diff -r 666f914201fb -r 2fe1408b6811 epoc32/include/stdapis/boost/graph/bc_clustering.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/epoc32/include/stdapis/boost/graph/bc_clustering.hpp Tue Mar 16 16:12:26 2010 +0000 @@ -0,0 +1,164 @@ +// Copyright 2004 The Trustees of Indiana University. + +// 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) + +// Authors: Douglas Gregor +// Andrew Lumsdaine +#ifndef BOOST_GRAPH_BETWEENNESS_CENTRALITY_CLUSTERING_HPP +#define BOOST_GRAPH_BETWEENNESS_CENTRALITY_CLUSTERING_HPP + +#include +#include +#include +#include +#include +#include + +namespace boost { + +/** Threshold termination function for the betweenness centrality + * clustering algorithm. + */ +template +struct bc_clustering_threshold +{ + typedef T centrality_type; + + /// Terminate clustering when maximum absolute edge centrality is + /// below the given threshold. + explicit bc_clustering_threshold(T threshold) + : threshold(threshold), dividend(1.0) {} + + /** + * Terminate clustering when the maximum edge centrality is below + * the given threshold. + * + * @param threshold the threshold value + * + * @param g the graph on which the threshold will be calculated + * + * @param normalize when true, the threshold is compared against the + * normalized edge centrality based on the input graph; otherwise, + * the threshold is compared against the absolute edge centrality. + */ + template + bc_clustering_threshold(T threshold, const Graph& g, bool normalize = true) + : threshold(threshold), dividend(1.0) + { + if (normalize) { + typename graph_traits::vertices_size_type n = num_vertices(g); + dividend = T((n - 1) * (n - 2)) / T(2); + } + } + + /** Returns true when the given maximum edge centrality (potentially + * normalized) falls below the threshold. + */ + template + bool operator()(T max_centrality, Edge, const Graph&) + { + return (max_centrality / dividend) < threshold; + } + + protected: + T threshold; + T dividend; +}; + +/** Graph clustering based on edge betweenness centrality. + * + * This algorithm implements graph clustering based on edge + * betweenness centrality. It is an iterative algorithm, where in each + * step it compute the edge betweenness centrality (via @ref + * brandes_betweenness_centrality) and removes the edge with the + * maximum betweenness centrality. The @p done function object + * determines when the algorithm terminates (the edge found when the + * algorithm terminates will not be removed). + * + * @param g The graph on which clustering will be performed. The type + * of this parameter (@c MutableGraph) must be a model of the + * VertexListGraph, IncidenceGraph, EdgeListGraph, and Mutable Graph + * concepts. + * + * @param done The function object that indicates termination of the + * algorithm. It must be a ternary function object thats accepts the + * maximum centrality, the descriptor of the edge that will be + * removed, and the graph @p g. + * + * @param edge_centrality (UTIL/OUT) The property map that will store + * the betweenness centrality for each edge. When the algorithm + * terminates, it will contain the edge centralities for the + * graph. The type of this property map must model the + * ReadWritePropertyMap concept. Defaults to an @c + * iterator_property_map whose value type is + * @c Done::centrality_type and using @c get(edge_index, g) for the + * index map. + * + * @param vertex_index (IN) The property map that maps vertices to + * indices in the range @c [0, num_vertices(g)). This type of this + * property map must model the ReadablePropertyMap concept and its + * value type must be an integral type. Defaults to + * @c get(vertex_index, g). + */ +template +void +betweenness_centrality_clustering(MutableGraph& g, Done done, + EdgeCentralityMap edge_centrality, + VertexIndexMap vertex_index) +{ + typedef typename property_traits::value_type + centrality_type; + typedef typename graph_traits::edge_iterator edge_iterator; + typedef typename graph_traits::edge_descriptor edge_descriptor; + typedef typename graph_traits::vertices_size_type + vertices_size_type; + + if (edges(g).first == edges(g).second) return; + + // Function object that compares the centrality of edges + indirect_cmp > + cmp(edge_centrality); + + bool is_done; + do { + brandes_betweenness_centrality(g, + edge_centrality_map(edge_centrality) + .vertex_index_map(vertex_index)); + edge_descriptor e = *max_element(edges(g).first, edges(g).second, cmp); + is_done = done(get(edge_centrality, e), e, g); + if (!is_done) remove_edge(e, g); + } while (!is_done && edges(g).first != edges(g).second); +} + +/** + * \overload + */ +template +void +betweenness_centrality_clustering(MutableGraph& g, Done done, + EdgeCentralityMap edge_centrality) +{ + betweenness_centrality_clustering(g, done, edge_centrality, + get(vertex_index, g)); +} + +/** + * \overload + */ +template +void +betweenness_centrality_clustering(MutableGraph& g, Done done) +{ + typedef typename Done::centrality_type centrality_type; + std::vector edge_centrality(num_edges(g)); + betweenness_centrality_clustering(g, done, + make_iterator_property_map(edge_centrality.begin(), get(edge_index, g)), + get(vertex_index, g)); +} + +} // end namespace boost + +#endif // BOOST_GRAPH_BETWEENNESS_CENTRALITY_CLUSTERING_HPP