| 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 |
|
#ifndef LEMON_MIN_MEAN_CYCLE_H
|
| 20 |
|
#define LEMON_MIN_MEAN_CYCLE_H
|
|
19 |
#ifndef LEMON_HOWARD_H
|
|
20 |
#define LEMON_HOWARD_H
|
| 21 |
21 |
|
| 22 |
22 |
/// \ingroup shortest_path
|
| 23 |
23 |
///
|
| 24 |
24 |
/// \file
|
| 25 |
25 |
/// \brief Howard's algorithm for finding a minimum mean cycle.
|
| 26 |
26 |
|
| 27 |
27 |
#include <vector>
|
| 28 |
28 |
#include <limits>
|
| 29 |
29 |
#include <lemon/core.h>
|
| 30 |
30 |
#include <lemon/path.h>
|
| 31 |
31 |
#include <lemon/tolerance.h>
|
| 32 |
32 |
#include <lemon/connectivity.h>
|
| 33 |
33 |
|
| 34 |
34 |
namespace lemon {
|
| 35 |
35 |
|
| 36 |
|
/// \brief Default traits class of MinMeanCycle class.
|
|
36 |
/// \brief Default traits class of Howard class.
|
| 37 |
37 |
///
|
| 38 |
|
/// Default traits class of MinMeanCycle class.
|
|
38 |
/// Default traits class of Howard class.
|
| 39 |
39 |
/// \tparam GR The type of the digraph.
|
| 40 |
40 |
/// \tparam LEN The type of the length map.
|
| 41 |
41 |
/// It must conform to the \ref concepts::ReadMap "ReadMap" concept.
|
| 42 |
42 |
#ifdef DOXYGEN
|
| 43 |
43 |
template <typename GR, typename LEN>
|
| 44 |
44 |
#else
|
| 45 |
45 |
template <typename GR, typename LEN,
|
| 46 |
46 |
bool integer = std::numeric_limits<typename LEN::Value>::is_integer>
|
| 47 |
47 |
#endif
|
| 48 |
|
struct MinMeanCycleDefaultTraits
|
|
48 |
struct HowardDefaultTraits
|
| 49 |
49 |
{
|
| 50 |
50 |
/// The type of the digraph
|
| 51 |
51 |
typedef GR Digraph;
|
| 52 |
52 |
/// The type of the length map
|
| 53 |
53 |
typedef LEN LengthMap;
|
| 54 |
54 |
/// The type of the arc lengths
|
| 55 |
55 |
typedef typename LengthMap::Value Value;
|
| 56 |
56 |
|
| 57 |
57 |
/// \brief The large value type used for internal computations
|
| 58 |
58 |
///
|
| 59 |
59 |
/// The large value type used for internal computations.
|
| 60 |
60 |
/// It is \c long \c long if the \c Value type is integer,
|
| 61 |
61 |
/// otherwise it is \c double.
|
| 62 |
62 |
/// \c Value must be convertible to \c LargeValue.
|
| 63 |
63 |
typedef double LargeValue;
|
| 64 |
64 |
|
| 65 |
65 |
/// The tolerance type used for internal computations
|
| 66 |
66 |
typedef lemon::Tolerance<LargeValue> Tolerance;
|
| 67 |
67 |
|
| 68 |
68 |
/// \brief The path type of the found cycles
|
| 69 |
69 |
///
|
| 70 |
70 |
/// The path type of the found cycles.
|
| 71 |
71 |
/// It must conform to the \ref lemon::concepts::Path "Path" concept
|
| 72 |
72 |
/// and it must have an \c addBack() function.
|
| 73 |
73 |
typedef lemon::Path<Digraph> Path;
|
| 74 |
74 |
};
|
| 75 |
75 |
|
| 76 |
76 |
// Default traits class for integer value types
|
| 77 |
77 |
template <typename GR, typename LEN>
|
| 78 |
|
struct MinMeanCycleDefaultTraits<GR, LEN, true>
|
|
78 |
struct HowardDefaultTraits<GR, LEN, true>
|
| 79 |
79 |
{
|
| 80 |
80 |
typedef GR Digraph;
|
| 81 |
81 |
typedef LEN LengthMap;
|
| 82 |
82 |
typedef typename LengthMap::Value Value;
|
| 83 |
83 |
#ifdef LEMON_HAVE_LONG_LONG
|
| 84 |
84 |
typedef long long LargeValue;
|
| 85 |
85 |
#else
|
| 86 |
86 |
typedef long LargeValue;
|
| 87 |
87 |
#endif
|
| 88 |
88 |
typedef lemon::Tolerance<LargeValue> Tolerance;
|
| 89 |
89 |
typedef lemon::Path<Digraph> Path;
|
| 90 |
90 |
};
|
| 91 |
91 |
|
| 92 |
92 |
|
| 93 |
93 |
/// \addtogroup shortest_path
|
| 94 |
94 |
/// @{
|
| 95 |
95 |
|
| 96 |
96 |
/// \brief Implementation of Howard's algorithm for finding a minimum
|
| 97 |
97 |
/// mean cycle.
