1// Copyright Louis Dionne 2013
2
3// Use, modification and distribution is subject to the Boost Software
4// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy
5// at http://www.boost.org/LICENSE_1_0.txt)
6
7#ifndef BOOST_GRAPH_HAWICK_CIRCUITS_HPP
8#define BOOST_GRAPH_HAWICK_CIRCUITS_HPP
9
10#include <algorithm>
11#include <boost/assert.hpp>
12#include <boost/foreach.hpp>
13#include <boost/graph/graph_traits.hpp>
14#include <boost/graph/one_bit_color_map.hpp>
15#include <boost/graph/properties.hpp>
16#include <boost/move/utility.hpp>
17#include <boost/property_map/property_map.hpp>
18#include <boost/range/begin.hpp>
19#include <boost/range/end.hpp>
20#include <boost/range/iterator.hpp>
21#include <boost/tuple/tuple.hpp> // for boost::tie
22#include <boost/type_traits/remove_reference.hpp>
23#include <boost/utility/result_of.hpp>
24#include <set>
25#include <utility> // for std::pair
26#include <vector>
27
28namespace boost
29{
30namespace hawick_circuits_detail
31{
32 //! @internal Functor returning all the vertices adjacent to a vertex.
33 struct get_all_adjacent_vertices
34 {
35 template < typename Sig > struct result;
36
37 template < typename This, typename Vertex, typename Graph >
38 struct result< This(Vertex, Graph) >
39 {
40 private:
41 typedef typename remove_reference< Graph >::type RawGraph;
42 typedef graph_traits< RawGraph > Traits;
43 typedef typename Traits::adjacency_iterator AdjacencyIterator;
44
45 public:
46 typedef std::pair< AdjacencyIterator, AdjacencyIterator > type;
47 };
48
49 template < typename Vertex, typename Graph >
50 typename result< get_all_adjacent_vertices(
51 BOOST_FWD_REF(Vertex), BOOST_FWD_REF(Graph)) >::type
52 operator()(BOOST_FWD_REF(Vertex) v, BOOST_FWD_REF(Graph) g) const
53 {
54 return adjacent_vertices(
55 boost::forward< Vertex >(v), boost::forward< Graph >(g));
56 }
57 };
58
59 //! @internal Functor returning a set of the vertices adjacent to a vertex.
60 struct get_unique_adjacent_vertices
61 {
62 template < typename Sig > struct result;
63
64 template < typename This, typename Vertex, typename Graph >
65 struct result< This(Vertex, Graph) >
66 {
67 typedef std::set< typename remove_reference< Vertex >::type > type;
68 };
69
70 template < typename Vertex, typename Graph >
71 typename result< get_unique_adjacent_vertices(
72 Vertex, Graph const&) >::type
73 operator()(Vertex v, Graph const& g) const
74 {
75 typedef typename result< get_unique_adjacent_vertices(
76 Vertex, Graph const&) >::type Set;
77 return Set(
78 adjacent_vertices(v, g).first, adjacent_vertices(v, g).second);
79 }
80 };
81
82 //! @internal
83 //! Return whether a container contains a given value.
84 //! This is not meant as a general purpose membership testing function; it
85 //! would have to be more clever about possible optimizations.
86 template < typename Container, typename Value >
87 bool contains(Container const& c, Value const& v)
88 {
89 return std::find(boost::begin(c), boost::end(c), v) != boost::end(c);
90 }
91
92 /*!
93 * @internal
94 * Algorithm finding all the cycles starting from a given vertex.
95 *
96 * The search is only done in the subgraph induced by the starting vertex
97 * and the vertices with an index higher than the starting vertex.
98 */
99 template < typename Graph, typename Visitor, typename VertexIndexMap,
100 typename Stack, typename ClosedMatrix, typename GetAdjacentVertices >
101 struct hawick_circuits_from
102 {
103 private:
104 typedef graph_traits< Graph > Traits;
105 typedef typename Traits::vertex_descriptor Vertex;
106 typedef typename Traits::edge_descriptor Edge;
107 typedef typename Traits::vertices_size_type VerticesSize;
108 typedef
109 typename property_traits< VertexIndexMap >::value_type VertexIndex;
110
111 typedef typename result_of< GetAdjacentVertices(
112 Vertex, Graph const&) >::type AdjacentVertices;
113 typedef typename range_iterator< AdjacentVertices const >::type
114 AdjacencyIterator;
115
116 // The one_bit_color_map starts all white, i.e. not blocked.
117 // Since we make that assumption (I looked at the implementation, but
118 // I can't find anything that documents this behavior), we're gonna
119 // assert it in the constructor.
120 typedef one_bit_color_map< VertexIndexMap > BlockedMap;
121 typedef typename property_traits< BlockedMap >::value_type BlockedColor;
122
123 static BlockedColor blocked_false_color()
124 {
125 return color_traits< BlockedColor >::white();
126 }
127
128 static BlockedColor blocked_true_color()
129 {
130 return color_traits< BlockedColor >::black();
131 }
132
133 // This is used by the constructor to secure the assumption
134 // documented above.
