boost/graph/howard_cycle_ratio.hpp
// Copyright (C) 2006-2009 Dmitry Bufistov and Andrey Parfenov // Use, modification and distribution is subject to 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_CYCLE_RATIO_HOWARD_HPP #define BOOST_GRAPH_CYCLE_RATIO_HOWARD_HPP #include <vector> #include <list> #include <algorithm> #include <limits> #include <boost/bind.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/remove_const.hpp> #include <boost/concept_check.hpp> #include <boost/pending/queue.hpp> #include <boost/property_map/property_map.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/graph_concepts.hpp> /** @file howard_cycle_ratio.hpp * @brief The implementation of the maximum/minimum cycle ratio/mean algorithm. * @author Dmitry Bufistov * @author Andrey Parfenov */ namespace boost { /** * The mcr_float is like numeric_limits, but only for floating point types * and only defines infinity() and epsilon(). This class is primarily used * to encapsulate a less-precise epsilon than natively supported by the * floating point type. */ template <typename Float = double> struct mcr_float { typedef Float value_type; static Float infinity() { return std::numeric_limits<value_type>::infinity(); } static Float epsilon() { return Float(-0.005); } }; namespace detail { template <typename FloatTraits> struct min_comparator_props { typedef std::greater<typename FloatTraits::value_type> comparator; static const int multiplier = 1; }; template <typename FloatTraits> struct max_comparator_props { typedef std::less<typename FloatTraits::value_type> comparator; static const int multiplier = -1; }; template <typename FloatTraits, typename ComparatorProps> struct float_wrapper { typedef typename FloatTraits::value_type value_type; typedef ComparatorProps comparator_props_t; typedef typename ComparatorProps::comparator comparator; static value_type infinity() { return FloatTraits::infinity() * ComparatorProps::multiplier; } static value_type epsilon() { return FloatTraits::epsilon() * ComparatorProps::multiplier; } }; /*! @class mcr_howard * @brief Calculates optimum (maximum/minimum) cycle ratio of a directed graph. * Uses Howard's iteration policy algorithm. </br>(It is described in the paper * "Experimental Analysis of the Fastest Optimum Cycle Ratio and Mean Algorithm" * by Ali Dasdan). */ template <typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeight1, typename EdgeWeight2> class mcr_howard { public: typedef typename FloatTraits::value_type float_t; typedef typename FloatTraits::comparator_props_t cmp_props_t; typedef typename FloatTraits::comparator comparator_t; typedef enum{ my_white = 0, my_black } my_color_type; typedef typename graph_traits<Graph>::vertex_descriptor vertex_t; typedef typename graph_traits<Graph>::edge_descriptor edge_t; typedef typename graph_traits<Graph>::vertices_size_type vn_t; typedef std::vector<float_t> vp_t; typedef typename boost::iterator_property_map< typename vp_t::iterator, VertexIndexMap > distance_map_t; //V -> float_t typedef typename std::vector<edge_t> ve_t; typedef std::vector<my_color_type> vcol_t; typedef typename ::boost::iterator_property_map< typename ve_t::iterator, VertexIndexMap > policy_t; //Vertex -> Edge typedef typename ::boost::iterator_property_map< typename vcol_t::iterator, VertexIndexMap > color_map_t; typedef typename std::list<vertex_t> pinel_t;// The