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kpeter (Peter Kovacs)
kpeter@inf.elte.hu
Minor doc improvements related to Suurballe (#47)
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2 files changed with 87 insertions and 85 deletions:
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Ignore white space 24 line context
... ...
@@ -24,82 +24,84 @@
24 24
///\brief An algorithm for finding arc-disjoint paths between two
25 25
/// nodes having minimum total length.
26 26

	
27 27
#include <vector>
28 28
#include <lemon/bin_heap.h>
29 29
#include <lemon/path.h>
30 30

	
31 31
namespace lemon {
32 32

	
33 33
  /// \addtogroup shortest_path
34 34
  /// @{
35 35

	
36
  /// \brief Implementation of an algorithm for finding arc-disjoint
37
  /// paths between two nodes having minimum total length.
36
  /// \brief Algorithm for finding arc-disjoint paths between two nodes
37
  /// having minimum total length.
38 38
  ///
39 39
  /// \ref lemon::Suurballe "Suurballe" implements an algorithm for
40 40
  /// finding arc-disjoint paths having minimum total length (cost)
41
  /// from a given source node to a given target node in a directed
42
  /// digraph.
41
  /// from a given source node to a given target node in a digraph.
43 42
  ///
44 43
  /// In fact, this implementation is the specialization of the
45 44
  /// \ref CapacityScaling "successive shortest path" algorithm.
46 45
  ///
47
  /// \tparam Digraph The directed digraph type the algorithm runs on.
46
  /// \tparam Digraph The digraph type the algorithm runs on.
47
  /// The default value is \c ListDigraph.
48 48
  /// \tparam LengthMap The type of the length (cost) map.
49
  /// The default value is <tt>Digraph::ArcMap<int></tt>.
49 50
  ///
50 51
  /// \warning Length values should be \e non-negative \e integers.
51 52
  ///
52 53
  /// \note For finding node-disjoint paths this algorithm can be used
53 54
  /// with \ref SplitDigraphAdaptor.
54
  ///
55
  /// \author Attila Bernath and Peter Kovacs
56
  
57
  template < typename Digraph, 
55
#ifdef DOXYGEN
56
  template <typename Digraph, typename LengthMap>
57
#else
58
  template < typename Digraph = ListDigraph,
58 59
             typename LengthMap = typename Digraph::template ArcMap<int> >
60
#endif
59 61
  class Suurballe
60 62
  {
61 63
    TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
62 64

	
63 65
    typedef typename LengthMap::Value Length;
64 66
    typedef ConstMap<Arc, int> ConstArcMap;
65 67
    typedef typename Digraph::template NodeMap<Arc> PredMap;
66 68

	
67 69
  public:
68 70

	
69 71
    /// The type of the flow map.
70 72
    typedef typename Digraph::template ArcMap<int> FlowMap;
71 73
    /// The type of the potential map.
72 74
    typedef typename Digraph::template NodeMap<Length> PotentialMap;
73 75
    /// The type of the path structures.
74 76
    typedef SimplePath<Digraph> Path;
75 77

	
76 78
  private:
77 79
  
78
    /// \brief Special implementation of the \ref Dijkstra algorithm
80
    /// \brief Special implementation of the Dijkstra algorithm
79 81
    /// for finding shortest paths in the residual network.
80 82
    ///
81 83
    /// \ref ResidualDijkstra is a special implementation of the
82 84
    /// \ref Dijkstra algorithm for finding shortest paths in the
83 85
    /// residual network of the digraph with respect to the reduced arc
84 86
    /// lengths and modifying the node potentials according to the
85 87
    /// distance of the nodes.
86 88
    class ResidualDijkstra
87 89
    {
88 90
      typedef typename Digraph::template NodeMap<int> HeapCrossRef;
89 91
      typedef BinHeap<Length, HeapCrossRef> Heap;
90 92

	
91 93
    private:
92 94

	
93
      // The directed digraph the algorithm runs on
95
      // The digraph the algorithm runs on
94 96
      const Digraph &_graph;
95 97