135 bool blocked_map_starts_all_unblocked() const
136 {
137 BOOST_FOREACH (Vertex v, vertices(graph_))
138 if (is_blocked(v))
139 return false;
140 return true;
141 }
142
143 // This is only used in the constructor to make sure the optimization of
144 // sharing data structures between iterations does not break the code.
145 bool all_closed_rows_are_empty() const
146 {
147 BOOST_FOREACH (typename ClosedMatrix::reference row, closed_)
148 if (!row.empty())
149 return false;
150 return true;
151 }
152
153 public:
154 hawick_circuits_from(Graph const& graph, Visitor& visitor,
155 VertexIndexMap const& vim, Stack& stack, ClosedMatrix& closed,
156 VerticesSize n_vertices)
157 : graph_(graph)
158 , visitor_(visitor)
159 , vim_(vim)
160 , stack_(stack)
161 , closed_(closed)
162 , blocked_(n_vertices, vim_)
163 {
164 BOOST_ASSERT(blocked_map_starts_all_unblocked());
165
166 // Since sharing the data structures between iterations is
167 // just an optimization, it must always be equivalent to
168 // constructing new ones in this constructor.
169 BOOST_ASSERT(stack_.empty());
170 BOOST_ASSERT(closed_.size() == n_vertices);
171 BOOST_ASSERT(all_closed_rows_are_empty());
172 }
173
174 private:
175 //! @internal Return the index of a given vertex.
176 VertexIndex index_of(Vertex v) const { return get(vim_, v); }
177
178 //! @internal Return whether a vertex `v` is closed to a vertex `u`.
179 bool is_closed_to(Vertex u, Vertex v) const
180 {
181 typedef typename ClosedMatrix::const_reference VertexList;
182 VertexList closed_to_u = closed_[index_of(v: u)];
183 return contains(closed_to_u, v);
184 }
185
186 //! @internal Close a vertex `v` to a vertex `u`.
187 void close_to(Vertex u, Vertex v)
188 {
189 BOOST_ASSERT(!is_closed_to(u, v));
190 closed_[index_of(v: u)].push_back(v);
191 }
192
193 //! @internal Return whether a given vertex is blocked.
194 bool is_blocked(Vertex v) const
195 {
196 return get(blocked_, v) == blocked_true_color();
197 }
198
199 //! @internal Block a given vertex.
200 void block(Vertex v) { put(blocked_, v, blocked_true_color()); }
201
202 //! @internal Unblock a given vertex.
203 void unblock(Vertex u)
204 {
205 typedef typename ClosedMatrix::reference VertexList;
206
207 put(blocked_, u, blocked_false_color());
208 VertexList closed_to_u = closed_[index_of(v: u)];
209
210 while (!closed_to_u.empty())
211 {
212 Vertex const w = closed_to_u.back();
213 closed_to_u.pop_back();
214 if (is_blocked(v: w))
215 unblock(u: w);
216 }
217 BOOST_ASSERT(closed_to_u.empty());
218 }
219
220 //! @internal Main procedure as described in the paper.
221 bool circuit(Vertex start, Vertex v)
222 {
223 bool found_circuit = false;
224 stack_.push_back(v);
225 block(v);
226
227 // Cache some values that are used more than once in the function.
228 VertexIndex const index_of_start = index_of(v: start);
229 AdjacentVertices const adj_vertices
230 = GetAdjacentVertices()(v, graph_);
231 AdjacencyIterator const w_end = boost::end(adj_vertices);
232
233 for (AdjacencyIterator w_it = boost::begin(adj_vertices);
234 w_it != w_end; ++w_it)
235 {
236 Vertex const w = *w_it;
237 // Since we're only looking in the subgraph induced by `start`
238 // and the vertices with an index higher than `start`, we skip
239 // any vertex that does not satisfy that.
240 if (index_of(v: w) < index_of_start)
241 continue;
242
243 // If the last vertex is equal to `start`, we have a circuit.
244 else if (w == start)
245 {
246 // const_cast to ensure the visitor does not modify the
247 // stack
248 visitor_.cycle(const_cast< Stack const& >(stack_), graph_);
249 found_circuit = true;
250 }
251
252 // If `w` is not blocked, we continue searching further down the
253 // same path for a cycle with `w` in it.
254 else if (!is_blocked(v: w) && circuit(start, v: w))
255 found_circuit = true;
256 }
257
258 if (found_circuit)
259 unblock(u: v);
260 else
261 for (AdjacencyIterator w_it = boost::begin(adj_vertices);
262 w_it != w_end; ++w_it)
263 {
264 Vertex const w = *w_it;
265 // Like above, we skip vertices that are not in the subgraph
266 // we're considering.
267 if (index_of(v: w) < index_of_start)
268 continue;
269
270 // If `v` is not closed to `w`, we make it so.
