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/graph/detail/mpi_include.hpp> 28 #include <boost/concept/assert.hpp> 29 30 #include BOOST_GRAPH_MPI_INCLUDE(<boost/graph/distributed/concepts.hpp>) 31 32 namespace boost { 33 34 template <class Visitor, class Graph> 35 struct BFSVisitorConcept { constraintsboost::BFSVisitorConcept36 void constraints() { 37 BOOST_CONCEPT_ASSERT(( CopyConstructibleConcept<Visitor> )); 38 vis.initialize_vertex(u, g); 39 vis.discover_vertex(u, g); 40 vis.examine_vertex(u, g); 41 vis.examine_edge(e, g); 42 vis.tree_edge(e, g); 43 vis.non_tree_edge(e, g); 44 vis.gray_target(e, g); 45 vis.black_target(e, g); 46 vis.finish_vertex(u, g); 47 } 48 Visitor vis; 49 Graph g; 50 typename graph_traits<Graph>::vertex_descriptor u; 51 typename graph_traits<Graph>::edge_descriptor e; 52 }; 53 54 55 // Multiple-source version 56 template <class IncidenceGraph, class Buffer, class BFSVisitor, 57 class ColorMap, class SourceIterator> breadth_first_visit(const IncidenceGraph & g,SourceIterator sources_begin,SourceIterator sources_end,Buffer & Q,BFSVisitor vis,ColorMap color)58 void breadth_first_visit 59 (const IncidenceGraph& g, 60 SourceIterator sources_begin, SourceIterator sources_end, 61 Buffer& Q, BFSVisitor vis, ColorMap color) 62 { 63 BOOST_CONCEPT_ASSERT(( IncidenceGraphConcept<IncidenceGraph> )); 64 typedef graph_traits<IncidenceGraph> GTraits; 65 typedef typename GTraits::vertex_descriptor Vertex; 66 BOOST_CONCEPT_ASSERT(( BFSVisitorConcept<BFSVisitor, IncidenceGraph> )); 67 BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<ColorMap, Vertex> )); 68 typedef typename property_traits<ColorMap>::value_type ColorValue; 69 typedef color_traits<ColorValue> Color; 70 typename GTraits::out_edge_iterator ei, ei_end; 71 72 for (; sources_begin != sources_end; ++sources_begin) { 73 Vertex s = *sources_begin; 74 put(color, s, Color::gray()); vis.discover_vertex(s, g); 75 Q.push(s); 76 } 77 while (! Q.empty()) { 78 Vertex u = Q.top(); Q.pop(); vis.examine_vertex(u, g); 79 for (boost::tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) { 80 Vertex v = target(*ei, g); vis.examine_edge(*ei, g); 81 ColorValue v_color = get(color, v); 82 if (v_color == Color::white()) { vis.tree_edge(*ei, g); 83 put(color, v, Color::gray()); vis.discover_vertex(v, g); 84 Q.push(v); 85 } else { vis.non_tree_edge(*ei, g); 86 if (v_color == Color::gray()) vis.gray_target(*ei, g); 87 else vis.black_target(*ei, g); 88 } 89 } // end for 90 put(color, u, Color::black()); vis.finish_vertex(u, g); 91 } // end while 92 } // breadth_first_visit 93 94 // Single-source version 95 template <class IncidenceGraph, class Buffer, class BFSVisitor, 96 class ColorMap> breadth_first_visit(const IncidenceGraph & g,typename graph_traits<IncidenceGraph>::vertex_descriptor s,Buffer & Q,BFSVisitor vis,ColorMap color)97 void breadth_first_visit 98 (const IncidenceGraph& g, 99 typename graph_traits<IncidenceGraph>::vertex_descriptor s, 100 Buffer& Q, BFSVisitor vis, ColorMap color) 101 { 102 typename graph_traits<IncidenceGraph>::vertex_descriptor sources[1] = {s}; 103 breadth_first_visit(g, sources, sources + 1, Q, vis, color); 104 } 105 106 107 template <class VertexListGraph, class SourceIterator, 108 class Buffer, class BFSVisitor, 109 class ColorMap> breadth_first_search(const VertexListGraph & g,SourceIterator sources_begin,SourceIterator sources_end,Buffer & Q,BFSVisitor vis,ColorMap color)110 void breadth_first_search 111 (const VertexListGraph& g, 112 SourceIterator sources_begin, SourceIterator sources_end, 113 Buffer& Q, BFSVisitor vis, ColorMap color) 114 { 115 // Initialization 