bfs.cpp
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//=======================================================================
// Copyright 2001 University of Notre Dame.
// Author: Andrew Janiszewski, 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/core/lightweight_test.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/random.hpp>
#include <boost/graph/graph_utility.hpp>
#include <boost/graph/graph_archetypes.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/random/mersenne_twister.hpp>
#ifdef BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP
using namespace boost;
#endif
template < typename DistanceMap, typename ParentMap, typename Graph,
typename ColorMap >
class bfs_testing_visitor
{
typedef typename boost::graph_traits< Graph >::vertex_descriptor Vertex;
typedef typename boost::graph_traits< Graph >::edge_descriptor Edge;
typedef typename boost::color_traits<
typename boost::property_traits< ColorMap >::value_type >
Color;
public:
bfs_testing_visitor(Vertex s, DistanceMap d, ParentMap p, ColorMap c)
: current_distance(0), distance(d), parent(p), color(c), src(s)
{
}
void initialize_vertex(const Vertex& u, const Graph&) const
{
BOOST_TEST(get(color, u) == Color::white());
}
void examine_vertex(const Vertex& u, const Graph&) const
{
current_vertex = u;
// Ensure that the distances monotonically increase.
BOOST_TEST(distance[u] == current_distance
|| distance[u] == current_distance + 1);
if (distance[u] == current_distance + 1) // new level
++current_distance;
}
void discover_vertex(const Vertex& u, const Graph&) const
{
BOOST_TEST(get(color, u) == Color::gray());
if (u == src)
{
current_vertex = src;
}
else
{
BOOST_TEST(parent[u] == current_vertex);
BOOST_TEST(distance[u] == current_distance + 1);
BOOST_TEST(distance[u] == distance[parent[u]] + 1);
}
}
void examine_edge(const Edge& e, const Graph& g) const
{
BOOST_TEST(source(e, g) == current_vertex);
}
void tree_edge(const Edge& e, const Graph& g) const
{
BOOST_TEST(get(color, target(e, g)) == Color::white());
Vertex u = source(e, g), v = target(e, g);
BOOST_TEST(distance[u] == current_distance);
parent[v] = u;
distance[v] = distance[u] + 1;
}
void non_tree_edge(const Edge& e, const Graph& g) const
{
BOOST_TEST(color[target(e, g)] != Color::white());
if (boost::is_directed(g))
// cross or back edge
BOOST_TEST(distance[target(e, g)] <= distance[source(e, g)] + 1);
else
{
// cross edge (or going backwards on a tree edge)
BOOST_TEST(distance[target(e, g)] == distance[source(e, g)]
|| distance[target(e, g)] == distance[source(e, g)] + 1
|| distance[target(e, g)] == distance[source(e, g)] - 1);
}
}
void gray_target(const Edge& e, const Graph& g) const
{
BOOST_TEST(color[target(e, g)] == Color::gray());
}
void black_target(const Edge& e, const Graph& g) const
{
BOOST_TEST(color[target(e, g)] == Color::black());
// All vertices adjacent to a black vertex must already be discovered
typename boost::graph_traits< Graph >::adjacency_iterator ai, ai_end;
for (boost::tie(ai, ai_end) = adjacent_vertices(target(e, g), g);
ai != ai_end; ++ai)
BOOST_TEST(color[*ai] != Color::white());
}
void finish_vertex(const Vertex& u, const Graph&) const
{
BOOST_TEST(color[u] == Color::black());
}
private:
mutable Vertex current_vertex;
mutable typename boost::property_traits< DistanceMap >::value_type
current_distance;
DistanceMap distance;
ParentMap parent;
ColorMap color;
Vertex src;
};
template < class Graph > struct bfs_test
{
typedef boost::graph_traits< Graph > Traits;
typedef typename Traits::vertices_size_type vertices_size_type;
static void go(vertices_size_type max_V)
{
typedef typename Traits::vertex_descriptor vertex_descriptor;
typedef boost::color_traits< boost::default_color_type > Color;
vertices_size_type i;
typename Traits::edges_size_type j;
typename Traits::vertex_iterator ui, ui_end;
boost::mt19937 gen;
for (i = 0; i < max_V; ++i)
for (j = 0; j < i * i; ++j)
{
Graph g;
boost::generate_random_graph(g, i, j, gen);
// declare the "start" variable
vertex_descriptor start = boost::random_vertex(g, gen);
// vertex properties
std::vector< int > distance(
i, (std::numeric_limits< int >::max)());
distance[start] = 0;
std::vector< vertex_descriptor > parent(i);
for (boost::tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui)
parent[*ui] = *ui;
std::vector< boost::default_color_type > color(i);
// Get vertex index map
typedef typename boost::property_map< Graph,
boost::vertex_index_t >::const_type idx_type;
idx_type idx = get(boost::vertex_index, g);
// Make property maps from vectors
typedef boost::iterator_property_map<
std::vector< int >::iterator, idx_type >
distance_pm_type;
distance_pm_type distance_pm(distance.begin(), idx);
typedef boost::iterator_property_map<
typename std::vector< vertex_descriptor >::iterator,
idx_type >
parent_pm_type;
parent_pm_type parent_pm(parent.begin(), idx);
typedef boost::iterator_property_map<
std::vector< boost::default_color_type >::iterator,
idx_type >
color_pm_type;
color_pm_type color_pm(color.begin(), idx);
// Create the testing visitor.
bfs_testing_visitor< distance_pm_type, parent_pm_type, Graph,
color_pm_type >
vis(start, distance_pm, parent_pm, color_pm);
boost::breadth_first_search(
g, start, visitor(vis).color_map(color_pm));
// All white vertices should be unreachable from the source.
for (boost::tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui)
if (color[*ui] == Color::white())
{
std::vector< boost::default_color_type > color2(
i, Color::white());
BOOST_TEST(!boost::is_reachable(
start, *ui, g, color_pm_type(color2.begin(), idx)));
}
// The shortest path to a child should be one longer than
// shortest path to the parent.
for (boost::tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui)
if (parent[*ui] != *ui) // *ui not the root of the bfs tree
BOOST_TEST(distance[*ui] == distance[parent[*ui]] + 1);
}
}
};
int main(int argc, char* argv[])
{
using namespace boost;
int max_V = 7;
if (argc > 1)
max_V = atoi(argv[1]);
bfs_test< adjacency_list< vecS, vecS, directedS > >::go(max_V);
bfs_test< adjacency_list< vecS, vecS, undirectedS > >::go(max_V);
return boost::report_errors();
}