test/tsp_test.cc
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     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
       
     2  *
       
     3  * This file is a part of LEMON, a generic C++ optimization library.
       
     4  *
       
     5  * Copyright (C) 2003-2010
       
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
       
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
       
     8  *
       
     9  * Permission to use, modify and distribute this software is granted
       
    10  * provided that this copyright notice appears in all copies. For
       
    11  * precise terms see the accompanying LICENSE file.
       
    12  *
       
    13  * This software is provided "AS IS" with no warranty of any kind,
       
    14  * express or implied, and with no claim as to its suitability for any
       
    15  * purpose.
       
    16  *
       
    17  */
       
    18 
       
    19 #include <iostream>
       
    20 
       
    21 #include <lemon/full_graph.h>
       
    22 #include <lemon/math.h>
       
    23 #include <lemon/maps.h>
       
    24 #include <lemon/random.h>
       
    25 #include <lemon/dim2.h>
       
    26 
       
    27 #include <lemon/nearest_neighbor_tsp.h>
       
    28 #include <lemon/greedy_tsp.h>
       
    29 #include <lemon/insertion_tsp.h>
       
    30 #include <lemon/christofides_tsp.h>
       
    31 #include <lemon/opt2_tsp.h>
       
    32 
       
    33 #include "test_tools.h"
       
    34 
       
    35 using namespace lemon;
       
    36 
       
    37 // // Tests checkMetricCost() function
       
    38 // void metricCostTest() {
       
    39 //   GRAPH_TYPEDEFS(FullGraph);
       
    40 //   FullGraph g(10);
       
    41 //   check(checkMetricCost(g, constMap<Edge>(0)), "Wrong checkMetricCost()");
       
    42 //   check(checkMetricCost(g, constMap<Edge>(1)), "Wrong checkMetricCost()");
       
    43 //   check(!checkMetricCost(g, constMap<Edge>(-1)), "Wrong checkMetricCost()");
       
    44 //   
       
    45 //   FullGraph::EdgeMap<float> cost(g);
       
    46 //   for (NodeIt u(g); u != INVALID; ++u) {
       
    47 //     for (NodeIt v(g); v != INVALID; ++v) {
       
    48 //       if (u == v) continue;
       
    49 //       float x1 = g.id(u), x2 = g.id(v);
       
    50 //       float y1 = x1 * x1, y2 = x2 * x2;
       
    51 //       cost[g.edge(u, v)] = std::sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));
       
    52 //     }
       
    53 //   }
       
    54 //   check(checkMetricCost(g, cost), "Wrong checkMetricCost()");
       
    55 //   float eps = Tolerance<float>::defaultEpsilon();
       
    56 //   cost[g.edge(g(0), g(9))] =
       
    57 //     cost[g.edge(g(0), g(8))] + cost[g.edge(g(8), g(9))] + eps * 2;
       
    58 //   check(!checkMetricCost(g, cost), "Wrong checkMetricCost()");
       
    59 //   check(checkMetricCost(g, cost, Tolerance<float>(eps * 4)),
       
    60 //     "Wrong checkMetricCost()");
       
    61 // }
       
    62 
       
    63 // Checks tour validity
       
    64 bool checkTour(const FullGraph &gr, const std::vector<FullGraph::Node> &p) {
       
    65   FullGraph::NodeMap<bool> used(gr, false);
       
    66   
       
    67   int nodes = 0;
       
    68   for (int i = 0; i < int(p.size()); ++i) {
       
    69     if (used[p[i]]) return false;
       
    70     used[p[i]] = true;
       
    71     ++nodes;
       
    72   }
       
    73   
       
    74   return (nodes == gr.nodeNum());
       
    75 }
       
    76 
       
    77 // Checks tour validity
       
    78 bool checkTour(const FullGraph &gr, const Path<FullGraph> &p) {
       
    79   FullGraph::NodeMap<bool> used(gr, false);
       
    80   
       
    81   if (!checkPath(gr, p)) return false;
       
    82   if (gr.nodeNum() <= 1 && p.length() != 0) return false;
       
    83   if (gr.nodeNum() > 1 && p.length() != gr.nodeNum()) return false;
       
    84 
       
    85   for (int i = 0; i < p.length(); ++i) {
       
    86     if (used[gr.target(p.nth(i))]) return false;
       
    87     used[gr.target(p.nth(i))] = true;
       
    88   }
       
    89   return true;
       
    90 }
       
    91 
       
    92 // Checks tour cost
       
    93 template <typename CostMap>
       
    94 bool checkCost(const FullGraph &gr, const std::vector<FullGraph::Node> &p,
       
    95                const CostMap &cost, typename CostMap::Value total)
       
    96 {
       
    97   typedef typename CostMap::Value Cost;
       
    98 
       
    99   Cost s = 0;
       
   100   for (int i = 0; i < int(p.size()) - 1; ++i)
       
