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Diffstat (limited to 'boost/graph/strong_components.hpp')
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diff --git a/boost/graph/strong_components.hpp b/boost/graph/strong_components.hpp new file mode 100644 index 0000000000..ba5d45907a --- /dev/null +++ b/boost/graph/strong_components.hpp @@ -0,0 +1,342 @@ +// +//======================================================================= +// Copyright 1997, 1998, 1999, 2000 University of Notre Dame. +// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek +// +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) +//======================================================================= +// + +#ifndef BOOST_GRAPH_STRONG_COMPONENTS_HPP +#define BOOST_GRAPH_STRONG_COMPONENTS_HPP + +#include <stack> +#include <boost/config.hpp> +#include <boost/graph/depth_first_search.hpp> +#include <boost/type_traits/conversion_traits.hpp> +#include <boost/static_assert.hpp> +#include <boost/graph/overloading.hpp> +#include <boost/concept/assert.hpp> + +namespace boost { + + //========================================================================== + // This is Tarjan's algorithm for strongly connected components + // from his paper "Depth first search and linear graph algorithms". + // It calculates the components in a single application of DFS. + // We implement the algorithm as a dfs-visitor. + + namespace detail { + + template <typename ComponentMap, typename RootMap, typename DiscoverTime, + typename Stack> + class tarjan_scc_visitor : public dfs_visitor<> + { + typedef typename property_traits<ComponentMap>::value_type comp_type; + typedef typename property_traits<DiscoverTime>::value_type time_type; + public: + tarjan_scc_visitor(ComponentMap comp_map, RootMap r, DiscoverTime d, + comp_type& c_, Stack& s_) + : c(c_), comp(comp_map), root(r), discover_time(d), + dfs_time(time_type()), s(s_) { } + + template <typename Graph> + void discover_vertex(typename graph_traits<Graph>::vertex_descriptor v, + const Graph&) { + put(root, v, v); + put(comp, v, (std::numeric_limits<comp_type>::max)()); + put(discover_time, v, dfs_time++); + s.push(v); + } + template <typename Graph> + void finish_vertex(typename graph_traits<Graph>::vertex_descriptor v, + const Graph& g) { + typename graph_traits<Graph>::vertex_descriptor w; + typename graph_traits<Graph>::out_edge_iterator ei, ei_end; + for (boost::tie(ei, ei_end) = out_edges(v, g); ei != ei_end; ++ei) { + w = target(*ei, g); + if (get(comp, w) == (std::numeric_limits<comp_type>::max)()) + put(root, v, this->min_discover_time(get(root,v), get(root,w))); + } + if (get(root, v) == v) { + do { + w = s.top(); s.pop(); + put(comp, w, c); + } while (w != v); + ++c; + } + } + private: + template <typename Vertex> + Vertex min_discover_time(Vertex u, Vertex v) { + return get(discover_time, u) < get(discover_time,v) ? u : v; + } + + comp_type& c; + ComponentMap comp; + RootMap root; + DiscoverTime discover_time; + time_type dfs_time; + Stack& s; + }; + + template <class Graph, class ComponentMap, class RootMap, + class DiscoverTime, class P, class T, class R> + typename property_traits<ComponentMap>::value_type + strong_components_impl + (const Graph& g, // Input + ComponentMap comp, // Output + // Internal record keeping + RootMap root, + DiscoverTime discover_time, + const bgl_named_params<P, T, R>& params) + { + typedef typename graph_traits<Graph>::vertex_descriptor Vertex; + BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<ComponentMap, Vertex> )); + BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<RootMap, Vertex> )); + typedef typename property_traits<RootMap>::value_type RootV; + BOOST_CONCEPT_ASSERT(( ConvertibleConcept<RootV, Vertex> )); + BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<DiscoverTime, Vertex> )); + + typename property_traits<ComponentMap>::value_type total = 