	
96 98
      // The main maps
97 99
      const FlowMap &_flow;
98 100
      const LengthMap &_length;
99 101
      PotentialMap &_potential;
100 102

	
101 103
      // The distance map
102 104
      PotentialMap _dist;
103 105
      // The pred arc map
104 106
      PredMap &_pred;
105 107
      // The processed (i.e. permanently labeled) nodes
... ...
@@ -111,99 +113,99 @@
111 113
    public:
112 114

	
113 115
      /// Constructor.
114 116
      ResidualDijkstra( const Digraph &digraph,
115 117
                        const FlowMap &flow,
116 118
                        const LengthMap &length,
117 119
                        PotentialMap &potential,
118 120
                        PredMap &pred,
119 121
                        Node s, Node t ) :
120 122
        _graph(digraph), _flow(flow), _length(length), _potential(potential),
121 123
        _dist(digraph), _pred(pred), _s(s), _t(t) {}
122 124

	
123
      /// \brief Runs the algorithm. Returns \c true if a path is found
125
      /// \brief Run the algorithm. It returns \c true if a path is found
124 126
      /// from the source node to the target node.
125 127
      bool run() {
126 128
        HeapCrossRef heap_cross_ref(_graph, Heap::PRE_HEAP);
127 129
        Heap heap(heap_cross_ref);
128 130
        heap.push(_s, 0);
129 131
        _pred[_s] = INVALID;
130 132
        _proc_nodes.clear();
131 133

	
132
        // Processing nodes
134
        // Process nodes
133 135
        while (!heap.empty() && heap.top() != _t) {
134 136
          Node u = heap.top(), v;
135 137
          Length d = heap.prio() + _potential[u], nd;
136 138
          _dist[u] = heap.prio();
137 139
          heap.pop();
138 140
          _proc_nodes.push_back(u);
139 141

	
140
          // Traversing outgoing arcs
142
          // Traverse outgoing arcs
141 143
          for (OutArcIt e(_graph, u); e != INVALID; ++e) {
142 144
            if (_flow[e] == 0) {
143 145
              v = _graph.target(e);
144 146
              switch(heap.state(v)) {
145 147
              case Heap::PRE_HEAP:
146 148
                heap.push(v, d + _length[e] - _potential[v]);
147 149
                _pred[v] = e;
148 150
                break;
149 151
              case Heap::IN_HEAP:
150 152
                nd = d + _length[e] - _potential[v];
151 153
                if (nd < heap[v]) {
152 154
                  heap.decrease(v, nd);
153 155
                  _pred[v] = e;
154 156
                }
155 157
                break;
156 158
              case Heap::POST_HEAP:
157 159
                break;
158 160
              }
159 161
            }
160 162
          }
161 163

	
162
          // Traversing incoming arcs
164
          // Traverse incoming arcs
163 165
          for (InArcIt e(_graph, u); e != INVALID; ++e) {
164 166
            if (_flow[e] == 1) {
165 167
              v = _graph.source(e);
166 168
              switch(heap.state(v)) {
167 169
              case Heap::PRE_HEAP:
168 170
                heap.push(v, d - _length[e] - _potential[v]);
169 171
                _pred[v] = e;
170 172
                break;
171 173
              case Heap::IN_HEAP:
172 174
                nd = d - _length[e] - _potential[v];
173 175
                if (nd < heap[v]) {
174 176
                  heap.decrease(v, nd);
175 177
                  _pred[v] = e;
176 178
                }
177 179
                break;
178 180
              case Heap::POST_HEAP:
179 181
                break;
180 182
              }
181 183
            }
182 184
          }
183 185
        }
184 186
        if (heap.empty()) return false;
185 187

	
186
        // Updating potentials of processed nodes
188
        // Update potentials of processed nodes
187 189
        Length t_dist = heap.prio();
188 190
        for (int i = 0; i < int(_proc_nodes.size()); ++i)
189 191
          _potential[_proc_nodes[i]] += _dist[_proc_nodes[i]] - t_dist;
190 192
        return true;
191 193
      }
192 194

