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/uniform_real.hpp> #include <boost/random/variate_generator.hpp> #include <boost/pending/property.hpp> #include <boost/graph/properties.hpp> #include <boost/graph/iteration_macros.hpp> #include <boost/next_prior.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> #include <boost/assert.hpp> 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(BOOST_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; return *(boost::next(i, n)); } 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(BOOST_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; return *(boost::next(i, n)); } else return *edges(g).first; } template < typename Graph, typename RandomNumGen > typename graph_traits< Graph >::edge_descriptor random_out_edge(Graph& g, typename graph_traits< Graph >::vertex_descriptor src, RandomNumGen& gen) { typedef typename graph_traits< Graph >::degree_size_type degree_size_type; typedef boost::uniform_int< degree_size_type > ui_type; ui_type ui(0, out_degree(src, g) - 1); boost::variate_generator< RandomNumGen&, ui_type > variate(gen, ui); typename graph_traits< Graph >::out_edge_iterator it = out_edges(src, g).first; std::advance(it, variate()); return *it; } template < typename Graph, typename WeightMap, typename RandomNumGen > typename graph_traits< Graph >::edge_descriptor weighted_random_out_edge( Graph& g, typename graph_traits< Graph >::vertex_descriptor src, WeightMap weight, RandomNumGen& gen) { typedef typename property_traits< WeightMap >::value_type weight_type; weight_type weight_sum(0); BGL_FORALL_OUTEDGES_T(src, e, g, Graph) { weight_sum += get(weight, e); } typedef boost::uniform_real<> ur_type; ur_type ur(0, weight_sum); boost::variate_generator< RandomNumGen&, ur_type > variate(gen, ur); weight_type chosen_weight = variate(); BGL_FORALL_OUTEDGES_T(src, e, g, Graph) { weight_type w = get(weight, e); if (chosen_weight < w) { return e; } else { chosen_weight -= w; } } BOOST_ASSERT(false); // Should not get here return typename graph_traits< Graph >::edge_descriptor(); } 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::edge_descriptor edge_t; 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); e_size_t not_inserted_counter = 0; /* Number of edge insertion failures */ e_size_t num_vertices_squared = num_vertices(g) * num_vertices(g); for (e_size_t j = 0; j < E; /* Increment in body */) { vertex_descriptor a = random_vertex(g, gen), b; do { b = random_vertex(g, gen); } while (self_edges == false && a == b); edge_t e; bool inserted; boost::tie(e, inserted) = add_edge(a, b, g); if (inserted) { ++j; } else { ++not_inserted_counter; } if (not_inserted_counter >= num_vertices_squared) { return; /* Rather than looping forever on complete graph */ } } } } 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); e_size_t not_inserted_counter = 0; /* Number of edge insertion failures */ e_size_t num_vertices_squared = num_vertices(g) * num_vertices(g); for (e_size_t j = 0; j < E; /* Increment in body */) { 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; boost::tie(e, inserted) = add_edge(a, b, g); if (inserted) { *edge_out++ = std::make_pair(source(e, g), target(e, g)); ++j; } else { ++not_inserted_counter; } if (not_inserted_counter >= num_vertices_squared) { return; /* Rather than looping forever on complete graph */ } } } 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 (boost::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 (boost::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()); } } #include <boost/graph/iteration_macros_undef.hpp> #endif