271 if (!is_closed_to(u: w, v))
272 close_to(u: w, v);
273 }
274
275 BOOST_ASSERT(v == stack_.back());
276 stack_.pop_back();
277 return found_circuit;
278 }
279
280 public:
281 void operator()(Vertex start) { circuit(start, v: start); }
282
283 private:
284 Graph const& graph_;
285 Visitor& visitor_;
286 VertexIndexMap const& vim_;
287 Stack& stack_;
288 ClosedMatrix& closed_;
289 BlockedMap blocked_;
290 };
291
292 template < typename GetAdjacentVertices, typename Graph, typename Visitor,
293 typename VertexIndexMap >
294 void call_hawick_circuits(Graph const& graph,
295 Visitor /* by value */ visitor, VertexIndexMap const& vertex_index_map)
296 {
297 typedef graph_traits< Graph > Traits;
298 typedef typename Traits::vertex_descriptor Vertex;
299 typedef typename Traits::vertices_size_type VerticesSize;
300 typedef typename Traits::vertex_iterator VertexIterator;
301
302 typedef std::vector< Vertex > Stack;
303 typedef std::vector< std::vector< Vertex > > ClosedMatrix;
304
305 typedef hawick_circuits_from< Graph, Visitor, VertexIndexMap, Stack,
306 ClosedMatrix, GetAdjacentVertices >
307 SubAlgorithm;
308
309 VerticesSize const n_vertices = num_vertices(graph);
310 Stack stack;
311 stack.reserve(n_vertices);
312 ClosedMatrix closed(n_vertices);
313
314 VertexIterator start, last;
315 for (boost::tie(start, last) = vertices(graph); start != last; ++start)
316 {
317 // Note1: The sub algorithm may NOT be reused once it has been
318 // called.
319
320 // Note2: We reuse the Stack and the ClosedMatrix (after clearing
321 // them) in each iteration to avoid redundant destruction and
322 // construction. It would be strictly equivalent to have these as
323 // member variables of the sub algorithm.
324 SubAlgorithm sub_algo(
325 graph, visitor, vertex_index_map, stack, closed, n_vertices);
326 sub_algo(*start);
327 stack.clear();
328 typename ClosedMatrix::iterator row, last_row = closed.end();
329 for (row = closed.begin(); row != last_row; ++row)
330 row->clear();
331 }
332 }
333
334 template < typename GetAdjacentVertices, typename Graph, typename Visitor >
335 void call_hawick_circuits(
336 Graph const& graph, BOOST_FWD_REF(Visitor) visitor)
337 {
338 call_hawick_circuits< GetAdjacentVertices >(graph,
339 boost::forward< Visitor >(visitor), get(vertex_index, graph));
340 }
341} // end namespace hawick_circuits_detail
342
343//! Enumerate all the elementary circuits in a directed multigraph.
344template < typename Graph, typename Visitor, typename VertexIndexMap >
345void hawick_circuits(BOOST_FWD_REF(Graph) graph, BOOST_FWD_REF(Visitor) visitor,
346 BOOST_FWD_REF(VertexIndexMap) vertex_index_map)
347{
348 hawick_circuits_detail::call_hawick_circuits<
349 hawick_circuits_detail::get_all_adjacent_vertices >(
350 boost::forward< Graph >(graph), boost::forward< Visitor >(visitor),
351 boost::forward< VertexIndexMap >(vertex_index_map));
352}
353
354template < typename Graph, typename Visitor >
355void hawick_circuits(BOOST_FWD_REF(Graph) graph, BOOST_FWD_REF(Visitor) visitor)
356{
357 hawick_circuits_detail::call_hawick_circuits<
358 hawick_circuits_detail::get_all_adjacent_vertices >(
359 boost::forward< Graph >(graph), boost::forward< Visitor >(visitor));
360}
361
362/*!
363 * Same as `boost::hawick_circuits`, but duplicate circuits caused by parallel
364 * edges will not be considered. Each circuit will be considered only once.
365 */
366template < typename Graph, typename Visitor, typename VertexIndexMap >
367void hawick_unique_circuits(BOOST_FWD_REF(Graph) graph,
368 BOOST_FWD_REF(Visitor) visitor,
369 BOOST_FWD_REF(VertexIndexMap) vertex_index_map)
370{
371 hawick_circuits_detail::call_hawick_circuits<
372 hawick_circuits_detail::get_unique_adjacent_vertices >(
373 boost::forward< Graph >(graph), boost::forward< Visitor >(visitor),
374 boost::forward< VertexIndexMap >(vertex_index_map));
375}
376
377template < typename Graph, typename Visitor >
378void hawick_unique_circuits(
379 BOOST_FWD_REF(Graph) graph, BOOST_FWD_REF(Visitor) visitor)
380{
381 hawick_circuits_detail::call_hawick_circuits<
382 hawick_circuits_detail::get_unique_adjacent_vertices >(
383 boost::forward< Graph >(graph), boost::forward< Visitor >(visitor));
384}
385} // end namespace boost
386
387#endif // !BOOST_GRAPH_HAWICK_CIRCUITS_HPP
388

source code of boost/libs/graph/include/boost/graph/hawick_circuits.hpp