_reached; |
851 | 856 |
//Pointer to the map of processed nodes. |
852 | 857 |
void *_processed; |
853 | 858 |
//Pointer to the map of predecessors arcs. |
854 | 859 |
void *_pred; |
855 | 860 |
//Pointer to the map of distances. |
856 | 861 |
void *_dist; |
857 | 862 |
//Pointer to the DFS path to the target node. |
858 | 863 |
void *_path; |
859 | 864 |
//Pointer to the distance of the target node. |
860 | 865 |
int *_di; |
861 | 866 |
|
862 | 867 |
public: |
863 | 868 |
/// Constructor. |
864 | 869 |
|
865 | 870 |
/// This constructor does not require parameters, it initiates |
866 | 871 |
/// all of the attributes to \c 0. |
867 | 872 |
DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
868 | 873 |
_dist(0), _path(0), _di(0) {} |
869 | 874 |
|
870 | 875 |
/// Constructor. |
871 | 876 |
|
872 | 877 |
/// This constructor requires one parameter, |
873 | 878 |
/// others are initiated to \c 0. |
874 | 879 |
/// \param g The digraph the algorithm runs on. |
875 | 880 |
DfsWizardBase(const GR &g) : |
876 | 881 |
_g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
877 | 882 |
_reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
878 | 883 |
|
879 | 884 |
}; |
880 | 885 |
|
881 | 886 |
/// Auxiliary class for the function-type interface of DFS algorithm. |
882 | 887 |
|
883 | 888 |
/// This auxiliary class is created to implement the |
884 | 889 |
/// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
885 | 890 |
/// It does not have own \ref run(Node) "run()" method, it uses the |
886 | 891 |
/// functions and features of the plain \ref Dfs. |
887 | 892 |
/// |
888 | 893 |
/// This class should only be used through the \ref dfs() function, |
889 | 894 |
/// which makes it easier to use the algorithm. |
895 |
/// |
|
896 |
/// \tparam TR The traits class that defines various types used by the |
|
897 |
/// algorithm. |
|
890 | 898 |
template<class TR> |
891 | 899 |
class DfsWizard : public TR |
892 | 900 |
{ |
893 | 901 |
typedef TR Base; |
894 | 902 |
|
895 | 903 |
typedef typename TR::Digraph Digraph; |
896 | 904 |
|
897 | 905 |
typedef typename Digraph::Node Node; |
898 | 906 |
typedef typename Digraph::NodeIt NodeIt; |
899 | 907 |
typedef typename Digraph::Arc Arc; |
900 | 908 |
typedef typename Digraph::OutArcIt OutArcIt; |
901 | 909 |
|
902 | 910 |
typedef typename TR::PredMap PredMap; |
903 | 911 |
typedef typename TR::DistMap DistMap; |
904 | 912 |
typedef typename TR::ReachedMap ReachedMap; |
905 | 913 |
typedef typename TR::ProcessedMap ProcessedMap; |
906 | 914 |
typedef typename TR::Path Path; |
907 | 915 |
|
908 | 916 |
public: |
909 | 917 |
|
910 | 918 |
/// Constructor. |
911 | 919 |
DfsWizard() : TR() {} |
912 | 920 |
|
913 | 921 |
/// Constructor that requires parameters. |
914 | 922 |
|
915 | 923 |
/// Constructor that requires parameters. |
916 | 924 |
/// These parameters will be the default values for the traits class. |
917 | 925 |
/// \param g The digraph the algorithm runs on. |
918 | 926 |
DfsWizard(const Digraph &g) : |
919 | 927 |
TR(g) {} |
920 | 928 |
|
921 | 929 |
///Copy constructor |
922 | 930 |
DfsWizard(const TR &b) : TR(b) {} |
923 | 931 |
|
924 | 932 |
~DfsWizard() {} |
925 | 933 |
|
926 | 934 |
///Runs DFS algorithm from the given source node. |
927 | 935 |
|
928 | 936 |
///This method runs DFS algorithm from node \c s |
929 | 937 |
///in order to compute the DFS path to each node. |
930 | 938 |
void run(Node s) |
931 | 939 |
{ |
932 | 940 |
Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
933 | 941 |
if (Base::_pred) |
934 | 942 |
alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
935 | 943 |
if (Base::_dist) |
936 | 944 |
alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
937 | 945 |
if (Base::_reached) |
938 | 946 |
alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
939 | 947 |
if (Base::_processed) |
940 | 948 |
alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
941 | 949 |
if (s!=INVALID) |
942 | 950 |
alg.run(s); |
943 | 951 |
else |
944 | 952 |
alg.run(); |
945 | 953 |
} |
946 | 954 |
|
947 | 955 |
///Finds the DFS path between \c s and \c t. |
948 | 956 |
|
949 | 957 |
///This method runs DFS algorithm from node \c s |
950 | 958 |
///in order to compute the DFS path to node \c t |
951 | 959 |
///(it stops searching when \c t is processed). |
952 | 960 |
/// |
953 | 961 |
///\return \c true if \c t is reachable form \c s. |
954 | 962 |
bool run(Node s, Node t) |
955 | 963 |
{ |
956 | 964 |
Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
957 | 965 |
if (Base::_pred) |
958 | 966 |
alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
959 | 967 |
if (Base::_dist) |
960 | 968 |
alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
961 | 969 |
if (Base::_reached) |
962 | 970 |
alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
963 | 971 |
if (Base::_processed) |
964 | 972 |
alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
965 | 973 |
alg.run(s,t); |
966 | 974 |
if (Base::_path) |
967 | 975 |
*reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
968 | 976 |
if (Base::_di) |
969 | 977 |
*Base::_di = alg.dist(t); |
970 | 978 |
return alg.reached(t); |
971 | 979 |
} |
972 | 980 |
|
973 | 981 |
///Runs DFS algorithm to visit all nodes in the digraph. |
974 | 982 |
|
975 | 983 |
///This method runs DFS algorithm in order to visit all nodes |
976 | 984 |
///in the digraph. |
977 | 985 |
void run() |
978 | 986 |
{ |
979 | 987 |
run(INVALID); |
980 | 988 |
} |
981 | 989 |
|
982 | 990 |
template<class T> |
983 | 991 |
struct SetPredMapBase : public Base { |
984 | 992 |
typedef T PredMap; |
985 | 993 |
static PredMap *createPredMap(const Digraph &) { return 0; }; |
986 | 994 |
SetPredMapBase(const TR &b) : TR(b) {} |
987 | 995 |
}; |
988 | 996 |
|
989 | 997 |
///\brief \ref named-templ-param "Named parameter" for setting |
990 | 998 |
///the predecessor map. |
991 | 999 |
/// |
992 | 1000 |
///\ref named-templ-param "Named parameter" function for setting |
993 | 1001 |
///the map that stores the predecessor arcs of the nodes. |
994 | 1002 |
template<class T> |
995 | 1003 |
DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
996 | 1004 |
{ |
997 | 1005 |
Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
998 | 1006 |
return DfsWizard<SetPredMapBase<T> >(*this); |
999 | 1007 |
} |
1000 | 1008 |
|
1001 | 1009 |
template<class T> |
1002 | 1010 |
struct SetReachedMapBase : public Base { |
1003 | 1011 |
typedef T ReachedMap; |
1004 | 1012 |
static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
1005 | 1013 |
SetReachedMapBase(const TR &b) : TR(b) {} |
1006 | 1014 |
}; |
1007 | 1015 |
|
1008 | 1016 |
///\brief \ref named-templ-param "Named parameter" for setting |
1009 | 1017 |
///the reached map. |
1010 | 1018 |
/// |
1011 | 1019 |
///\ref named-templ-param "Named parameter" function for setting |
1012 | 1020 |
///the map that indicates which nodes are reached. |
1013 | 1021 |
template<class T> |
1014 | 1022 |
DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
1015 | 1023 |
{ |
1016 | 1024 |
Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1017 | 1025 |
return DfsWizard<SetReachedMapBase<T> >(*this); |
1018 | 1026 |
} |
1019 | 1027 |
|
1020 | 1028 |
template<class T> |
1021 | 1029 |
struct SetDistMapBase : public Base { |
1022 | 1030 |
typedef T DistMap; |
1023 | 1031 |
static DistMap *createDistMap(const Digraph &) { return 0; }; |
1024 | 1032 |
SetDistMapBase(const TR &b) : TR(b) {} |
1025 | 1033 |
}; |
1026 | 1034 |
|
1027 | 1035 |
///\brief \ref named-templ-param "Named parameter" for setting |
1028 | 1036 |
///the distance map. |
1029 | 1037 |
/// |
1030 | 1038 |
///\ref named-templ-param "Named parameter" function for setting |
1031 | 1039 |
///the map that stores the distances of the nodes calculated |
1032 | 1040 |
///by the algorithm. |
1033 | 1041 |
template<class T> |
1034 | 1042 |
DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
1035 | 1043 |
{ |
1036 | 1044 |
Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1037 | 1045 |
return DfsWizard<SetDistMapBase<T> >(*this); |
1038 | 1046 |
} |
1039 | 1047 |
|
1040 | 1048 |
template<class T> |
1041 | 1049 |
struct SetProcessedMapBase : public Base { |
1042 | 1050 |
typedef T ProcessedMap; |
1043 | 1051 |
static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
1044 | 1052 |
SetProcessedMapBase(const TR &b) : TR(b) {} |
1045 | 1053 |
}; |
1046 | 1054 |
|
1047 | 1055 |
///\brief \ref named-func-param "Named parameter" for setting |
1048 | 1056 |
///the processed map. |
1049 | 1057 |
/// |
1050 | 1058 |
///\ref named-templ-param "Named parameter" function for setting |
1051 | 1059 |
///the map that indicates which nodes are processed. |
1052 | 1060 |
template<class T> |
1053 | 1061 |
DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
1054 | 1062 |
{ |
1055 | 1063 |
Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1056 | 1064 |
return DfsWizard<SetProcessedMapBase<T> >(*this); |
1057 | 1065 |
} |
1058 | 1066 |
|
1059 | 1067 |
template<class T> |
1060 | 1068 |
struct SetPathBase : public Base { |
1061 | 1069 |
typedef T Path; |
1062 | 1070 |
SetPathBase(const TR &b) : TR(b) {} |
1063 | 1071 |
}; |
1064 | 1072 |
///\brief \ref named-func-param "Named parameter" |
1065 | 1073 |
///for getting the DFS path to the target node. |
1066 | 1074 |
/// |
1067 | 1075 |
///\ref named-func-param "Named parameter" |
1068 | 1076 |
///for getting the DFS path to the target node. |
1069 | 1077 |
template<class T> |
1070 | 1078 |
DfsWizard<SetPathBase<T> > path(const T &t) |
1071 | 1079 |
{ |
1072 | 1080 |
Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1073 | 1081 |
return DfsWizard<SetPathBase<T> >(*this); |
1074 | 1082 |
} |
1075 | 1083 |
|
1076 | 1084 |
///\brief \ref named-func-param "Named parameter" |
1077 | 1085 |
///for getting the distance of the target node. |
1078 | 1086 |
/// |
1079 | 1087 |
///\ref named-func-param "Named parameter" |
1080 | 1088 |
///for getting the distance of the target node. |
1081 | 1089 |
DfsWizard dist(const int &d) |
1082 | 1090 |
{ |
1083 | 1091 |
Base::_di=const_cast<int*>(&d); |
1084 | 1092 |
return *this; |
1085 | 1093 |
} |
1086 | 1094 |
|
1087 | 1095 |
}; |
1088 | 1096 |
|
1089 | 1097 |
///Function-type interface for DFS algorithm. |
1090 | 1098 |
|
1091 | 1099 |
///\ingroup search |
1092 | 1100 |
///Function-type interface for DFS algorithm. |
1093 | 1101 |
/// |
1094 | 1102 |
///This function also has several \ref named-func-param "named parameters", |
1095 | 1103 |
///they are declared as the members of class \ref DfsWizard. |
1096 | 1104 |
///The following examples show how to use these parameters. |
1097 | 1105 |
