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158 lines
5.5 KiB
158 lines
5.5 KiB
// (C) Copyright 2007-2009 Andrew Sutton |
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// |
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// Use, modification and distribution are subject to the |
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// Boost Software License, Version 1.0 (See accompanying file |
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// LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_GRAPH_CLUSTERING_COEFFICIENT_HPP |
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#define BOOST_GRAPH_CLUSTERING_COEFFICIENT_HPP |
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#include <boost/utility.hpp> |
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#include <boost/graph/graph_traits.hpp> |
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#include <boost/graph/graph_concepts.hpp> |
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#include <boost/graph/lookup_edge.hpp> |
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namespace boost |
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{ |
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namespace detail |
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{ |
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template <class Graph> |
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inline typename graph_traits<Graph>::degree_size_type |
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possible_edges(const Graph& g, std::size_t k, directed_tag) |
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{ |
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function_requires< GraphConcept<Graph> >(); |
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typedef typename graph_traits<Graph>::degree_size_type T; |
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return T(k) * (T(k) - 1); |
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} |
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template <class Graph> |
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inline typename graph_traits<Graph>::degree_size_type |
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possible_edges(const Graph& g, size_t k, undirected_tag) |
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{ |
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// dirty little trick... |
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return possible_edges(g, k, directed_tag()) / 2; |
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} |
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// This template matches directedS and bidirectionalS. |
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template <class Graph> |
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inline typename graph_traits<Graph>::degree_size_type |
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count_edges(const Graph& g, |
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typename graph_traits<Graph>::vertex_descriptor u, |
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typename graph_traits<Graph>::vertex_descriptor v, |
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directed_tag) |
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{ |
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function_requires< AdjacencyMatrixConcept<Graph> >(); |
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return (lookup_edge(u, v, g).second ? 1 : 0) + |
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(lookup_edge(v, u, g).second ? 1 : 0); |
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} |
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// This template matches undirectedS |
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template <class Graph> |
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inline typename graph_traits<Graph>::degree_size_type |
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count_edges(const Graph& g, |
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typename graph_traits<Graph>::vertex_descriptor u, |
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typename graph_traits<Graph>::vertex_descriptor v, |
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undirected_tag) |
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{ |
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function_requires< AdjacencyMatrixConcept<Graph> >(); |
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return lookup_edge(u, v, g).second ? 1 : 0; |
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} |
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} |
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template <typename Graph, typename Vertex> |
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inline typename graph_traits<Graph>::degree_size_type |
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num_paths_through_vertex(const Graph& g, Vertex v) |
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{ |
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function_requires< AdjacencyGraphConcept<Graph> >(); |
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typedef typename graph_traits<Graph>::directed_category Directed; |
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typedef typename graph_traits<Graph>::adjacency_iterator AdjacencyIterator; |
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// TODO: There should actually be a set of neighborhood functions |
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// for things like this (num_neighbors() would be great). |
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AdjacencyIterator i, end; |
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boost::tie(i, end) = adjacent_vertices(v, g); |
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std::size_t k = std::distance(i, end); |
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return detail::possible_edges(g, k, Directed()); |
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} |
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template <typename Graph, typename Vertex> |
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inline typename graph_traits<Graph>::degree_size_type |
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num_triangles_on_vertex(const Graph& g, Vertex v) |
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{ |
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function_requires< IncidenceGraphConcept<Graph> >(); |
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function_requires< AdjacencyGraphConcept<Graph> >(); |
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typedef typename graph_traits<Graph>::degree_size_type Degree; |
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typedef typename graph_traits<Graph>::directed_category Directed; |
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typedef typename graph_traits<Graph>::adjacency_iterator AdjacencyIterator; |
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// TODO: I might be able to reduce the requirement from adjacency graph |
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// to incidence graph by using out edges. |
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Degree count(0); |
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AdjacencyIterator i, j, end; |
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for(boost::tie(i, end) = adjacent_vertices(v, g); i != end; ++i) { |
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for(j = boost::next(i); j != end; ++j) { |
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count += detail::count_edges(g, *i, *j, Directed()); |
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} |
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} |
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return count; |
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} /* namespace detail */ |
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template <typename T, typename Graph, typename Vertex> |
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inline T |
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clustering_coefficient(const Graph& g, Vertex v) |
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{ |
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T zero(0); |
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T routes = T(num_paths_through_vertex(g, v)); |
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return (routes > zero) ? |
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T(num_triangles_on_vertex(g, v)) / routes : zero; |
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} |
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template <typename Graph, typename Vertex> |
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inline double |
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clustering_coefficient(const Graph& g, Vertex v) |
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{ return clustering_coefficient<double>(g, v); } |
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template <typename Graph, typename ClusteringMap> |
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inline typename property_traits<ClusteringMap>::value_type |
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all_clustering_coefficients(const Graph& g, ClusteringMap cm) |
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{ |
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function_requires< VertexListGraphConcept<Graph> >(); |
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typedef typename graph_traits<Graph>::vertex_descriptor Vertex; |
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typedef typename graph_traits<Graph>::vertex_iterator VertexIterator; |
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function_requires< WritablePropertyMapConcept<ClusteringMap,Vertex> >(); |
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typedef typename property_traits<ClusteringMap>::value_type Coefficient; |
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Coefficient sum(0); |
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VertexIterator i, end; |
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for(boost::tie(i, end) = vertices(g); i != end; ++i) { |
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Coefficient cc = clustering_coefficient<Coefficient>(g, *i); |
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put(cm, *i, cc); |
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sum += cc; |
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} |
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return sum / Coefficient(num_vertices(g)); |
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} |
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template <typename Graph, typename ClusteringMap> |
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inline typename property_traits<ClusteringMap>::value_type |
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mean_clustering_coefficient(const Graph& g, ClusteringMap cm) |
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{ |
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function_requires< VertexListGraphConcept<Graph> >(); |
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typedef typename graph_traits<Graph>::vertex_descriptor Vertex; |
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typedef typename graph_traits<Graph>::vertex_iterator VertexIterator; |
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function_requires< ReadablePropertyMapConcept<ClusteringMap,Vertex> >(); |
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typedef typename property_traits<ClusteringMap>::value_type Coefficient; |
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Coefficient cc(0); |
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VertexIterator i, end; |
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for(boost::tie(i, end) = vertices(g); i != end; ++i) { |
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cc += get(cm, *i); |
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} |
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return cc / Coefficient(num_vertices(g)); |
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} |
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} /* namespace boost */ |
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#endif
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