	
193 195
    }; //class ResidualDijkstra
194 196

	
195 197
  private:
196 198

	
197
    // The directed digraph the algorithm runs on
199
    // The digraph the algorithm runs on
198 200
    const Digraph &_graph;
199 201
    // The length map
200 202
    const LengthMap &_length;
201 203
    
202 204
    // Arc map of the current flow
203 205
    FlowMap *_flow;
204 206
    bool _local_flow;
205 207
    // Node map of the current potentials
206 208
    PotentialMap *_potential;
207 209
    bool _local_potential;
208 210

	
209 211
    // The source node
... ...
@@ -218,281 +220,281 @@
218 220
    // The pred arc map
219 221
    PredMap _pred;
220 222
    // Implementation of the Dijkstra algorithm for finding augmenting
221 223
    // shortest paths in the residual network
222 224
    ResidualDijkstra *_dijkstra;
223 225

	
224 226
  public:
225 227

	
226 228
    /// \brief Constructor.
227 229
    ///
228 230
    /// Constructor.
229 231
    ///
230
    /// \param digraph The directed digraph the algorithm runs on.
232
    /// \param digraph The digraph the algorithm runs on.
231 233
    /// \param length The length (cost) values of the arcs.
232 234
    /// \param s The source node.
233 235
    /// \param t The target node.
234 236
    Suurballe( const Digraph &digraph,
235 237
               const LengthMap &length,
236 238
               Node s, Node t ) :
237 239
      _graph(digraph), _length(length), _flow(0), _local_flow(false),
238 240
      _potential(0), _local_potential(false), _source(s), _target(t),
239 241
      _pred(digraph) {}
240 242

	
241 243
    /// Destructor.
242 244
    ~Suurballe() {
243 245
      if (_local_flow) delete _flow;
244 246
      if (_local_potential) delete _potential;
245 247
      delete _dijkstra;
246 248
    }
247 249

	
248
    /// \brief Sets the flow map.
250
    /// \brief Set the flow map.
249 251
    ///
250
    /// Sets the flow map.
252
    /// This function sets the flow map.
251 253
    ///
252 254
    /// The found flow contains only 0 and 1 values. It is the union of
253 255
    /// the found arc-disjoint paths.
254 256
    ///
255 257
    /// \return \c (*this)
256 258
    Suurballe& flowMap(FlowMap &map) {
257 259
      if (_local_flow) {
258 260
        delete _flow;
259 261
        _local_flow = false;
260 262
      }
261 263
      _flow = &map;
262 264
      return *this;
263 265
    }
264 266

	
265
    /// \brief Sets the potential map.
267
    /// \brief Set the potential map.
266 268
    ///
267
    /// Sets the potential map.
269
    /// This function sets the potential map.
268 270
    ///
269 271
    /// The potentials provide the dual solution of the underlying 
270 272
    /// minimum cost flow problem.
271 273
    ///
272 274
    /// \return \c (*this)
273 275
    Suurballe& potentialMap(PotentialMap &map) {
274 276
      if (_local_potential) {
275 277
        delete _potential;
276 278
        _local_potential = false;
277 279
      }
278 280
      _potential = &map;
279 281
      return *this;
280 282
    }
281 283

	
282 284
    /// \name Execution control
283 285
    /// The simplest way to execute the algorithm is to call the run()
284 286
    /// function.
285 287
    /// \n
286 288
    /// If you only need the flow that is the union of the found
287 289
    /// arc-disjoint paths, you may call init() and findFlow().
288 290

	
289 291
    /// @{
290 292

	
291
    /// \brief Runs the algorithm.
293
    /// \brief Run the algorithm.
292 294
    ///
293
    /// Runs the algorithm.
295
    /// This function runs the algorithm.
294 296
    ///
295 297
    /// \param k The number of paths to be found.
296 298
    ///
297
    /// \return \c k if there are at least \c k arc-disjoint paths
298
    /// from \c s to \c t. Otherwise it returns the number of
299
    /// \return \c k if there are at least \c k arc-disjoint paths from
300
    /// \c s to \c t in the digraph. Otherwise it returns the number of
299 301
    /// arc-disjoint paths found.
300 302
    ///
301 303
    /// \note Apart from the return value, <tt>s.run(k)</tt> is just a
302 304
    /// shortcut of the following code.
303 305
    /// \code
304 306
    ///   s.init();
305 307
    ///   s.findFlow(k);
306 308
    ///   s.findPaths();
307 309
    /// \endcode
308 310
    int run(int k = 2) {
309 311
      init();
310 312
      findFlow(k);
311 313
      findPaths();
312 314
      return _path_num;
313 315
    }
314 316

