1 | // |
2 | //======================================================================= |
3 | // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. |
4 | // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek |
5 | // |
6 | // Distributed under the Boost Software License, Version 1.0. (See |
7 | // accompanying file LICENSE_1_0.txt or copy at |
8 | // http://www.boost.org/LICENSE_1_0.txt) |
9 | //======================================================================= |
10 | // |
11 | #ifndef BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP |
12 | #define BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP |
13 | |
14 | /* |
15 | Breadth First Search Algorithm (Cormen, Leiserson, and Rivest p. 470) |
16 | */ |
17 | #include <boost/config.hpp> |
18 | #include <vector> |
19 | #include <boost/pending/queue.hpp> |
20 | #include <boost/graph/graph_traits.hpp> |
21 | #include <boost/graph/graph_concepts.hpp> |
22 | #include <boost/graph/visitors.hpp> |
23 | #include <boost/graph/named_function_params.hpp> |
24 | #include <boost/graph/overloading.hpp> |
25 | #include <boost/graph/graph_concepts.hpp> |
26 | #include <boost/graph/two_bit_color_map.hpp> |
27 | #include <boost/concept/assert.hpp> |
28 | |
29 | #ifdef BOOST_GRAPH_USE_MPI |
30 | #include <boost/graph/distributed/concepts.hpp> |
31 | #endif // BOOST_GRAPH_USE_MPI |
32 | |
33 | namespace boost { |
34 | |
35 | template <class Visitor, class Graph> |
36 | struct BFSVisitorConcept { |
37 | void constraints() { |
38 | BOOST_CONCEPT_ASSERT(( CopyConstructibleConcept<Visitor> )); |
39 | vis.initialize_vertex(u, g); |
40 | vis.discover_vertex(u, g); |
41 | vis.examine_vertex(u, g); |
42 | vis.examine_edge(e, g); |
43 | vis.tree_edge(e, g); |
44 | vis.non_tree_edge(e, g); |
45 | vis.gray_target(e, g); |
46 | vis.black_target(e, g); |
47 | vis.finish_vertex(u, g); |
48 | } |
49 | Visitor vis; |
50 | Graph g; |
51 | typename graph_traits<Graph>::vertex_descriptor u; |
52 | typename graph_traits<Graph>::edge_descriptor e; |
53 | }; |
54 | |
55 | |
56 | // Multiple-source version |
57 | template <class IncidenceGraph, class Buffer, class BFSVisitor, |
58 | class ColorMap, class SourceIterator> |
59 | void breadth_first_visit |
60 | (const IncidenceGraph& g, |
61 | SourceIterator sources_begin, SourceIterator sources_end, |
62 | Buffer& Q, BFSVisitor vis, ColorMap color) |
63 | { |
64 | BOOST_CONCEPT_ASSERT(( IncidenceGraphConcept<IncidenceGraph> )); |
65 | typedef graph_traits<IncidenceGraph> GTraits; |
66 | typedef typename GTraits::vertex_descriptor Vertex; |
67 | BOOST_CONCEPT_ASSERT(( BFSVisitorConcept<BFSVisitor, IncidenceGraph> )); |
68 | BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<ColorMap, Vertex> )); |
69 | typedef typename property_traits<ColorMap>::value_type ColorValue; |
70 | typedef color_traits<ColorValue> Color; |
71 | typename GTraits::out_edge_iterator ei, ei_end; |
72 | |
73 | for (; sources_begin != sources_end; ++sources_begin) { |
74 | Vertex s = *sources_begin; |
75 | put(color, s, Color::gray()); vis.discover_vertex(s, g); |
76 | Q.push(s); |
77 | } |
78 | while (! Q.empty()) { |
79 | Vertex u = Q.top(); Q.pop(); vis.examine_vertex(u, g); |
80 | for (boost::tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) { |
81 | Vertex v = target(*ei, g); vis.examine_edge(*ei, g); |
82 | ColorValue v_color = get(color, v); |
83 | if (v_color == Color::white()) { vis.tree_edge(*ei, g); |
84 | put(color, v, Color::gray()); vis.discover_vertex(v, g); |
85 | Q.push(v); |
86 | } else { vis.non_tree_edge(*ei, g); |
87 | if (v_color == Color::gray()) vis.gray_target(*ei, g); |
88 | else vis.black_target(*ei, g); |
89 | } |
90 | } // end for |
91 | put(color, u, Color::black()); vis.finish_vertex(u, g); |
92 | } // end while |
93 | } // breadth_first_visit |
94 | |
95 | // Single-source version |
96 | template <class IncidenceGraph, class Buffer, class BFSVisitor, |
