Chris@16: //=======================================================================
Chris@16: // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
Chris@16: // Copyright (C) Vladimir Prus 2003
Chris@16: // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //=======================================================================
Chris@16: #ifndef BOOST_GRAPH_RANDOM_HPP
Chris@16: #define BOOST_GRAPH_RANDOM_HPP
Chris@16: 
Chris@16: #include <boost/graph/graph_traits.hpp>
Chris@16: #include <boost/random/uniform_int.hpp>
Chris@16: #include <boost/random/uniform_real.hpp>
Chris@16: #include <boost/random/variate_generator.hpp>
Chris@16: 
Chris@16: #include <boost/pending/property.hpp>
Chris@16: #include <boost/graph/properties.hpp>
Chris@16: #include <boost/graph/iteration_macros.hpp>
Chris@16: #include <boost/next_prior.hpp>
Chris@16: 
Chris@16: #include <boost/graph/adjacency_list.hpp>
Chris@16: #include <boost/graph/copy.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: 
Chris@16: #include <iostream>
Chris@16: #include <boost/assert.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16:   // grab a random vertex from the graph's vertex set
Chris@16:   template <class Graph, class RandomNumGen>
Chris@16:   typename graph_traits<Graph>::vertex_descriptor
Chris@16:   random_vertex(Graph& g, RandomNumGen& gen)
Chris@16:   {
Chris@16:     if (num_vertices(g) > 1) {
Chris@16:     #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581))
Chris@16:       std::size_t n = std::random( num_vertices(g) );
Chris@16:     #else
Chris@16:       uniform_int<> distrib(0, num_vertices(g)-1);
Chris@16:       variate_generator<RandomNumGen&, uniform_int<> > rand_gen(gen, distrib);
Chris@16:       std::size_t n = rand_gen();
Chris@16:     #endif
Chris@16:       typename graph_traits<Graph>::vertex_iterator
Chris@16:         i = vertices(g).first;
Chris@16:       return *(boost::next(i, n));
Chris@16:     } else
Chris@16:       return *vertices(g).first;
Chris@16:   }
Chris@16: 
Chris@16:   template <class Graph, class RandomNumGen>
Chris@16:   typename graph_traits<Graph>::edge_descriptor
Chris@16:   random_edge(Graph& g, RandomNumGen& gen) {
Chris@16:     if (num_edges(g) > 1) {
Chris@16:     #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581))
Chris@16:       typename graph_traits<Graph>::edges_size_type
Chris@16:         n = std::random( num_edges(g) );
Chris@16:     #else
Chris@16:       uniform_int<> distrib(0, num_edges(g)-1);
Chris@16:       variate_generator<RandomNumGen&, uniform_int<> > rand_gen(gen, distrib);
Chris@16:       typename graph_traits<Graph>::edges_size_type
Chris@16:         n = rand_gen();
Chris@16:     #endif
Chris@16:       typename graph_traits<Graph>::edge_iterator
Chris@16:         i = edges(g).first;
Chris@16:       return *(boost::next(i, n));
Chris@16:     } else
Chris@16:       return *edges(g).first;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Graph, typename RandomNumGen>
Chris@16:   typename graph_traits<Graph>::edge_descriptor
Chris@16:   random_out_edge(Graph& g, typename graph_traits<Graph>::vertex_descriptor src, RandomNumGen& gen) {
Chris@16:     typedef typename graph_traits<Graph>::degree_size_type degree_size_type;