	
315
    /// \brief Initializes the algorithm.
317
    /// \brief Initialize the algorithm.
316 318
    ///
317
    /// Initializes the algorithm.
319
    /// This function initializes the algorithm.
318 320
    void init() {
319
      // Initializing maps
321
      // Initialize maps
320 322
      if (!_flow) {
321 323
        _flow = new FlowMap(_graph);
322 324
        _local_flow = true;
323 325
      }
324 326
      if (!_potential) {
325 327
        _potential = new PotentialMap(_graph);
326 328
        _local_potential = true;
327 329
      }
328 330
      for (ArcIt e(_graph); e != INVALID; ++e) (*_flow)[e] = 0;
329 331
      for (NodeIt n(_graph); n != INVALID; ++n) (*_potential)[n] = 0;
330 332

	
331 333
      _dijkstra = new ResidualDijkstra( _graph, *_flow, _length, 
332 334
                                        *_potential, _pred,
333 335
                                        _source, _target );
334 336
    }
335 337

	
336
    /// \brief Executes the successive shortest path algorithm to find
338
    /// \brief Execute the successive shortest path algorithm to find
337 339
    /// an optimal flow.
338 340
    ///
339
    /// Executes the successive shortest path algorithm to find a
340
    /// minimum cost flow, which is the union of \c k or less
341
    /// This function executes the successive shortest path algorithm to
342
    /// find a minimum cost flow, which is the union of \c k or less
341 343
    /// arc-disjoint paths.
342 344
    ///
343
    /// \return \c k if there are at least \c k arc-disjoint paths
344
    /// from \c s to \c t. Otherwise it returns the number of
345
    /// \return \c k if there are at least \c k arc-disjoint paths from
346
    /// \c s to \c t in the digraph. Otherwise it returns the number of
345 347
    /// arc-disjoint paths found.
346 348
    ///
347 349
    /// \pre \ref init() must be called before using this function.
348 350
    int findFlow(int k = 2) {
349
      // Finding shortest paths
351
      // Find shortest paths
350 352
      _path_num = 0;
351 353
      while (_path_num < k) {
352
        // Running Dijkstra
354
        // Run Dijkstra
353 355
        if (!_dijkstra->run()) break;
354 356
        ++_path_num;
355 357

	
356
        // Setting the flow along the found shortest path
358
        // Set the flow along the found shortest path
357 359
        Node u = _target;
358 360
        Arc e;
359 361
        while ((e = _pred[u]) != INVALID) {
360 362
          if (u == _graph.target(e)) {
361 363
            (*_flow)[e] = 1;
362 364
            u = _graph.source(e);
363 365
          } else {
364 366
            (*_flow)[e] = 0;
365 367
            u = _graph.target(e);
366 368
          }
367 369
        }
368 370
      }
369 371
      return _path_num;
370 372
    }
371 373
    
372
    /// \brief Computes the paths from the flow.
374
    /// \brief Compute the paths from the flow.
373 375
    ///
374
    /// Computes the paths from the flow.
376
    /// This function computes the paths from the flow.
375 377
    ///
376 378
    /// \pre \ref init() and \ref findFlow() must be called before using
377 379
    /// this function.
378 380
    void findPaths() {
379
      // Creating the residual flow map (the union of the paths not
380
      // found so far)
381
      // Create the residual flow map (the union of the paths not found
382
      // so far)
381 383
      FlowMap res_flow(_graph);
382
      for(ArcIt a(_graph);a!=INVALID;++a) res_flow[a]=(*_flow)[a];
384
      for(ArcIt a(_graph); a != INVALID; ++a) res_flow[a] = (*_flow)[a];
383 385