97 | class ColorMap> |
98 | void breadth_first_visit |
99 | (const IncidenceGraph& g, |
100 | typename graph_traits<IncidenceGraph>::vertex_descriptor s, |
101 | Buffer& Q, BFSVisitor vis, ColorMap color) |
102 | { |
103 | typename graph_traits<IncidenceGraph>::vertex_descriptor sources[1] = {s}; |
104 | breadth_first_visit(g, sources, sources + 1, Q, vis, color); |
105 | } |
106 | |
107 | |
108 | template <class VertexListGraph, class SourceIterator, |
109 | class Buffer, class BFSVisitor, |
110 | class ColorMap> |
111 | void breadth_first_search |
112 | (const VertexListGraph& g, |
113 | SourceIterator sources_begin, SourceIterator sources_end, |
114 | Buffer& Q, BFSVisitor vis, ColorMap color) |
115 | { |
116 | // Initialization |
117 | typedef typename property_traits<ColorMap>::value_type ColorValue; |
118 | typedef color_traits<ColorValue> Color; |
119 | typename boost::graph_traits<VertexListGraph>::vertex_iterator i, i_end; |
120 | for (boost::tie(i, i_end) = vertices(g); i != i_end; ++i) { |
121 | vis.initialize_vertex(*i, g); |
122 | put(color, *i, Color::white()); |
123 | } |
124 | breadth_first_visit(g, sources_begin, sources_end, Q, vis, color); |
125 | } |
126 | |
127 | template <class VertexListGraph, class Buffer, class BFSVisitor, |
128 | class ColorMap> |
129 | void breadth_first_search |
130 | (const VertexListGraph& g, |
131 | typename graph_traits<VertexListGraph>::vertex_descriptor s, |
132 | Buffer& Q, BFSVisitor vis, ColorMap color) |
133 | { |
134 | typename graph_traits<VertexListGraph>::vertex_descriptor sources[1] = {s}; |
135 | breadth_first_search(g, sources, sources + 1, Q, vis, color); |
136 | } |
137 | |
138 | namespace graph { struct bfs_visitor_event_not_overridden {}; } |
139 | |
140 | |
141 | template <class Visitors = null_visitor> |
142 | class bfs_visitor { |
143 | public: |
144 | bfs_visitor() { } |
145 | bfs_visitor(Visitors vis) : m_vis(vis) { } |
146 | |
147 | template <class Vertex, class Graph> |
148 | graph::bfs_visitor_event_not_overridden |
149 | initialize_vertex(Vertex u, Graph& g) |
150 | { |
151 | invoke_visitors(m_vis, u, g, ::boost::on_initialize_vertex()); |
152 | return graph::bfs_visitor_event_not_overridden(); |
153 | } |
154 | |
155 | template <class Vertex, class Graph> |
156 | graph::bfs_visitor_event_not_overridden |
157 | discover_vertex(Vertex u, Graph& g) |
158 | { |
159 | invoke_visitors(m_vis, u, g, ::boost::on_discover_vertex()); |
160 | return graph::bfs_visitor_event_not_overridden(); |
161 | } |
162 | |
163 | template <class Vertex, class Graph> |
164 | graph::bfs_visitor_event_not_overridden |
165 | examine_vertex(Vertex u, Graph& g) |
166 | { |
167 | invoke_visitors(m_vis, u, g, ::boost::on_examine_vertex()); |
168 | return graph::bfs_visitor_event_not_overridden(); |
169 | } |
170 | |
171 | template <class Edge, class Graph> |
172 | graph::bfs_visitor_event_not_overridden |
173 | examine_edge(Edge e, Graph& g) |
174 | { |
175 | invoke_visitors(m_vis, e, g, ::boost::on_examine_edge()); |
176 | return graph::bfs_visitor_event_not_overridden(); |
177 | } |
178 | |
179 | template <class Edge, class Graph> |
180 | graph::bfs_visitor_event_not_overridden |
181 | tree_edge(Edge e, Graph& g) |
182 | { |
183 | invoke_visitors(m_vis, e, g, ::boost::on_tree_edge()); |
184 | return graph::bfs_visitor_event_not_overridden(); |
185 | } |
186 | |
187 | template <class Edge, class Graph> |
188 | graph::bfs_visitor_event_not_overridden |
189 | non_tree_edge(Edge e, Graph& g) |
190 | { |
191 | invoke_visitors(m_vis, e, g, ::boost::on_non_tree_edge()); |
192 | return graph::bfs_visitor_event_not_overridden(); |
193 | } |
194 | |
195 | template <class Edge, class Graph> |
196 | graph::bfs_visitor_event_not_overridden |
197 | gray_target(Edge e, Graph& g) |
198 | { |
199 | invoke_visitors(m_vis, e, g, ::boost::on_gray_target()); |
200 | return graph::bfs_visitor_event_not_overridden(); |
201 | } |