116 typedef typename property_traits<ColorMap>::value_type ColorValue; 117 typedef color_traits<ColorValue> Color; 118 typename boost::graph_traits<VertexListGraph>::vertex_iterator i, i_end; 119 for (boost::tie(i, i_end) = vertices(g); i != i_end; ++i) { 120 vis.initialize_vertex(*i, g); 121 put(color, *i, Color::white()); 122 } 123 breadth_first_visit(g, sources_begin, sources_end, Q, vis, color); 124 } 125 126 template <class VertexListGraph, class Buffer, class BFSVisitor, 127 class ColorMap> breadth_first_search(const VertexListGraph & g,typename graph_traits<VertexListGraph>::vertex_descriptor s,Buffer & Q,BFSVisitor vis,ColorMap color)128 void breadth_first_search 129 (const VertexListGraph& g, 130 typename graph_traits<VertexListGraph>::vertex_descriptor s, 131 Buffer& Q, BFSVisitor vis, ColorMap color) 132 { 133 typename graph_traits<VertexListGraph>::vertex_descriptor sources[1] = {s}; 134 breadth_first_search(g, sources, sources + 1, Q, vis, color); 135 } 136 137 namespace graph { struct bfs_visitor_event_not_overridden {}; } 138 139 140 template <class Visitors = null_visitor> 141 class bfs_visitor { 142 public: bfs_visitor()143 bfs_visitor() { } bfs_visitor(Visitors vis)144 bfs_visitor(Visitors vis) : m_vis(vis) { } 145 146 template <class Vertex, class Graph> 147 graph::bfs_visitor_event_not_overridden initialize_vertex(Vertex u,Graph & g)148 initialize_vertex(Vertex u, Graph& g) 149 { 150 invoke_visitors(m_vis, u, g, ::boost::on_initialize_vertex()); 151 return graph::bfs_visitor_event_not_overridden(); 152 } 153 154 template <class Vertex, class Graph> 155 graph::bfs_visitor_event_not_overridden discover_vertex(Vertex u,Graph & g)156 discover_vertex(Vertex u, Graph& g) 157 { 158 invoke_visitors(m_vis, u, g, ::boost::on_discover_vertex()); 159 return graph::bfs_visitor_event_not_overridden(); 160 } 161 162 template <class Vertex, class Graph> 163 graph::bfs_visitor_event_not_overridden examine_vertex(Vertex u,Graph & g)164 examine_vertex(Vertex u, Graph& g) 165 { 166 invoke_visitors(m_vis, u, g, ::boost::on_examine_vertex()); 167 return graph::bfs_visitor_event_not_overridden(); 168 } 169 170 template <class Edge, class Graph> 171 graph::bfs_visitor_event_not_overridden examine_edge(Edge e,Graph & g)172 examine_edge(Edge e, Graph& g) 173 { 174 invoke_visitors(m_vis, e, g, ::boost::on_examine_edge()); 175 return graph::bfs_visitor_event_not_overridden(); 176 } 177 178 template <class Edge, class Graph> 179 graph::bfs_visitor_event_not_overridden tree_edge(Edge e,Graph & g)180 tree_edge(Edge e, Graph& g) 181 { 182 invoke_visitors(m_vis, e, g, ::boost::on_tree_edge()); 183 return graph::bfs_visitor_event_not_overridden(); 184 } 185 186 template <class Edge, class Graph> 187 graph::bfs_visitor_event_not_overridden non_tree_edge(Edge e,Graph & g)188 non_tree_edge(Edge e, Graph& g) 189 { 190 invoke_visitors(m_vis, e, g, ::boost::on_non_tree_edge()); 191 return graph::bfs_visitor_event_not_overridden(); 192 } 193 194 template <class Edge, class Graph> 195 graph::bfs_visitor_event_not_overridden gray_target(Edge e,Graph & g)196 gray_target(Edge e, Graph& g) 197 { 198 invoke_visitors(m_vis, e, g, ::boost::on_gray_target()); 199 return graph::bfs_visitor_event_not_overridden(); 200 } 201 202 template <class Edge, class Graph> 203 graph::bfs_visitor_event_not_overridden black_target(Edge e,Graph & g)204 black_target(Edge e, Graph& g) 205 { 206 invoke_visitors(m_vis, e, g, ::boost::on_black_target()); 207 return graph::bfs_visitor_event_not_overridden(); 208 } 209 210 template <class Vertex, class Graph> 211 graph::bfs_visitor_event_not_overridden