	
384 386
      paths.clear();
385 387
      paths.resize(_path_num);
386 388
      for (int i = 0; i < _path_num; ++i) {
387 389
        Node n = _source;
388 390
        while (n != _target) {
389 391
          OutArcIt e(_graph, n);
390 392
          for ( ; res_flow[e] == 0; ++e) ;
391 393
          n = _graph.target(e);
392 394
          paths[i].addBack(e);
393 395
          res_flow[e] = 0;
394 396
        }
395 397
      }
396 398
    }
397 399

	
398 400
    /// @}
399 401

	
400 402
    /// \name Query Functions
401
    /// The result of the algorithm can be obtained using these
403
    /// The results of the algorithm can be obtained using these
402 404
    /// functions.
403 405
    /// \n The algorithm should be executed before using them.
404 406

	
405 407
    /// @{
406 408

	
407
    /// \brief Returns a const reference to the arc map storing the
409
    /// \brief Return a const reference to the arc map storing the
408 410
    /// found flow.
409 411
    ///
410
    /// Returns a const reference to the arc map storing the flow that
411
    /// is the union of the found arc-disjoint paths.
412
    /// This function returns a const reference to the arc map storing
413
    /// the flow that is the union of the found arc-disjoint paths.
412 414
    ///
413
    /// \pre \ref run() or findFlow() must be called before using this
414
    /// function.
415
    /// \pre \ref run() or \ref findFlow() must be called before using
416
    /// this function.
415 417
    const FlowMap& flowMap() const {
416 418
      return *_flow;
417 419
    }
418 420

	
419
    /// \brief Returns a const reference to the node map storing the
421
    /// \brief Return a const reference to the node map storing the
420 422
    /// found potentials (the dual solution).
421 423
    ///
422
    /// Returns a const reference to the node map storing the found
423
    /// potentials that provide the dual solution of the underlying 
424
    /// minimum cost flow problem.
424
    /// This function returns a const reference to the node map storing
425
    /// the found potentials that provide the dual solution of the
426
    /// underlying minimum cost flow problem.
425 427
    ///
426
    /// \pre \ref run() or findFlow() must be called before using this
427
    /// function.
428
    /// \pre \ref run() or \ref findFlow() must be called before using
429
    /// this function.
428 430
    const PotentialMap& potentialMap() const {
429 431
      return *_potential;
430 432
    }
431 433

	
432
    /// \brief Returns the flow on the given arc.
434
    /// \brief Return the flow on the given arc.
433 435
    ///
434
    /// Returns the flow on the given arc.
436
    /// This function returns the flow on the given arc.
435 437
    /// It is \c 1 if the arc is involved in one of the found paths,
436 438
    /// otherwise it is \c 0.
437 439
    ///
438
    /// \pre \ref run() or findFlow() must be called before using this
439
    /// function.
440
    /// \pre \ref run() or \ref findFlow() must be called before using
441
    /// this function.
440 442
    int flow(const Arc& arc) const {
441 443
      return (*_flow)[arc];
442 444
    }
443 445

	
444
    /// \brief Returns the potential of the given node.
446
    /// \brief Return the potential of the given node.
445 447
    ///
446
    /// Returns the potential of the given node.
448
    /// This function returns the potential of the given node.
447 449
    ///
448
    /// \pre \ref run() or findFlow() must be called before using this
449
    /// function.
450
    /// \pre \ref run() or \ref findFlow() must be called before using
451
    /// this function.
450 452
    Length potential(const Node& node) const {
451 453
      return (*_potential)[node];
452 454
    }
453 455

