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//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// 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)
//=======================================================================
#include <boost/config.hpp>
#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include <map>
#include <boost/pending/stringtok.hpp>
#include <boost/utility.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/visitors.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/graph/depth_first_search.hpp>
template <class Distance>
class calc_distance_visitor : public boost::bfs_visitor<>
{
public:
calc_distance_visitor(Distance d) : distance(d) { }
template <class Graph>
void tree_edge(typename boost::graph_traits<Graph>::edge_descriptor e,
Graph& g)
{
typename boost::graph_traits<Graph>::vertex_descriptor u, v;
u = boost::source(e, g);
v = boost::target(e, g);
distance[v] = distance[u] + 1;
}
private:
Distance distance;
};
template <class VertexNameMap, class DistanceMap>
class print_tree_visitor : public boost::dfs_visitor<>
{
public:
print_tree_visitor(VertexNameMap n, DistanceMap d) : name(n), distance(d) { }
template <class Graph>
void
discover_vertex(typename boost::graph_traits<Graph>::vertex_descriptor v,
Graph&)
{
typedef typename boost::property_traits<DistanceMap>::value_type Dist;
// indentation based on depth
for (Dist i = 0; i < distance[v]; ++i)
std::cout << " ";
std::cout << name[v] << std::endl;
}
template <class Graph>
void tree_edge(typename boost::graph_traits<Graph>::edge_descriptor e,
Graph& g)
{
distance[boost::target(e, g)] = distance[boost::source(e, g)] + 1;
}
private:
VertexNameMap name;
DistanceMap distance;
};
int
main()
{
using namespace boost;
std::ifstream datafile("./boost_web.dat");
if (!datafile) {
std::cerr << "No ./boost_web.dat file" << std::endl;
return -1;
}
//===========================================================================
// Declare the graph type and object, and some property maps.
typedef adjacency_list<vecS, vecS, directedS,
property<vertex_name_t, std::string,
property<vertex_color_t, default_color_type> >,
property<edge_name_t, std::string, property<edge_weight_t, int> >
> Graph;
typedef graph_traits<Graph> Traits;
typedef Traits::vertex_descriptor Vertex;
typedef Traits::edge_descriptor Edge;
typedef std::map<std::string, Vertex> NameVertexMap;
NameVertexMap name2vertex;
Graph g;
typedef property_map<Graph, vertex_name_t>::type NameMap;
NameMap node_name = get(vertex_name, g);
property_map<Graph, edge_name_t>::type link_name = get(edge_name, g);
//===========================================================================
// Read the data file and construct the graph.
std::string line;
while (std::getline(datafile,line)) {
std::list<std::string> line_toks;
boost::stringtok(line_toks, line, "|");
NameVertexMap::iterator pos;
bool inserted;
Vertex u, v;
std::list<std::string>::iterator i = line_toks.begin();
tie(pos, inserted) = name2vertex.insert(std::make_pair(*i, Vertex()));
if (inserted) {
u = add_vertex(g);
put(node_name, u, *i);
pos->second = u;
} else
u = pos->second;
++i;
std::string hyperlink_name = *i++;
tie(pos, inserted) = name2vertex.insert(std::make_pair(*i, Vertex()));
if (inserted) {
v = add_vertex(g);
put(node_name, v, *i);
pos->second = v;
} else
v = pos->second;
Edge e;
tie(e, inserted) = add_edge(u, v, g);
if (inserted) {
put(link_name, e, hyperlink_name);
}
}
//===========================================================================
// Calculate the diameter of the graph.
typedef Traits::vertices_size_type size_type;
typedef std::vector<size_type> IntVector;
// Create N x N matrix for storing the shortest distances
// between each vertex. Initialize all distances to zero.
std::vector<IntVector> d_matrix(num_vertices(g),
IntVector(num_vertices(g), 0));
size_type i;
for (i = 0; i < num_vertices(g); ++i) {
calc_distance_visitor<size_type*> vis(&d_matrix[i][0]);
Traits::vertex_descriptor src = vertices(g).first[i];
breadth_first_search(g, src, boost::visitor(vis));
}
size_type diameter = 0;
BOOST_USING_STD_MAX();
for (i = 0; i < num_vertices(g); ++i)
diameter = max BOOST_PREVENT_MACRO_SUBSTITUTION(diameter, *std::max_element(d_matrix[i].begin(),
d_matrix[i].end()));
std::cout << "The diameter of the boost web-site graph is " << diameter
<< std::endl << std::endl;
std::cout << "Number of clicks from the home page: " << std::endl;
Traits::vertex_iterator vi, vi_end;
for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
std::cout << d_matrix[0][*vi] << "\t" << node_name[*vi] << std::endl;
std::cout << std::endl;
//===========================================================================
// Print out the breadth-first search tree starting at the home page
// Create storage for a mapping from vertices to their parents
std::vector<Traits::vertex_descriptor> parent(num_vertices(g));
for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
parent[*vi] = *vi;
// Do a BFS starting at the home page, recording the parent of each
// vertex (where parent is with respect to the search tree).
Traits::vertex_descriptor src = vertices(g).first[0];
breadth_first_search
(g, src,
boost::visitor(make_bfs_visitor(record_predecessors(&parent[0],
on_tree_edge()))));
// Add all the search tree edges into a new graph
Graph search_tree(num_vertices(g));
tie(vi, vi_end) = vertices(g);
++vi;
for (; vi != vi_end; ++vi)
add_edge(parent[*vi], *vi, search_tree);
std::cout << "The breadth-first search tree:" << std::endl;
// Print out the search tree. We use DFS because it visits
// the tree nodes in the order that we want to print out:
// a directory-structure like format.
std::vector<size_type> dfs_distances(num_vertices(g), 0);
print_tree_visitor<NameMap, size_type*>
tree_printer(node_name, &dfs_distances[0]);
for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
get(vertex_color, g)[*vi] = white_color;
depth_first_visit(search_tree, src, tree_printer, get(vertex_color, g));
return EXIT_SUCCESS;
}
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