finish_vertex(Vertex u,Graph & g)212 finish_vertex(Vertex u, Graph& g) 213 { 214 invoke_visitors(m_vis, u, g, ::boost::on_finish_vertex()); 215 return graph::bfs_visitor_event_not_overridden(); 216 } 217 218 BOOST_GRAPH_EVENT_STUB(on_initialize_vertex,bfs) 219 BOOST_GRAPH_EVENT_STUB(on_discover_vertex,bfs) 220 BOOST_GRAPH_EVENT_STUB(on_examine_vertex,bfs) 221 BOOST_GRAPH_EVENT_STUB(on_examine_edge,bfs) 222 BOOST_GRAPH_EVENT_STUB(on_tree_edge,bfs) 223 BOOST_GRAPH_EVENT_STUB(on_non_tree_edge,bfs) 224 BOOST_GRAPH_EVENT_STUB(on_gray_target,bfs) 225 BOOST_GRAPH_EVENT_STUB(on_black_target,bfs) 226 BOOST_GRAPH_EVENT_STUB(on_finish_vertex,bfs) 227 228 protected: 229 Visitors m_vis; 230 }; 231 template <class Visitors> 232 bfs_visitor<Visitors> make_bfs_visitor(Visitors vis)233 make_bfs_visitor(Visitors vis) { 234 return bfs_visitor<Visitors>(vis); 235 } 236 typedef bfs_visitor<> default_bfs_visitor; 237 238 239 namespace detail { 240 241 template <class VertexListGraph, class ColorMap, class BFSVisitor, 242 class P, class T, class R> bfs_helper(VertexListGraph & g,typename graph_traits<VertexListGraph>::vertex_descriptor s,ColorMap color,BFSVisitor vis,const bgl_named_params<P,T,R> & params,boost::mpl::false_)243 void bfs_helper 244 (VertexListGraph& g, 245 typename graph_traits<VertexListGraph>::vertex_descriptor s, 246 ColorMap color, 247 BFSVisitor vis, 248 const bgl_named_params<P, T, R>& params, 249 boost::mpl::false_) 250 { 251 typedef graph_traits<VertexListGraph> Traits; 252 // Buffer default 253 typedef typename Traits::vertex_descriptor Vertex; 254 typedef boost::queue<Vertex> queue_t; 255 queue_t Q; 256 breadth_first_search 257 (g, s, 258 choose_param(get_param(params, buffer_param_t()), boost::ref(Q)).get(), 259 vis, color); 260 } 261 262 #ifdef BOOST_GRAPH_USE_MPI 263 template <class DistributedGraph, class ColorMap, class BFSVisitor, 264 class P, class T, class R> 265 void bfs_helper 266 (DistributedGraph& g, 267 typename graph_traits<DistributedGraph>::vertex_descriptor s, 268 ColorMap color, 269 BFSVisitor vis, 270 const bgl_named_params<P, T, R>& params, 271 boost::mpl::true_); 272 #endif // BOOST_GRAPH_USE_MPI 273 274 //------------------------------------------------------------------------- 275 // Choose between default color and color parameters. Using 276 // function dispatching so that we don't require vertex index if 277 // the color default is not being used. 278 279 template <class ColorMap> 280 struct bfs_dispatch { 281 template <class VertexListGraph, class P, class T, class R> applyboost::detail::bfs_dispatch282 static void apply 283 (VertexListGraph& g, 284 typename graph_traits<VertexListGraph>::vertex_descriptor s, 285 const bgl_named_params<P, T, R>& params, 286 ColorMap color) 287 { 288 bfs_helper 289 (g, s, color, 290 choose_param(get_param(params, graph_visitor), 291 make_bfs_visitor(null_visitor())), 292 params, 293 boost::mpl::bool_< 294 boost::is_base_and_derived< 295 distributed_graph_tag, 296 typename graph_traits<VertexListGraph>::traversal_category>::value>()); 297 } 298 }; 299 300 template <> 301 struct bfs_dispatch<param_not_found> { 302 template <class VertexListGraph, class P, class T, class R> applyboost::detail::bfs_dispatch303 static void apply 304 (VertexListGraph& g, 305 typename graph_traits<VertexListGraph>::vertex_descriptor s, 306 const bgl_named_params<P, T, R>& params, 307 param_not_found) 308 { 309 null_visitor null_vis; 310 311 bfs_helper 312 (g, s, 313 make_two_bit_color_map 314 (num_vertices(g), 315 choose_const_pmap(get_param(params, vertex_index), 316 g, vertex_index)), 317 