in_edges list of the policy graph typedef typename std::vector<pinel_t> inedges1_t; typedef typename ::boost::iterator_property_map< typename inedges1_t::iterator, VertexIndexMap > inedges_t; typedef typename std::vector<edge_t> critical_cycle_t; //Bad vertex flag. If true, then the vertex is "bad". // Vertex is "bad" if its out_degree is equal to zero. typedef typename boost::iterator_property_map< std::vector<int>::iterator, VertexIndexMap > badv_t; /*! * Constructor * \param g = (V, E) - a directed multigraph. * \param vim Vertex Index Map. Read property Map: V -> [0, num_vertices(g)). * \param ewm edge weight map. Read property map: E -> R * \param ew2m edge weight map. Read property map: E -> R+ * \param infty A big enough value to guaranty that there exist a cycle with * better ratio. * \param cmp The compare operator for float_ts. */ mcr_howard(const Graph &g, VertexIndexMap vim, EdgeWeight1 ewm, EdgeWeight2 ew2m) : m_g(g), m_vim(vim), m_ew1m(ewm), m_ew2m(ew2m), m_bound(mcr_bound()), m_cr(m_bound), m_V(num_vertices(m_g)), m_dis(m_V, 0), m_dm(m_dis.begin(), m_vim), m_policyc(m_V), m_policy(m_policyc.begin(), m_vim), m_inelc(m_V), m_inel(m_inelc.begin(), m_vim), m_badvc(m_V, false), m_badv(m_badvc.begin(), m_vim), m_colcv(m_V), m_col_bfs(m_V) { } /*! * \return maximum/minimum_{for all cycles C} * [sum_{e in C} w1(e)] / [sum_{e in C} w2(e)], * or FloatTraits::infinity() if graph has no cycles. */ float_t ocr_howard() { construct_policy_graph(); int k = 0; float_t mcr = 0; do { mcr = policy_mcr(); ++k; } while (try_improve_policy(mcr) && k < 100); //To avoid infinite loop const float_t eps_ = -0.00000001 * cmp_props_t::multiplier; if (m_cmp(mcr, m_bound + eps_)) { return FloatTraits::infinity(); } else { return mcr; } } virtual ~mcr_howard() {} protected: virtual void store_critical_edge(edge_t, critical_cycle_t &) {} virtual void store_critical_cycle(critical_cycle_t &) {} private: /*! * \return lower/upper bound for the maximal/minimal cycle ratio */ float_t mcr_bound() { typename graph_traits<Graph>::vertex_iterator vi, vie; typename graph_traits<Graph>::out_edge_iterator oei, oeie; float_t cz = (std::numeric_limits<float_t>::max)(); //Closest to zero value float_t s = 0; const float_t eps_ = std::numeric_limits<float_t>::epsilon(); for (tie(vi, vie) = vertices(m_g); vi != vie; ++vi) { for (tie(oei, oeie) = out_edges(*vi, m_g); oei != oeie; ++oei) { s += std::abs(m_ew1m[*oei]); float_t a = std::abs(m_ew2m[*oei]); if ( a > eps_ && a < cz) { cz = a; } } } return cmp_props_t::multiplier * (s / cz); } /*! * Constructs an arbitrary policy graph. */ void construct_policy_graph() { m_sink = graph_traits<Graph>().null_vertex(); typename graph_traits<Graph>::vertex_iterator vi, vie; typename graph_traits<Graph>::out_edge_iterator oei, oeie; for ( tie(vi, vie) = vertices(m_g); vi != vie; ++vi ) { tie(oei, oeie) = out_edges(*vi, m_g); typename graph_traits<Graph>::out_edge_iterator mei = std::max_element(oei, oeie, boost::bind(m_cmp, boost::bind(&EdgeWeight1::operator[], m_ew1m, _1), boost::bind(&EdgeWeight1::operator[], m_ew1m, _2) ) ); if (mei == oeie) { if (m_sink == graph_traits<Graph>().null_vertex()) { m_sink = *vi; } m_badv[*vi] = true; m_inel[m_sink].push_back(*vi); } else { m_inel[target(*mei, m_g)].push_back(*vi); m_policy[*vi] = *mei; } } } /*! Sets the distance value for all