///\code |
1098 | 1106 |
/// // Compute the DFS tree |
1099 | 1107 |
/// dfs(g).predMap(preds).distMap(dists).run(s); |
1100 | 1108 |
/// |
1101 | 1109 |
/// // Compute the DFS path from s to t |
1102 | 1110 |
/// bool reached = dfs(g).path(p).dist(d).run(s,t); |
1103 | 1111 |
///\endcode |
1104 | 1112 |
///\warning Don't forget to put the \ref DfsWizard::run(Node) "run()" |
1105 | 1113 |
///to the end of the parameter list. |
1106 | 1114 |
///\sa DfsWizard |
1107 | 1115 |
///\sa Dfs |
1108 | 1116 |
template<class GR> |
1109 | 1117 |
DfsWizard<DfsWizardBase<GR> > |
1110 | 1118 |
dfs(const GR &digraph) |
1111 | 1119 |
{ |
1112 | 1120 |
return DfsWizard<DfsWizardBase<GR> >(digraph); |
1113 | 1121 |
} |
1114 | 1122 |
|
1115 | 1123 |
#ifdef DOXYGEN |
1116 | 1124 |
/// \brief Visitor class for DFS. |
1117 | 1125 |
/// |
1118 | 1126 |
/// This class defines the interface of the DfsVisit events, and |
1119 | 1127 |
/// it could be the base of a real visitor class. |
1120 | 1128 |
template <typename GR> |
1121 | 1129 |
struct DfsVisitor { |
1122 | 1130 |
typedef GR Digraph; |
1123 | 1131 |
typedef typename Digraph::Arc Arc; |
1124 | 1132 |
typedef typename Digraph::Node Node; |
1125 | 1133 |
/// \brief Called for the source node of the DFS. |
1126 | 1134 |
/// |
1127 | 1135 |
/// This function is called for the source node of the DFS. |
1128 | 1136 |
void start(const Node& node) {} |
1129 | 1137 |
/// \brief Called when the source node is leaved. |
1130 | 1138 |
/// |
1131 | 1139 |
/// This function is called when the source node is leaved. |
1132 | 1140 |
void stop(const Node& node) {} |
1133 | 1141 |
/// \brief Called when a node is reached first time. |
1134 | 1142 |
/// |
1135 | 1143 |
/// This function is called when a node is reached first time. |
1136 | 1144 |
void reach(const Node& node) {} |
1137 | 1145 |
/// \brief Called when an arc reaches a new node. |
1138 | 1146 |
/// |
1139 | 1147 |
/// This function is called when the DFS finds an arc whose target node |
1140 | 1148 |
/// is not reached yet. |
1141 | 1149 |
void discover(const Arc& arc) {} |
1142 | 1150 |
/// \brief Called when an arc is examined but its target node is |
1143 | 1151 |
/// already discovered. |
1144 | 1152 |
/// |
1145 | 1153 |
/// This function is called when an arc is examined but its target node is |
1146 | 1154 |
/// already discovered. |
1147 | 1155 |
void examine(const Arc& arc) {} |
1148 | 1156 |
/// \brief Called when the DFS steps back from a node. |
1149 | 1157 |
/// |
1150 | 1158 |
/// This function is called when the DFS steps back from a node. |
1151 | 1159 |
void leave(const Node& node) {} |
1152 | 1160 |
/// \brief Called when the DFS steps back on an arc. |
1153 | 1161 |
/// |
1154 | 1162 |
/// This function is called when the DFS steps back on an arc. |
1155 | 1163 |
void backtrack(const Arc& arc) {} |
1156 | 1164 |
}; |
1157 | 1165 |
#else |
1158 | 1166 |
template <typename GR> |
1159 | 1167 |
struct DfsVisitor { |
1160 | 1168 |
typedef GR Digraph; |
1161 | 1169 |
typedef typename Digraph::Arc Arc; |
1162 | 1170 |
typedef typename Digraph::Node Node; |
1163 | 1171 |
void start(const Node&) {} |
1164 | 1172 |
void stop(const Node&) {} |
1165 | 1173 |
void reach(const Node&) {} |
1166 | 1174 |
void discover(const Arc&) {} |
1167 | 1175 |
void examine(const Arc&) {} |
1168 | 1176 |
void leave(const Node&) {} |
1169 | 1177 |
void backtrack(const Arc&) {} |
1170 | 1178 |
|
1171 | 1179 |
template <typename _Visitor> |
1172 | 1180 |
struct Constraints { |
1173 | 1181 |
void constraints() { |
1174 | 1182 |
Arc arc; |
1175 | 1183 |
Node node; |
1176 | 1184 |
visitor.start(node); |
1177 | 1185 |
visitor.stop(arc); |
1178 | 1186 |
visitor.reach(node); |
1179 | 1187 |
visitor.discover(arc); |
1180 | 1188 |
visitor.examine(arc); |
1181 | 1189 |
visitor.leave(node); |
1182 | 1190 |
visitor.backtrack(arc); |
1183 | 1191 |
} |
1184 | 1192 |
_Visitor& visitor; |
1185 | 1193 |
}; |
1186 | 1194 |
}; |
1187 | 1195 |
#endif |
1188 | 1196 |
|
1189 | 1197 |
/// \brief Default traits class of DfsVisit class. |
1190 | 1198 |
/// |
1191 | 1199 |
/// Default traits class of DfsVisit class. |
1192 | 1200 |
/// \tparam _Digraph The type of the digraph the algorithm runs on. |
1193 | 1201 |
template<class GR> |
1194 | 1202 |
struct DfsVisitDefaultTraits { |
1195 | 1203 |
|
1196 | 1204 |
/// \brief The type of the digraph the algorithm runs on. |
1197 | 1205 |
typedef GR Digraph; |
1198 | 1206 |
|
1199 | 1207 |
/// \brief The type of the map that indicates which nodes are reached. |
1200 | 1208 |
/// |
1201 | 1209 |
/// The type of the map that indicates which nodes are reached. |
1202 | 1210 |
/// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
1203 | 1211 |
typedef typename Digraph::template NodeMap<bool> ReachedMap; |
1204 | 1212 |
|
1205 | 1213 |
/// \brief Instantiates a ReachedMap. |
1206 | 1214 |
/// |
1207 | 1215 |
/// This function instantiates a ReachedMap. |
1208 | 1216 |
/// \param digraph is the digraph, to which |
1209 | 1217 |
/// we would like to define the ReachedMap. |
1210 | 1218 |
static ReachedMap *createReachedMap(const Digraph &digraph) { |
1211 | 1219 |
return new ReachedMap(digraph); |
1212 | 1220 |
} |
1213 | 1221 |
|
1214 | 1222 |
}; |
1215 | 1223 |
|
1216 | 1224 |
/// \ingroup search |
1217 | 1225 |
/// |
1218 | 1226 |
/// \brief DFS algorithm class with visitor interface. |
1219 | 1227 |
/// |
1220 | 1228 |
/// This class provides an efficient implementation of the DFS algorithm |
1221 | 1229 |
/// with visitor interface. |
1222 | 1230 |
/// |
1223 | 1231 |
/// The DfsVisit class provides an alternative interface to the Dfs |
1224 | 1232 |
/// class. It works with callback mechanism, the DfsVisit object calls |
1225 | 1233 |
/// the member functions of the \c Visitor class on every DFS event. |
1226 | 1234 |
/// |
1227 | 1235 |
/// This interface of the DFS algorithm should be used in special cases |
1228 | 1236 |
/// when extra actions have to be performed in connection with certain |
1229 | 1237 |
/// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
1230 | 1238 |
/// instead. |
1231 | 1239 |
/// |
1232 | 1240 |
/// \tparam GR The type of the digraph the algorithm runs on. |
1233 | 1241 |
/// The default type is \ref ListDigraph. |
1234 | 1242 |
/// The value of GR is not used directly by \ref DfsVisit, |
1235 | 1243 |
/// it is only passed to \ref DfsVisitDefaultTraits. |
1236 | 1244 |
/// \tparam VS The Visitor type that is used by the algorithm. |
1237 | 1245 |
/// \ref DfsVisitor "DfsVisitor<GR>" is an empty visitor, which |
1238 | 1246 |
/// does not observe the DFS events. If you want to observe the DFS |
1239 | 1247 |
/// events, you should implement your own visitor class. |
1240 |
/// \tparam TR Traits class to set various data types used by the |
|
1241 |
/// algorithm. The default traits class is |
|
1242 |
/// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<GR>". |
|
1243 |
/// See \ref DfsVisitDefaultTraits for the documentation of |
|
1244 |
/// |
|
1248 |
/// \tparam TR The traits class that defines various types used by the |
|
1249 |
/// algorithm. By default, it is \ref DfsVisitDefaultTraits |
|
1250 |
/// "DfsVisitDefaultTraits<GR>". |
|
1251 |
/// In most cases, this parameter should not be set directly, |
|
1252 |
/// consider to use the named template parameters instead. |
|
1245 | 1253 |
#ifdef DOXYGEN |
1246 | 1254 |
template <typename GR, typename VS, typename TR> |
1247 | 1255 |
#else |
1248 | 1256 |
template <typename GR = ListDigraph, |
1249 | 1257 |
typename VS = DfsVisitor<GR>, |
1250 | 1258 |
typename TR = DfsVisitDefaultTraits<GR> > |
1251 | 1259 |
#endif |
1252 | 1260 |
class DfsVisit { |
1253 | 1261 |
public: |
1254 | 1262 |
|
1255 | 1263 |
///The traits class. |
1256 | 1264 |
typedef TR Traits; |
1257 | 1265 |
|
1258 | 1266 |
///The type of the digraph the algorithm runs on. |
1259 | 1267 |
typedef typename Traits::Digraph Digraph; |
1260 | 1268 |
|
1261 | 1269 |
///The visitor type used by the algorithm. |
1262 | 1270 |
typedef VS Visitor; |
1263 | 1271 |
|
1264 | 1272 |
///The type of the map that indicates which nodes are reached. |
1265 | 1273 |
typedef typename Traits::ReachedMap ReachedMap; |
1266 | 1274 |
|
1267 | 1275 |
private: |
1268 | 1276 |
|
1269 | 1277 |
typedef typename Digraph::Node Node; |
1270 | 1278 |
typedef typename Digraph::NodeIt NodeIt; |
1271 | 1279 |
typedef typename Digraph::Arc Arc; |
1272 | 1280 |
typedef typename Digraph::OutArcIt OutArcIt; |
1273 | 1281 |
|
1274 | 1282 |
//Pointer to the underlying digraph. |
1275 | 1283 |
const Digraph *_digraph; |
1276 | 1284 |
//Pointer to the visitor object. |
1277 | 1285 |
Visitor *_visitor; |
1278 | 1286 |
//Pointer to the map of reached status of the nodes. |
1279 | 1287 |
ReachedMap *_reached; |
1280 | 1288 |
//Indicates if _reached is locally allocated (true) or not. |
1281 | 1289 |
bool local_reached; |
1282 | 1290 |
|
1283 | 1291 |
std::vector<typename Digraph::Arc> _stack; |
1284 | 1292 |
int _stack_head; |
1285 | 1293 |
|
1286 | 1294 |
//Creates the maps if necessary. |
1287 | 1295 |
void create_maps() { |
1288 | 1296 |
if(!_reached) { |
1289 | 1297 |
local_reached = true; |
1290 | 1298 |
_reached = Traits::createReachedMap(*_digraph); |
1291 | 1299 |
} |
1292 | 1300 |
} |
1293 | 1301 |
|
1294 | 1302 |
protected: |
1295 | 1303 |
|
1296 | 1304 |
DfsVisit() {} |
1297 | 1305 |
|
1298 | 1306 |
public: |
1299 | 1307 |
|
1300 | 1308 |
typedef DfsVisit Create; |
1301 | 1309 |
|
1302 | 1310 |
/// \name Named Template Parameters |
1303 | 1311 |
|
1304 | 1312 |
///@{ |
1305 | 1313 |
template <class T> |
1306 | 1314 |
struct SetReachedMapTraits : public Traits { |
1307 | 1315 |
typedef T ReachedMap; |
1308 | 1316 |
static ReachedMap *createReachedMap(const Digraph &digraph) { |
1309 | 1317 |
LEMON_ASSERT(false, "ReachedMap is not initialized"); |
1310 | 1318 |
return 0; // ignore warnings |
1311 | 1319 |
} |
1312 | 1320 |
}; |
1313 | 1321 |
/// \brief \ref named-templ-param "Named parameter" for setting |
1314 | 1322 |
/// ReachedMap type. |
1315 | 1323 |
/// |
1316 | 1324 |
/// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
1317 | 1325 |
template <class T> |
1318 | 1326 |
struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
1319 | 1327 |
SetReachedMapTraits<T> > { |
1320 | 1328 |
typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
1321 | 1329 |
}; |
1322 | 1330 |
///@} |
1323 | 1331 |
|
1324 | 1332 |
public: |
1325 | 1333 |
|
1326 | 1334 |
/// \brief Constructor. |
1327 | 1335 |
/// |
1328 | 1336 |
/// Constructor. |
1329 | 1337 |
/// |
1330 | 1338 |
/// \param digraph The digraph the algorithm runs on. |
