1 | #ifndef LEMON_INSERTION_TSP_H |
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2 | #define LEMON_INSERTION_TSP_H |
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3 | |
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4 | #include <lemon/full_graph.h> |
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5 | #include <lemon/path.h> |
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6 | #include <lemon/maps.h> |
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7 | #include <lemon/random.h> |
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8 | #include <vector> |
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9 | |
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10 | namespace lemon { |
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11 | |
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12 | namespace insertion_tsp_helper { |
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13 | |
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14 | template <class L> |
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15 | L vectorConvert(const std::vector<FullGraph::Node> &_path) { |
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16 | return L(_path.begin(), _path.end()); |
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17 | }; |
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18 | |
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19 | template <> |
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20 | std::vector<FullGraph::Node> vectorConvert( |
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21 | const std::vector<FullGraph::Node> &_path) { |
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22 | return _path; |
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23 | }; |
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24 | |
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25 | }; |
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26 | |
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27 | template <typename CM> |
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28 | class InsertionTsp { |
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29 | private: |
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30 | GRAPH_TYPEDEFS(FullGraph); |
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31 | |
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32 | public: |
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33 | typedef CM CostMap; |
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34 | typedef typename CM::Value Cost; |
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35 | |
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36 | InsertionTsp(const FullGraph &gr, const CostMap &cost) : |
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37 | _gr(gr), _cost(cost) {} |
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38 | |
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39 | enum InsertionMethod { |
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40 | INSERT_NEAREST, |
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41 | INSERT_FARTHEST, |
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42 | INSERT_CHEAPEST, |
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43 | INSERT_RANDOM |
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44 | }; |
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45 | |
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46 | Cost run(InsertionMethod method = INSERT_FARTHEST) { |
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47 | switch (method) { |
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48 | case INSERT_NEAREST: |
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49 | start<InitTour<true>, NearestSelection, DefaultInsert>(); |
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50 | break; |
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51 | case INSERT_FARTHEST: |
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52 | start<InitTour<false>, FarthestSelection, DefaultInsert>(); |
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53 | break; |
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54 | case INSERT_CHEAPEST: |
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55 | start<InitTour<true>, CheapestSelection, CheapestInsert>(); |
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56 | break; |
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57 | case INSERT_RANDOM: |
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58 | start<InitTour<true>, RandomSelection, DefaultInsert>(); |
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59 | break; |
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60 | } |
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61 | return sum; |
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62 | } |
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63 | |
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64 | template <typename L> |
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65 | void tourNodes(L &container) { |
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66 | container(insertion_tsp_helper::vectorConvert<L>(nodesPath)); |
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67 | } |
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68 | |
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69 | template <template <typename> class L> |
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70 | L<Node> tourNodes() { |
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71 | return insertion_tsp_helper::vectorConvert<L<Node> >(nodesPath); |
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72 | } |
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73 | |
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74 | const std::vector<Node>& tourNodes() { |
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75 | return nodesPath; |
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76 | } |
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77 | |
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78 | Path<FullGraph> tour() { |
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79 | Path<FullGraph> p; |
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80 | if (nodesPath.size()<2) |
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81 | return p; |
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82 | |
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83 | for (unsigned int i=0; i<nodesPath.size()-1; ++i) |
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84 | p.addBack(_gr.arc(nodesPath[i], nodesPath[i+1])); |
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85 | |
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86 | p.addBack(_gr.arc(nodesPath.back(), nodesPath.front())); |
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87 | return p; |
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88 | } |
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89 | |
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90 | Cost tourCost() { |
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91 | return sum; |
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92 | } |
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93 | |
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94 | |
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95 | private: |
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96 | |
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97 | template <bool MIN> |
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98 | class InitTour { |
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99 | public: |
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100 | InitTour(const FullGraph &gr, const CostMap &cost, |
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101 | std::vector<Node> &used, std::vector<Node> ¬used, |
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102 | Cost &fullcost) : |
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103 | _gr(gr), _cost(cost), _used(used), _notused(notused), |
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104 | _fullcost(fullcost) {} |
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105 | |
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106 | std::vector<Node> init() const { |
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107 | Edge min = (MIN) ? mapMin(_gr, _cost) : mapMax(_gr, _cost); |
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108 | std::vector<Node> path; |
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109 | path.push_back(_gr.u(min)); |
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110 | path.push_back(_gr.v(min)); |
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111 | |
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112 | _used.clear(); |
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113 | _notused.clear(); |
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114 | for (NodeIt n(_gr); n!=INVALID; ++n) { |
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115 | if (n != _gr.u(min) && n != _gr.v(min)) { |
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116 | _notused.push_back(n); |
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117 | } |
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118 | } |
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119 | _used.push_back(_gr.u(min)); |
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120 | _used.push_back(_gr.v(min)); |
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121 | |
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122 | _fullcost = _cost[min]*2; |
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123 | return path; |
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124 | } |
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125 | |
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126 | private: |
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127 | const FullGraph &_gr; |
