| // (C) Copyright Andrew Sutton 2007 |
| // |
| // Use, modification and distribution are subject to the |
| // Boost Software License, Version 1.0 (See accompanying file |
| // LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
| |
| //[mean_geodesic_example |
| #include <iostream> |
| #include <iomanip> |
| |
| #include <boost/graph/undirected_graph.hpp> |
| #include <boost/graph/exterior_property.hpp> |
| #include <boost/graph/floyd_warshall_shortest.hpp> |
| #include <boost/graph/geodesic_distance.hpp> |
| #include "helper.hpp" |
| |
| using namespace std; |
| using namespace boost; |
| |
| // The Actor type stores the name of each vertex in the graph. |
| struct Actor |
| { |
| string name; |
| }; |
| |
| // Declare the graph type and its vertex and edge types. |
| typedef undirected_graph<Actor> Graph; |
| typedef graph_traits<Graph>::vertex_descriptor Vertex; |
| typedef graph_traits<Graph>::edge_descriptor Edge; |
| |
| // The name map provides an abstract accessor for the names of |
| // each vertex. This is used during graph creation. |
| typedef property_map<Graph, string Actor::*>::type NameMap; |
| |
| // Declare a matrix type and its corresponding property map that |
| // will contain the distances between each pair of vertices. |
| typedef exterior_vertex_property<Graph, int> DistanceProperty; |
| typedef DistanceProperty::matrix_type DistanceMatrix; |
| typedef DistanceProperty::matrix_map_type DistanceMatrixMap; |
| |
| // Declare the weight map so that each edge returns the same value. |
| typedef constant_property_map<Edge, int> WeightMap; |
| |
| // Declare a container and its corresponding property map that |
| // will contain the resulting mean geodesic distances of each |
| // vertex in the graph. |
| typedef exterior_vertex_property<Graph, float> GeodesicProperty; |
| typedef GeodesicProperty::container_type GeodesicContainer; |
| typedef GeodesicProperty::map_type GeodesicMap; |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| // Create the graph and a property map that provides access |
| // to the actor names. |
| Graph g; |
| NameMap nm(get(&Actor::name, g)); |
| |
| // Read the graph from standad input. |
| read_graph(g, nm, cin); |
| |
| // Compute the distances between all pairs of vertices using |
| // the Floyd-Warshall algorithm. Note that the weight map is |
| // created so that every edge has a weight of 1. |
| DistanceMatrix distances(num_vertices(g)); |
| DistanceMatrixMap dm(distances, g); |
| WeightMap wm(1); |
| floyd_warshall_all_pairs_shortest_paths(g, dm, weight_map(wm)); |
| |
| // Compute the mean geodesic distances for each vertex in |
| // the graph and get the average mean geodesic distace (the |
| // so-called small-world distance) as a result. |
| GeodesicContainer geodesics(num_vertices(g)); |
| GeodesicMap gm(geodesics, g); |
| float sw = all_mean_geodesics(g, dm, gm); |
| |
| // Print the mean geodesic distance of each vertex and finally, |
| // the graph itself. |
| graph_traits<Graph>::vertex_iterator i, end; |
| for(tie(i, end) = vertices(g); i != end; ++i) { |
| cout << setw(12) << setiosflags(ios::left) |
| << g[*i].name << get(gm, *i) << endl; |
| } |
| cout << "small world distance: " << sw << endl; |
| |
| |
| return 0; |
| } |
| //] |