dlib C++ Library - graph.cpp

    // Copyright (C) 2007  Davis E. King (davisking@users.sourceforge.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #include <sstream>
    #include <string>
    #include <cstdlib>
    #include <ctime>
    #include <dlib/graph.h>
    #include <dlib/graph_utils.h>
    #include <dlib/set.h>

    #include "tester.h"

    // This is called an unnamed-namespace and it has the effect of making everything inside this file "private"
    // so that everything you declare will have static linkage.  Thus we won't have any multiply
    // defined symbol errors coming out of the linker when we try to compile the test suite.
    namespace
    {

        using namespace test;
        using namespace dlib;
        using namespace std;

        // Declare the logger we will use in this test.  The name of the tester
        // should start with "test."
        logger dlog("test.graph");

        template <
            typename graph
            >
        void graph_test (
        )
        /*!
            requires
                - graph is an implementation of graph/graph_kernel_abstract.h
                  is instantiated with int
            ensures
                - runs tests on graph for compliance with the specs
        !*/
        {

            print_spinner();

            COMPILE_TIME_ASSERT(is_graph<graph>::value);

            graph a, b;
            set<unsigned long>::compare_1b_c s;

            DLIB_CASSERT(graph_contains_length_one_cycle(a) == false,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");

            DLIB_CASSERT(a.number_of_nodes() == 0,"");

            a.set_number_of_nodes(5);
            DLIB_CASSERT(graph_is_connected(a) == false,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");
            DLIB_CASSERT(a.number_of_nodes() == 5,"");
            DLIB_CASSERT(graph_contains_length_one_cycle(a) == false,"");

            for (int i = 0; i < 5; ++i)
            {
                a.node(i).data = i;
                DLIB_CASSERT(a.node(i).index() == (unsigned int)i,"");
            }

            a.remove_node(1);

            DLIB_CASSERT(a.number_of_nodes() == 4,"");

            // make sure that only the number with data == 1 was removed
            int count = 0;
            for (int i = 0; i < 4; ++i)
            {
                count += a.node(i).data;
                DLIB_CASSERT(a.node(i).number_of_neighbors() == 0,"");
                DLIB_CASSERT(a.node(i).index() == (unsigned int)i,"");
            }

            DLIB_CASSERT(count == 9,"");

            a.add_edge(1,1);
            DLIB_CASSERT(graph_contains_length_one_cycle(a) == true,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == true,"");
            DLIB_CASSERT(a.has_edge(1,1),"");
            DLIB_CASSERT(a.node(1).number_of_neighbors() == 1,"");

            a.add_edge(1,3);
            DLIB_CASSERT(a.node(1).number_of_neighbors() == 2,"");
            DLIB_CASSERT(a.node(2).number_of_neighbors() == 0,"");
            DLIB_CASSERT(a.node(3).number_of_neighbors() == 1,"");
            DLIB_CASSERT(a.has_edge(1,1),"");
            DLIB_CASSERT(a.has_edge(1,3),"");
            DLIB_CASSERT(a.has_edge(3,1),"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == true,"");
            a.remove_edge(1,1);
            DLIB_CASSERT(graph_contains_length_one_cycle(a) == false,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");
            DLIB_CASSERT(a.node(1).number_of_neighbors() == 1,"");
            DLIB_CASSERT(a.node(2).number_of_neighbors() == 0,"");
            DLIB_CASSERT(a.node(3).number_of_neighbors() == 1,"");
            DLIB_CASSERT(a.has_edge(1,1) == false,"");
            DLIB_CASSERT(a.has_edge(1,3),"");
            DLIB_CASSERT(a.has_edge(3,1),"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");

            swap(a,b);

            DLIB_CASSERT(graph_contains_undirected_cycle(b) == false,"");
            DLIB_CASSERT(b.node(1).number_of_neighbors() == 1,"");
            DLIB_CASSERT(b.node(2).number_of_neighbors() == 0,"");
            DLIB_CASSERT(b.node(3).number_of_neighbors() == 1,"");
            DLIB_CASSERT(b.has_edge(1,1) == false,"");
            DLIB_CASSERT(b.has_edge(1,3),"");
            DLIB_CASSERT(b.has_edge(3,1),"");
            DLIB_CASSERT(graph_contains_undirected_cycle(b) == false,"");

