90 lines
3.0 KiB
C++
90 lines
3.0 KiB
C++
// (C) Copyright Andrew Sutton 2007
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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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//[mean_geodesic_example
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#include <iostream>
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#include <iomanip>
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#include <boost/graph/undirected_graph.hpp>
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#include <boost/graph/exterior_property.hpp>
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#include <boost/graph/floyd_warshall_shortest.hpp>
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#include <boost/graph/geodesic_distance.hpp>
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#include "helper.hpp"
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using namespace std;
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using namespace boost;
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// The Actor type stores the name of each vertex in the graph.
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struct Actor
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{
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string name;
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};
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// Declare the graph type and its vertex and edge types.
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typedef undirected_graph<Actor> Graph;
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typedef graph_traits<Graph>::vertex_descriptor Vertex;
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typedef graph_traits<Graph>::edge_descriptor Edge;
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// The name map provides an abstract accessor for the names of
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// each vertex. This is used during graph creation.
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typedef property_map<Graph, string Actor::*>::type NameMap;
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// Declare a matrix type and its corresponding property map that
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// will contain the distances between each pair of vertices.
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typedef exterior_vertex_property<Graph, int> DistanceProperty;
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typedef DistanceProperty::matrix_type DistanceMatrix;
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typedef DistanceProperty::matrix_map_type DistanceMatrixMap;
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// Declare the weight map so that each edge returns the same value.
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typedef constant_property_map<Edge, int> WeightMap;
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// Declare a container and its corresponding property map that
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// will contain the resulting mean geodesic distances of each
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// vertex in the graph.
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typedef exterior_vertex_property<Graph, float> GeodesicProperty;
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typedef GeodesicProperty::container_type GeodesicContainer;
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typedef GeodesicProperty::map_type GeodesicMap;
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int
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main(int argc, char *argv[])
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{
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// Create the graph and a property map that provides access
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// to the actor names.
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Graph g;
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NameMap nm(get(&Actor::name, g));
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// Read the graph from standad input.
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read_graph(g, nm, cin);
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// Compute the distances between all pairs of vertices using
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// the Floyd-Warshall algorithm. Note that the weight map is
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// created so that every edge has a weight of 1.
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DistanceMatrix distances(num_vertices(g));
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DistanceMatrixMap dm(distances, g);
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WeightMap wm(1);
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floyd_warshall_all_pairs_shortest_paths(g, dm, weight_map(wm));
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// Compute the mean geodesic distances for each vertex in
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// the graph and get the average mean geodesic distace (the
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// so-called small-world distance) as a result.
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GeodesicContainer geodesics(num_vertices(g));
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GeodesicMap gm(geodesics, g);
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float sw = all_mean_geodesics(g, dm, gm);
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// Print the mean geodesic distance of each vertex and finally,
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// the graph itself.
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graph_traits<Graph>::vertex_iterator i, end;
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for(boost::tie(i, end) = vertices(g); i != end; ++i) {
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cout << setw(12) << setiosflags(ios::left)
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<< g[*i].name << get(gm, *i) << endl;
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}
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cout << "small world distance: " << sw << endl;
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return 0;
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}
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//]
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