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16#include <cstdint>

17#include <cstdlib>

18#include <sstream>

19#include <vector>

20

21#include "google/protobuf/duration.pb.h"

28

29

31

32struct DataModel {

33 const std::vector<std::vector<int64_t>> distance_matrix{

34 {0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468,

35 776, 662},

36 {548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674,

37 1016, 868, 1210},

38 {776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130,

39 788, 1552, 754},

40 {696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822,

41 1164, 560, 1358},

42 {582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708,

43 1050, 674, 1244},

44 {274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514,

45 1050, 708},

46 {502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514,

47 1278, 480},

48 {194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662,

49 742, 856},

50 {308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320,

51 1084, 514},

52 {194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274,

53 810, 468},

54 {536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730,

55 388, 1152, 354},

56 {502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308,

57 650, 274, 844},

58 {388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536,

59 388, 730},

60 {354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342,

61 422, 536},

62 {468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342,

63 0, 764, 194},

64 {776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388,

65 422, 764, 0, 798},

66 {662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536,

67 194, 798, 0},

68 };

69

70 const std::vector<int64_t> demands{

71 0, 1, 1, 3, 6, 3, 6, 8, 8, 1, 2, 1, 2, 6, 6, 8, 8,

72 };

73 const std::vector<int64_t> vehicle_capacities{15, 15, 15, 15};

74

75 const int num_vehicles = 4;

76 const RoutingIndexManager::NodeIndex depot{0};

77};

78

79

80

86void PrintSolution(const DataModel& data, const RoutingIndexManager& manager,

87 const RoutingModel& routing, const Assignment& solution) {

88

89 std::ostringstream dropped_nodes;

90 for (int64_t node = 0; node < routing.Size(); ++node) {

91 if (routing.IsStart(node) || routing.IsEnd(node)) continue;

92 if (solution.Value(routing.NextVar(node)) == node) {

93 dropped_nodes << " " << manager.IndexToNode(node).value();

94 }

95 }

96 LOG(INFO) << "Dropped nodes:" << dropped_nodes.str();

97

98 int64_t total_distance{0};

99 int64_t total_load{0};

100 for (int vehicle_id = 0; vehicle_id < data.num_vehicles; ++vehicle_id) {

101 if (!routing.IsVehicleUsed(solution, vehicle_id)) {

102 continue;

103 }

104 int64_t index = routing.Start(vehicle_id);

105 LOG(INFO) << "Route for Vehicle " << vehicle_id << ":";

106 int64_t route_distance{0};

107 int64_t route_load{0};

108 std::ostringstream route;

109 while (!routing.IsEnd(index)) {

110 const int node_index = manager.IndexToNode(index).value();

111 route_load += data.demands[node_index];

112 route << node_index << " Load(" << route_load << ") -> ";

113 const int64_t previous_index = index;

114 index = solution.Value(routing.NextVar(index));

115 route_distance += routing.GetArcCostForVehicle(previous_index, index,

116 int64_t{vehicle_id});

117 }

118 LOG(INFO) << route.str() << manager.IndexToNode(index).value();

119 LOG(INFO) << "Distance of the route: " << route_distance << "m";

120 LOG(INFO) << "Load of the route: " << route_load;

121 total_distance += route_distance;

122 total_load += route_load;

123 }

124 LOG(INFO) << "Total distance of all routes: " << total_distance << "m";

125 LOG(INFO) << "Total load of all routes: " << total_load;

126 LOG(INFO) << "";

127 LOG(INFO) << "Advanced usage:";

128 LOG(INFO) << "Problem solved in " << routing.solver()->wall_time() << "ms";

129}

130

131

132void VrpDropNodes() {

133

134

135 DataModel data;

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140 RoutingIndexManager manager(data.distance_matrix.size(), data.num_vehicles,

141 data.depot);

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145

146 RoutingModel routing(manager);

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149

150

151 const int transit_callback_index = routing.RegisterTransitCallback(

152 [&data, &manager](const int64_t from_index,

153 const int64_t to_index) -> int64_t {

154

155 const int from_node = manager.IndexToNode(from_index).value();

156 const int to_node = manager.IndexToNode(to_index).value();

157 return data.distance_matrix[from_node][to_node];

158 });

159

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161

162

163 routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index);

164

165

166

167

168 const int demand_callback_index = routing.RegisterUnaryTransitCallback(

169 [&data, &manager](const int64_t from_index) -> int64_t {

170

171 const int from_node = manager.IndexToNode(from_index).value();

172 return data.demands[from_node];

173 });

174 routing.AddDimensionWithVehicleCapacity(

175 demand_callback_index,

176 int64_t{0},

177 data.vehicle_capacities,

178 true,

179 "Capacity");

180

181 int64_t penalty{1000};

182 for (int i = 1; i < data.distance_matrix.size(); ++i) {

183 routing.AddDisjunction(

185 }

186

187

188

189

191 search_parameters.set_first_solution_strategy(

193 search_parameters.set_local_search_metaheuristic(

195 search_parameters.mutable_time_limit()->set_seconds(1);

196

197

198

199

200 const Assignment* solution = routing.SolveWithParameters(search_parameters);

201

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203

204

205 PrintSolution(data, manager, routing, *solution);

206

207}

208}

209

210int main(int , char* []) {

211 operations_research::VrpDropNodes();

212 return EXIT_SUCCESS;

213}

214