Chris@16:     typedef boost::uniform_int<degree_size_type> ui_type;
Chris@16:     ui_type ui(0, out_degree(src, g) - 1);
Chris@16:     boost::variate_generator<RandomNumGen&, ui_type>
Chris@16:       variate(gen, ui);
Chris@16:     typename graph_traits<Graph>::out_edge_iterator it = out_edges(src, g).first;
Chris@16:     std::advance(it, variate());
Chris@16:     return *it;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Graph, typename WeightMap, typename RandomNumGen>
Chris@16:   typename graph_traits<Graph>::edge_descriptor
Chris@16:   weighted_random_out_edge(Graph& g, typename graph_traits<Graph>::vertex_descriptor src, WeightMap weight, RandomNumGen& gen) {
Chris@16:     typedef typename property_traits<WeightMap>::value_type weight_type;
Chris@16:     weight_type weight_sum(0);
Chris@16:     BGL_FORALL_OUTEDGES_T(src, e, g, Graph) {weight_sum += get(weight, e);}
Chris@16:     typedef boost::uniform_real<> ur_type;
Chris@16:     ur_type ur(0, weight_sum);
Chris@16:     boost::variate_generator<RandomNumGen&, ur_type>
Chris@16:       variate(gen, ur);
Chris@16:     weight_type chosen_weight = variate();
Chris@16:     BGL_FORALL_OUTEDGES_T(src, e, g, Graph) {
Chris@16:       weight_type w = get(weight, e);
Chris@16:       if (chosen_weight < w) {
Chris@16:         return e;
Chris@16:       } else {
Chris@16:         chosen_weight -= w;
Chris@16:       }
Chris@16:     }
Chris@16:     BOOST_ASSERT (false); // Should not get here
Chris@16:   }
Chris@16: 
Chris@16:   namespace detail {
Chris@16:     class dummy_property_copier {
Chris@16:     public:
Chris@16:       template<class V1, class V2>
Chris@16:       void operator()(const V1&, const V2&) const {}
Chris@16:     };
Chris@16:   }
Chris@16: 
Chris@16:   template <typename MutableGraph, class RandNumGen>
Chris@16:   void generate_random_graph1
Chris@16:     (MutableGraph& g,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type V,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type E,
Chris@16:      RandNumGen& gen,
Chris@16:      bool allow_parallel = true,
Chris@16:      bool self_edges = false)
Chris@16:   {
Chris@16:     typedef graph_traits<MutableGraph> Traits;
Chris@16:     typedef typename Traits::edge_descriptor edge_t;
Chris@16:     typedef typename Traits::vertices_size_type v_size_t;
Chris@16:     typedef typename Traits::edges_size_type e_size_t;
Chris@16:     typedef typename Traits::vertex_descriptor vertex_descriptor;
Chris@16: 
Chris@16:     // When parallel edges are not allowed, we create a new graph which
Chris@16:     // does not allow parallel edges, construct it and copy back.
Chris@16:     // This is not efficient if 'g' already disallow parallel edges,
Chris@16:     // but that's task for later.
Chris@16:     if (!allow_parallel) {
Chris@16: 
Chris@16:       typedef typename boost::graph_traits<MutableGraph>::directed_category dir;
Chris@16:       typedef typename mpl::if_<is_convertible<dir, directed_tag>,
Chris@16:           directedS, undirectedS>::type select;
Chris@16:       adjacency_list<setS, vecS, select> g2;
Chris@16:       generate_random_graph1(g2, V, E, gen, true, self_edges);
Chris@16: 
Chris@16:       copy_graph(g2, g, vertex_copy(detail::dummy_property_copier()).
