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// (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)
//[scaled_closeness_centrality_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/closeness_centrality.hpp>
#include "helper.hpp"
using namespace std;
using namespace boost;
// This template struct provides a generic version of a "scaling"
// closeness measure. Specifically, this implementation divides
// the number of vertices in the graph by the sum of geodesic
// distances of each vertex. This measure allows customization
// of the distance type, result type, and even the underlying
// divide operation.
template <typename Graph,
typename Distance,
typename Result,
typename Divide = divides<Result> >
struct scaled_closeness_measure
{
typedef Distance distance_type;
typedef Result result_type;
Result operator ()(Distance d, const Graph& g)
{
if(d == numeric_values<Distance>::infinity()) {
return numeric_values<Result>::zero();
}
else {
return div(Result(num_vertices(g)), Result(d));
}
}
Divide div;
};
// The Actor type stores the name of each vertex in the graph.
struct Actor
{
std::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 closeness centralities of each
// vertex in the graph.
typedef boost::exterior_vertex_property<Graph, float> ClosenessProperty;
typedef ClosenessProperty::container_type ClosenessContainer;
typedef ClosenessProperty::map_type ClosenessMap;
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 standard 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));
// Create the scaled closeness measure.
scaled_closeness_measure<Graph, int, float> m;
// Compute the degree centrality for graph
ClosenessContainer cents(num_vertices(g));
ClosenessMap cm(cents, g);
all_closeness_centralities(g, dm, cm, m);
// Print the scaled closeness centrality of each vertex.
graph_traits<Graph>::vertex_iterator i, end;
for(boost::tie(i, end) = vertices(g); i != end; ++i) {
cout << setw(12) << setiosflags(ios::left)
<< g[*i].name << get(cm, *i) << endl;
}
return 0;
}
//]
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