|
| 98 |
98 |
///
|
| 99 |
|
/// \ref MinMeanCycle implements Howard's algorithm for finding a
|
| 100 |
|
/// directed cycle of minimum mean length (cost) in a digraph.
|
|
99 |
/// This class implements Howard's policy iteration algorithm for finding
|
|
100 |
/// a directed cycle of minimum mean length (cost) in a digraph.
|
| 101 |
101 |
///
|
| 102 |
102 |
/// \tparam GR The type of the digraph the algorithm runs on.
|
| 103 |
103 |
/// \tparam LEN The type of the length map. The default
|
| 104 |
104 |
/// map type is \ref concepts::Digraph::ArcMap "GR::ArcMap<int>".
|
| 105 |
105 |
#ifdef DOXYGEN
|
| 106 |
106 |
template <typename GR, typename LEN, typename TR>
|
| 107 |
107 |
#else
|
| 108 |
108 |
template < typename GR,
|
| 109 |
109 |
typename LEN = typename GR::template ArcMap<int>,
|
| 110 |
|
typename TR = MinMeanCycleDefaultTraits<GR, LEN> >
|
|
110 |
typename TR = HowardDefaultTraits<GR, LEN> >
|
| 111 |
111 |
#endif
|
| 112 |
|
class MinMeanCycle
|
|
112 |
class Howard
|
| 113 |
113 |
{
|
| 114 |
114 |
public:
|
| 115 |
115 |
|
| 116 |
116 |
/// The type of the digraph
|
| 117 |
117 |
typedef typename TR::Digraph Digraph;
|
| 118 |
118 |
/// The type of the length map
|
| 119 |
119 |
typedef typename TR::LengthMap LengthMap;
|
| 120 |
120 |
/// The type of the arc lengths
|
| 121 |
121 |
typedef typename TR::Value Value;
|
| 122 |
122 |
|
| 123 |
123 |
/// \brief The large value type
|
| 124 |
124 |
///
|
| 125 |
125 |
/// The large value type used for internal computations.
|
| 126 |
|
/// Using the \ref MinMeanCycleDefaultTraits "default traits class",
|
|
126 |
/// Using the \ref HowardDefaultTraits "default traits class",
|
| 127 |
127 |
/// it is \c long \c long if the \c Value type is integer,
|
| 128 |
128 |
/// otherwise it is \c double.
|
| 129 |
129 |
typedef typename TR::LargeValue LargeValue;
|
| 130 |
130 |
|
| 131 |
131 |
/// The tolerance type
|
| 132 |
132 |
typedef typename TR::Tolerance Tolerance;
|
| 133 |
133 |
|
| 134 |
134 |
/// \brief The path type of the found cycles
|
| 135 |
135 |
///
|
| 136 |
136 |
/// The path type of the found cycles.
|
| 137 |
|
/// Using the \ref MinMeanCycleDefaultTraits "default traits class",
|
|
137 |
/// Using the \ref HowardDefaultTraits "default traits class",
|
| 138 |
138 |
/// it is \ref lemon::Path "Path<Digraph>".
