boost/graph/random.hpp
//======================================================================= // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. // Copyright (C) Vladimir Prus 2003 // 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_RANDOM_HPP #define BOOST_GRAPH_RANDOM_HPP #include <boost/graph/graph_traits.hpp> #include <boost/random/uniform_int.hpp> #include <boost/random/variate_generator.hpp> #include <boost/pending/property.hpp> #include <boost/graph/properties.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/copy.hpp> #include <boost/mpl/if.hpp> #include <boost/type_traits/is_convertible.hpp> #include <iostream> namespace boost { // grab a random vertex from the graph's vertex set template <class Graph, class RandomNumGen> typename graph_traits<Graph>::vertex_descriptor random_vertex(Graph& g, RandomNumGen& gen) { if (num_vertices(g) > 1) { #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581)) std::size_t n = std::random( num_vertices(g) ); #else uniform_int<> distrib(0, num_vertices(g)-1); variate_generator<RandomNumGen&, uniform_int<> > rand_gen(gen, distrib); std::size_t n = rand_gen(); #endif typename graph_traits<Graph>::vertex_iterator i = vertices(g).first; while (n-- > 0) ++i; // std::advance not VC++ portable return *i; } else return *vertices(g).first; } template <class Graph, class RandomNumGen> typename graph_traits<Graph>::edge_descriptor random_edge(Graph& g, RandomNumGen& gen) { if (num_edges(g) > 1) { #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581)) typename graph_traits<Graph>::edges_size_type n = std::random( num_edges(g) ); #else uniform_int<> distrib(0, num_edges(g)-1); variate_generator<RandomNumGen&, uniform_int<> > rand_gen(gen, distrib); typename graph_traits<Graph>::edges_size_type n = rand_gen(); #endif typename graph_traits<Graph>::edge_iterator i = edges(g).first; while (n-- > 0) ++i; // std::advance not VC++ portable return *i; } else return *edges(g).first; } namespace detail { class dummy_property_copier { public: template<class V1, class V2> void operator()(const V1&, const V2&) const {} }; } template <typename MutableGraph, class RandNumGen> void generate_random_graph1 (MutableGraph& g, typename graph_traits<MutableGraph>::vertices_size_type V, typename graph_traits<MutableGraph>::vertices_size_type E, RandNumGen& gen, bool allow_parallel = true, bool self_edges = false) { typedef graph_traits<MutableGraph> Traits; typedef typename Traits::vertices_size_type v_size_t; typedef typename Traits::edges_size_type e_size_t; typedef typename Traits::vertex_descriptor vertex_descriptor; // When parallel edges are not allowed, we create a new graph which // does not allow parallel edges, construct it and copy back. // This is not efficient if 'g' already disallow parallel edges, // but that's task for later. if (!allow_parallel) { typedef typename boost::graph_traits<MutableGraph>::directed_category dir; typedef typename mpl::if_<is_convertible<dir, directed_tag>, directedS, undirectedS>::type select; adjacency_list<setS, vecS, select> g2; generate_random_graph1(g2, V, E, gen, true, self_edges); copy_graph(g2, g, vertex_copy(detail::dummy_property_copier()). edge_copy(detail::dummy_property_copier())); } else { for (v_size_t i = 0; i < V; ++i) add_vertex(g); for (e_size_t j = 0; j < E; ++j) { vertex_descriptor a = random_vertex(g, gen), b; do { b = random_vertex(g, gen); } while (self_edges == false && a == b); add_edge(a, b, g); } } } template <typename MutableGraph, class RandNumGen> void generate_random_graph (MutableGraph& g, typename graph_traits<MutableGraph>::vertices_size_type V, typename graph_traits<MutableGraph>::vertices_size_type E, RandNumGen& gen, bool allow_parallel = true, bool self_edges = false) { generate_random_graph1(g, V, E, gen, allow_parallel, self_edges); } template <typename MutableGraph, typename RandNumGen, typename VertexOutputIterator, typename EdgeOutputIterator> void generate_random_graph (MutableGraph& g, typename graph_traits<MutableGraph>::vertices_size_type V, typename graph_traits<MutableGraph>::vertices_size_type E, RandNumGen& gen, VertexOutputIterator vertex_out, EdgeOutputIterator edge_out, bool self_edges = false) { typedef graph_traits<MutableGraph> Traits; typedef typename Traits::vertices_size_type v_size_t; typedef typename Traits::edges_size_type e_size_t; typedef typename Traits::vertex_descriptor vertex_t; typedef typename Traits::edge_descriptor edge_t; for (v_size_t i = 0; i < V; ++i) *vertex_out++ = add_vertex(g); for (e_size_t j = 0; j < E; ++j) { vertex_t a = random_vertex(g, gen), b; do { b = random_vertex(g, gen); } while (self_edges == false && a == b); edge_t e; bool inserted; tie(e, inserted) = add_edge(a, b, g); if (inserted) *edge_out++ = std::make_pair(source(e, g), target(e, g)); } } namespace detail { template<class Property, class G, class RandomGenerator> void randomize_property(G& g, RandomGenerator& rg, Property, vertex_property_tag) { typename property_map<G, Property>::type pm = get(Property(), g); typename graph_traits<G>::vertex_iterator vi, ve; for (tie(vi, ve) = vertices(g); vi != ve; ++vi) { pm[*vi] = rg(); } } template<class Property, class G, class RandomGenerator> void randomize_property(G& g, RandomGenerator& rg, Property, edge_property_tag) { typename property_map<G, Property>::type pm = get(Property(), g); typename graph_traits<G>::edge_iterator ei, ee; for (tie(ei, ee) = edges(g); ei != ee; ++ei) { pm[*ei] = rg(); } } } template<class Property, class G, class RandomGenerator> void randomize_property(G& g, RandomGenerator& rg) { detail::randomize_property (g, rg, Property(), typename property_kind<Property>::type()); } } #endif