            DLIB_CASSERT(a.number_of_nodes() == 0,"");
            DLIB_CASSERT(b.number_of_nodes() == 4,"");

            copy_graph_structure(b,b);
            DLIB_CASSERT(b.number_of_nodes() == 4,"");

            b.add_edge(1,2);
            DLIB_CASSERT(graph_contains_undirected_cycle(b) == false,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(b) == false,"");
            b.add_edge(3,2);
            DLIB_CASSERT(graph_contains_undirected_cycle(b) == true,"");
            b.add_edge(1,1);
            DLIB_CASSERT(graph_is_connected(b) == false,"");
            b.add_edge(0,2);
            DLIB_CASSERT(graph_is_connected(b) == true,"");

            DLIB_CASSERT(graph_contains_undirected_cycle(b) == true,"");

            DLIB_CASSERT(a.number_of_nodes() == 0,"");

            for (unsigned long i = 0; i < b.number_of_nodes(); ++i)
            {
                for (unsigned long j = 0; j < b.node(i).number_of_neighbors(); ++j)
                {
                    b.node(i).edge(j) = 'c';
                }
            }

            b.node(1).edge(0) = 'a';
            const unsigned long e1 = b.node(1).neighbor(0).index();
            b.node(0).edge(0) = 'n';
            const unsigned long e2 = b.node(0).neighbor(0).index();

            ostringstream sout;
            serialize(b, sout);
            istringstream sin(sout.str());

            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");

            a.set_number_of_nodes(10);
            deserialize(a, sin);
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == true,"");

            for (unsigned long i = 0; i < a.number_of_nodes(); ++i)
            {
                for (unsigned long j = 0; j < a.node(i).number_of_neighbors(); ++j)
                {
                    if ((i == 0 && a.node(i).neighbor(j).index() == e2) ||
                        (i == e2 && a.node(i).neighbor(j).index() == 0) )
                    {
                        DLIB_CASSERT(a.node(i).edge(j) == 'n',"");
                    }
                    else if ((i == 1 && a.node(i).neighbor(j).index() == e1) ||
                             (i == e1 && a.node(i).neighbor(j).index() == 1))
                    {
                        DLIB_CASSERT(a.node(i).edge(j) == 'a',"");
                    }
                    else
                    {
                        DLIB_CASSERT(i != 0 || a.node(i).neighbor(j).index() != e2,"");
                        DLIB_CASSERT(a.node(i).edge(j) == 'c',a.node(i).edge(j));
                    }
                }
            }

            DLIB_CASSERT(a.number_of_nodes() == 4,"");
            DLIB_CASSERT(a.has_edge(1,2) == true,"");
            DLIB_CASSERT(a.has_edge(3,2) == true,"");
            DLIB_CASSERT(a.has_edge(1,1) == true,"");
            DLIB_CASSERT(a.has_edge(0,2) == true,"");
            DLIB_CASSERT(a.has_edge(1,3) == true,"");
            DLIB_CASSERT(a.has_edge(0,1) == false,"");
            DLIB_CASSERT(a.has_edge(0,3) == false,"");
            DLIB_CASSERT(a.has_edge(0,0) == false,"");
            DLIB_CASSERT(a.has_edge(1,0) == false,"");
            DLIB_CASSERT(a.has_edge(3,0) == false,"");

            for (unsigned long i = 0; i < a.number_of_nodes(); ++i)
            {
                a.node(i).data = static_cast<int>(i);
            }

            a.remove_node(2);
            DLIB_CASSERT(a.number_of_nodes() == 3,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == true,"");

            count = 0;
            for (unsigned long i = 0; i < a.number_of_nodes(); ++i)
            {
                if (a.node(i).data == 0)
                {
                    DLIB_CASSERT(a.node(i).number_of_neighbors() == 0,"");
                }
                else if (a.node(i).data == 1)
                {
                    DLIB_CASSERT(a.node(i).number_of_neighbors() == 2,"");
                }
                else if (a.node(i).data == 3)
                {
                    DLIB_CASSERT(a.node(i).number_of_neighbors() == 1,"");
                }
                else
                {
                    DLIB_CASSERT(false,"this is impossible");
                }