|
| 139 |
139 |
typedef typename TR::Path Path;
|
| 140 |
140 |
|
| 141 |
|
/// The \ref MinMeanCycleDefaultTraits "traits class" of the algorithm
|
|
141 |
/// The \ref HowardDefaultTraits "traits class" of the algorithm
|
| 142 |
142 |
typedef TR Traits;
|
| 143 |
143 |
|
| 144 |
144 |
private:
|
| 145 |
145 |
|
| 146 |
146 |
TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
|
| 147 |
147 |
|
| 148 |
148 |
// The digraph the algorithm runs on
|
| 149 |
149 |
const Digraph &_gr;
|
| 150 |
150 |
// The length of the arcs
|
| 151 |
151 |
const LengthMap &_length;
|
| 152 |
152 |
|
| 153 |
153 |
// Data for the found cycles
|
| 154 |
154 |
bool _curr_found, _best_found;
|
| 155 |
155 |
LargeValue _curr_length, _best_length;
|
| 156 |
156 |
int _curr_size, _best_size;
|
| 157 |
157 |
Node _curr_node, _best_node;
|
| 158 |
158 |
|
| 159 |
159 |
Path *_cycle_path;
|
| 160 |
160 |
bool _local_path;
|
| 161 |
161 |
|
| 162 |
162 |
// Internal data used by the algorithm
|
| 163 |
163 |
typename Digraph::template NodeMap<Arc> _policy;
|
| 164 |
164 |
typename Digraph::template NodeMap<bool> _reached;
|
| 165 |
165 |
typename Digraph::template NodeMap<int> _level;
|
| ... |
... |
@@ -175,107 +175,107 @@
|
| 175 |
175 |
// Queue used for BFS search
|
| 176 |
176 |
std::vector<Node> _queue;
|
| 177 |
177 |
int _qfront, _qback;
|
| 178 |
178 |
|
| 179 |
179 |
Tolerance _tolerance;
|
| 180 |
180 |
|
| 181 |
181 |
public:
|
| 182 |
182 |
|
| 183 |
183 |
/// \name Named Template Parameters
|
| 184 |
184 |
/// @{
|
| 185 |
185 |
|
| 186 |
186 |
template <typename T>
|
| 187 |
187 |
struct SetLargeValueTraits : public Traits {
|
| 188 |
188 |
typedef T LargeValue;
|
| 189 |
189 |
typedef lemon::Tolerance<T> Tolerance;
|
| 190 |
190 |
};
|
| 191 |
191 |
|
| 192 |
192 |
/// \brief \ref named-templ-param "Named parameter" for setting
|
| 193 |
193 |
/// \c LargeValue type.
|
| 194 |
194 |
///
|
| 195 |
195 |
/// \ref named-templ-param "Named parameter" for setting \c LargeValue
|
| 196 |
196 |
/// type. It is used for internal computations in the algorithm.
|
| 197 |
197 |
template <typename T>
|
| 198 |
198 |
struct SetLargeValue
|
| 199 |
|
: public MinMeanCycle<GR, LEN, SetLargeValueTraits<T> > {
|
| 200 |
|
typedef MinMeanCycle<GR, LEN, SetLargeValueTraits<T> > Create;
|
|
199 |
: public Howard<GR, LEN, SetLargeValueTraits<T> > {
|
|
200 |
typedef Howard<GR, LEN, SetLargeValueTraits<T> > Create;
|
| 201 |
201 |
};
|
| 202 |
202 |
|
| 203 |
203 |
template <typename T>
|
| 204 |
204 |
struct SetPathTraits : public Traits {
|
| 205 |
205 |
typedef T Path;
|
| 206 |
206 |
};
|
| 207 |
207 |
|
| 208 |
208 |
/// \brief \ref named-templ-param "Named parameter" for setting
|
| 209 |
209 |
/// \c %Path type.
|
| 210 |
210 |
///
|
| 211 |
211 |
/// \ref named-templ-param "Named parameter" for setting the \c %Path
|
| 212 |
212 |
/// type of the found cycles.
|
| 213 |
213 |
/// It must conform to the \ref lemon::concepts::Path "Path" concept
|
| 214 |
214 |
/// and it must have an \c addBack() function.
|
| 215 |
215 |
template <typename T>
|
| 216 |
216 |
struct SetPath
|
| 217 |
|
: public MinMeanCycle<GR, LEN, SetPathTraits<T> > {
|
| 218 |
|
typedef MinMeanCycle<GR, LEN, SetPathTraits<T> > Create;
|
|
217 |
: public Howard<GR, LEN, SetPathTraits<T> > {
|
|
218 |
typedef Howard<GR, LEN, SetPathTraits<T> > Create;
|
| 219 |
219 |
};
|
| 220 |
220 |
|
| 221 |
221 |
/// @}
|
| 222 |
222 |
|
| 223 |
223 |
public:
|
| 224 |
224 |
|
| 225 |
225 |
/// \brief Constructor.
|
| 226 |
226 |
///
|
| 227 |
227 |
/// The constructor of the class.
|
| 228 |
228 |
///
|
| 229 |
229 |
/// \param digraph The digraph the algorithm runs on.
|
| 230 |
230 |
/// \param length The lengths (costs) of the arcs.
|
| 231 |
|
MinMeanCycle( const Digraph &digraph,
|
| 232 |
|
const LengthMap &length ) :
|
|
231 |
Howard( const Digraph &digraph,
|
|
232 |
const LengthMap &length ) :
|
| 233 |
233 |
_gr(digraph), _length(length), _cycle_path(NULL), _local_path(false),
|
| 234 |
234 |
_policy(digraph), _reached(digraph), _level(digraph), _dist(digraph),
|
| 235 |
235 |
_comp(digraph), _in_arcs(digraph)
|
| 236 |
236 |
{}
|
| 237 |
237 |
|
| 238 |
238 |
/// Destructor.