1331 | 1339 |
/// \param visitor The visitor object of the algorithm. |
1332 | 1340 |
DfsVisit(const Digraph& digraph, Visitor& visitor) |
1333 | 1341 |
: _digraph(&digraph), _visitor(&visitor), |
1334 | 1342 |
_reached(0), local_reached(false) {} |
1335 | 1343 |
|
1336 | 1344 |
/// \brief Destructor. |
1337 | 1345 |
~DfsVisit() { |
1338 | 1346 |
if(local_reached) delete _reached; |
1339 | 1347 |
} |
1340 | 1348 |
|
1341 | 1349 |
/// \brief Sets the map that indicates which nodes are reached. |
1342 | 1350 |
/// |
1343 | 1351 |
/// Sets the map that indicates which nodes are reached. |
1344 | 1352 |
/// If you don't use this function before calling \ref run(Node) "run()" |
1345 | 1353 |
/// or \ref init(), an instance will be allocated automatically. |
1346 | 1354 |
/// The destructor deallocates this automatically allocated map, |
1347 | 1355 |
/// of course. |
1348 | 1356 |
/// \return <tt> (*this) </tt> |
1349 | 1357 |
DfsVisit &reachedMap(ReachedMap &m) { |
1350 | 1358 |
if(local_reached) { |
1351 | 1359 |
delete _reached; |
1352 | 1360 |
local_reached=false; |
1353 | 1361 |
} |
1354 | 1362 |
_reached = &m; |
1355 | 1363 |
return *this; |
1356 | 1364 |
} |
1357 | 1365 |
|
1358 | 1366 |
public: |
1359 | 1367 |
|
1360 | 1368 |
/// \name Execution Control |
1361 | 1369 |
/// The simplest way to execute the DFS algorithm is to use one of the |
1362 | 1370 |
/// member functions called \ref run(Node) "run()".\n |
1363 | 1371 |
/// If you need better control on the execution, you have to call |
1364 | 1372 |
/// \ref init() first, then you can add a source node with \ref addSource() |
1365 | 1373 |
/// and perform the actual computation with \ref start(). |
1366 | 1374 |
/// This procedure can be repeated if there are nodes that have not |
1367 | 1375 |
/// been reached. |
1368 | 1376 |
|
1369 | 1377 |
/// @{ |
1370 | 1378 |
|
1371 | 1379 |
/// \brief Initializes the internal data structures. |
1372 | 1380 |
/// |
1373 | 1381 |
/// Initializes the internal data structures. |
1374 | 1382 |
void init() { |
1375 | 1383 |
create_maps(); |
1376 | 1384 |
_stack.resize(countNodes(*_digraph)); |
1377 | 1385 |
_stack_head = -1; |
1378 | 1386 |
for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
1379 | 1387 |
_reached->set(u, false); |
1380 | 1388 |
} |
1381 | 1389 |
} |
1382 | 1390 |
|
1383 | 1391 |
/// \brief Adds a new source node. |
1384 | 1392 |
/// |
1385 | 1393 |
/// Adds a new source node to the set of nodes to be processed. |
1386 | 1394 |
/// |
1387 | 1395 |
/// \pre The stack must be empty. Otherwise the algorithm gives |
1388 | 1396 |
/// wrong results. (One of the outgoing arcs of all the source nodes |
1389 | 1397 |
/// except for the last one will not be visited and distances will |
1390 | 1398 |
/// also be wrong.) |
1391 | 1399 |
void addSource(Node s) |
1392 | 1400 |
{ |
1393 | 1401 |
LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
1394 | 1402 |
if(!(*_reached)[s]) { |
1395 | 1403 |
_reached->set(s,true); |
1396 | 1404 |
_visitor->start(s); |
1397 | 1405 |
_visitor->reach(s); |
1398 | 1406 |
Arc e; |
1399 | 1407 |
_digraph->firstOut(e, s); |
1400 | 1408 |
if (e != INVALID) { |
1401 | 1409 |
_stack[++_stack_head] = e; |
1402 | 1410 |
} else { |
1403 | 1411 |
_visitor->leave(s); |
1404 | 1412 |
_visitor->stop(s); |
1405 | 1413 |
} |
1406 | 1414 |
} |
1407 | 1415 |
} |
1408 | 1416 |
|
1409 | 1417 |
/// \brief Processes the next arc. |
1410 | 1418 |
/// |
1411 | 1419 |
/// Processes the next arc. |
1412 | 1420 |
/// |
1413 | 1421 |
/// \return The processed arc. |
1414 | 1422 |
/// |
1415 | 1423 |
/// \pre The stack must not be empty. |
1416 | 1424 |
Arc processNextArc() { |
1417 | 1425 |
Arc e = _stack[_stack_head]; |
1418 | 1426 |
Node m = _digraph->target(e); |
1419 | 1427 |
if(!(*_reached)[m]) { |
1420 | 1428 |
_visitor->discover(e); |
1421 | 1429 |
_visitor->reach(m); |
1422 | 1430 |
_reached->set(m, true); |
1423 | 1431 |
_digraph->firstOut(_stack[++_stack_head], m); |
1424 | 1432 |
} else { |
1425 | 1433 |
_visitor->examine(e); |
1426 | 1434 |
m = _digraph->source(e); |
1427 | 1435 |
_digraph->nextOut(_stack[_stack_head]); |
1428 | 1436 |
} |
1429 | 1437 |
while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
1430 | 1438 |
_visitor->leave(m); |
1431 | 1439 |
--_stack_head; |
1432 | 1440 |
if (_stack_head >= 0) { |
1433 | 1441 |
_visitor->backtrack(_stack[_stack_head]); |
1434 | 1442 |
m = _digraph->source(_stack[_stack_head]); |
1435 | 1443 |
_digraph->nextOut(_stack[_stack_head]); |
1436 | 1444 |
} else { |
1437 | 1445 |
_visitor->stop(m); |
1438 | 1446 |
} |
1439 | 1447 |
} |
1440 | 1448 |
return e; |
1441 | 1449 |
} |
1442 | 1450 |
|
1443 | 1451 |
/// \brief Next arc to be processed. |
1444 | 1452 |
/// |
1445 | 1453 |
/// Next arc to be processed. |
1446 | 1454 |
/// |
1447 | 1455 |
/// \return The next arc to be processed or INVALID if the stack is |
1448 | 1456 |
/// empty. |
1449 | 1457 |
Arc nextArc() const { |
1450 | 1458 |
return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
1451 | 1459 |
} |
1452 | 1460 |
|
1453 | 1461 |
/// \brief Returns \c false if there are nodes |
1454 | 1462 |
/// to be processed. |
1455 | 1463 |
/// |
1456 | 1464 |
/// Returns \c false if there are nodes |
1457 | 1465 |
/// to be processed in the queue (stack). |
1458 | 1466 |
bool emptyQueue() const { return _stack_head < 0; } |
1459 | 1467 |
|
1460 | 1468 |
/// \brief Returns the number of the nodes to be processed. |
1461 | 1469 |
/// |
1462 | 1470 |
/// Returns the number of the nodes to be processed in the queue (stack). |
1463 | 1471 |
int queueSize() const { return _stack_head + 1; } |
1464 | 1472 |
|
1465 | 1473 |
/// \brief Executes the algorithm. |
1466 | 1474 |
/// |
1467 | 1475 |
/// Executes the algorithm. |
1468 | 1476 |
/// |
1469 | 1477 |
/// This method runs the %DFS algorithm from the root node |
1470 | 1478 |
/// in order to compute the %DFS path to each node. |
1471 | 1479 |
/// |
1472 | 1480 |
/// The algorithm computes |
1473 | 1481 |
/// - the %DFS tree, |
1474 | 1482 |
/// - the distance of each node from the root in the %DFS tree. |
1475 | 1483 |
/// |
1476 | 1484 |
/// \pre init() must be called and a root node should be |
1477 | 1485 |
/// added with addSource() before using this function. |
1478 | 1486 |
/// |
1479 | 1487 |
/// \note <tt>d.start()</tt> is just a shortcut of the following code. |
1480 | 1488 |
/// \code |
1481 | 1489 |
/// while ( !d.emptyQueue() ) { |
1482 | 1490 |
/// d.processNextArc(); |
1483 | 1491 |
/// } |
1484 | 1492 |
/// \endcode |
1485 | 1493 |
void start() { |
1486 | 1494 |
while ( !emptyQueue() ) processNextArc(); |
1487 | 1495 |
} |
1488 | 1496 |
|
1489 | 1497 |
/// \brief Executes the algorithm until the given target node is reached. |
1490 | 1498 |
/// |
1491 | 1499 |
/// Executes the algorithm until the given target node is reached. |
1492 | 1500 |
/// |
1493 | 1501 |
/// This method runs the %DFS algorithm from the root node |
1494 | 1502 |
/// in order to compute the DFS path to \c t. |
1495 | 1503 |
/// |
1496 | 1504 |
/// The algorithm computes |
1497 | 1505 |
/// - the %DFS path to \c t, |
1498 | 1506 |
/// - the distance of \c t from the root in the %DFS tree. |
1499 | 1507 |
/// |
1500 | 1508 |
/// \pre init() must be called and a root node should be added |
1501 | 1509 |
/// with addSource() before using this function. |
1502 | 1510 |
void start(Node t) { |
1503 | 1511 |
while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != t ) |
1504 | 1512 |
processNextArc(); |
1505 | 1513 |
} |
1506 | 1514 |
|
1507 | 1515 |
/// \brief Executes the algorithm until a condition is met. |
1508 | 1516 |
/// |
1509 | 1517 |
/// Executes the algorithm until a condition is met. |
1510 | 1518 |
/// |
1511 | 1519 |
/// This method runs the %DFS algorithm from the root node |
1512 | 1520 |
/// until an arc \c a with <tt>am[a]</tt> true is found. |
1513 | 1521 |
/// |
1514 | 1522 |
/// \param am A \c bool (or convertible) arc map. The algorithm |
1515 | 1523 |
/// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
1516 | 1524 |
/// |
1517 | 1525 |
/// \return The reached arc \c a with <tt>am[a]</tt> true or |
1518 | 1526 |
/// \c INVALID if no such arc was found. |
1519 | 1527 |
/// |
1520 | 1528 |
/// \pre init() must be called and a root node should be added |
1521 | 1529 |
/// with addSource() before using this function. |
1522 | 1530 |
/// |
1523 | 1531 |
/// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
1524 | 1532 |
/// not a node map. |
1525 | 1533 |
template <typename AM> |
1526 | 1534 |
Arc start(const AM &am) { |
1527 | 1535 |
while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
1528 | 1536 |
processNextArc(); |
1529 | 1537 |
return emptyQueue() ? INVALID : _stack[_stack_head]; |
1530 | 1538 |
} |
1531 | 1539 |
|
1532 | 1540 |
/// \brief Runs the algorithm from the given source node. |
1533 | 1541 |
/// |
1534 | 1542 |
/// This method runs the %DFS algorithm from node \c s. |
1535 | 1543 |
/// in order to compute the DFS path to each node. |
1536 | 1544 |
/// |
1537 | 1545 |
/// The algorithm computes |
1538 | 1546 |
/// - the %DFS tree, |
1539 | 1547 |
/// - the distance of each node from the root in the %DFS tree. |
1540 | 1548 |
/// |
1541 | 1549 |
/// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
1542 | 1550 |
///\code |
1543 | 1551 |
/// d.init(); |
1544 | 1552 |
/// d.addSource(s); |
1545 | 1553 |
/// d.start(); |
1546 | 1554 |
///\endcode |
1547 | 1555 |
void run(Node s) { |
1548 | 1556 |
init(); |
1549 | 1557 |
addSource(s); |
1550 | 1558 |
start(); |
1551 | 1559 |
} |
1552 | 1560 |
|
1553 | 1561 |
/// \brief Finds the %DFS path between \c s and \c t. |
1554 | 1562 |
|
1555 | 1563 |
/// This method runs the %DFS algorithm from node \c s |
1556 | 1564 |
/// in order to compute the DFS path to node \c t |
1557 | 1565 |
/// (it stops searching when \c t is processed). |
1558 | 1566 |
/// |
1559 | 1567 |
/// \return \c true if \c t is reachable form \c s. |
1560 | 1568 |
/// |
1561 | 1569 |
/// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
1562 | 1570 |
/// just a shortcut of the following code. |
1563 | 1571 |
///\code |
1564 | 1572 |
/// d.init(); |
1565 | 1573 |
/// d.addSource(s); |
1566 | 1574 |
/// d.start(t); |
1567 | 1575 |
///\endcode |
1568 | 1576 |
bool run(Node s,Node t) { |
1569 | 1577 |
init(); |
1570 | 1578 |
addSource(s); |
1571 | 1579 |
start(t); |
1572 | 1580 |
return reached(t); |
1573 | 1581 |
} |
1574 | 1582 |
|
1575 | 1583 |
/// \brief Runs the algorithm to visit all nodes in the digraph. |
1576 | 1584 |
|
1577 | 1585 |
/// This method runs the %DFS algorithm in order to visit all nodes |