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128 | const CostMap &_cost; |
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129 | std::vector<Node> &_used; |
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130 | std::vector<Node> &_notused; |
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131 | Cost &_fullcost; |
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132 | }; |
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133 | |
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134 | class NearestSelection { |
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135 | public: |
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136 | NearestSelection(const FullGraph &gr, const CostMap &cost, |
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137 | std::vector<Node> &used, std::vector<Node> ¬used) : |
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138 | _gr(gr), _cost(cost), _used(used), _notused(notused) {} |
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139 | |
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140 | Node select() const { |
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141 | |
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142 | Cost insert_val = |
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143 | std::numeric_limits<Cost>::max(); |
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144 | int insert_node = -1; |
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145 | |
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146 | for (unsigned int i=0; i<_notused.size(); ++i) { |
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147 | Cost min_val = _cost[_gr.edge(_notused[i], _used[0])]; |
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148 | int min_node = 0; |
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149 | |
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150 | for (unsigned int j=1; j<_used.size(); ++j) { |
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151 | if (min_val > _cost[_gr.edge(_notused[i], _used[j])]) { |
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152 | min_val = _cost[_gr.edge(_notused[i], _used[j])]; |
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153 | min_node = j; |
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154 | } |
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155 | } |
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156 | |
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157 | if (insert_val > min_val) { |
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158 | insert_val = min_val; |
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159 | insert_node = i; |
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160 | } |
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161 | } |
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162 | |
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163 | Node n = _notused[insert_node]; |
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164 | _notused.erase(_notused.begin()+insert_node); |
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165 | |
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166 | return n; |
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167 | } |
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168 | |
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169 | private: |
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170 | const FullGraph &_gr; |
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171 | const CostMap &_cost; |
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172 | std::vector<Node> &_used; |
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173 | std::vector<Node> &_notused; |
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174 | }; |
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175 | |
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176 | class FarthestSelection { |
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177 | public: |
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178 | FarthestSelection(const FullGraph &gr, const CostMap &cost, |
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179 | std::vector<Node> &used, std::vector<Node> ¬used) : |
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180 | _gr(gr), _cost(cost), _used(used), _notused(notused) {} |
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181 | |
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182 | Node select() const { |
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183 | |
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184 | Cost insert_val = |
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185 | std::numeric_limits<Cost>::min(); |
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186 | int insert_node = -1; |
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187 | |
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188 | for (unsigned int i=0; i<_notused.size(); ++i) { |
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189 | Cost min_val = _cost[_gr.edge(_notused[i], _used[0])]; |
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190 | int min_node = 0; |
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191 | |
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192 | for (unsigned int j=1; j<_used.size(); ++j) { |
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193 | if (min_val > _cost[_gr.edge(_notused[i], _used[j])]) { |
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194 | min_val = _cost[_gr.edge(_notused[i], _used[j])]; |
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195 | min_node = j; |
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196 | } |
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197 | } |
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198 | |
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199 | if (insert_val < min_val || insert_node == -1) { |
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200 | insert_val = min_val; |
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201 | insert_node = i; |
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202 | } |
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203 | } |
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204 | |
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205 | Node n = _notused[insert_node]; |
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206 | _notused.erase(_notused.begin()+insert_node); |
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207 | |
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208 | return n; |
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209 | } |
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210 | |
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211 | private: |
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212 | const FullGraph &_gr; |
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213 | const CostMap &_cost; |
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214 | std::vector<Node> &_used; |
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215 | std::vector<Node> &_notused; |
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216 | }; |
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217 | |
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218 | |
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219 | class CheapestSelection { |
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220 | private: |
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221 | Cost costDiff(Node u, Node v, Node w) const { |
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222 | return |
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223 | _cost[_gr.edge(u, w)] + |
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224 | _cost[_gr.edge(v, w)] - |
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225 | _cost[_gr.edge(u, v)]; |
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226 | } |
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227 | |
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228 | public: |
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229 | CheapestSelection(const FullGraph &gr, const CostMap &cost, |
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230 | std::vector<Node> &used, std::vector<Node> ¬used) : |
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231 | _gr(gr), _cost(cost), _used(used), _notused(notused) {} |
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232 | |
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233 | Cost select() const { |
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234 | int insert_notused = -1; |
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235 | int best_insert_index = -1; |
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236 | Cost insert_val = |
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237 | std::numeric_limits<Cost>::max(); |
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238 | |
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239 | for (unsigned int i=0; i<_notused.size(); ++i) { |
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240 | int min = i; |
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241 | int best_insert_tmp = 0; |
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242 | Cost min_val = |
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243 | costDiff(_used.front(), _used.back(), _notused[i]); |
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244 | |
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245 | for (unsigned int j=1; j<_used.size(); ++j) { |
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246 | Cost tmp = |
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247 | costDiff(_used[j-1], _used[j], _notused[i]); |
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248 | |
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249 | if (min_val > tmp) { |
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250 | min = i; |