|
| 239 |
|
~MinMeanCycle() {
|
|
239 |
~Howard() {
|
| 240 |
240 |
if (_local_path) delete _cycle_path;
|
| 241 |
241 |
}
|
| 242 |
242 |
|
| 243 |
243 |
/// \brief Set the path structure for storing the found cycle.
|
| 244 |
244 |
///
|
| 245 |
245 |
/// This function sets an external path structure for storing the
|
| 246 |
246 |
/// found cycle.
|
| 247 |
247 |
///
|
| 248 |
248 |
/// If you don't call this function before calling \ref run() or
|
| 249 |
249 |
/// \ref findMinMean(), it will allocate a local \ref Path "path"
|
| 250 |
250 |
/// structure. The destuctor deallocates this automatically
|
| 251 |
251 |
/// allocated object, of course.
|
| 252 |
252 |
///
|
| 253 |
253 |
/// \note The algorithm calls only the \ref lemon::Path::addBack()
|
| 254 |
254 |
/// "addBack()" function of the given path structure.
|
| 255 |
255 |
///
|
| 256 |
256 |
/// \return <tt>(*this)</tt>
|
| 257 |
|
MinMeanCycle& cycle(Path &path) {
|
|
257 |
Howard& cycle(Path &path) {
|
| 258 |
258 |
if (_local_path) {
|
| 259 |
259 |
delete _cycle_path;
|
| 260 |
260 |
_local_path = false;
|
| 261 |
261 |
}
|
| 262 |
262 |
_cycle_path = &path;
|
| 263 |
263 |
return *this;
|
| 264 |
264 |
}
|
| 265 |
265 |
|
| 266 |
266 |
/// \name Execution control
|
| 267 |
267 |
/// The simplest way to execute the algorithm is to call the \ref run()
|
| 268 |
268 |
/// function.\n
|
| 269 |
269 |
/// If you only need the minimum mean length, you may call
|
| 270 |
270 |
/// \ref findMinMean().
|
| 271 |
271 |
|
| 272 |
272 |
/// @{
|
| 273 |
273 |
|
| 274 |
274 |
/// \brief Run the algorithm.
|
| 275 |
275 |
///
|
| 276 |
276 |
/// This function runs the algorithm.
|
| 277 |
277 |
/// It can be called more than once (e.g. if the underlying digraph
|
| 278 |
278 |
/// and/or the arc lengths have been modified).
|
| 279 |
279 |
///
|
| 280 |
280 |
/// \return \c true if a directed cycle exists in the digraph.
|
| 281 |
281 |
///
|
| ... |
... |
@@ -538,31 +538,31 @@
|
| 538 |
538 |
_dist[u] = _dist[v] + _length[e] * _curr_size - _curr_length;
|
| 539 |
539 |
_queue[++_qback] = u;
|
| 540 |
540 |
}
|
| 541 |
541 |
}
|
| 542 |
542 |
}
|
| 543 |
543 |
|
| 544 |
544 |
// Improve node distances
|
| 545 |
545 |
bool improved = false;
|
| 546 |
546 |
for (int i = 0; i < int(_nodes->size()); ++i) {
|
| 547 |
547 |
v = (*_nodes)[i];
|
| 548 |
548 |
for (int j = 0; j < int(_in_arcs[v].size()); ++j) {
|
| 549 |
549 |
e = _in_arcs[v][j];
|
| 550 |
550 |
u = _gr.source(e);
|
| 551 |
551 |
LargeValue delta = _dist[v] + _length[e] * _curr_size - _curr_length;
|
| 552 |
552 |
if (_tolerance.less(delta, _dist[u])) {
|
| 553 |
553 |
_dist[u] = delta;
|
| 554 |
554 |
_policy[u] = e;
|
| 555 |
555 |
improved = true;
|
| 556 |
556 |
}
|
| 557 |
557 |
}
|
| 558 |
558 |
}
|
| 559 |
559 |
return improved;
|
| 560 |
560 |
}
|
| 561 |
561 |
|
| 562 |
|
}; //class MinMeanCycle
|
|
562 |
}; //class Howard
|
| 563 |
563 |
|
| 564 |
564 |
///@}
|
| 565 |
565 |
|
| 566 |
566 |
} //namespace lemon
|
| 567 |
567 |
|
| 568 |
|
#endif //LEMON_MIN_MEAN_CYCLE_H
|
|
568 |
#endif //LEMON_HOWARD_H
|