1578 | 1586 |
/// in the digraph. |
1579 | 1587 |
/// |
1580 | 1588 |
/// \note <tt>d.run()</tt> is just a shortcut of the following code. |
1581 | 1589 |
///\code |
1582 | 1590 |
/// d.init(); |
1583 | 1591 |
/// for (NodeIt n(digraph); n != INVALID; ++n) { |
1584 | 1592 |
/// if (!d.reached(n)) { |
1585 | 1593 |
/// d.addSource(n); |
1586 | 1594 |
/// d.start(); |
1587 | 1595 |
/// } |
1588 | 1596 |
/// } |
1589 | 1597 |
///\endcode |
1590 | 1598 |
void run() { |
1591 | 1599 |
init(); |
1592 | 1600 |
for (NodeIt it(*_digraph); it != INVALID; ++it) { |
1593 | 1601 |
if (!reached(it)) { |
1594 | 1602 |
addSource(it); |
1595 | 1603 |
start(); |
1596 | 1604 |
} |
1597 | 1605 |
} |
1598 | 1606 |
} |
1599 | 1607 |
|
1600 | 1608 |
///@} |
1601 | 1609 |
|
1602 | 1610 |
/// \name Query Functions |
1603 | 1611 |
/// The results of the DFS algorithm can be obtained using these |
1604 | 1612 |
/// functions.\n |
1605 | 1613 |
/// Either \ref run(Node) "run()" or \ref start() should be called |
1606 | 1614 |
/// before using them. |
1607 | 1615 |
|
1608 | 1616 |
///@{ |
1609 | 1617 |
|
1610 | 1618 |
/// \brief Checks if the given node is reached from the root(s). |
1611 | 1619 |
/// |
1612 | 1620 |
/// Returns \c true if \c v is reached from the root(s). |
1613 | 1621 |
/// |
1614 | 1622 |
/// \pre Either \ref run(Node) "run()" or \ref init() |
1615 | 1623 |
/// must be called before using this function. |
1616 | 1624 |
bool reached(Node v) const { return (*_reached)[v]; } |
1617 | 1625 |
|
1618 | 1626 |
///@} |
1619 | 1627 |
|
1620 | 1628 |
}; |
1621 | 1629 |
|
1622 | 1630 |
} //END OF NAMESPACE LEMON |
1623 | 1631 |
|
1624 | 1632 |
#endif |
1 | 1 |
/* -*- mode: C++; indent-tabs-mode: nil; -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library. |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2009 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
#ifndef LEMON_DIJKSTRA_H |
20 | 20 |
#define LEMON_DIJKSTRA_H |
21 | 21 |
|
22 | 22 |
///\ingroup shortest_path |
23 | 23 |
///\file |
24 | 24 |
///\brief Dijkstra algorithm. |
25 | 25 |
|
26 | 26 |
#include <limits> |
27 | 27 |
#include <lemon/list_graph.h> |
28 | 28 |
#include <lemon/bin_heap.h> |
29 | 29 |
#include <lemon/bits/path_dump.h> |
30 | 30 |
#include <lemon/core.h> |
31 | 31 |
#include <lemon/error.h> |
32 | 32 |
#include <lemon/maps.h> |
33 | 33 |
#include <lemon/path.h> |
34 | 34 |
|
35 | 35 |
namespace lemon { |
36 | 36 |
|
37 | 37 |
/// \brief Default operation traits for the Dijkstra algorithm class. |
38 | 38 |
/// |
39 | 39 |
/// This operation traits class defines all computational operations and |
40 | 40 |
/// constants which are used in the Dijkstra algorithm. |
41 | 41 |
template <typename V> |
42 | 42 |
struct DijkstraDefaultOperationTraits { |
43 | 43 |
/// \e |
44 | 44 |
typedef V Value; |
45 | 45 |
/// \brief Gives back the zero value of the type. |
46 | 46 |
static Value zero() { |
47 | 47 |
return static_cast<Value>(0); |
48 | 48 |
} |
49 | 49 |
/// \brief Gives back the sum of the given two elements. |
50 | 50 |
static Value plus(const Value& left, const Value& right) { |
51 | 51 |
return left + right; |
52 | 52 |
} |
53 | 53 |
/// \brief Gives back true only if the first value is less than the second. |
54 | 54 |
static bool less(const Value& left, const Value& right) { |
55 | 55 |
return left < right; |
56 | 56 |
} |
57 | 57 |
}; |
58 | 58 |
|
59 | 59 |
///Default traits class of Dijkstra class. |
60 | 60 |
|
61 | 61 |
///Default traits class of Dijkstra class. |
62 | 62 |
///\tparam GR The type of the digraph. |
63 | 63 |
///\tparam LEN The type of the length map. |
64 | 64 |
template<typename GR, typename LEN> |
65 | 65 |
struct DijkstraDefaultTraits |
66 | 66 |
{ |
67 | 67 |
///The type of the digraph the algorithm runs on. |
68 | 68 |
typedef GR Digraph; |
69 | 69 |
|
70 | 70 |
///The type of the map that stores the arc lengths. |
71 | 71 |
|
72 | 72 |
///The type of the map that stores the arc lengths. |
73 | 73 |
///It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
74 | 74 |
typedef LEN LengthMap; |
75 | 75 |
///The type of the arc lengths. |
76 | 76 |
typedef typename LEN::Value Value; |
77 | 77 |
|
78 | 78 |
/// Operation traits for %Dijkstra algorithm. |
79 | 79 |
|
80 | 80 |
/// This class defines the operations that are used in the algorithm. |
81 | 81 |
/// \see DijkstraDefaultOperationTraits |
82 | 82 |
typedef DijkstraDefaultOperationTraits<Value> OperationTraits; |
83 | 83 |
|
84 | 84 |
/// The cross reference type used by the heap. |
85 | 85 |
|
86 | 86 |
/// The cross reference type used by the heap. |
87 | 87 |
/// Usually it is \c Digraph::NodeMap<int>. |
88 | 88 |
typedef typename Digraph::template NodeMap<int> HeapCrossRef; |
89 | 89 |
///Instantiates a \c HeapCrossRef. |
90 | 90 |
|
91 | 91 |
///This function instantiates a \ref HeapCrossRef. |
92 | 92 |
/// \param g is the digraph, to which we would like to define the |
93 | 93 |
/// \ref HeapCrossRef. |
94 | 94 |
static HeapCrossRef *createHeapCrossRef(const Digraph &g) |
95 | 95 |
{ |
96 | 96 |
return new HeapCrossRef(g); |
97 | 97 |
} |
98 | 98 |
|
99 | 99 |
///The heap type used by the %Dijkstra algorithm. |
100 | 100 |
|
101 | 101 |
///The heap type used by the Dijkstra algorithm. |
102 | 102 |
/// |
103 | 103 |
///\sa BinHeap |
104 | 104 |
///\sa Dijkstra |
105 | 105 |
typedef BinHeap<typename LEN::Value, HeapCrossRef, std::less<Value> > Heap; |
106 | 106 |
///Instantiates a \c Heap. |
107 | 107 |
|
108 | 108 |
///This function instantiates a \ref Heap. |
109 | 109 |
static Heap *createHeap(HeapCrossRef& r) |
110 | 110 |
{ |
111 | 111 |
return new Heap(r); |
112 | 112 |
} |
113 | 113 |
|
114 | 114 |
///\brief The type of the map that stores the predecessor |
115 | 115 |
///arcs of the shortest paths. |
116 | 116 |
/// |
117 | 117 |
///The type of the map that stores the predecessor |
118 | 118 |
///arcs of the shortest paths. |
119 | 119 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
120 | 120 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
121 | 121 |
///Instantiates a \c PredMap. |
122 | 122 |
|
123 | 123 |
///This function instantiates a \ref PredMap. |
124 | 124 |
///\param g is the digraph, to which we would like to define the |
125 | 125 |
///\ref PredMap. |
126 | 126 |
static PredMap *createPredMap(const Digraph &g) |
127 | 127 |
{ |
128 | 128 |
return new PredMap(g); |
129 | 129 |
} |
130 | 130 |
|
131 | 131 |
///The type of the map that indicates which nodes are processed. |
132 | 132 |
|
133 | 133 |
///The type of the map that indicates which nodes are processed. |
134 | 134 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
135 | 135 |
///By default, it is a NullMap. |
136 | 136 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
137 | 137 |
///Instantiates a \c ProcessedMap. |
138 | 138 |
|
139 | 139 |
///This function instantiates a \ref ProcessedMap. |
140 | 140 |
///\param g is the digraph, to which |
141 | 141 |
///we would like to define the \ref ProcessedMap. |
142 | 142 |
#ifdef DOXYGEN |
143 | 143 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
144 | 144 |
#else |
145 | 145 |
static ProcessedMap *createProcessedMap(const Digraph &) |
146 | 146 |
#endif |
147 | 147 |
{ |
148 | 148 |
return new ProcessedMap(); |
149 | 149 |
} |
150 | 150 |
|
151 | 151 |
///The type of the map that stores the distances of the nodes. |
152 | 152 |
|
153 | 153 |
///The type of the map that stores the distances of the nodes. |
154 | 154 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
155 | 155 |
typedef typename Digraph::template NodeMap<typename LEN::Value> DistMap; |
156 | 156 |
///Instantiates a \c DistMap. |
157 | 157 |
|
158 | 158 |
///This function instantiates a \ref DistMap. |
159 | 159 |
///\param g is the digraph, to which we would like to define |
160 | 160 |
///the \ref DistMap. |
161 | 161 |
static DistMap *createDistMap(const Digraph &g) |
162 | 162 |
{ |
163 | 163 |
return new DistMap(g); |
164 | 164 |
} |
165 | 165 |
}; |
166 | 166 |
|
167 | 167 |
///%Dijkstra algorithm class. |
168 | 168 |
|
169 | 169 |
/// \ingroup shortest_path |
170 | 170 |
///This class provides an efficient implementation of the %Dijkstra algorithm. |
171 | 171 |
/// |
172 | 172 |
///The %Dijkstra algorithm solves the single-source shortest path problem |
173 | 173 |
///when all arc lengths are non-negative. If there are negative lengths, |
174 | 174 |
///the BellmanFord algorithm should be used instead. |
175 | 175 |
/// |
176 | 176 |
///The arc lengths are passed to the algorithm using a |
177 | 177 |
///\ref concepts::ReadMap "ReadMap", |
178 | 178 |
///so it is easy to change it to any kind of length. |
179 | 179 |
///The type of the length is determined by the |
180 | 180 |
///\ref concepts::ReadMap::Value "Value" of the length map. |
181 | 181 |
///It is also possible to change the underlying priority heap. |
182 | 182 |
/// |
183 | 183 |
///There is also a \ref dijkstra() "function-type interface" for the |
184 | 184 |
///%Dijkstra algorithm, which is convenient in the simplier cases and |
185 | 185 |
///it can be used easier. |
186 | 186 |
/// |
187 | 187 |
///\tparam GR The type of the digraph the algorithm runs on. |
188 | 188 |
///The default type is \ref ListDigraph. |
189 | 189 |
///\tparam LEN A \ref concepts::ReadMap "readable" arc map that specifies |
190 | 190 |
///the lengths of the arcs. |
191 | 191 |
///It is read once for each arc, so the map may involve in |
192 | 192 |
///relatively time consuming process to compute the arc lengths if |
193 | 193 |
///it is necessary. The default map type is \ref |
194 | 194 |
///concepts::Digraph::ArcMap "GR::ArcMap<int>". |
195 |
///\tparam TR The traits class that defines various types used by the |
|
196 |
///algorithm. By default, it is \ref DijkstraDefaultTraits |
|
197 |
///"DijkstraDefaultTraits<GR, LEN>". |
|
198 |
///In most cases, this parameter should not be set directly, |
|
199 |
///consider to use the named template parameters instead. |
|
195 | 200 |
#ifdef DOXYGEN |
196 | 201 |
template <typename GR, typename LEN, typename TR> |
197 | 202 |
#else |
198 | 203 |
template <typename GR=ListDigraph, |
199 | 204 |
typename LEN=typename GR::template ArcMap<int>, |
200 | 205 |
typename TR=DijkstraDefaultTraits<GR,LEN> > |
201 | 206 |
#endif |
202 | 207 |
class Dijkstra { |
203 | 208 |
public: |
204 | 209 |
|
205 | 210 |
///The type of the digraph the algorithm runs on. |
206 | 211 |
typedef typename TR::Digraph Digraph; |
207 | 212 |
|
208 | 213 |
///The type of the arc lengths. |
209 | 214 |
typedef typename TR::Value Value; |
210 | 215 |