	
454
    /// \brief Returns the total length (cost) of the found paths (flow).
456
    /// \brief Return the total length (cost) of the found paths (flow).
455 457
    ///
456
    /// Returns the total length (cost) of the found paths (flow).
457
    /// The complexity of the function is \f$ O(e) \f$.
458
    /// This function returns the total length (cost) of the found paths
459
    /// (flow). The complexity of the function is \f$ O(e) \f$.
458 460
    ///
459
    /// \pre \ref run() or findFlow() must be called before using this
460
    /// function.
461
    /// \pre \ref run() or \ref findFlow() must be called before using
462
    /// this function.
461 463
    Length totalLength() const {
462 464
      Length c = 0;
463 465
      for (ArcIt e(_graph); e != INVALID; ++e)
464 466
        c += (*_flow)[e] * _length[e];
465 467
      return c;
466 468
    }
467 469

	
468
    /// \brief Returns the number of the found paths.
470
    /// \brief Return the number of the found paths.
469 471
    ///
470
    /// Returns the number of the found paths.
472
    /// This function returns the number of the found paths.
471 473
    ///
472
    /// \pre \ref run() or findFlow() must be called before using this
473
    /// function.
474
    /// \pre \ref run() or \ref findFlow() must be called before using
475
    /// this function.
474 476
    int pathNum() const {
475 477
      return _path_num;
476 478
    }
477 479

	
478
    /// \brief Returns a const reference to the specified path.
480
    /// \brief Return a const reference to the specified path.
479 481
    ///
480
    /// Returns a const reference to the specified path.
482
    /// This function returns a const reference to the specified path.
481 483
    ///
482 484
    /// \param i The function returns the \c i-th path.
483 485
    /// \c i must be between \c 0 and <tt>%pathNum()-1</tt>.
484 486
    ///
485
    /// \pre \ref run() or findPaths() must be called before using this
486
    /// function.
487
    /// \pre \ref run() or \ref findPaths() must be called before using
488
    /// this function.
487 489
    Path path(int i) const {
488 490
      return paths[i];
489 491
    }
490 492

	
491 493
    /// @}
492 494

	
493 495
  }; //class Suurballe
494 496

	
495 497
  ///@}
496 498

	
497 499
} //namespace lemon
498 500

	
Ignore white space 6 line context
... ...
@@ -19,138 +19,138 @@
19 19
#include <iostream>
20 20
#include <fstream>
21 21

	
22 22
#include <lemon/list_graph.h>
23 23
#include <lemon/lgf_reader.h>
24 24
#include <lemon/path.h>
25 25
#include <lemon/suurballe.h>
26 26

	
27 27
#include "test_tools.h"
28 28

	
29 29
using namespace lemon;
30 30

	
31
// Checks the feasibility of the flow
31
// Check the feasibility of the flow
32 32
template <typename Digraph, typename FlowMap>
33 33
bool checkFlow( const Digraph& gr, const FlowMap& flow, 
34 34
                typename Digraph::Node s, typename Digraph::Node t,
35 35
                int value )
36 36
{
37 37
  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
38 38
  for (ArcIt e(gr); e != INVALID; ++e)
39 39
    if (!(flow[e] == 0 || flow[e] == 1)) return false;
40 40

	
41 41
  for (NodeIt n(gr); n != INVALID; ++n) {
42 42
    int sum = 0;
43 43
    for (OutArcIt e(gr, n); e != INVALID; ++e)
44 44
      sum += flow[e];
45 45
    for (InArcIt e(gr, n); e != INVALID; ++e)
46 46
      sum -= flow[e];
47 47
    if (n == s && sum != value) return false;
48 48
    if (n == t && sum != -value) return false;
49 49
    if (n != s && n != t && sum != 0) return false;
50 50
  }
51 51

	
52 52
  return true;
53 53
}
54 54

	
55
// Checks the optimalitiy of the flow
55
// Check the optimalitiy of the flow
56 56
template < typename Digraph, typename CostMap, 
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           typename FlowMap, typename PotentialMap >
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bool checkOptimality( const Digraph& gr, const CostMap& cost,
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                      const FlowMap& flow, const PotentialMap& pi )
60 60
{
61
  // Checking the Complementary Slackness optimality condition
61
  // Check the "Complementary Slackness" optimality condition
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  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
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  bool opt = true;
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  for (ArcIt e(gr); e != INVALID; ++e) {
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    typename CostMap::Value red_cost =
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      cost[e] + pi[gr.source(e)] - pi[gr.target(e)];
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    opt = (flow[e] == 0 && red_cost >= 0) ||
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          (flow[e] == 1 && red_cost <= 0);
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    if (!opt) break;
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  }
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  return opt;
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}
73 73