202 | |
203 | template <class Edge, class Graph> |
204 | graph::bfs_visitor_event_not_overridden |
205 | black_target(Edge e, Graph& g) |
206 | { |
207 | invoke_visitors(m_vis, e, g, ::boost::on_black_target()); |
208 | return graph::bfs_visitor_event_not_overridden(); |
209 | } |
210 | |
211 | template <class Vertex, class Graph> |
212 | graph::bfs_visitor_event_not_overridden |
213 | finish_vertex(Vertex u, Graph& g) |
214 | { |
215 | invoke_visitors(m_vis, u, g, ::boost::on_finish_vertex()); |
216 | return graph::bfs_visitor_event_not_overridden(); |
217 | } |
218 | |
219 | BOOST_GRAPH_EVENT_STUB(on_initialize_vertex,bfs) |
220 | BOOST_GRAPH_EVENT_STUB(on_discover_vertex,bfs) |
221 | BOOST_GRAPH_EVENT_STUB(on_examine_vertex,bfs) |
222 | BOOST_GRAPH_EVENT_STUB(on_examine_edge,bfs) |
223 | BOOST_GRAPH_EVENT_STUB(on_tree_edge,bfs) |
224 | BOOST_GRAPH_EVENT_STUB(on_non_tree_edge,bfs) |
225 | BOOST_GRAPH_EVENT_STUB(on_gray_target,bfs) |
226 | BOOST_GRAPH_EVENT_STUB(on_black_target,bfs) |
227 | BOOST_GRAPH_EVENT_STUB(on_finish_vertex,bfs) |
228 | |
229 | protected: |
230 | Visitors m_vis; |
231 | }; |
232 | template <class Visitors> |
233 | bfs_visitor<Visitors> |
234 | make_bfs_visitor(Visitors vis) { |
235 | return bfs_visitor<Visitors>(vis); |
236 | } |
237 | typedef bfs_visitor<> default_bfs_visitor; |
238 | |
239 | |
240 | namespace detail { |
241 | |
242 | template <class VertexListGraph, class ColorMap, class BFSVisitor, |
243 | class P, class T, class R> |
244 | void bfs_helper |
245 | (VertexListGraph& g, |
246 | typename graph_traits<VertexListGraph>::vertex_descriptor s, |
247 | ColorMap color, |
248 | BFSVisitor vis, |
249 | const bgl_named_params<P, T, R>& params, |
250 | boost::mpl::false_) |
251 | { |
252 | typedef graph_traits<VertexListGraph> Traits; |
253 | // Buffer default |
254 | typedef typename Traits::vertex_descriptor Vertex; |
255 | typedef boost::queue<Vertex> queue_t; |
256 | queue_t Q; |
257 | breadth_first_search |
258 | (g, s, |
259 | choose_param(get_param(params, buffer_param_t()), boost::ref(Q)).get(), |
260 | vis, color); |
261 | } |
262 | |
263 | #ifdef BOOST_GRAPH_USE_MPI |
264 | template <class DistributedGraph, class ColorMap, class BFSVisitor, |
265 | class P, class T, class R> |
266 | void bfs_helper |
267 | (DistributedGraph& g, |
268 | typename graph_traits<DistributedGraph>::vertex_descriptor s, |
269 | ColorMap color, |
270 | BFSVisitor vis, |
271 | const bgl_named_params<P, T, R>& params, |
272 | boost::mpl::true_); |
273 | #endif // BOOST_GRAPH_USE_MPI |
274 | |
275 | //------------------------------------------------------------------------- |
276 | // Choose between default color and color parameters. Using |
277 | // function dispatching so that we don't require vertex index if |
278 | // the color default is not being used. |
279 | |
280 | template <class ColorMap> |
281 | struct bfs_dispatch { |
282 | template <class VertexListGraph, class P, class T, class R> |
283 | static void apply |
284 | (VertexListGraph& g, |
285 | typename graph_traits<VertexListGraph>::vertex_descriptor s, |
286 | const bgl_named_params<P, T, R>& params, |
287 | ColorMap color) |
288 | { |
289 | bfs_helper |
290 | (g, s, color, |
291 | choose_param(get_param(params, graph_visitor), |
292 | make_bfs_visitor(vis: null_visitor())), |
293 | params, |
294 | boost::mpl::bool_< |
295 | boost::is_base_and_derived< |
296 | distributed_graph_tag, |
297 | typename graph_traits<VertexListGraph>::traversal_category>::value>()); |
298 | } |
299 | }; |
300 | |
301 | template <> |
302 | struct bfs_dispatch<param_not_found> { |
303 | template <class VertexListGraph, class P, class T, class R> |
304 | static void apply |
305 | (VertexListGraph& g, |
306 | typename graph_traits<VertexListGraph>::vertex_descriptor s, |
307 | const bgl_named_params<P, T, R>& params, |
308 | param_not_found) |
309 | { |
310 | null_visitor null_vis; |
311 | |