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251 | min_val = tmp; |
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252 | best_insert_tmp = j; |
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253 | } |
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254 | } |
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255 | |
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256 | if (insert_val > min_val) { |
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257 | insert_notused = min; |
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258 | insert_val = min_val; |
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259 | best_insert_index = best_insert_tmp; |
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260 | } |
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261 | } |
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262 | |
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263 | _used.insert(_used.begin()+best_insert_index, _notused[insert_notused]); |
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264 | _notused.erase(_notused.begin()+insert_notused); |
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265 | |
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266 | return insert_val; |
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267 | } |
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268 | |
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269 | private: |
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270 | const FullGraph &_gr; |
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271 | const CostMap &_cost; |
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272 | std::vector<Node> &_used; |
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273 | std::vector<Node> &_notused; |
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274 | }; |
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275 | |
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276 | class RandomSelection { |
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277 | public: |
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278 | RandomSelection(const FullGraph &, const CostMap &, |
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279 | std::vector<Node> &, std::vector<Node> ¬used) : |
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280 | _notused(notused) { |
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281 | rnd.seedFromTime(); |
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282 | } |
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283 | |
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284 | Node select() const { |
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285 | const int index = rnd[_notused.size()]; |
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286 | Node n = _notused[index]; |
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287 | _notused.erase(_notused.begin()+index); |
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288 | return n; |
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289 | } |
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290 | private: |
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291 | std::vector<Node> &_notused; |
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292 | }; |
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293 | |
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294 | |
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295 | class DefaultInsert { |
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296 | private: |
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297 | Cost costDiff(Node u, Node v, Node w) const { |
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298 | return |
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299 | _cost[_gr.edge(u, w)] + |
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300 | _cost[_gr.edge(v, w)] - |
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301 | _cost[_gr.edge(u, v)]; |
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302 | } |
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303 | |
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304 | public: |
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305 | DefaultInsert(const FullGraph &gr, const CostMap &cost, |
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306 | std::vector<Node> &path, Cost &fullcost) : |
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307 | _gr(gr), _cost(cost), _path(path), _fullcost(fullcost) {} |
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308 | |
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309 | void insert(Node n) const { |
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310 | int min = 0; |
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311 | Cost min_val = |
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312 | costDiff(_path.front(), _path.back(), n); |
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313 | |
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314 | for (unsigned int i=1; i<_path.size(); ++i) { |
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315 | Cost tmp = costDiff(_path[i-1], _path[i], n); |
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316 | if (tmp < min_val) { |
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317 | min = i; |
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318 | min_val = tmp; |
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319 | } |
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320 | } |
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321 | |
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322 | _path.insert(_path.begin()+min, n); |
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323 | _fullcost += min_val; |
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324 | } |
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325 | |
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326 | private: |
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327 | const FullGraph &_gr; |
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328 | const CostMap &_cost; |
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329 | std::vector<Node> &_path; |
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330 | Cost &_fullcost; |
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331 | }; |
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332 | |
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333 | class CheapestInsert { |
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334 | TEMPLATE_GRAPH_TYPEDEFS(FullGraph); |
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335 | public: |
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336 | CheapestInsert(const FullGraph &, const CostMap &, |
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337 | std::vector<Node> &, Cost &fullcost) : |
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338 | _fullcost(fullcost) {} |
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339 | |
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340 | void insert(Cost diff) const { |
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341 | _fullcost += diff; |
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342 | } |
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343 | |
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344 | private: |
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345 | Cost &_fullcost; |
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346 | }; |
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347 | |
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348 | |
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349 | template <class InitFunctor, class SelectionFunctor, class InsertFunctor> |
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350 | void start() { |
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351 | InitFunctor init(_gr, _cost, nodesPath, notused, sum); |
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352 | SelectionFunctor selectNode(_gr, _cost, nodesPath, notused); |
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353 | InsertFunctor insertNode(_gr, _cost, nodesPath, sum); |
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354 | |
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355 | nodesPath = init.init(); |
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356 | |
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357 | for (int i=0; i<_gr.nodeNum()-2; ++i) { |
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358 | insertNode.insert(selectNode.select()); |
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359 | } |
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360 | |
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361 | sum = _cost[ _gr.edge(nodesPath.front(), nodesPath.back()) ]; |
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362 | for (unsigned int i=0; i<nodesPath.size()-1; ++i) |
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363 | sum += _cost[ _gr.edge(nodesPath[i], nodesPath[i+1]) ]; |
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364 | } |
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365 | |
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366 | const FullGraph &_gr; |
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367 | const CostMap &_cost; |
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368 | std::vector<Node> notused; |
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369 | std::vector<Node> nodesPath; |
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370 | Cost sum; |
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371 | }; |
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372 | |
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373 | }; // namespace lemon |
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374 | |
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375 | #endif |
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