vertices "v" such that there is * a path from "v" to "sv". It does "inverse" breadth first visit of the policy * graph, starting from the vertex "sv". */ void mcr_bfv(vertex_t sv, float_t cr, color_map_t c) { boost::queue<vertex_t> Q; c[sv] = my_black; Q.push(sv); while (!Q.empty()) { vertex_t v = Q.top(); Q.pop(); for (typename pinel_t::const_iterator itr = m_inel[v].begin(); itr != m_inel[v].end(); ++itr) //For all in_edges of the policy graph { if (*itr != sv) { if (m_badv[*itr]) { m_dm[*itr] = m_dm[v] + m_bound - cr; } else { m_dm[*itr] = m_dm[v] + m_ew1m[m_policy[*itr]] - m_ew2m[m_policy[*itr]] * cr; } c[*itr] = my_black; Q.push(*itr); } } } } /*! * \param sv an arbitrary (undiscovered) vertex of the policy graph. * \return a vertex in the policy graph that belongs to a cycle. * Performs a depth first visit until a cycle edge is found. */ vertex_t find_cycle_vertex(vertex_t sv) { vertex_t gv = sv; std::fill(m_colcv.begin(), m_colcv.end(), my_white); color_map_t cm(m_colcv.begin(), m_vim); do { cm[gv] = my_black; if (! m_badv[gv]) { gv = target(m_policy[gv], m_g); } else { gv = m_sink; } } while (cm[gv] != my_black); return gv; } /*! * \param sv - vertex that belongs to a cycle in the policy graph. */ float_t cycle_ratio(vertex_t sv) { if (sv == m_sink) return m_bound; std::pair<float_t, float_t> sums_(float_t(0), float_t(0)); vertex_t v = sv; critical_cycle_t cc; do { store_critical_edge(m_policy[v], cc); sums_.first += m_ew1m[m_policy[v]]; sums_.second += m_ew2m[m_policy[v]]; v = target(m_policy[v], m_g); } while (v != sv); float_t cr = sums_.first / sums_.second; if ( m_cmp(m_cr, cr) ) { m_cr = cr; store_critical_cycle(cc); } return cr; } /*! * Finds the optimal cycle ratio of the policy graph */ float_t policy_mcr() { std::fill(m_col_bfs.begin(), m_col_bfs.end(), my_white); color_map_t vcm_ = color_map_t(m_col_bfs.begin(), m_vim); typename graph_traits<Graph>::vertex_iterator uv_itr, vie; tie(uv_itr, vie) = vertices(m_g); float_t mcr = m_bound; while ( (uv_itr = std::find_if(uv_itr, vie, boost::bind(std::equal_to<my_color_type>(), my_white, boost::bind(&color_map_t::operator[], vcm_, _1) ) ) ) != vie ) ///While there are undiscovered vertices { vertex_t gv = find_cycle_vertex(*uv_itr); float_t cr = cycle_ratio(gv) ; mcr_bfv(gv, cr, vcm_); if ( m_cmp(mcr, cr) ) mcr = cr; ++uv_itr; } return mcr; } /*! * Changes the edge m_policy[s] to the new_edge. */ void improve_policy(vertex_t s, edge_t new_edge) { vertex_t t = target(m_policy[s], m_g); typename property_traits<VertexIndexMap>::value_type ti = m_vim[t]; m_inelc[ti].erase( std::find(m_inelc[ti].begin(), m_inelc[ti].end(), s)); m_policy[s] = new_edge; t = target(new_edge, m_g); m_inel[t].push_back(s); ///Maintain in_edge list } /*! * A negative cycle detector. */ bool try_improve_policy(float_t cr) { bool improved = false; typename graph_traits<Graph>::vertex_iterator vi, vie; typename graph_traits<Graph>::out_edge_iterator oei, oeie; const float_t eps_ = FloatTraits::epsilon(); for (tie(vi, vie) = vertices(m_g); vi != vie; ++vi) { if (!m_badv[*vi]) { for (tie(oei, oeie) = out_edges(*vi, m_g); oei != oeie; ++oei) { vertex_t t = target(*oei, m_g); //Current distance from *vi to some vertex float_t dis_ = m_ew1m[*oei] - m_ew2m[*oei] * cr + m_dm[t]; if ( m_cmp(m_dm[*vi] + eps_, dis_) ) { improve_policy(*vi, *oei); m_dm[*vi] = dis_; improved = true; } } } else { float_t dis_ = m_bound - cr + m_dm[m_sink]; if ( m_cmp(m_dm[*vi] + eps_, dis_) ) { m_dm[*vi] = dis_; } } } return improved; } private: const Graph &m_g; VertexIndexMap m_vim; EdgeWeight1 m_ew1m; EdgeWeight2 m_ew2m; comparator_t m_cmp; float_t m_bound; //> The lower/upper bound to the maximal/minimal cycle ratio float_t m_cr; //>The best cycle ratio that has been found so far vn_t m_V; //>The number of the vertices in the graph vp_t m_dis; //>Container for the distance map distance_map_t m_dm; //>Distance map ve_t m_policyc; //>Container for the policy graph policy_t m_policy; //>The interface for the policy graph inedges1_t m_inelc; //>Container fot in edges list inedges_t m_inel; //>Policy graph, input edges list std::vector<int> m_badvc; badv_t m_badv; //Marks "bad" vertices vcol_t m_colcv, m_col_bfs; //Color maps vertex_t m_sink; //To convert any graph to "good" }; /*! \class mcr_howard1 * \brief Finds optimum cycle raio and a critical cycle */ template <typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeight1, typename EdgeWeight2> class mcr_howard1 : public mcr_howard<FloatTraits, Graph, VertexIndexMap, EdgeWeight1, EdgeWeight2> { public: typedef mcr_howard<FloatTraits, Graph, VertexIndexMap, EdgeWeight1, EdgeWeight2> inhr_t; mcr_howard1(const Graph &g, VertexIndexMap vim, EdgeWeight1 ewm, EdgeWeight2 ew2m) : inhr_t(g, vim, ewm, ew2m) { } void get_critical_cycle(typename inhr_t::critical_cycle_t &cc) { return cc.swap(m_cc); } protected: void store_critical_edge(typename inhr_t::edge_t ed, typename inhr_t::critical_cycle_t &cc) { cc.push_back(ed); } void store_critical_cycle(typename inhr_t::critical_cycle_t &cc) { m_cc.swap(cc); } private: typename inhr_t::critical_cycle_t m_cc; //Critical cycle }; /*! * \param g a directed multigraph. * \param vim Vertex Index Map. A map V->[0, num_vertices(g)) * \param ewm Edge weight1 map. * \param ew2m Edge weight2 map. * \param pcc pointer to the critical edges list. * \return Optimum cycle ratio of g or FloatTraits::infinity() if g has no cycles. */ template <typename FT, typename TG, typename TVIM, typename TEW1, typename TEW2, typename EV> typename FT::value_type optimum_cycle_ratio(const TG &g, TVIM vim, TEW1 ewm, TEW2 ew2m, EV* pcc) { typedef typename graph_traits<TG>::directed_category DirCat; BOOST_STATIC_ASSERT((is_convertible<DirCat*, directed_tag*>::value == true)); function_requires< IncidenceGraphConcept<TG> >(); function_requires< VertexListGraphConcept<TG> >(); typedef typename graph_traits<TG>::vertex_descriptor Vertex; function_requires< ReadablePropertyMapConcept<TVIM, Vertex> >(); typedef typename graph_traits<TG>::edge_descriptor Edge; function_requires< ReadablePropertyMapConcept<TEW1, Edge> >(); function_requires< ReadablePropertyMapConcept<TEW2, Edge> >(); if(pcc == 0) { return detail::mcr_howard<FT,TG, TVIM, TEW1, TEW2>( g, vim, ewm, ew2m ).ocr_howard(); } detail::mcr_howard1<FT, TG, TVIM, TEW1, TEW2> obj(g, vim, ewm, ew2m); double ocr = obj.ocr_howard(); obj.get_critical_cycle(*pcc); return ocr; } } // namespace detail // Algorithms // Maximum Cycle Ratio template < typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeight1Map, typename EdgeWeight2Map> inline typename FloatTraits::value_type maximum_cycle_ratio(const Graph &g, VertexIndexMap vim, EdgeWeight1Map ew1m, EdgeWeight2Map