1 // (C) Copyright Andrew Sutton 2007
2 //
3 // Use, modification and distribution are subject to the
4 // Boost Software License, Version 1.0 (See accompanying file
5 // LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
6
7 //[scaled_closeness_centrality_example
8 #include <iostream>
9 #include <iomanip>
10
11 #include <boost/graph/undirected_graph.hpp>
12 #include <boost/graph/exterior_property.hpp>
13 #include <boost/graph/floyd_warshall_shortest.hpp>
14 #include <boost/graph/closeness_centrality.hpp>
15 #include "helper.hpp"
16
17 using namespace std;
18 using namespace boost;
19
20 // This template struct provides a generic version of a "scaling"
21 // closeness measure. Specifically, this implementation divides
22 // the number of vertices in the graph by the sum of geodesic
23 // distances of each vertex. This measure allows customization
24 // of the distance type, result type, and even the underlying
25 // divide operation.
26 template < typename Graph, typename Distance, typename Result,
27 typename Divide = divides< Result > >
28 struct scaled_closeness_measure
29 {
30 typedef Distance distance_type;
31 typedef Result result_type;
32
operator ()scaled_closeness_measure33 Result operator()(Distance d, const Graph& g)
34 {
35 if (d == numeric_values< Distance >::infinity())
36 {
37 return numeric_values< Result >::zero();
38 }
39 else
40 {
41 return div(Result(num_vertices(g)), Result(d));
42 }
43 }
44 Divide div;
45 };
46
47 // The Actor type stores the name of each vertex in the graph.
48 struct Actor
49 {
50 std::string name;
51 };
52
53 // Declare the graph type and its vertex and edge types.
54 typedef undirected_graph< Actor > Graph;
55 typedef graph_traits< Graph >::vertex_descriptor Vertex;
56 typedef graph_traits< Graph >::edge_descriptor Edge;
57
58 // The name map provides an abstract accessor for the names of
59 // each vertex. This is used during graph creation.
60 typedef property_map< Graph, string Actor::* >::type NameMap;
61
62 // Declare a matrix type and its corresponding property map that
63 // will contain the distances between each pair of vertices.
64 typedef exterior_vertex_property< Graph, int > DistanceProperty;
65 typedef DistanceProperty::matrix_type DistanceMatrix;
66 typedef DistanceProperty::matrix_map_type DistanceMatrixMap;
67
68 // Declare the weight map so that each edge returns the same value.
69 typedef constant_property_map< Edge, int > WeightMap;
70
71 // Declare a container and its corresponding property map that
72 // will contain the resulting closeness centralities of each
73 // vertex in the graph.
74 typedef boost::exterior_vertex_property< Graph, float > ClosenessProperty;
75 typedef ClosenessProperty::container_type ClosenessContainer;
76 typedef ClosenessProperty::map_type ClosenessMap;
77
main(int argc,char * argv[])78 int main(int argc, char* argv[])
79 {
80 // Create the graph and a property map that provides access
81 // to the actor names.
82 Graph g;
83 NameMap nm(get(&Actor::name, g));
84
85 // Read the graph from standard input.
86 read_graph(g, nm, cin);
87
88 // Compute the distances between all pairs of vertices using
89 // the Floyd-Warshall algorithm. Note that the weight map is
90 // created so that every edge has a weight of 1.
91 DistanceMatrix distances(num_vertices(g));
92 DistanceMatrixMap dm(distances, g);
93 WeightMap wm(1);
94 floyd_warshall_all_pairs_shortest_paths(g, dm, weight_map(wm));
95
96 // Create the scaled closeness measure.
97 scaled_closeness_measure< Graph, int, float > m;
98
99 // Compute the degree centrality for graph
100 ClosenessContainer cents(num_vertices(g));
101 ClosenessMap cm(cents, g);
102 all_closeness_centralities(g, dm, cm, m);
103
104 // Print the scaled closeness centrality of each vertex.
105 graph_traits< Graph >::vertex_iterator i, end;
106 for (boost::tie(i, end) = vertices(g); i != end; ++i)
107 {
108 cout << setw(12) << setiosflags(ios::left) << g[*i].name << get(cm, *i)
109 << endl;
110 }
111
112 return 0;
113 }
114 //]
115