312 | bfs_helper |
313 | (g, s, |
314 | make_two_bit_color_map |
315 | (num_vertices(g), |
316 | choose_const_pmap(get_param(params, vertex_index), |
317 | g, vertex_index)), |
318 | choose_param(get_param(params, graph_visitor), |
319 | make_bfs_visitor(vis: null_vis)), |
320 | params, |
321 | boost::mpl::bool_< |
322 | boost::is_base_and_derived< |
323 | distributed_graph_tag, |
324 | typename graph_traits<VertexListGraph>::traversal_category>::value>()); |
325 | } |
326 | }; |
327 | |
328 | } // namespace detail |
329 | |
330 | #if 1 |
331 | // Named Parameter Variant |
332 | template <class VertexListGraph, class P, class T, class R> |
333 | void breadth_first_search |
334 | (const VertexListGraph& g, |
335 | typename graph_traits<VertexListGraph>::vertex_descriptor s, |
336 | const bgl_named_params<P, T, R>& params) |
337 | { |
338 | // The graph is passed by *const* reference so that graph adaptors |
339 | // (temporaries) can be passed into this function. However, the |
340 | // graph is not really const since we may write to property maps |
341 | // of the graph. |
342 | VertexListGraph& ng = const_cast<VertexListGraph&>(g); |
343 | typedef typename get_param_type< vertex_color_t, bgl_named_params<P,T,R> >::type C; |
344 | detail::bfs_dispatch<C>::apply(ng, s, params, |
345 | get_param(params, vertex_color)); |
346 | } |
347 | #endif |
348 | |
349 | |
350 | // This version does not initialize colors, user has to. |
351 | |
352 | template <class IncidenceGraph, class P, class T, class R> |
353 | void breadth_first_visit |
354 | (const IncidenceGraph& g, |
355 | typename graph_traits<IncidenceGraph>::vertex_descriptor s, |
356 | const bgl_named_params<P, T, R>& params) |
357 | { |
358 | // The graph is passed by *const* reference so that graph adaptors |
359 | // (temporaries) can be passed into this function. However, the |
360 | // graph is not really const since we may write to property maps |
361 | // of the graph. |
362 | IncidenceGraph& ng = const_cast<IncidenceGraph&>(g); |
363 | |
364 | typedef graph_traits<IncidenceGraph> Traits; |
365 | // Buffer default |
366 | typedef typename Traits::vertex_descriptor vertex_descriptor; |
367 | typedef boost::queue<vertex_descriptor> queue_t; |
368 | queue_t Q; |
369 | |
370 | breadth_first_visit |
371 | (ng, s, |
372 | choose_param(get_param(params, buffer_param_t()), boost::ref(Q)).get(), |
373 | choose_param(get_param(params, graph_visitor), |
374 | make_bfs_visitor(vis: null_visitor())), |
375 | choose_pmap(get_param(params, vertex_color), ng, vertex_color) |
376 | ); |
377 | } |
378 | |
379 | namespace graph { |
380 | namespace detail { |
381 | template <typename Graph, typename Source> |
382 | struct breadth_first_search_impl { |
383 | typedef void result_type; |
384 | template <typename ArgPack> |
385 | void operator()(const Graph& g, const Source& source, const ArgPack& arg_pack) { |
386 | using namespace boost::graph::keywords; |
387 | typename boost::graph_traits<Graph>::vertex_descriptor sources[1] = {source}; |
388 | boost::queue<typename boost::graph_traits<Graph>::vertex_descriptor> Q; |
389 | boost::breadth_first_search(g, |
390 | &sources[0], |
391 | &sources[1], |
392 | boost::unwrap_ref(arg_pack[_buffer | boost::ref(Q)]), |
393 | arg_pack[_visitor | make_bfs_visitor(vis: null_visitor())], |
394 | boost::detail::make_color_map_from_arg_pack(g, arg_pack)); |
395 | } |
396 | }; |
397 | } |
398 | BOOST_GRAPH_MAKE_FORWARDING_FUNCTION(breadth_first_search, 2, 4) |
399 | } |
400 | |
401 | #if 0 |
402 | // Named Parameter Variant |
403 | BOOST_GRAPH_MAKE_OLD_STYLE_PARAMETER_FUNCTION(breadth_first_search, 2) |
404 | #endif |
405 | |
406 | } // namespace boost |
407 | |
408 | #ifdef BOOST_GRAPH_USE_MPI |
409 | # include <boost/graph/distributed/breadth_first_search.hpp> |
410 | #endif |
411 | |
412 | #endif // BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP |
413 | |
414 | |