Chris@16:                         edge_copy(detail::dummy_property_copier()));
Chris@16: 
Chris@16:     } else {
Chris@16: 
Chris@16:       for (v_size_t i = 0; i < V; ++i)
Chris@16:         add_vertex(g);
Chris@16: 
Chris@16:       e_size_t not_inserted_counter = 0; /* Number of edge insertion failures */
Chris@16:       e_size_t num_vertices_squared = num_vertices(g) * num_vertices(g);
Chris@16:       for (e_size_t j = 0; j < E; /* Increment in body */) {
Chris@16:         vertex_descriptor a = random_vertex(g, gen), b;
Chris@16:         do {
Chris@16:           b = random_vertex(g, gen);
Chris@16:         } while (self_edges == false && a == b);
Chris@16:         edge_t e; bool inserted;
Chris@16:         boost::tie(e, inserted) = add_edge(a, b, g);
Chris@16:         if (inserted) {
Chris@16:           ++j;
Chris@16:         } else {
Chris@16:           ++not_inserted_counter;
Chris@16:         }
Chris@16:         if (not_inserted_counter >= num_vertices_squared) {
Chris@16:           return; /* Rather than looping forever on complete graph */
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   template <typename MutableGraph, class RandNumGen>
Chris@16:   void generate_random_graph
Chris@16:     (MutableGraph& g,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type V,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type E,
Chris@16:      RandNumGen& gen,
Chris@16:      bool allow_parallel = true,
Chris@16:      bool self_edges = false)
Chris@16:   {
Chris@16:       generate_random_graph1(g, V, E, gen, allow_parallel, self_edges);
Chris@16:   }
Chris@16: 
Chris@16:   template <typename MutableGraph, typename RandNumGen,
Chris@16:             typename VertexOutputIterator, typename EdgeOutputIterator>
Chris@16:   void generate_random_graph
Chris@16:     (MutableGraph& g,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type V,
Chris@16:      typename graph_traits<MutableGraph>::vertices_size_type E,
Chris@16:      RandNumGen& gen,
Chris@16:      VertexOutputIterator vertex_out,
Chris@16:      EdgeOutputIterator edge_out,
Chris@16:      bool self_edges = false)
Chris@16:   {
Chris@16:     typedef graph_traits<MutableGraph> Traits;
Chris@16:     typedef typename Traits::vertices_size_type v_size_t;
Chris@16:     typedef typename Traits::edges_size_type e_size_t;
Chris@16:     typedef typename Traits::vertex_descriptor vertex_t;
Chris@16:     typedef typename Traits::edge_descriptor edge_t;
Chris@16: 
Chris@16:     for (v_size_t i = 0; i < V; ++i)
Chris@16:       *vertex_out++ = add_vertex(g);
Chris@16: 
Chris@16:     e_size_t not_inserted_counter = 0; /* Number of edge insertion failures */
Chris@16:     e_size_t num_vertices_squared = num_vertices(g) * num_vertices(g);
Chris@16:     for (e_size_t j = 0; j < E; /* Increment in body */) {
Chris@16:       vertex_t a = random_vertex(g, gen), b;
Chris@16:       do {
Chris@16:         b = random_vertex(g, gen);
Chris@16:       } while (self_edges == false && a == b);
Chris@16:       edge_t e; bool inserted;
Chris@16:       boost::tie(e, inserted) = add_edge(a, b, g);
Chris@16:       if (inserted) {
Chris@16:         *edge_out++ = std::make_pair(source(e, g), target(e, g));
Chris@16:         ++j;
Chris@16:       } else {
Chris@16:         ++not_inserted_counter;
Chris@16:       }
Chris@16:       if (not_inserted_counter >= num_vertices_squared) {
Chris@16:         return; /* Rather than looping forever on complete graph */
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   namespace detail {
Chris@16: 
Chris@16:     template<class Property, class G, class RandomGenerator>
Chris@16:     void randomize_property(G& g, RandomGenerator& rg,
Chris@16:                             Property, vertex_property_tag)
Chris@16:     {
Chris@16:       typename property_map<G, Property>::type pm = get(Property(), g);
Chris@16:       typename graph_traits<G>::vertex_iterator vi, ve;
Chris@16:       for (boost::tie(vi, ve) = vertices(g); vi != ve; ++vi) {
Chris@16:         pm[*vi] = rg();
Chris@16:       }
Chris@16:     }
Chris@16: 
Chris@16:     template<class Property, class G, class RandomGenerator>
Chris@16:     void randomize_property(G& g, RandomGenerator& rg,
Chris@16:                             Property, edge_property_tag)
Chris@16:     {
Chris@16:       typename property_map<G, Property>::type pm = get(Property(), g);
Chris@16:       typename graph_traits<G>::edge_iterator ei, ee;
Chris@16:       for (boost::tie(ei, ee) = edges(g); ei != ee; ++ei) {
Chris@16:         pm[*ei] = rg();
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   template<class Property, class G, class RandomGenerator>
Chris@16:   void randomize_property(G& g, RandomGenerator& rg)
Chris@16:   {
Chris@16:     detail::randomize_property
Chris@16:         (g, rg, Property(), typename property_kind<Property>::type());
Chris@16:   }
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16:   
Chris@16: }
Chris@16: 
Chris@16: #include <boost/graph/iteration_macros_undef.hpp>
Chris@16: 
Chris@16: #endif