///The type of the map that stores the arc lengths. |
211 | 216 |
typedef typename TR::LengthMap LengthMap; |
212 | 217 |
///\brief The type of the map that stores the predecessor arcs of the |
213 | 218 |
///shortest paths. |
214 | 219 |
typedef typename TR::PredMap PredMap; |
215 | 220 |
///The type of the map that stores the distances of the nodes. |
216 | 221 |
typedef typename TR::DistMap DistMap; |
217 | 222 |
///The type of the map that indicates which nodes are processed. |
218 | 223 |
typedef typename TR::ProcessedMap ProcessedMap; |
219 | 224 |
///The type of the paths. |
220 | 225 |
typedef PredMapPath<Digraph, PredMap> Path; |
221 | 226 |
///The cross reference type used for the current heap. |
222 | 227 |
typedef typename TR::HeapCrossRef HeapCrossRef; |
223 | 228 |
///The heap type used by the algorithm. |
224 | 229 |
typedef typename TR::Heap Heap; |
225 | 230 |
///\brief The \ref DijkstraDefaultOperationTraits "operation traits class" |
226 | 231 |
///of the algorithm. |
227 | 232 |
typedef typename TR::OperationTraits OperationTraits; |
228 | 233 |
|
229 | 234 |
///The \ref DijkstraDefaultTraits "traits class" of the algorithm. |
230 | 235 |
typedef TR Traits; |
231 | 236 |
|
232 | 237 |
private: |
233 | 238 |
|
234 | 239 |
typedef typename Digraph::Node Node; |
235 | 240 |
typedef typename Digraph::NodeIt NodeIt; |
236 | 241 |
typedef typename Digraph::Arc Arc; |
237 | 242 |
typedef typename Digraph::OutArcIt OutArcIt; |
238 | 243 |
|
239 | 244 |
//Pointer to the underlying digraph. |
240 | 245 |
const Digraph *G; |
241 | 246 |
//Pointer to the length map. |
242 | 247 |
const LengthMap *_length; |
243 | 248 |
//Pointer to the map of predecessors arcs. |
244 | 249 |
PredMap *_pred; |
245 | 250 |
//Indicates if _pred is locally allocated (true) or not. |
246 | 251 |
bool local_pred; |
247 | 252 |
//Pointer to the map of distances. |
248 | 253 |
DistMap *_dist; |
249 | 254 |
//Indicates if _dist is locally allocated (true) or not. |
250 | 255 |
bool local_dist; |
251 | 256 |
//Pointer to the map of processed status of the nodes. |
252 | 257 |
ProcessedMap *_processed; |
253 | 258 |
//Indicates if _processed is locally allocated (true) or not. |
254 | 259 |
bool local_processed; |
255 | 260 |
//Pointer to the heap cross references. |
256 | 261 |
HeapCrossRef *_heap_cross_ref; |
257 | 262 |
//Indicates if _heap_cross_ref is locally allocated (true) or not. |
258 | 263 |
bool local_heap_cross_ref; |
259 | 264 |
//Pointer to the heap. |
260 | 265 |
Heap *_heap; |
261 | 266 |
//Indicates if _heap is locally allocated (true) or not. |
262 | 267 |
bool local_heap; |
263 | 268 |
|
264 | 269 |
//Creates the maps if necessary. |
265 | 270 |
void create_maps() |
266 | 271 |
{ |
267 | 272 |
if(!_pred) { |
268 | 273 |
local_pred = true; |
269 | 274 |
_pred = Traits::createPredMap(*G); |
270 | 275 |
} |
271 | 276 |
if(!_dist) { |
272 | 277 |
local_dist = true; |
273 | 278 |
_dist = Traits::createDistMap(*G); |
274 | 279 |
} |
275 | 280 |
if(!_processed) { |
276 | 281 |
local_processed = true; |
277 | 282 |
_processed = Traits::createProcessedMap(*G); |
278 | 283 |
} |
279 | 284 |
if (!_heap_cross_ref) { |
280 | 285 |
local_heap_cross_ref = true; |
281 | 286 |
_heap_cross_ref = Traits::createHeapCrossRef(*G); |
282 | 287 |
} |
283 | 288 |
if (!_heap) { |
284 | 289 |
local_heap = true; |
285 | 290 |
_heap = Traits::createHeap(*_heap_cross_ref); |
286 | 291 |
} |
287 | 292 |
} |
288 | 293 |
|
289 | 294 |
public: |
290 | 295 |
|
291 | 296 |
typedef Dijkstra Create; |
292 | 297 |
|
293 | 298 |
///\name Named Template Parameters |
294 | 299 |
|
295 | 300 |
///@{ |
296 | 301 |
|
297 | 302 |
template <class T> |
298 | 303 |
struct SetPredMapTraits : public Traits { |
299 | 304 |
typedef T PredMap; |
300 | 305 |
static PredMap *createPredMap(const Digraph &) |
301 | 306 |
{ |
302 | 307 |
LEMON_ASSERT(false, "PredMap is not initialized"); |
303 | 308 |
return 0; // ignore warnings |
304 | 309 |
} |
305 | 310 |
}; |
306 | 311 |
///\brief \ref named-templ-param "Named parameter" for setting |
307 | 312 |
///\c PredMap type. |
308 | 313 |
/// |
309 | 314 |
///\ref named-templ-param "Named parameter" for setting |
310 | 315 |
///\c PredMap type. |
311 | 316 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
312 | 317 |
template <class T> |
313 | 318 |
struct SetPredMap |
314 | 319 |
: public Dijkstra< Digraph, LengthMap, SetPredMapTraits<T> > { |
315 | 320 |
typedef Dijkstra< Digraph, LengthMap, SetPredMapTraits<T> > Create; |
316 | 321 |
}; |
317 | 322 |
|
318 | 323 |
template <class T> |
319 | 324 |
struct SetDistMapTraits : public Traits { |
320 | 325 |
typedef T DistMap; |
321 | 326 |
static DistMap *createDistMap(const Digraph &) |
322 | 327 |
{ |
323 | 328 |
LEMON_ASSERT(false, "DistMap is not initialized"); |
324 | 329 |
return 0; // ignore warnings |
325 | 330 |
} |
326 | 331 |
}; |
327 | 332 |
///\brief \ref named-templ-param "Named parameter" for setting |
328 | 333 |
///\c DistMap type. |
329 | 334 |
/// |
330 | 335 |
///\ref named-templ-param "Named parameter" for setting |
331 | 336 |
///\c DistMap type. |
332 | 337 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
333 | 338 |
template <class T> |
334 | 339 |
struct SetDistMap |
335 | 340 |
: public Dijkstra< Digraph, LengthMap, SetDistMapTraits<T> > { |
336 | 341 |
typedef Dijkstra< Digraph, LengthMap, SetDistMapTraits<T> > Create; |
337 | 342 |
}; |
338 | 343 |
|
339 | 344 |
template <class T> |
340 | 345 |
struct SetProcessedMapTraits : public Traits { |
341 | 346 |
typedef T ProcessedMap; |
342 | 347 |
static ProcessedMap *createProcessedMap(const Digraph &) |
343 | 348 |
{ |
344 | 349 |
LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
345 | 350 |
return 0; // ignore warnings |
346 | 351 |
} |
347 | 352 |
}; |
348 | 353 |
///\brief \ref named-templ-param "Named parameter" for setting |
349 | 354 |
///\c ProcessedMap type. |
350 | 355 |
/// |
351 | 356 |
///\ref named-templ-param "Named parameter" for setting |
352 | 357 |
///\c ProcessedMap type. |
353 | 358 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
354 | 359 |
template <class T> |
355 | 360 |
struct SetProcessedMap |
356 | 361 |
: public Dijkstra< Digraph, LengthMap, SetProcessedMapTraits<T> > { |
357 | 362 |
typedef Dijkstra< Digraph, LengthMap, SetProcessedMapTraits<T> > Create; |
358 | 363 |
}; |
359 | 364 |
|
360 | 365 |
struct SetStandardProcessedMapTraits : public Traits { |
361 | 366 |
typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
362 | 367 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
363 | 368 |
{ |
364 | 369 |
return new ProcessedMap(g); |
365 | 370 |
} |
366 | 371 |
}; |
367 | 372 |
///\brief \ref named-templ-param "Named parameter" for setting |
368 | 373 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
369 | 374 |
/// |
370 | 375 |
///\ref named-templ-param "Named parameter" for setting |
371 | 376 |
///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
372 | 377 |
///If you don't set it explicitly, it will be automatically allocated. |
373 | 378 |
struct SetStandardProcessedMap |
374 | 379 |
: public Dijkstra< Digraph, LengthMap, SetStandardProcessedMapTraits > { |
375 | 380 |
typedef Dijkstra< Digraph, LengthMap, SetStandardProcessedMapTraits > |
376 | 381 |
Create; |
377 | 382 |
}; |
378 | 383 |
|
379 | 384 |
template <class H, class CR> |
380 | 385 |
struct SetHeapTraits : public Traits { |
381 | 386 |
typedef CR HeapCrossRef; |
382 | 387 |
typedef H Heap; |
383 | 388 |
static HeapCrossRef *createHeapCrossRef(const Digraph &) { |
384 | 389 |
LEMON_ASSERT(false, "HeapCrossRef is not initialized"); |
385 | 390 |
return 0; // ignore warnings |
386 | 391 |
} |
387 | 392 |
static Heap *createHeap(HeapCrossRef &) |
388 | 393 |
{ |
389 | 394 |
LEMON_ASSERT(false, "Heap is not initialized"); |
390 | 395 |
return 0; // ignore warnings |
391 | 396 |
} |
392 | 397 |
}; |
393 | 398 |
///\brief \ref named-templ-param "Named parameter" for setting |
394 | 399 |
///heap and cross reference types |
395 | 400 |
/// |
396 | 401 |
///\ref named-templ-param "Named parameter" for setting heap and cross |
397 | 402 |
///reference types. If this named parameter is used, then external |
398 | 403 |
///heap and cross reference objects must be passed to the algorithm |
399 | 404 |
///using the \ref heap() function before calling \ref run(Node) "run()" |
400 | 405 |
///or \ref init(). |
401 | 406 |
///\sa SetStandardHeap |
402 | 407 |
template <class H, class CR = typename Digraph::template NodeMap<int> > |
403 | 408 |
struct SetHeap |
404 | 409 |
: public Dijkstra< Digraph, LengthMap, SetHeapTraits<H, CR> > { |
405 | 410 |
typedef Dijkstra< Digraph, LengthMap, SetHeapTraits<H, CR> > Create; |
406 | 411 |
}; |
407 | 412 |
|
408 | 413 |
template <class H, class CR> |
409 | 414 |
struct SetStandardHeapTraits : public Traits { |
410 | 415 |
typedef CR HeapCrossRef; |
411 | 416 |
typedef H Heap; |
412 | 417 |
static HeapCrossRef *createHeapCrossRef(const Digraph &G) { |
413 | 418 |
return new HeapCrossRef(G); |
414 | 419 |
} |
415 | 420 |
static Heap *createHeap(HeapCrossRef &R) |
416 | 421 |
{ |
417 | 422 |
return new Heap(R); |
418 | 423 |
} |
419 | 424 |
}; |
420 | 425 |
///\brief \ref named-templ-param "Named parameter" for setting |
421 | 426 |
///heap and cross reference types with automatic allocation |
422 | 427 |
/// |
423 | 428 |
///\ref named-templ-param "Named parameter" for setting heap and cross |
424 | 429 |
///reference types with automatic allocation. |
425 | 430 |
///They should have standard constructor interfaces to be able to |
426 | 431 |
///automatically created by the algorithm (i.e. the digraph should be |
427 | 432 |
///passed to the constructor of the cross reference and the cross |
428 | 433 |
///reference should be passed to the constructor of the heap). |
429 | 434 |
///However, external heap and cross reference objects could also be |
430 | 435 |
///passed to the algorithm using the \ref heap() function before |
431 | 436 |
///calling \ref run(Node) "run()" or \ref init(). |
432 | 437 |
///\sa SetHeap |
433 | 438 |
template <class H, class CR = typename Digraph::template NodeMap<int> > |
434 | 439 |
struct SetStandardHeap |
435 | 440 |
: public Dijkstra< Digraph, LengthMap, SetStandardHeapTraits<H, CR> > { |
436 | 441 |
typedef Dijkstra< Digraph, LengthMap, SetStandardHeapTraits<H, CR> > |
437 | 442 |
Create; |
438 | 443 |
}; |
439 | 444 |
|
440 | 445 |
template <class T> |
441 | 446 |
struct SetOperationTraitsTraits : public Traits { |
442 | 447 |
typedef T OperationTraits; |
443 | 448 |
}; |
444 | 449 |
|
445 | 450 |
/// \brief \ref named-templ-param "Named parameter" for setting |
