boost/libs/graph/test/incremental_components_test.cpp

//=======================================================================
// Copyright 2009 Trustees of Indiana University.
// Authors: Michael Hansen, Andrew Lumsdaine
//
// 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 <iostream>
#include <map>
#include <set>
#include <ctime>

#include <boost/foreach.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/incremental_components.hpp>
#include <boost/graph/random.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/random.hpp>
#include <boost/core/lightweight_test.hpp>

using namespace boost;

typedef adjacency_list< vecS, vecS, undirectedS > VectorGraph;

typedef adjacency_list< listS, listS, undirectedS,
    property< vertex_index_t, unsigned int > >
    ListGraph;

template < typename Graph > void test_graph(const Graph& graph)
{
    typedef typename graph_traits< Graph >::vertex_descriptor vertex_descriptor;
    typedef typename graph_traits< Graph >::edge_descriptor edge_descriptor;
    typedef
        typename graph_traits< Graph >::vertices_size_type vertices_size_type;

    typedef
        typename property_map< Graph, vertex_index_t >::type IndexPropertyMap;

    typedef std::map< vertex_descriptor, vertices_size_type > RankMap;
    typedef associative_property_map< RankMap > RankPropertyMap;

    typedef std::vector< vertex_descriptor > ParentMap;
    typedef iterator_property_map< typename ParentMap::iterator,
        IndexPropertyMap, vertex_descriptor, vertex_descriptor& >
        IndexParentMap;

    RankMap rank_map;
    RankPropertyMap rank_property_map(rank_map);

    ParentMap parent_map(num_vertices(graph));
    IndexParentMap index_parent_map(parent_map.begin());

    // Create disjoint sets of vertices from the graph
    disjoint_sets< RankPropertyMap, IndexParentMap > vertex_sets(
        rank_property_map, index_parent_map);

    initialize_incremental_components(graph, vertex_sets);
    incremental_components(graph, vertex_sets);

    // Build component index from the graph's vertices, its index map,
    // and the disjoint sets.
    typedef component_index< vertices_size_type > Components;
    Components vertex_components(
        parent_map.begin(), parent_map.end(), get(boost::vertex_index, graph));

    // Create a reverse-lookup map for vertex indices
    std::vector< vertex_descriptor > reverse_index_map(num_vertices(graph));

    BOOST_FOREACH (vertex_descriptor vertex, vertices(graph))
    {
        reverse_index_map[get(get(boost::vertex_index, graph), vertex)]
            = vertex;
    }

    // Verify that components are really connected
    BOOST_FOREACH (vertices_size_type component_index, vertex_components)
    {

        std::set< vertex_descriptor > component_vertices;

        BOOST_FOREACH (
            vertices_size_type child_index, vertex_components[component_index])
        {

            vertex_descriptor child_vertex = reverse_index_map[child_index];
            component_vertices.insert(child_vertex);

        } // foreach child_index

        // Verify that children are connected to each other in some
        // manner, but not to vertices outside their component.
        BOOST_FOREACH (vertex_descriptor child_vertex, component_vertices)
        {

            // Skip orphan vertices
            if (out_degree(child_vertex, graph) == 0)
            {
                continue;
            }

            // Make sure at least one edge exists between [child_vertex] and
            // another vertex in the component.
            bool edge_exists = false;

            BOOST_FOREACH (
                edge_descriptor child_edge, out_edges(child_vertex, graph))
            {

                if (component_vertices.count(target(child_edge, graph)) > 0)
                {
                    edge_exists = true;
                    break;
                }

            } // foreach child_edge

            BOOST_TEST(edge_exists);

        } // foreach child_vertex

    } // foreach component_index

} // test_graph

int main(int argc, char* argv[])
{
    std::size_t vertices_to_generate = 100, edges_to_generate = 50,
                random_seed = std::time(0);

    // Parse command-line arguments

    if (argc > 1)
    {
        vertices_to_generate = lexical_cast< std::size_t >(argv[1]);
    }

    if (argc > 2)
    {
        edges_to_generate = lexical_cast< std::size_t >(argv[2]);
    }

    if (argc > 3)
    {
        random_seed = lexical_cast< std::size_t >(argv[3]);
    }

    minstd_rand generator(random_seed);

    // Generate random vector and list graphs
    VectorGraph vector_graph;
    generate_random_graph(vector_graph, vertices_to_generate, edges_to_generate,
        generator, false);

    test_graph(vector_graph);

    ListGraph list_graph;
    generate_random_graph(
        list_graph, vertices_to_generate, edges_to_generate, generator, false);

    // Assign indices to list_graph's vertices
    graph_traits< ListGraph >::vertices_size_type index = 0;
    BOOST_FOREACH (graph_traits< ListGraph >::vertex_descriptor vertex,
        vertices(list_graph))
    {
        put(get(boost::vertex_index, list_graph), vertex, index++);
    }

    test_graph(list_graph);

    return boost::report_errors();
}