ew2m, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0, FloatTraits = FloatTraits()) { typedef detail::float_wrapper< FloatTraits, detail::max_comparator_props<FloatTraits> > Traits; return detail::optimum_cycle_ratio<Traits>(g, vim, ew1m, ew2m, pcc); } template < typename Graph, typename VertexIndexMap, typename EdgeWeight1Map, typename EdgeWeight2Map> inline double maximum_cycle_ratio(const Graph &g, VertexIndexMap vim, EdgeWeight1Map ew1m, EdgeWeight2Map ew2m, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0) { return maximum_cycle_ratio(g, vim, ew1m, ew2m, pcc, mcr_float<>()); } // Minimum Cycle Ratio template < typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeight1Map, typename EdgeWeight2Map> typename FloatTraits::value_type minimum_cycle_ratio(const Graph &g, VertexIndexMap vim, EdgeWeight1Map ew1m, EdgeWeight2Map ew2m, std::vector<typename graph_traits<Graph>::edge_descriptor> *pcc = 0, FloatTraits = FloatTraits()) { typedef detail::float_wrapper< FloatTraits, detail::min_comparator_props<FloatTraits> > Traits; return detail::optimum_cycle_ratio<Traits>(g, vim, ew1m, ew2m, pcc); } template < typename Graph, typename VertexIndexMap, typename EdgeWeight1Map, typename EdgeWeight2Map> inline double minimum_cycle_ratio(const Graph &g, VertexIndexMap vim, EdgeWeight1Map ew1m, EdgeWeight2Map ew2m, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0) { return minimum_cycle_ratio(g, vim, ew1m, ew2m, pcc, mcr_float<>()); } // Maximum Cycle Mean template < typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeightMap, typename EdgeIndexMap> inline typename FloatTraits::value_type maximum_cycle_mean(const Graph &g, VertexIndexMap vim, EdgeWeightMap ewm, EdgeIndexMap eim, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0, FloatTraits ft = FloatTraits()) { typedef typename remove_const< typename property_traits<EdgeWeightMap>::value_type >::type Weight; typename std::vector<Weight> ed_w2(boost::num_edges(g), 1); return maximum_cycle_ratio(g, vim, ewm, make_iterator_property_map(ed_w2.begin(), eim), pcc, ft); } template < typename Graph, typename VertexIndexMap, typename EdgeWeightMap, typename EdgeIndexMap> inline double maximum_cycle_mean(const Graph& g, VertexIndexMap vim, EdgeWeightMap ewm, EdgeIndexMap eim, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0) { return maximum_cycle_mean(g, vim, ewm, eim, pcc, mcr_float<>()); } // Minimum Cycle Mean template < typename FloatTraits, typename Graph, typename VertexIndexMap, typename EdgeWeightMap, typename EdgeIndexMap> inline typename FloatTraits::value_type minimum_cycle_mean(const Graph &g, VertexIndexMap vim, EdgeWeightMap ewm, EdgeIndexMap eim, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0, FloatTraits ft = FloatTraits()) { typedef typename remove_const< typename property_traits<EdgeWeightMap>::value_type >::type Weight; typename std::vector<Weight> ed_w2(boost::num_edges(g), 1); return minimum_cycle_ratio(g, vim, ewm, make_iterator_property_map(ed_w2.begin(), eim), pcc, ft); } template < typename Graph, typename VertexIndexMap, typename EdgeWeightMap, typename EdgeIndexMap> inline double minimum_cycle_mean(const Graph &g, VertexIndexMap vim, EdgeWeightMap ewm, EdgeIndexMap eim, std::vector<typename graph_traits<Graph>::edge_descriptor>* pcc = 0) { return minimum_cycle_mean(g, vim, ewm, eim, pcc, mcr_float<>()); } } //namespace boost #endif