446 | 451 |
///\c OperationTraits type |
447 | 452 |
/// |
448 | 453 |
///\ref named-templ-param "Named parameter" for setting |
449 | 454 |
///\c OperationTraits type. |
450 | 455 |
/// For more information, see \ref DijkstraDefaultOperationTraits. |
451 | 456 |
template <class T> |
452 | 457 |
struct SetOperationTraits |
453 | 458 |
: public Dijkstra<Digraph, LengthMap, SetOperationTraitsTraits<T> > { |
454 | 459 |
typedef Dijkstra<Digraph, LengthMap, SetOperationTraitsTraits<T> > |
455 | 460 |
Create; |
456 | 461 |
}; |
457 | 462 |
|
458 | 463 |
///@} |
459 | 464 |
|
460 | 465 |
protected: |
461 | 466 |
|
462 | 467 |
Dijkstra() {} |
463 | 468 |
|
464 | 469 |
public: |
465 | 470 |
|
466 | 471 |
///Constructor. |
467 | 472 |
|
468 | 473 |
///Constructor. |
469 | 474 |
///\param g The digraph the algorithm runs on. |
470 | 475 |
///\param length The length map used by the algorithm. |
471 | 476 |
Dijkstra(const Digraph& g, const LengthMap& length) : |
472 | 477 |
G(&g), _length(&length), |
473 | 478 |
_pred(NULL), local_pred(false), |
474 | 479 |
_dist(NULL), local_dist(false), |
475 | 480 |
_processed(NULL), local_processed(false), |
476 | 481 |
_heap_cross_ref(NULL), local_heap_cross_ref(false), |
477 | 482 |
_heap(NULL), local_heap(false) |
478 | 483 |
{ } |
479 | 484 |
|
480 | 485 |
///Destructor. |
481 | 486 |
~Dijkstra() |
482 | 487 |
{ |
483 | 488 |
if(local_pred) delete _pred; |
484 | 489 |
if(local_dist) delete _dist; |
485 | 490 |
if(local_processed) delete _processed; |
486 | 491 |
if(local_heap_cross_ref) delete _heap_cross_ref; |
487 | 492 |
if(local_heap) delete _heap; |
488 | 493 |
} |
489 | 494 |
|
490 | 495 |
///Sets the length map. |
491 | 496 |
|
492 | 497 |
///Sets the length map. |
493 | 498 |
///\return <tt> (*this) </tt> |
494 | 499 |
Dijkstra &lengthMap(const LengthMap &m) |
495 | 500 |
{ |
496 | 501 |
_length = &m; |
497 | 502 |
return *this; |
498 | 503 |
} |
499 | 504 |
|
500 | 505 |
///Sets the map that stores the predecessor arcs. |
501 | 506 |
|
502 | 507 |
///Sets the map that stores the predecessor arcs. |
503 | 508 |
///If you don't use this function before calling \ref run(Node) "run()" |
504 | 509 |
///or \ref init(), an instance will be allocated automatically. |
505 | 510 |
///The destructor deallocates this automatically allocated map, |
506 | 511 |
///of course. |
507 | 512 |
///\return <tt> (*this) </tt> |
508 | 513 |
Dijkstra &predMap(PredMap &m) |
509 | 514 |
{ |
510 | 515 |
if(local_pred) { |
511 | 516 |
delete _pred; |
512 | 517 |
local_pred=false; |
513 | 518 |
} |
514 | 519 |
_pred = &m; |
515 | 520 |
return *this; |
516 | 521 |
} |
517 | 522 |
|
518 | 523 |
///Sets the map that indicates which nodes are processed. |
519 | 524 |
|
520 | 525 |
///Sets the map that indicates which nodes are processed. |
521 | 526 |
///If you don't use this function before calling \ref run(Node) "run()" |
522 | 527 |
///or \ref init(), an instance will be allocated automatically. |
523 | 528 |
///The destructor deallocates this automatically allocated map, |
524 | 529 |
///of course. |
525 | 530 |
///\return <tt> (*this) </tt> |
526 | 531 |
Dijkstra &processedMap(ProcessedMap &m) |
527 | 532 |
{ |
528 | 533 |
if(local_processed) { |
529 | 534 |
delete _processed; |
530 | 535 |
local_processed=false; |
531 | 536 |
} |
532 | 537 |
_processed = &m; |
533 | 538 |
return *this; |
534 | 539 |
} |
535 | 540 |
|
536 | 541 |
///Sets the map that stores the distances of the nodes. |
537 | 542 |
|
538 | 543 |
///Sets the map that stores the distances of the nodes calculated by the |
539 | 544 |
///algorithm. |
540 | 545 |
///If you don't use this function before calling \ref run(Node) "run()" |
541 | 546 |
///or \ref init(), an instance will be allocated automatically. |
542 | 547 |
///The destructor deallocates this automatically allocated map, |
543 | 548 |
///of course. |
544 | 549 |
///\return <tt> (*this) </tt> |
545 | 550 |
Dijkstra &distMap(DistMap &m) |
546 | 551 |
{ |
547 | 552 |
if(local_dist) { |
548 | 553 |
delete _dist; |
549 | 554 |
local_dist=false; |
550 | 555 |
} |
551 | 556 |
_dist = &m; |
552 | 557 |
return *this; |
553 | 558 |
} |
554 | 559 |
|
555 | 560 |
///Sets the heap and the cross reference used by algorithm. |
556 | 561 |
|
557 | 562 |
///Sets the heap and the cross reference used by algorithm. |
558 | 563 |
///If you don't use this function before calling \ref run(Node) "run()" |
559 | 564 |
///or \ref init(), heap and cross reference instances will be |
560 | 565 |
///allocated automatically. |
561 | 566 |
///The destructor deallocates these automatically allocated objects, |
562 | 567 |
///of course. |
563 | 568 |
///\return <tt> (*this) </tt> |
564 | 569 |
Dijkstra &heap(Heap& hp, HeapCrossRef &cr) |
565 | 570 |
{ |
566 | 571 |
if(local_heap_cross_ref) { |
567 | 572 |
delete _heap_cross_ref; |
568 | 573 |
local_heap_cross_ref=false; |
569 | 574 |
} |
570 | 575 |
_heap_cross_ref = &cr; |
571 | 576 |
if(local_heap) { |
572 | 577 |
delete _heap; |
573 | 578 |
local_heap=false; |
574 | 579 |
} |
575 | 580 |
_heap = &hp; |
576 | 581 |
return *this; |
577 | 582 |
} |
578 | 583 |
|
... | ... |
@@ -711,585 +716,588 @@ |
711 | 716 |
while ( !emptyQueue() ) processNextNode(); |
712 | 717 |
} |
713 | 718 |
|
714 | 719 |
///Executes the algorithm until the given target node is processed. |
715 | 720 |
|
716 | 721 |
///Executes the algorithm until the given target node is processed. |
717 | 722 |
/// |
718 | 723 |
///This method runs the %Dijkstra algorithm from the root node(s) |
719 | 724 |
///in order to compute the shortest path to \c t. |
720 | 725 |
/// |
721 | 726 |
///The algorithm computes |
722 | 727 |
///- the shortest path to \c t, |
723 | 728 |
///- the distance of \c t from the root(s). |
724 | 729 |
/// |
725 | 730 |
///\pre init() must be called and at least one root node should be |
726 | 731 |
///added with addSource() before using this function. |
727 | 732 |
void start(Node t) |
728 | 733 |
{ |
729 | 734 |
while ( !_heap->empty() && _heap->top()!=t ) processNextNode(); |
730 | 735 |
if ( !_heap->empty() ) { |
731 | 736 |
finalizeNodeData(_heap->top(),_heap->prio()); |
732 | 737 |
_heap->pop(); |
733 | 738 |
} |
734 | 739 |
} |
735 | 740 |
|
736 | 741 |
///Executes the algorithm until a condition is met. |
737 | 742 |
|
738 | 743 |
///Executes the algorithm until a condition is met. |
739 | 744 |
/// |
740 | 745 |
///This method runs the %Dijkstra algorithm from the root node(s) in |
741 | 746 |
///order to compute the shortest path to a node \c v with |
742 | 747 |
/// <tt>nm[v]</tt> true, if such a node can be found. |
743 | 748 |
/// |
744 | 749 |
///\param nm A \c bool (or convertible) node map. The algorithm |
745 | 750 |
///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
746 | 751 |
/// |
747 | 752 |
///\return The reached node \c v with <tt>nm[v]</tt> true or |
748 | 753 |
///\c INVALID if no such node was found. |
749 | 754 |
/// |
750 | 755 |
///\pre init() must be called and at least one root node should be |
751 | 756 |
///added with addSource() before using this function. |
752 | 757 |
template<class NodeBoolMap> |
753 | 758 |
Node start(const NodeBoolMap &nm) |
754 | 759 |
{ |
755 | 760 |
while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode(); |
756 | 761 |
if ( _heap->empty() ) return INVALID; |
757 | 762 |
finalizeNodeData(_heap->top(),_heap->prio()); |
758 | 763 |
return _heap->top(); |
759 | 764 |
} |
760 | 765 |
|
761 | 766 |
///Runs the algorithm from the given source node. |
762 | 767 |
|
763 | 768 |
///This method runs the %Dijkstra algorithm from node \c s |
764 | 769 |
///in order to compute the shortest path to each node. |
765 | 770 |
/// |
766 | 771 |
///The algorithm computes |
767 | 772 |
///- the shortest path tree, |
768 | 773 |
///- the distance of each node from the root. |
769 | 774 |
/// |
770 | 775 |
///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
771 | 776 |
///\code |
772 | 777 |
/// d.init(); |
773 | 778 |
/// d.addSource(s); |
774 | 779 |
/// d.start(); |
775 | 780 |
///\endcode |
776 | 781 |
void run(Node s) { |
777 | 782 |
init(); |
778 | 783 |
addSource(s); |
779 | 784 |
start(); |
780 | 785 |
} |
781 | 786 |
|
782 | 787 |
///Finds the shortest path between \c s and \c t. |
783 | 788 |
|
784 | 789 |
///This method runs the %Dijkstra algorithm from node \c s |
785 | 790 |
///in order to compute the shortest path to node \c t |
786 | 791 |
///(it stops searching when \c t is processed). |
787 | 792 |
/// |
788 | 793 |
///\return \c true if \c t is reachable form \c s. |
789 | 794 |
/// |
790 | 795 |
///\note Apart from the return value, <tt>d.run(s,t)</tt> is just a |
791 | 796 |
///shortcut of the following code. |
792 | 797 |
///\code |
793 | 798 |
/// d.init(); |
794 | 799 |
/// d.addSource(s); |
795 | 800 |
/// d.start(t); |
796 | 801 |
///\endcode |
797 | 802 |
bool run(Node s,Node t) { |
798 | 803 |
init(); |
799 | 804 |
addSource(s); |
800 | 805 |
start(t); |
801 | 806 |
return (*_heap_cross_ref)[t] == Heap::POST_HEAP; |
802 | 807 |
} |
803 | 808 |
|
804 | 809 |
///@} |
805 | 810 |
|
806 | 811 |
///\name Query Functions |
807 | 812 |
///The results of the %Dijkstra algorithm can be obtained using these |
808 | 813 |
///functions.\n |
809 | 814 |
///Either \ref run(Node) "run()" or \ref init() should be called |
810 | 815 |
///before using them. |
811 | 816 |
|
812 | 817 |
///@{ |
813 | 818 |
|
814 | 819 |
///The shortest path to the given node. |
815 | 820 |
|
816 | 821 |
///Returns the shortest path to the given node from the root(s). |
817 | 822 |
/// |
818 | 823 |
///\warning \c t should be reached from the root(s). |
819 | 824 |
/// |
820 | 825 |
///\pre Either \ref run(Node) "run()" or \ref init() |
821 | 826 |
///must be called before using this function. |
822 | 827 |
Path path(Node t) const { return Path(*G, *_pred, t); } |
823 | 828 |
|
824 | 829 |
///The distance of the given node from the root(s). |
825 | 830 |
|
826 | 831 |
///Returns the distance of the given node from the root(s). |
827 | 832 |
/// |
828 | 833 |
///\warning If node \c v is not reached from the root(s), then |
829 | 834 |
///the return value of this function is undefined. |
830 | 835 |
/// |
831 | 836 |
///\pre Either \ref run(Node) "run()" or \ref init() |
832 | 837 |
///must be called before using this function. |
833 | 838 |
Value dist(Node v) const { return (*_dist)[v]; } |
834 | 839 |
|
835 | 840 |
///\brief Returns the 'previous arc' of the shortest path tree for |
836 | 841 |
///the given node. |
837 | 842 |
/// |
838 | 843 |
///This function returns the 'previous arc' of the shortest path |