choose_param(get_param(params, graph_visitor), 318 make_bfs_visitor(null_vis)), 319 params, 320 boost::mpl::bool_< 321 boost::is_base_and_derived< 322 distributed_graph_tag, 323 typename graph_traits<VertexListGraph>::traversal_category>::value>()); 324 } 325 }; 326 327 } // namespace detail 328 329 #if 1 330 // Named Parameter Variant 331 template <class VertexListGraph, class P, class T, class R> breadth_first_search(const VertexListGraph & g,typename graph_traits<VertexListGraph>::vertex_descriptor s,const bgl_named_params<P,T,R> & params)332 void breadth_first_search 333 (const VertexListGraph& g, 334 typename graph_traits<VertexListGraph>::vertex_descriptor s, 335 const bgl_named_params<P, T, R>& params) 336 { 337 // The graph is passed by *const* reference so that graph adaptors 338 // (temporaries) can be passed into this function. However, the 339 // graph is not really const since we may write to property maps 340 // of the graph. 341 VertexListGraph& ng = const_cast<VertexListGraph&>(g); 342 typedef typename get_param_type< vertex_color_t, bgl_named_params<P,T,R> >::type C; 343 detail::bfs_dispatch<C>::apply(ng, s, params, 344 get_param(params, vertex_color)); 345 } 346 #endif 347 348 349 // This version does not initialize colors, user has to. 350 351 template <class IncidenceGraph, class P, class T, class R> breadth_first_visit(const IncidenceGraph & g,typename graph_traits<IncidenceGraph>::vertex_descriptor s,const bgl_named_params<P,T,R> & params)352 void breadth_first_visit 353 (const IncidenceGraph& g, 354 typename graph_traits<IncidenceGraph>::vertex_descriptor s, 355 const bgl_named_params<P, T, R>& params) 356 { 357 // The graph is passed by *const* reference so that graph adaptors 358 // (temporaries) can be passed into this function. However, the 359 // graph is not really const since we may write to property maps 360 // of the graph. 361 IncidenceGraph& ng = const_cast<IncidenceGraph&>(g); 362 363 typedef graph_traits<IncidenceGraph> Traits; 364 // Buffer default 365 typedef typename Traits::vertex_descriptor vertex_descriptor; 366 typedef boost::queue<vertex_descriptor> queue_t; 367 queue_t Q; 368 369 breadth_first_visit 370 (ng, s, 371 choose_param(get_param(params, buffer_param_t()), boost::ref(Q)).get(), 372 choose_param(get_param(params, graph_visitor), 373 make_bfs_visitor(null_visitor())), 374 choose_pmap(get_param(params, vertex_color), ng, vertex_color) 375 ); 376 } 377 378 namespace graph { 379 namespace detail { 380 template <typename Graph, typename Source> 381 struct breadth_first_search_impl { 382 typedef void result_type; 383 template <typename ArgPack> operator ()boost::graph::detail::breadth_first_search_impl384 void operator()(const Graph& g, const Source& source, const ArgPack& arg_pack) { 385 using namespace boost::graph::keywords; 386 typename boost::graph_traits<Graph>::vertex_descriptor sources[1] = {source}; 387 boost::queue<typename boost::graph_traits<Graph>::vertex_descriptor> Q; 388 boost::breadth_first_search(g, 389 &sources[0], 390 &sources[1], 391 boost::unwrap_ref(arg_pack[_buffer | boost::ref(Q)]), 392 arg_pack[_visitor | make_bfs_visitor(null_visitor())], 393 boost::detail::make_color_map_from_arg_pack(g, arg_pack)); 394 } 395 }; 396 } 397 BOOST_GRAPH_MAKE_FORWARDING_FUNCTION(breadth_first_search, 2, 4) 398 } 399 400 #if 0 401 // Named Parameter Variant 402 BOOST_GRAPH_MAKE_OLD_STYLE_PARAMETER_FUNCTION(breadth_first_search, 2) 403 #endif 404 405 } // namespace boost 406 407 #include BOOST_GRAPH_MPI_INCLUDE(<boost/graph/distributed/breadth_first_search.hpp>) 408 409 #endif // BOOST_GRAPH_BREADTH_FIRST_SEARCH_HPP 410 411