	
74
// Checks a path
75
template < typename Digraph, typename Path >
74
// Check a path
75
template <typename Digraph, typename Path>
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bool checkPath( const Digraph& gr, const Path& path,
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                typename Digraph::Node s, typename Digraph::Node t)
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{
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  // Checking the Complementary Slackness optimality condition
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  // Check the "Complementary Slackness" optimality condition
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  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
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  Node n = s;
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  for (int i = 0; i < path.length(); ++i) {
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    if (gr.source(path.nth(i)) != n) return false;
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    n = gr.target(path.nth(i));
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  }
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  return n == t;
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}
88 88

	
89 89

	
90 90
int main()
91 91
{
92 92
  DIGRAPH_TYPEDEFS(ListDigraph);
93 93

	
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  // Reading the test digraph
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  // Read the test digraph
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  ListDigraph digraph;
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  ListDigraph::ArcMap<int> length(digraph);
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  Node source, target;
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  std::string fname;
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  if(getenv("srcdir"))
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    fname = std::string(getenv("srcdir"));
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  else fname = ".";
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  fname += "/test/min_cost_flow_test.lgf";
104 104

	
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  std::ifstream input(fname.c_str());
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  check(input, "Input file '" << fname << "' not found");
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  DigraphReader<ListDigraph>(digraph, input).
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    arcMap("cost", length).
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    node("source", source).
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    node("target", target).
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    run();
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  input.close();
113 113
  
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  // Finding 2 paths
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  // Find 2 paths
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  {
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    Suurballe<ListDigraph> suurballe(digraph, length, source, target);
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    check(suurballe.run(2) == 2, "Wrong number of paths");
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    check(checkFlow(digraph, suurballe.flowMap(), source, target, 2),
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          "The flow is not feasible");
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    check(suurballe.totalLength() == 510, "The flow is not optimal");
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    check(checkOptimality(digraph, length, suurballe.flowMap(), 
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                          suurballe.potentialMap()),
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          "Wrong potentials");
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    for (int i = 0; i < suurballe.pathNum(); ++i)
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      check(checkPath(digraph, suurballe.path(i), source, target),
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            "Wrong path");
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  }
128 128

	
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  // Finding 3 paths
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  // Find 3 paths
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  {
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    Suurballe<ListDigraph> suurballe(digraph, length, source, target);
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    check(suurballe.run(3) == 3, "Wrong number of paths");
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    check(checkFlow(digraph, suurballe.flowMap(), source, target, 3),
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          "The flow is not feasible");
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    check(suurballe.totalLength() == 1040, "The flow is not optimal");
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    check(checkOptimality(digraph, length, suurballe.flowMap(), 
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                          suurballe.potentialMap()),
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          "Wrong potentials");
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    for (int i = 0; i < suurballe.pathNum(); ++i)
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      check(checkPath(digraph, suurballe.path(i), source, target),
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            "Wrong path");
142 142
  }
143 143

	
144
  // Finding 5 paths (only 3 can be found)
144
  // Find 5 paths (only 3 can be found)
145 145
  {
146 146
    Suurballe<ListDigraph> suurballe(digraph, length, source, target);
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    check(suurballe.run(5) == 3, "Wrong number of paths");
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    check(checkFlow(digraph, suurballe.flowMap(), source, target, 3),
149 149
          "The flow is not feasible");
150 150
    check(suurballe.totalLength() == 1040, "The flow is not optimal");
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    check(checkOptimality(digraph, length, suurballe.flowMap(), 
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                          suurballe.potentialMap()),
153 153
          "Wrong potentials");
154 154
    for (int i = 0; i < suurballe.pathNum(); ++i)
155 155
      check(checkPath(digraph, suurballe.path(i), source, target),
156 156
            "Wrong path");
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