839 | 844 |
///tree for the node \c v, i.e. it returns the last arc of a |
840 | 845 |
///shortest path from a root to \c v. It is \c INVALID if \c v |
841 | 846 |
///is not reached from the root(s) or if \c v is a root. |
842 | 847 |
/// |
843 | 848 |
///The shortest path tree used here is equal to the shortest path |
844 | 849 |
///tree used in \ref predNode() and \ref predMap(). |
845 | 850 |
/// |
846 | 851 |
///\pre Either \ref run(Node) "run()" or \ref init() |
847 | 852 |
///must be called before using this function. |
848 | 853 |
Arc predArc(Node v) const { return (*_pred)[v]; } |
849 | 854 |
|
850 | 855 |
///\brief Returns the 'previous node' of the shortest path tree for |
851 | 856 |
///the given node. |
852 | 857 |
/// |
853 | 858 |
///This function returns the 'previous node' of the shortest path |
854 | 859 |
///tree for the node \c v, i.e. it returns the last but one node |
855 | 860 |
///of a shortest path from a root to \c v. It is \c INVALID |
856 | 861 |
///if \c v is not reached from the root(s) or if \c v is a root. |
857 | 862 |
/// |
858 | 863 |
///The shortest path tree used here is equal to the shortest path |
859 | 864 |
///tree used in \ref predArc() and \ref predMap(). |
860 | 865 |
/// |
861 | 866 |
///\pre Either \ref run(Node) "run()" or \ref init() |
862 | 867 |
///must be called before using this function. |
863 | 868 |
Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
864 | 869 |
G->source((*_pred)[v]); } |
865 | 870 |
|
866 | 871 |
///\brief Returns a const reference to the node map that stores the |
867 | 872 |
///distances of the nodes. |
868 | 873 |
/// |
869 | 874 |
///Returns a const reference to the node map that stores the distances |
870 | 875 |
///of the nodes calculated by the algorithm. |
871 | 876 |
/// |
872 | 877 |
///\pre Either \ref run(Node) "run()" or \ref init() |
873 | 878 |
///must be called before using this function. |
874 | 879 |
const DistMap &distMap() const { return *_dist;} |
875 | 880 |
|
876 | 881 |
///\brief Returns a const reference to the node map that stores the |
877 | 882 |
///predecessor arcs. |
878 | 883 |
/// |
879 | 884 |
///Returns a const reference to the node map that stores the predecessor |
880 | 885 |
///arcs, which form the shortest path tree (forest). |
881 | 886 |
/// |
882 | 887 |
///\pre Either \ref run(Node) "run()" or \ref init() |
883 | 888 |
///must be called before using this function. |
884 | 889 |
const PredMap &predMap() const { return *_pred;} |
885 | 890 |
|
886 | 891 |
///Checks if the given node is reached from the root(s). |
887 | 892 |
|
888 | 893 |
///Returns \c true if \c v is reached from the root(s). |
889 | 894 |
/// |
890 | 895 |
///\pre Either \ref run(Node) "run()" or \ref init() |
891 | 896 |
///must be called before using this function. |
892 | 897 |
bool reached(Node v) const { return (*_heap_cross_ref)[v] != |
893 | 898 |
Heap::PRE_HEAP; } |
894 | 899 |
|
895 | 900 |
///Checks if a node is processed. |
896 | 901 |
|
897 | 902 |
///Returns \c true if \c v is processed, i.e. the shortest |
898 | 903 |
///path to \c v has already found. |
899 | 904 |
/// |
900 | 905 |
///\pre Either \ref run(Node) "run()" or \ref init() |
901 | 906 |
///must be called before using this function. |
902 | 907 |
bool processed(Node v) const { return (*_heap_cross_ref)[v] == |
903 | 908 |
Heap::POST_HEAP; } |
904 | 909 |
|
905 | 910 |
///The current distance of the given node from the root(s). |
906 | 911 |
|
907 | 912 |
///Returns the current distance of the given node from the root(s). |
908 | 913 |
///It may be decreased in the following processes. |
909 | 914 |
/// |
910 | 915 |
///\pre Either \ref run(Node) "run()" or \ref init() |
911 | 916 |
///must be called before using this function and |
912 | 917 |
///node \c v must be reached but not necessarily processed. |
913 | 918 |
Value currentDist(Node v) const { |
914 | 919 |
return processed(v) ? (*_dist)[v] : (*_heap)[v]; |
915 | 920 |
} |
916 | 921 |
|
917 | 922 |
///@} |
918 | 923 |
}; |
919 | 924 |
|
920 | 925 |
|
921 | 926 |
///Default traits class of dijkstra() function. |
922 | 927 |
|
923 | 928 |
///Default traits class of dijkstra() function. |
924 | 929 |
///\tparam GR The type of the digraph. |
925 | 930 |
///\tparam LEN The type of the length map. |
926 | 931 |
template<class GR, class LEN> |
927 | 932 |
struct DijkstraWizardDefaultTraits |
928 | 933 |
{ |
929 | 934 |
///The type of the digraph the algorithm runs on. |
930 | 935 |
typedef GR Digraph; |
931 | 936 |
///The type of the map that stores the arc lengths. |
932 | 937 |
|
933 | 938 |
///The type of the map that stores the arc lengths. |
934 | 939 |
///It must conform to the \ref concepts::ReadMap "ReadMap" concept. |
935 | 940 |
typedef LEN LengthMap; |
936 | 941 |
///The type of the arc lengths. |
937 | 942 |
typedef typename LEN::Value Value; |
938 | 943 |
|
939 | 944 |
/// Operation traits for Dijkstra algorithm. |
940 | 945 |
|
941 | 946 |
/// This class defines the operations that are used in the algorithm. |
942 | 947 |
/// \see DijkstraDefaultOperationTraits |
943 | 948 |
typedef DijkstraDefaultOperationTraits<Value> OperationTraits; |
944 | 949 |
|
945 | 950 |
/// The cross reference type used by the heap. |
946 | 951 |
|
947 | 952 |
/// The cross reference type used by the heap. |
948 | 953 |
/// Usually it is \c Digraph::NodeMap<int>. |
949 | 954 |
typedef typename Digraph::template NodeMap<int> HeapCrossRef; |
950 | 955 |
///Instantiates a \ref HeapCrossRef. |
951 | 956 |
|
952 | 957 |
///This function instantiates a \ref HeapCrossRef. |
953 | 958 |
/// \param g is the digraph, to which we would like to define the |
954 | 959 |
/// HeapCrossRef. |
955 | 960 |
static HeapCrossRef *createHeapCrossRef(const Digraph &g) |
956 | 961 |
{ |
957 | 962 |
return new HeapCrossRef(g); |
958 | 963 |
} |
959 | 964 |
|
960 | 965 |
///The heap type used by the Dijkstra algorithm. |
961 | 966 |
|
962 | 967 |
///The heap type used by the Dijkstra algorithm. |
963 | 968 |
/// |
964 | 969 |
///\sa BinHeap |
965 | 970 |
///\sa Dijkstra |
966 | 971 |
typedef BinHeap<Value, typename Digraph::template NodeMap<int>, |
967 | 972 |
std::less<Value> > Heap; |
968 | 973 |
|
969 | 974 |
///Instantiates a \ref Heap. |
970 | 975 |
|
971 | 976 |
///This function instantiates a \ref Heap. |
972 | 977 |
/// \param r is the HeapCrossRef which is used. |
973 | 978 |
static Heap *createHeap(HeapCrossRef& r) |
974 | 979 |
{ |
975 | 980 |
return new Heap(r); |
976 | 981 |
} |
977 | 982 |
|
978 | 983 |
///\brief The type of the map that stores the predecessor |
979 | 984 |
///arcs of the shortest paths. |
980 | 985 |
/// |
981 | 986 |
///The type of the map that stores the predecessor |
982 | 987 |
///arcs of the shortest paths. |
983 | 988 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
984 | 989 |
typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
985 | 990 |
///Instantiates a PredMap. |
986 | 991 |
|
987 | 992 |
///This function instantiates a PredMap. |
988 | 993 |
///\param g is the digraph, to which we would like to define the |
989 | 994 |
///PredMap. |
990 | 995 |
static PredMap *createPredMap(const Digraph &g) |
991 | 996 |
{ |
992 | 997 |
return new PredMap(g); |
993 | 998 |
} |
994 | 999 |
|
995 | 1000 |
///The type of the map that indicates which nodes are processed. |
996 | 1001 |
|
997 | 1002 |
///The type of the map that indicates which nodes are processed. |
998 | 1003 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
999 | 1004 |
///By default, it is a NullMap. |
1000 | 1005 |
typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
1001 | 1006 |
///Instantiates a ProcessedMap. |
1002 | 1007 |
|
1003 | 1008 |
///This function instantiates a ProcessedMap. |
1004 | 1009 |
///\param g is the digraph, to which |
1005 | 1010 |
///we would like to define the ProcessedMap. |
1006 | 1011 |
#ifdef DOXYGEN |
1007 | 1012 |
static ProcessedMap *createProcessedMap(const Digraph &g) |
1008 | 1013 |
#else |
1009 | 1014 |
static ProcessedMap *createProcessedMap(const Digraph &) |
1010 | 1015 |
#endif |
1011 | 1016 |
{ |
1012 | 1017 |
return new ProcessedMap(); |
1013 | 1018 |
} |
1014 | 1019 |
|
1015 | 1020 |
///The type of the map that stores the distances of the nodes. |
1016 | 1021 |
|
1017 | 1022 |
///The type of the map that stores the distances of the nodes. |
1018 | 1023 |
///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
1019 | 1024 |
typedef typename Digraph::template NodeMap<typename LEN::Value> DistMap; |
1020 | 1025 |
///Instantiates a DistMap. |
1021 | 1026 |
|
1022 | 1027 |
///This function instantiates a DistMap. |
1023 | 1028 |
///\param g is the digraph, to which we would like to define |
1024 | 1029 |
///the DistMap |
1025 | 1030 |
static DistMap *createDistMap(const Digraph &g) |
1026 | 1031 |
{ |
1027 | 1032 |
return new DistMap(g); |
1028 | 1033 |
} |
1029 | 1034 |
|
1030 | 1035 |
///The type of the shortest paths. |
1031 | 1036 |
|
1032 | 1037 |
///The type of the shortest paths. |
1033 | 1038 |
///It must conform to the \ref concepts::Path "Path" concept. |
1034 | 1039 |
typedef lemon::Path<Digraph> Path; |
1035 | 1040 |
}; |
1036 | 1041 |
|
1037 | 1042 |
/// Default traits class used by DijkstraWizard |
1038 | 1043 |
|
1039 | 1044 |
/// Default traits class used by DijkstraWizard. |
1040 | 1045 |
/// \tparam GR The type of the digraph. |
1041 | 1046 |
/// \tparam LEN The type of the length map. |
1042 | 1047 |
template<typename GR, typename LEN> |
1043 | 1048 |
class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LEN> |
1044 | 1049 |
{ |
1045 | 1050 |
typedef DijkstraWizardDefaultTraits<GR,LEN> Base; |
1046 | 1051 |
protected: |
1047 | 1052 |
//The type of the nodes in the digraph. |
1048 | 1053 |
typedef typename Base::Digraph::Node Node; |
1049 | 1054 |
|
1050 | 1055 |
//Pointer to the digraph the algorithm runs on. |
1051 | 1056 |
void *_g; |
1052 | 1057 |
//Pointer to the length map. |
1053 | 1058 |
void *_length; |
1054 | 1059 |
//Pointer to the map of processed nodes. |
1055 | 1060 |
void *_processed; |
1056 | 1061 |
//Pointer to the map of predecessors arcs. |
1057 | 1062 |
void *_pred; |
1058 | 1063 |
//Pointer to the map of distances. |
1059 | 1064 |
void *_dist; |
1060 | 1065 |
//Pointer to the shortest path to the target node. |
1061 | 1066 |
void *_path; |
1062 | 1067 |
//Pointer to the distance of the target node. |
1063 | 1068 |
void *_di; |
1064 | 1069 |
|
1065 | 1070 |
public: |
1066 | 1071 |
/// Constructor. |
1067 | 1072 |
|
1068 | 1073 |
/// This constructor does not require parameters, therefore it initiates |
1069 | 1074 |
/// all of the attributes to \c 0. |