0; + + std::stack<Vertex> s; + detail::tarjan_scc_visitor<ComponentMap, RootMap, DiscoverTime, + std::stack<Vertex> > + vis(comp, root, discover_time, total, s); + depth_first_search(g, params.visitor(vis)); + return total; + } + + //------------------------------------------------------------------------- + // The dispatch functions handle the defaults for the rank and discover + // time property maps. + // dispatch with class specialization to avoid VC++ bug + + template <class DiscoverTimeMap> + struct strong_comp_dispatch2 { + template <class Graph, class ComponentMap, class RootMap, class P, class T, class R> + inline static typename property_traits<ComponentMap>::value_type + apply(const Graph& g, + ComponentMap comp, + RootMap r_map, + const bgl_named_params<P, T, R>& params, + DiscoverTimeMap time_map) + { + return strong_components_impl(g, comp, r_map, time_map, params); + } + }; + + + template <> + struct strong_comp_dispatch2<detail::error_property_not_found> { + template <class Graph, class ComponentMap, class RootMap, + class P, class T, class R> + inline static typename property_traits<ComponentMap>::value_type + apply(const Graph& g, + ComponentMap comp, + RootMap r_map, + const bgl_named_params<P, T, R>& params, + detail::error_property_not_found) + { + typedef typename graph_traits<Graph>::vertices_size_type size_type; + size_type n = num_vertices(g) > 0 ? num_vertices(g) : 1; + std::vector<size_type> time_vec(n); + return strong_components_impl + (g, comp, r_map, + make_iterator_property_map(time_vec.begin(), choose_const_pmap + (get_param(params, vertex_index), + g, vertex_index), time_vec[0]), + params); + } + }; + + template <class Graph, class ComponentMap, class RootMap, + class P, class T, class R, class DiscoverTimeMap> + inline typename property_traits<ComponentMap>::value_type + scc_helper2(const Graph& g, + ComponentMap comp, + RootMap r_map, + const bgl_named_params<P, T, R>& params, + DiscoverTimeMap time_map) + { + return strong_comp_dispatch2<DiscoverTimeMap>::apply(g, comp, r_map, params, time_map); + } + + template <class RootMap> + struct strong_comp_dispatch1 { + + template <class Graph, class ComponentMap, class P, class T, class R> + inline static typename property_traits<ComponentMap>::value_type + apply(const Graph& g, + ComponentMap comp, + const bgl_named_params<P, T, R>& params, + RootMap r_map) + { + return scc_helper2(g, comp, r_map, params, get_param(params, vertex_discover_time)); + } + }; + template <> + struct strong_comp_dispatch1<detail::error_property_not_found> { + + template <class Graph, class ComponentMap, + class P, class T, class R> + inline static typename property_traits<ComponentMap>::value_type + apply(const Graph& g, + ComponentMap comp, + const bgl_named_params<P, T, R>& params, + detail::error_property_not_found) + { + typedef typename graph_traits<Graph>::vertex_descriptor Vertex; + typename std::vector<Vertex>::size_type + n = num_vertices(g) > 0 ? num_vertices(g) : 1; + std::vector<Vertex> root_vec(n); + return scc_helper2 + (g, comp, + make_iterator_property_map(root_vec.begin(), choose_const_pmap + (get_param(params, vertex_index), + g, vertex_index), root_vec[0]), + params, + get_param(params, vertex_discover_time)); + } + }; + + template <class Graph, class ComponentMap, class RootMap, + class P, class T, class R> + inline typename property_traits<ComponentMap>::value_type + scc_helper1(const Graph& g, + ComponentMap comp, + const bgl_named_params<P, T, R>& params, + RootMap r_map) + { + return detail::strong_comp_dispatch1<RootMap>::apply(g, comp, params, + r_map); + } + + } // namespace detail + + template <class Graph, class ComponentMap, + class P, class T, class R> + inline typename property_traits<ComponentMap>::value_type + strong_components(const Graph& g, ComponentMap comp, + const bgl_named_params<P, T, R>& params + BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, vertex_list_graph_tag)) + { + typedef