                for (unsigned long j = 0; j < a.number_of_nodes(); ++j)
                {
                    if ((a.node(i).data == 1 && a.node(j).data == 1) ||
                        (a.node(i).data == 1 && a.node(j).data == 3) ||
                        (a.node(i).data == 3 && a.node(j).data == 1))
                    {
                        DLIB_CASSERT(a.has_edge(i,j) == true,"");
                        ++count;
                    }
                    else
                    {
                        DLIB_CASSERT(a.has_edge(i,j) == false,"");
                    }
                }
            }
            DLIB_CASSERT(count == 3,count);
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == true,"");
            a.remove_edge(1,1);
            DLIB_CASSERT(graph_contains_undirected_cycle(a) == false,"");

            DLIB_CASSERT(b.number_of_nodes() == 4,"");
            b.clear();
            DLIB_CASSERT(b.number_of_nodes() == 0,"");

            a.clear();

                /*
                    1      7
                    |     / \
                    2    6   0
                     \  /    |
                       3    /
                      / \  /
                     4    5
                */
            a.set_number_of_nodes(8);
            a.add_edge(1,2);
            a.add_edge(2,3);
            a.add_edge(3,4);
            a.add_edge(3,5);
            a.add_edge(3,6);
            a.add_edge(6,7);
            a.add_edge(7,0);
            a.add_edge(0,5);

            DLIB_CASSERT(graph_is_connected(a),"");

            set<set<unsigned long>::compare_1b_c>::kernel_1b_c sos;

            dlib::graph<set<unsigned long>::compare_1b_c, set<unsigned long>::compare_1b_c>::kernel_1a_c join_tree;
            unsigned long temp;
            triangulate_graph_and_find_cliques(a,sos);
            DLIB_CASSERT(a.number_of_nodes() == 8,"");

            create_join_tree(a, join_tree);
            DLIB_CASSERT(join_tree.number_of_nodes() == 6,"");
            DLIB_CASSERT(graph_is_connected(join_tree) == true,"");
            DLIB_CASSERT(graph_contains_undirected_cycle(join_tree) == false,"");
            DLIB_CASSERT(is_join_tree(a, join_tree),"");

            // check old edges
            DLIB_CASSERT(a.has_edge(1,2),"");
            DLIB_CASSERT(a.has_edge(2,3),"");
            DLIB_CASSERT(a.has_edge(3,4),"");
            DLIB_CASSERT(a.has_edge(3,5),"");
            DLIB_CASSERT(a.has_edge(3,6),"");
            DLIB_CASSERT(a.has_edge(6,7),"");
            DLIB_CASSERT(a.has_edge(7,0),"");
            DLIB_CASSERT(a.has_edge(0,5),"");

            DLIB_CASSERT(graph_is_connected(a),"");

            DLIB_CASSERT(sos.size() == 6,"");

            temp = 1; s.add(temp);
            temp = 2; s.add(temp);
            DLIB_CASSERT(sos.is_member(s),"");
            s.clear();
            temp = 2; s.add(temp);
            temp = 3; s.add(temp);
            DLIB_CASSERT(sos.is_member(s),"");
            s.clear();
            temp = 4; s.add(temp);
            temp = 3; s.add(temp);
            DLIB_CASSERT(sos.is_member(s),"");

            sos.reset();
            while (sos.move_next())
            {
                DLIB_CASSERT(is_clique(a, sos.element()),"");
                DLIB_CASSERT(is_maximal_clique(a, sos.element()),"");
            }

        }

        class graph_tester : public tester
        {
            /*!
                WHAT THIS OBJECT REPRESENTS
                    This object represents a test for the graph object.  When it is constructed
                    it adds itself into the testing framework.  The command line switch is
                    specified as test_directed_graph by passing that string to the tester constructor.
            !*/
        public:
            graph_tester (
            ) :
                tester ("test_graph",
                        "Runs tests on the graph component.")
            {}

            void perform_test (
            )
            {
                dlog << LINFO << "testing kernel_1a_c";
                graph_test<graph<int>::kernel_1a_c>();

                dlog << LINFO << "testing kernel_1a";
                graph_test<graph<int>::kernel_1a>();
            }
        } a;

    }