1070 | 1075 |
DijkstraWizardBase() : _g(0), _length(0), _processed(0), _pred(0), |
1071 | 1076 |
_dist(0), _path(0), _di(0) {} |
1072 | 1077 |
|
1073 | 1078 |
/// Constructor. |
1074 | 1079 |
|
1075 | 1080 |
/// This constructor requires two parameters, |
1076 | 1081 |
/// others are initiated to \c 0. |
1077 | 1082 |
/// \param g The digraph the algorithm runs on. |
1078 | 1083 |
/// \param l The length map. |
1079 | 1084 |
DijkstraWizardBase(const GR &g,const LEN &l) : |
1080 | 1085 |
_g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
1081 | 1086 |
_length(reinterpret_cast<void*>(const_cast<LEN*>(&l))), |
1082 | 1087 |
_processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
1083 | 1088 |
|
1084 | 1089 |
}; |
1085 | 1090 |
|
1086 | 1091 |
/// Auxiliary class for the function-type interface of Dijkstra algorithm. |
1087 | 1092 |
|
1088 | 1093 |
/// This auxiliary class is created to implement the |
1089 | 1094 |
/// \ref dijkstra() "function-type interface" of \ref Dijkstra algorithm. |
1090 | 1095 |
/// It does not have own \ref run(Node) "run()" method, it uses the |
1091 | 1096 |
/// functions and features of the plain \ref Dijkstra. |
1092 | 1097 |
/// |
1093 | 1098 |
/// This class should only be used through the \ref dijkstra() function, |
1094 | 1099 |
/// which makes it easier to use the algorithm. |
1100 |
/// |
|
1101 |
/// \tparam TR The traits class that defines various types used by the |
|
1102 |
/// algorithm. |
|
1095 | 1103 |
template<class TR> |
1096 | 1104 |
class DijkstraWizard : public TR |
1097 | 1105 |
{ |
1098 | 1106 |
typedef TR Base; |
1099 | 1107 |
|
1100 | 1108 |
typedef typename TR::Digraph Digraph; |
1101 | 1109 |
|
1102 | 1110 |
typedef typename Digraph::Node Node; |
1103 | 1111 |
typedef typename Digraph::NodeIt NodeIt; |
1104 | 1112 |
typedef typename Digraph::Arc Arc; |
1105 | 1113 |
typedef typename Digraph::OutArcIt OutArcIt; |
1106 | 1114 |
|
1107 | 1115 |
typedef typename TR::LengthMap LengthMap; |
1108 | 1116 |
typedef typename LengthMap::Value Value; |
1109 | 1117 |
typedef typename TR::PredMap PredMap; |
1110 | 1118 |
typedef typename TR::DistMap DistMap; |
1111 | 1119 |
typedef typename TR::ProcessedMap ProcessedMap; |
1112 | 1120 |
typedef typename TR::Path Path; |
1113 | 1121 |
typedef typename TR::Heap Heap; |
1114 | 1122 |
|
1115 | 1123 |
public: |
1116 | 1124 |
|
1117 | 1125 |
/// Constructor. |
1118 | 1126 |
DijkstraWizard() : TR() {} |
1119 | 1127 |
|
1120 | 1128 |
/// Constructor that requires parameters. |
1121 | 1129 |
|
1122 | 1130 |
/// Constructor that requires parameters. |
1123 | 1131 |
/// These parameters will be the default values for the traits class. |
1124 | 1132 |
/// \param g The digraph the algorithm runs on. |
1125 | 1133 |
/// \param l The length map. |
1126 | 1134 |
DijkstraWizard(const Digraph &g, const LengthMap &l) : |
1127 | 1135 |
TR(g,l) {} |
1128 | 1136 |
|
1129 | 1137 |
///Copy constructor |
1130 | 1138 |
DijkstraWizard(const TR &b) : TR(b) {} |
1131 | 1139 |
|
1132 | 1140 |
~DijkstraWizard() {} |
1133 | 1141 |
|
1134 | 1142 |
///Runs Dijkstra algorithm from the given source node. |
1135 | 1143 |
|
1136 | 1144 |
///This method runs %Dijkstra algorithm from the given source node |
1137 | 1145 |
///in order to compute the shortest path to each node. |
1138 | 1146 |
void run(Node s) |
1139 | 1147 |
{ |
1140 | 1148 |
Dijkstra<Digraph,LengthMap,TR> |
1141 | 1149 |
dijk(*reinterpret_cast<const Digraph*>(Base::_g), |
1142 | 1150 |
*reinterpret_cast<const LengthMap*>(Base::_length)); |
1143 | 1151 |
if (Base::_pred) |
1144 | 1152 |
dijk.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
1145 | 1153 |
if (Base::_dist) |
1146 | 1154 |
dijk.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
1147 | 1155 |
if (Base::_processed) |
1148 | 1156 |
dijk.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
1149 | 1157 |
dijk.run(s); |
1150 | 1158 |
} |
1151 | 1159 |
|
1152 | 1160 |
///Finds the shortest path between \c s and \c t. |
1153 | 1161 |
|
1154 | 1162 |
///This method runs the %Dijkstra algorithm from node \c s |
1155 | 1163 |
///in order to compute the shortest path to node \c t |
1156 | 1164 |
///(it stops searching when \c t is processed). |
1157 | 1165 |
/// |
1158 | 1166 |
///\return \c true if \c t is reachable form \c s. |
1159 | 1167 |
bool run(Node s, Node t) |
1160 | 1168 |
{ |
1161 | 1169 |
Dijkstra<Digraph,LengthMap,TR> |
1162 | 1170 |
dijk(*reinterpret_cast<const Digraph*>(Base::_g), |
1163 | 1171 |
*reinterpret_cast<const LengthMap*>(Base::_length)); |
1164 | 1172 |
if (Base::_pred) |
1165 | 1173 |
dijk.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
1166 | 1174 |
if (Base::_dist) |
1167 | 1175 |
dijk.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
1168 | 1176 |
if (Base::_processed) |
1169 | 1177 |
dijk.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
1170 | 1178 |
dijk.run(s,t); |
1171 | 1179 |
if (Base::_path) |
1172 | 1180 |
*reinterpret_cast<Path*>(Base::_path) = dijk.path(t); |
1173 | 1181 |
if (Base::_di) |
1174 | 1182 |
*reinterpret_cast<Value*>(Base::_di) = dijk.dist(t); |
1175 | 1183 |
return dijk.reached(t); |
1176 | 1184 |
} |
1177 | 1185 |
|
1178 | 1186 |
template<class T> |
1179 | 1187 |
struct SetPredMapBase : public Base { |
1180 | 1188 |
typedef T PredMap; |
1181 | 1189 |
static PredMap *createPredMap(const Digraph &) { return 0; }; |
1182 | 1190 |
SetPredMapBase(const TR &b) : TR(b) {} |
1183 | 1191 |
}; |
1184 | 1192 |
|
1185 | 1193 |
///\brief \ref named-templ-param "Named parameter" for setting |
1186 | 1194 |
///the predecessor map. |
1187 | 1195 |
/// |
1188 | 1196 |
///\ref named-templ-param "Named parameter" function for setting |
1189 | 1197 |
///the map that stores the predecessor arcs of the nodes. |
1190 | 1198 |
template<class T> |
1191 | 1199 |
DijkstraWizard<SetPredMapBase<T> > predMap(const T &t) |
1192 | 1200 |
{ |
1193 | 1201 |
Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1194 | 1202 |
return DijkstraWizard<SetPredMapBase<T> >(*this); |
1195 | 1203 |
} |
1196 | 1204 |
|
1197 | 1205 |
template<class T> |
1198 | 1206 |
struct SetDistMapBase : public Base { |
1199 | 1207 |
typedef T DistMap; |
1200 | 1208 |
static DistMap *createDistMap(const Digraph &) { return 0; }; |
1201 | 1209 |
SetDistMapBase(const TR &b) : TR(b) {} |
1202 | 1210 |
}; |
1203 | 1211 |
|
1204 | 1212 |
///\brief \ref named-templ-param "Named parameter" for setting |
1205 | 1213 |
///the distance map. |
1206 | 1214 |
/// |
1207 | 1215 |
///\ref named-templ-param "Named parameter" function for setting |
1208 | 1216 |
///the map that stores the distances of the nodes calculated |
1209 | 1217 |
///by the algorithm. |
1210 | 1218 |
template<class T> |
1211 | 1219 |
DijkstraWizard<SetDistMapBase<T> > distMap(const T &t) |
1212 | 1220 |
{ |
1213 | 1221 |
Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1214 | 1222 |
return DijkstraWizard<SetDistMapBase<T> >(*this); |
1215 | 1223 |
} |
1216 | 1224 |
|
1217 | 1225 |
template<class T> |
1218 | 1226 |
struct SetProcessedMapBase : public Base { |
1219 | 1227 |
typedef T ProcessedMap; |
1220 | 1228 |
static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
1221 | 1229 |
SetProcessedMapBase(const TR &b) : TR(b) {} |
1222 | 1230 |
}; |
1223 | 1231 |
|
1224 | 1232 |
///\brief \ref named-func-param "Named parameter" for setting |
1225 | 1233 |
///the processed map. |
1226 | 1234 |
/// |
1227 | 1235 |
///\ref named-templ-param "Named parameter" function for setting |
1228 | 1236 |
///the map that indicates which nodes are processed. |
1229 | 1237 |
template<class T> |
1230 | 1238 |
DijkstraWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
1231 | 1239 |
{ |
1232 | 1240 |
Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1233 | 1241 |
return DijkstraWizard<SetProcessedMapBase<T> >(*this); |
1234 | 1242 |
} |
1235 | 1243 |
|
1236 | 1244 |
template<class T> |
1237 | 1245 |
struct SetPathBase : public Base { |
1238 | 1246 |
typedef T Path; |
1239 | 1247 |
SetPathBase(const TR &b) : TR(b) {} |
1240 | 1248 |
}; |
1241 | 1249 |
|
1242 | 1250 |
///\brief \ref named-func-param "Named parameter" |
1243 | 1251 |
///for getting the shortest path to the target node. |
1244 | 1252 |
/// |
1245 | 1253 |
///\ref named-func-param "Named parameter" |
1246 | 1254 |
///for getting the shortest path to the target node. |
1247 | 1255 |
template<class T> |
1248 | 1256 |
DijkstraWizard<SetPathBase<T> > path(const T &t) |
1249 | 1257 |
{ |
1250 | 1258 |
Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
1251 | 1259 |
return DijkstraWizard<SetPathBase<T> >(*this); |
1252 | 1260 |
} |
1253 | 1261 |
|
1254 | 1262 |
///\brief \ref named-func-param "Named parameter" |
1255 | 1263 |
///for getting the distance of the target node. |
1256 | 1264 |
/// |
1257 | 1265 |
///\ref named-func-param "Named parameter" |
1258 | 1266 |
///for getting the distance of the target node. |
1259 | 1267 |
DijkstraWizard dist(const Value &d) |
1260 | 1268 |
{ |
1261 | 1269 |
Base::_di=reinterpret_cast<void*>(const_cast<Value*>(&d)); |
1262 | 1270 |
return *this; |
1263 | 1271 |
} |
1264 | 1272 |
|
1265 | 1273 |
}; |
1266 | 1274 |
|
1267 | 1275 |
///Function-type interface for Dijkstra algorithm. |
1268 | 1276 |
|
1269 | 1277 |
/// \ingroup shortest_path |
1270 | 1278 |
///Function-type interface for Dijkstra algorithm. |
1271 | 1279 |
/// |
1272 | 1280 |
///This function also has several \ref named-func-param "named parameters", |
1273 | 1281 |
///they are declared as the members of class \ref DijkstraWizard. |
1274 | 1282 |
///The following examples show how to use these parameters. |
1275 | 1283 |
///\code |
1276 | 1284 |
/// // Compute shortest path from node s to each node |
1277 | 1285 |
/// dijkstra(g,length).predMap(preds).distMap(dists).run(s); |
1278 | 1286 |
/// |
1279 | 1287 |
/// // Compute shortest path from s to t |
1280 | 1288 |
/// bool reached = dijkstra(g,length).path(p).dist(d).run(s,t); |
1281 | 1289 |
///\endcode |
1282 | 1290 |
///\warning Don't forget to put the \ref DijkstraWizard::run(Node) "run()" |
1283 | 1291 |
///to the end of the parameter list. |
1284 | 1292 |
///\sa DijkstraWizard |
1285 | 1293 |
///\sa Dijkstra |
1286 | 1294 |
template<typename GR, typename LEN> |
1287 | 1295 |
DijkstraWizard<DijkstraWizardBase<GR,LEN> > |
1288 | 1296 |
dijkstra(const GR &digraph, const LEN &length) |
1289 | 1297 |
{ |
1290 | 1298 |
return DijkstraWizard<DijkstraWizardBase<GR,LEN> >(digraph,length); |
1291 | 1299 |
} |
1292 | 1300 |
|
1293 | 1301 |
} //END OF NAMESPACE LEMON |
1294 | 1302 |
|
1295 | 1303 |
#endif |
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