typename graph_traits<Graph>::directed_category DirCat; + BOOST_STATIC_ASSERT((is_convertible<DirCat*, directed_tag*>::value == true)); + return detail::scc_helper1(g, comp, params, + get_param(params, vertex_root_t())); + } + + template <class Graph, class ComponentMap> + inline typename property_traits<ComponentMap>::value_type + strong_components(const Graph& g, ComponentMap comp + BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, vertex_list_graph_tag)) + { + typedef typename graph_traits<Graph>::directed_category DirCat; + BOOST_STATIC_ASSERT((is_convertible<DirCat*, directed_tag*>::value == true)); + bgl_named_params<int, int> params(0); + return strong_components(g, comp, params); + } + + template <typename Graph, typename ComponentMap, typename ComponentLists> + void build_component_lists + (const Graph& g, + typename graph_traits<Graph>::vertices_size_type num_scc, + ComponentMap component_number, + ComponentLists& components) + { + components.resize(num_scc); + typename graph_traits<Graph>::vertex_iterator vi, vi_end; + for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi) + components[component_number[*vi]].push_back(*vi); + } + + +} // namespace boost + +#include <queue> +#include <vector> +#include <boost/graph/transpose_graph.hpp> +#include <boost/pending/indirect_cmp.hpp> +#include <boost/graph/connected_components.hpp> // for components_recorder + +namespace boost { + + //========================================================================== + // This is the version of strongly connected components from + // "Intro. to Algorithms" by Cormen, Leiserson, Rivest, which was + // adapted from "Data Structure and Algorithms" by Aho, Hopcroft, + // and Ullman, who credit the algorithm to S.R. Kosaraju and M. Sharir. + // The algorithm is based on computing DFS forests the graph + // and its transpose. + + // This algorithm is slower than Tarjan's by a constant factor, uses + // more memory, and puts more requirements on the graph type. + + template <class Graph, class DFSVisitor, class ComponentsMap, + class DiscoverTime, class FinishTime, + class ColorMap> + typename property_traits<ComponentsMap>::value_type + kosaraju_strong_components(Graph& G, ComponentsMap c, + FinishTime finish_time, ColorMap color) + { + BOOST_CONCEPT_ASSERT(( MutableGraphConcept<Graph> )); + // ... + + typedef typename graph_traits<Graph>::vertex_descriptor Vertex; + typedef typename property_traits<ColorMap>::value_type ColorValue; + typedef color_traits<ColorValue> Color; + typename property_traits<FinishTime>::value_type time = 0; + depth_first_search + (G, make_dfs_visitor(stamp_times(finish_time, time, on_finish_vertex())), + color); + + Graph G_T(num_vertices(G)); + transpose_graph(G, G_T); + + typedef typename property_traits<ComponentsMap>::value_type count_type; + + count_type c_count(0); + detail::components_recorder<ComponentsMap> + vis(c, c_count); + + // initialize G_T + typename graph_traits<Graph>::vertex_iterator ui, ui_end; + for (boost::tie(ui, ui_end) = vertices(G_T); ui != ui_end; ++ui) + put(color, *ui, Color::white()); + + typedef typename property_traits<FinishTime>::value_type D; + typedef indirect_cmp< FinishTime, std::less<D> > Compare; + + Compare fl(finish_time); + std::priority_queue<Vertex, std::vector<Vertex>, Compare > Q(fl); + + typename graph_traits<Graph>::vertex_iterator i, j, iend, jend; + boost::tie(i, iend) = vertices(G_T); + boost::tie(j, jend) = vertices(G); + for ( ; i != iend; ++i, ++j) { + put(finish_time, *i, get(finish_time, *j)); + Q.push(*i); + } + + while ( !Q.empty() ) { + Vertex u = Q.top(); + Q.pop(); + if (get(color, u) == Color::white()) { + depth_first_visit(G_T, u, vis, color); + ++c_count; + } + } + return c_count; + } + +} // namespace boost + +#ifdef BOOST_GRAPH_USE_MPI +# include <boost/graph/distributed/strong_components.hpp> +#endif + +#endif // BOOST_GRAPH_STRONG_COMPONENTS_HPP |