   101     s += cost[gr.edge(p[i], p[i+1])];
       
   102   if (int(p.size()) >= 2)
       
   103     s += cost[gr.edge(p.back(), p.front())];
       
   104 
       
   105   return !Tolerance<Cost>().different(s, total);
       
   106 }
       
   107 
       
   108 // Checks tour cost
       
   109 template <typename CostMap>
       
   110 bool checkCost(const FullGraph &, const Path<FullGraph> &p,
       
   111                const CostMap &cost, typename CostMap::Value total)
       
   112 {
       
   113   typedef typename CostMap::Value Cost;
       
   114 
       
   115   Cost s = 0;
       
   116   for (int i = 0; i < p.length(); ++i)
       
   117     s += cost[p.nth(i)];
       
   118 
       
   119   return !Tolerance<Cost>().different(s, total);
       
   120 }
       
   121 
       
   122 // Tests a TSP algorithm on small graphs
       
   123 template <typename TSP>
       
   124 void tspTestSmall(const std::string &alg_name) {
       
   125   GRAPH_TYPEDEFS(FullGraph);
       
   126 
       
   127   for (int n = 0; n <= 5; ++n) {
       
   128     FullGraph g(n);
       
   129     unsigned nsize = n;
       
   130     int esize = n <= 1 ? 0 : n;
       
   131 
       
   132     TSP alg(g, constMap<Edge, int>(1));
       
   133 
       
   134     check(alg.run() == esize, alg_name + ": Wrong total cost");
       
   135     check(alg.tourCost() == esize, alg_name + ": Wrong total cost");
       
   136 
       
   137     std::list<Node> list;
       
   138     std::vector<Node> vec;
       
   139     alg.tourNodes(list);
       
   140     alg.tourNodes(vec);
       
   141     check(list.size() == nsize, alg_name + ": Wrong node sequence");
       
   142     check(vec.size() == nsize,  alg_name + ": Wrong node sequence");
       
   143     check(alg.tourNodes().size() == nsize, alg_name + ": Wrong node sequence");
       
   144     check(checkTour(g, vec), alg_name + ": Wrong node sequence");
       
   145     check(checkCost(g, vec, constMap<Edge, int>(1), esize),
       
   146       alg_name + ": Wrong tour cost");
       
   147 
       
   148     SimplePath<FullGraph> path;
       
   149     alg.tour(path);
       
   150     check(path.length() == esize, alg_name + ": Wrong tour");
       
   151     check(checkTour(g, path), alg_name + ": Wrong tour");
       
   152     check(checkCost(g, path, constMap<Edge, int>(1), esize),
       
   153       alg_name + ": Wrong tour cost");
       
   154   }
       
   155 }
       
   156 
       
   157 // Tests a TSP algorithm on random graphs
       
   158 template <typename TSP>
       
   159 void tspTestRandom(const std::string &alg_name) {
       
   160   GRAPH_TYPEDEFS(FullGraph);
       
   161 
       
   162   FullGraph g(20);
       
   163   FullGraph::NodeMap<dim2::Point<double> > pos(g);
       
   164   DoubleEdgeMap cost(g);
       
   165 
       
   166   TSP alg(g, cost);
       
   167   Opt2Tsp<DoubleEdgeMap > opt2(g, cost);
       
   168 
       
   169   for (int i = 1; i <= 3; i++) {
       
   170     for (NodeIt u(g); u != INVALID; ++u) {
       
   171       pos[u] = dim2::Point<double>(rnd(), rnd());
       
   172     }
       
   173     for (NodeIt u(g); u != INVALID; ++u) {
       
   174       for (NodeIt v(g); v != INVALID; ++v) {
       
   175         if (u == v) continue;
       
   176         cost[g.edge(u, v)] = (pos[u] - pos[v]).normSquare();
       
   177       }
       
   178     }
       
   179     
       
   180     check(alg.run() > 0, alg_name + ": Wrong total cost");
       
   181 
       
   182     std::vector<Node> vec;
       
   183     alg.tourNodes(vec);
       
   184     check(checkTour(g, vec), alg_name + ": Wrong node sequence");
       
   185     check(checkCost(g, vec, cost, alg.tourCost()),
       
   186       alg_name + ": Wrong tour cost");
       
   187 
       
   188     SimplePath<FullGraph> path;
       
   189     alg.tour(path);
       
   190     check(checkTour(g, path), alg_name + ": Wrong tour");
       
   191     check(checkCost(g, path, cost, alg.tourCost()),
       
   192       alg_name + ": Wrong tour cost");
       
   193     
       
   194     check(!Tolerance<double>().less(alg.tourCost(), opt2.run(alg.tourNodes())),
       
   195       "2-opt improvement: Wrong total cost");
       
   196     check(checkTour(g, opt2.tourNodes()),
       
   197       "2-opt improvement: Wrong node sequence");
       
