williamr@2: // williamr@2: //======================================================================= williamr@2: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. williamr@2: // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek williamr@2: // williamr@2: // Distributed under the Boost Software License, Version 1.0. (See williamr@2: // accompanying file LICENSE_1_0.txt or copy at williamr@2: // http://www.boost.org/LICENSE_1_0.txt) williamr@2: //======================================================================= williamr@2: // williamr@2: williamr@2: #ifndef BOOST_GRAPH_STRONG_COMPONENTS_HPP williamr@2: #define BOOST_GRAPH_STRONG_COMPONENTS_HPP williamr@2: williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: williamr@2: namespace boost { williamr@2: williamr@2: //========================================================================== williamr@2: // This is Tarjan's algorithm for strongly connected components williamr@2: // from his paper "Depth first search and linear graph algorithms". williamr@2: // It calculates the components in a single application of DFS. williamr@2: // We implement the algorithm as a dfs-visitor. williamr@2: williamr@2: namespace detail { williamr@2: williamr@2: template williamr@2: class tarjan_scc_visitor : public dfs_visitor<> williamr@2: { williamr@2: typedef typename property_traits::value_type comp_type; williamr@2: typedef typename property_traits::value_type time_type; williamr@2: public: williamr@2: tarjan_scc_visitor(ComponentMap comp_map, RootMap r, DiscoverTime d, williamr@2: comp_type& c_, Stack& s_) williamr@2: : c(c_), comp(comp_map), root(r), discover_time(d), williamr@2: dfs_time(time_type()), s(s_) { } williamr@2: williamr@2: template williamr@2: void discover_vertex(typename graph_traits::vertex_descriptor v, williamr@2: const Graph&) { williamr@2: put(root, v, v); williamr@2: put(comp, v, (std::numeric_limits::max)()); williamr@2: put(discover_time, v, dfs_time++); williamr@2: s.push(v); williamr@2: } williamr@2: template williamr@2: void finish_vertex(typename graph_traits::vertex_descriptor v, williamr@2: const Graph& g) { williamr@2: typename graph_traits::vertex_descriptor w; williamr@2: typename graph_traits::out_edge_iterator ei, ei_end; williamr@2: for (tie(ei, ei_end) = out_edges(v, g); ei != ei_end; ++ei) { williamr@2: w = target(*ei, g); williamr@2: if (get(comp, w) == (std::numeric_limits::max)()) williamr@2: put(root, v, this->min_discover_time(get(root,v), get(root,w))); williamr@2: } williamr@2: if (get(root, v) == v) { williamr@2: do { williamr@2: w = s.top(); s.pop(); williamr@2: put(comp, w, c); williamr@2: } while (w != v); williamr@2: ++c; williamr@2: } williamr@2: } williamr@2: private: williamr@2: template williamr@2: Vertex min_discover_time(Vertex u, Vertex v) { williamr@2: return get(discover_time, u) < get(discover_time,v) ? u : v; williamr@2: } williamr@2: williamr@2: comp_type& c; williamr@2: ComponentMap comp; williamr@2: RootMap root; williamr@2: DiscoverTime discover_time; williamr@2: time_type dfs_time; williamr@2: Stack& s; williamr@2: }; williamr@2: williamr@2: template williamr@2: typename property_traits::value_type williamr@2: strong_components_impl williamr@2: (const Graph& g, // Input williamr@2: ComponentMap comp, // Output williamr@2: // Internal record keeping williamr@2: RootMap root, williamr@2: DiscoverTime discover_time, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: typedef typename graph_traits::vertex_descriptor Vertex; williamr@2: function_requires< ReadWritePropertyMapConcept >(); williamr@2: function_requires< ReadWritePropertyMapConcept >(); williamr@2: typedef typename property_traits::value_type RootV; williamr@2: function_requires< ConvertibleConcept >(); williamr@2: function_requires< ReadWritePropertyMapConcept >(); williamr@2: williamr@2: typename property_traits::value_type total = 0; williamr@2: williamr@2: std::stack s; williamr@2: detail::tarjan_scc_visitor > williamr@2: vis(comp, root, discover_time, total, s); williamr@2: depth_first_search(g, params.visitor(vis)); williamr@2: return total; williamr@2: } williamr@2: williamr@2: //------------------------------------------------------------------------- williamr@2: // The dispatch functions handle the defaults for the rank and discover williamr@2: // time property maps. williamr@2: // dispatch with class specialization to avoid VC++ bug williamr@2: williamr@2: template williamr@2: struct strong_comp_dispatch2 { williamr@2: template williamr@2: inline static typename property_traits::value_type williamr@2: apply(const Graph& g, williamr@2: ComponentMap comp, williamr@2: RootMap r_map, williamr@2: const bgl_named_params& params, williamr@2: DiscoverTimeMap time_map) williamr@2: { williamr@2: return strong_components_impl(g, comp, r_map, time_map, params); williamr@2: } williamr@2: }; williamr@2: williamr@2: williamr@2: template <> williamr@2: struct strong_comp_dispatch2 { williamr@2: template williamr@2: inline static typename property_traits::value_type williamr@2: apply(const Graph& g, williamr@2: ComponentMap comp, williamr@2: RootMap r_map, williamr@2: const bgl_named_params& params, williamr@2: detail::error_property_not_found) williamr@2: { williamr@2: typedef typename graph_traits::vertices_size_type size_type; williamr@2: size_type n = num_vertices(g) > 0 ? num_vertices(g) : 1; williamr@2: std::vector time_vec(n); williamr@2: return strong_components_impl williamr@2: (g, comp, r_map, williamr@2: make_iterator_property_map(time_vec.begin(), choose_const_pmap williamr@2: (get_param(params, vertex_index), williamr@2: g, vertex_index), time_vec[0]), williamr@2: params); williamr@2: } williamr@2: }; williamr@2: williamr@2: template williamr@2: inline typename property_traits::value_type williamr@2: scc_helper2(const Graph& g, williamr@2: ComponentMap comp, williamr@2: RootMap r_map, williamr@2: const bgl_named_params& params, williamr@2: DiscoverTimeMap time_map) williamr@2: { williamr@2: return strong_comp_dispatch2::apply(g, comp, r_map, params, time_map); williamr@2: } williamr@2: williamr@2: template williamr@2: struct strong_comp_dispatch1 { williamr@2: williamr@2: template williamr@2: inline static typename property_traits::value_type williamr@2: apply(const Graph& g, williamr@2: ComponentMap comp, williamr@2: const bgl_named_params& params, williamr@2: RootMap r_map) williamr@2: { williamr@2: return scc_helper2(g, comp, r_map, params, get_param(params, vertex_discover_time)); williamr@2: } williamr@2: }; williamr@2: template <> williamr@2: struct strong_comp_dispatch1 { williamr@2: williamr@2: template williamr@2: inline static typename property_traits::value_type williamr@2: apply(const Graph& g, williamr@2: ComponentMap comp, williamr@2: const bgl_named_params& params, williamr@2: detail::error_property_not_found) williamr@2: { williamr@2: typedef typename graph_traits::vertex_descriptor Vertex; williamr@2: typename std::vector::size_type williamr@2: n = num_vertices(g) > 0 ? num_vertices(g) : 1; williamr@2: std::vector root_vec(n); williamr@2: return scc_helper2 williamr@2: (g, comp, williamr@2: make_iterator_property_map(root_vec.begin(), choose_const_pmap williamr@2: (get_param(params, vertex_index), williamr@2: g, vertex_index), root_vec[0]), williamr@2: params, williamr@2: get_param(params, vertex_discover_time)); williamr@2: } williamr@2: }; williamr@2: williamr@2: template williamr@2: inline typename property_traits::value_type williamr@2: scc_helper1(const Graph& g, williamr@2: ComponentMap comp, williamr@2: const bgl_named_params& params, williamr@2: RootMap r_map) williamr@2: { williamr@2: return detail::strong_comp_dispatch1::apply(g, comp, params, williamr@2: r_map); williamr@2: } williamr@2: williamr@2: } // namespace detail williamr@2: williamr@2: template williamr@2: inline typename property_traits::value_type williamr@2: strong_components(const Graph& g, ComponentMap comp, williamr@2: const bgl_named_params& params) williamr@2: { williamr@2: typedef typename graph_traits::directed_category DirCat; williamr@2: BOOST_STATIC_ASSERT((is_convertible::value == true)); williamr@2: return detail::scc_helper1(g, comp, params, williamr@2: get_param(params, vertex_root_t())); williamr@2: } williamr@2: williamr@2: template williamr@2: inline typename property_traits::value_type williamr@2: strong_components(const Graph& g, ComponentMap comp) williamr@2: { williamr@2: typedef typename graph_traits::directed_category DirCat; williamr@2: BOOST_STATIC_ASSERT((is_convertible::value == true)); williamr@2: bgl_named_params params(0); williamr@2: return strong_components(g, comp, params); williamr@2: } williamr@2: williamr@2: template williamr@2: void build_component_lists williamr@2: (const Graph& g, williamr@2: typename graph_traits::vertices_size_type num_scc, williamr@2: ComponentMap component_number, williamr@2: ComponentLists& components) williamr@2: { williamr@2: components.resize(num_scc); williamr@2: typename graph_traits::vertex_iterator vi, vi_end; williamr@2: for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi) williamr@2: components[component_number[*vi]].push_back(*vi); williamr@2: } williamr@2: williamr@2: williamr@2: } // namespace boost williamr@2: williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include // for components_recorder williamr@2: williamr@2: namespace boost { williamr@2: williamr@2: //========================================================================== williamr@2: // This is the version of strongly connected components from williamr@2: // "Intro. to Algorithms" by Cormen, Leiserson, Rivest, which was williamr@2: // adapted from "Data Structure and Algorithms" by Aho, Hopcroft, williamr@2: // and Ullman, who credit the algorithm to S.R. Kosaraju and M. Sharir. williamr@2: // The algorithm is based on computing DFS forests the graph williamr@2: // and its transpose. williamr@2: williamr@2: // This algorithm is slower than Tarjan's by a constant factor, uses williamr@2: // more memory, and puts more requirements on the graph type. williamr@2: williamr@2: template williamr@2: typename property_traits::value_type williamr@2: kosaraju_strong_components(Graph& G, ComponentsMap c, williamr@2: FinishTime finish_time, ColorMap color) williamr@2: { williamr@2: function_requires< MutableGraphConcept >(); williamr@2: // ... williamr@2: williamr@2: typedef typename graph_traits::vertex_descriptor Vertex; williamr@2: typedef typename property_traits::value_type ColorValue; williamr@2: typedef color_traits Color; williamr@2: typename property_traits::value_type time = 0; williamr@2: depth_first_search williamr@2: (G, make_dfs_visitor(stamp_times(finish_time, time, on_finish_vertex())), williamr@2: color); williamr@2: williamr@2: Graph G_T(num_vertices(G)); williamr@2: transpose_graph(G, G_T); williamr@2: williamr@2: typedef typename property_traits::value_type count_type; williamr@2: williamr@2: count_type c_count(0); williamr@2: detail::components_recorder williamr@2: vis(c, c_count); williamr@2: williamr@2: // initialize G_T williamr@2: typename graph_traits::vertex_iterator ui, ui_end; williamr@2: for (tie(ui, ui_end) = vertices(G_T); ui != ui_end; ++ui) williamr@2: put(color, *ui, Color::white()); williamr@2: williamr@2: typedef typename property_traits::value_type D; williamr@2: typedef indirect_cmp< FinishTime, std::less > Compare; williamr@2: williamr@2: Compare fl(finish_time); williamr@2: std::priority_queue, Compare > Q(fl); williamr@2: williamr@2: typename graph_traits::vertex_iterator i, j, iend, jend; williamr@2: tie(i, iend) = vertices(G_T); williamr@2: tie(j, jend) = vertices(G); williamr@2: for ( ; i != iend; ++i, ++j) { williamr@2: put(finish_time, *i, get(finish_time, *j)); williamr@2: Q.push(*i); williamr@2: } williamr@2: williamr@2: while ( !Q.empty() ) { williamr@2: Vertex u = Q.top(); williamr@2: Q.pop(); williamr@2: if (get(color, u) == Color::white()) { williamr@2: depth_first_visit(G_T, u, vis, color); williamr@2: ++c_count; williamr@2: } williamr@2: } williamr@2: return c_count; williamr@2: } williamr@2: williamr@2: } // namespace boost williamr@2: williamr@2: #endif // BOOST_GRAPH_STRONG_COMPONENTS_HPP