graph/test/max_flow_test.cpp

//  Copyright (c) 2006, Stephan Diederich
//
//  This code may be used under either of the following two licences:
//
//    Permission is hereby granted, free of charge, to any person
//    obtaining a copy of this software and associated documentation
//    files (the "Software"), to deal in the Software without
//    restriction, including without limitation the rights to use,
//    copy, modify, merge, publish, distribute, sublicense, and/or
//    sell copies of the Software, and to permit persons to whom the
//    Software is furnished to do so, subject to the following
//    conditions:
//
//    The above copyright notice and this permission notice shall be
//    included in all copies or substantial portions of the Software.
//
//    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//    OTHER DEALINGS IN THE SOFTWARE. OF SUCH DAMAGE.
//
//  Or:
//
//    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 <vector>
#include <iterator>
#include <iostream>
#include <algorithm>
#include <fstream>

#include <boost/core/lightweight_test.hpp>
// three max_flows we test here
#include <boost/graph/boykov_kolmogorov_max_flow.hpp>
#include <boost/graph/push_relabel_max_flow.hpp>
#include <boost/graph/edmonds_karp_max_flow.hpp>
// boost utilities we use
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/random.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/random/linear_congruential.hpp>
#include <boost/lexical_cast.hpp>

/***************
 * test which compares results of the three different max_flow implementations
 * command line parameters:
 *   number_of_vertices: defaults to 100
 *   number_of_edges:    defaults to 1000
 *   seeed:              defaults to 1
 ***************/

using namespace boost;

int main(int argc, char* argv[])
{

    typedef adjacency_list_traits< vecS, vecS, directedS > Traits;
    typedef adjacency_list< vecS, vecS, directedS,
        property< vertex_index_t, long,
            property< vertex_color_t, boost::default_color_type,
                property< vertex_distance_t, long,
                    property< vertex_predecessor_t,
                        Traits::edge_descriptor > > > >,
        property< edge_capacity_t, long,
            property< edge_residual_capacity_t, long,
                property< edge_reverse_t, Traits::edge_descriptor > > > >
        Graph;

    typedef graph_traits< Graph >::edge_descriptor tEdge;
    typedef graph_traits< Graph >::vertex_descriptor tVertex;

    graph_traits< Graph >::vertices_size_type n_verts = 100;
    graph_traits< Graph >::edges_size_type n_edges = 1000;
    std::size_t seed = 1;

    if (argc > 1)
        n_verts = lexical_cast< std::size_t >(argv[1]);
    if (argc > 2)
        n_edges = lexical_cast< std::size_t >(argv[2]);
    if (argc > 3)
        seed = lexical_cast< std::size_t >(argv[3]);

    Graph g;
    const int cap_low = 1;
    const int cap_high = 1000;

    // init random numer generator
    minstd_rand gen(seed);
    // generate graph
    generate_random_graph(g, n_verts, n_edges, gen);

    // init an uniform distribution int generator
    typedef variate_generator< minstd_rand, uniform_int< int > > tIntGen;
    tIntGen int_gen(gen, uniform_int< int >(cap_low, cap_high));
    // init edge-capacities
    randomize_property< edge_capacity_t, Graph, tIntGen >(g, int_gen);

    // get source and sink node
    tVertex source_vertex = random_vertex(g, gen);
    tVertex sink_vertex = graph_traits< Graph >::null_vertex();
    while (sink_vertex == graph_traits< Graph >::null_vertex()
        || sink_vertex == source_vertex)
        sink_vertex = random_vertex(g, gen);

    // add reverse edges (ugly... how to do better?!)
    property_map< Graph, edge_reverse_t >::type rev = get(edge_reverse, g);
    property_map< Graph, edge_capacity_t >::type cap = get(edge_capacity, g);
    std::list< tEdge > edges_copy;
    graph_traits< Graph >::edge_iterator ei, e_end;
    boost::tie(ei, e_end) = edges(g);
    std::copy(
        ei, e_end, std::back_insert_iterator< std::list< tEdge > >(edges_copy));
    while (!edges_copy.empty())
    {
        tEdge old_edge = edges_copy.front();
        edges_copy.pop_front();
        tVertex source_vertex = target(old_edge, g);
        tVertex target_vertex = source(old_edge, g);
        bool inserted;
        tEdge new_edge;
        boost::tie(new_edge, inserted)
            = add_edge(source_vertex, target_vertex, g);
        assert(inserted);
        rev[old_edge] = new_edge;
        rev[new_edge] = old_edge;
        cap[new_edge] = 0;
    }

    typedef property_traits< property_map< Graph,
        edge_capacity_t >::const_type >::value_type tEdgeVal;

    tEdgeVal bk = boykov_kolmogorov_max_flow(g, source_vertex, sink_vertex);
    tEdgeVal push_relabel
        = push_relabel_max_flow(g, source_vertex, sink_vertex);
    tEdgeVal edmonds_karp
        = edmonds_karp_max_flow(g, source_vertex, sink_vertex);

    BOOST_TEST(bk == push_relabel);
    BOOST_TEST(push_relabel == edmonds_karp);

    return boost::report_errors();
}