   198     check(checkCost(g, opt2.tourNodes(), cost, opt2.tourCost()),
       
   199       "2-opt improvement: Wrong tour cost");
       
   200     
       
   201     check(!Tolerance<double>().less(alg.tourCost(), opt2.run(path)),
       
   202       "2-opt improvement: Wrong total cost");
       
   203     check(checkTour(g, opt2.tourNodes()),
       
   204       "2-opt improvement: Wrong node sequence");
       
   205     check(checkCost(g, opt2.tourNodes(), cost, opt2.tourCost()),
       
   206       "2-opt improvement: Wrong tour cost");
       
   207   }
       
   208 }
       
   209 
       
   210 // Algorithm class for Nearest Insertion 
       
   211 template <typename CM>
       
   212 class NearestInsertionTsp : public InsertionTsp<CM> {
       
   213 public:
       
   214   NearestInsertionTsp(const FullGraph &gr, const CM &cost)
       
   215     : InsertionTsp<CM>(gr, cost) {}
       
   216   typename CM::Value run() {
       
   217     return InsertionTsp<CM>::run(InsertionTsp<CM>::NEAREST);
       
   218   }
       
   219 };
       
   220 
       
   221 // Algorithm class for Farthest Insertion 
       
   222 template <typename CM>
       
   223 class FarthestInsertionTsp : public InsertionTsp<CM> {
       
   224 public:
       
   225   FarthestInsertionTsp(const FullGraph &gr, const CM &cost)
       
   226     : InsertionTsp<CM>(gr, cost) {}
       
   227   typename CM::Value run() {
       
   228     return InsertionTsp<CM>::run(InsertionTsp<CM>::FARTHEST);
       
   229   }
       
   230 };
       
   231 
       
   232 // Algorithm class for Cheapest Insertion 
       
   233 template <typename CM>
       
   234 class CheapestInsertionTsp : public InsertionTsp<CM> {
       
   235 public:
       
   236   CheapestInsertionTsp(const FullGraph &gr, const CM &cost)
       
   237     : InsertionTsp<CM>(gr, cost) {}
       
   238   typename CM::Value run() {
       
   239     return InsertionTsp<CM>::run(InsertionTsp<CM>::CHEAPEST);
       
   240   }
       
   241 };
       
   242 
       
   243 // Algorithm class for Random Insertion 
       
   244 template <typename CM>
       
   245 class RandomInsertionTsp : public InsertionTsp<CM> {
       
   246 public:
       
   247   RandomInsertionTsp(const FullGraph &gr, const CM &cost)
       
   248     : InsertionTsp<CM>(gr, cost) {}
       
   249   typename CM::Value run() {
       
   250     return InsertionTsp<CM>::run(InsertionTsp<CM>::RANDOM);
       
   251   }
       
   252 };
       
   253 
       
   254 int main() {
       
   255   GRAPH_TYPEDEFS(FullGraph);
       
   256 
       
   257   // metricCostTest();
       
   258 
       
   259   tspTestSmall<NearestNeighborTsp<ConstMap<Edge, int> > >("Nearest Neighbor");
       
   260   tspTestSmall<GreedyTsp<ConstMap<Edge, int> > >("Greedy");
       
   261   tspTestSmall<NearestInsertionTsp<ConstMap<Edge, int> > >("Nearest Insertion");
       
   262   tspTestSmall<FarthestInsertionTsp<ConstMap<Edge, int> > >("Farthest Insertion");
       
   263   tspTestSmall<CheapestInsertionTsp<ConstMap<Edge, int> > >("Cheapest Insertion");
       
   264   tspTestSmall<RandomInsertionTsp<ConstMap<Edge, int> > >("Random Insertion");
       
   265   tspTestSmall<ChristofidesTsp<ConstMap<Edge, int> > >("Christofides");
       
   266   tspTestSmall<Opt2Tsp<ConstMap<Edge, int> > >("2-opt");
       
   267 
       
   268   tspTestRandom<NearestNeighborTsp<DoubleEdgeMap > >("Nearest Neighbor");
       
   269   tspTestRandom<GreedyTsp<DoubleEdgeMap > >("Greedy");
       
   270   tspTestRandom<NearestInsertionTsp<DoubleEdgeMap > >("Nearest Insertion");
       
   271   tspTestRandom<FarthestInsertionTsp<DoubleEdgeMap > >("Farthest Insertion");
       
   272   tspTestRandom<CheapestInsertionTsp<DoubleEdgeMap > >("Cheapest Insertion");
       
   273   tspTestRandom<RandomInsertionTsp<DoubleEdgeMap > >("Random Insertion");
       
   274   tspTestRandom<ChristofidesTsp<DoubleEdgeMap > >("Christofides");
       
   275   tspTestRandom<Opt2Tsp<DoubleEdgeMap > >("2-opt");
       
   276 
       
   277   return 0;
       
   278 }