224 lines
8.0 KiB
C++
224 lines
8.0 KiB
C++
// Copyright 2010-2022 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// [START program]
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// [START import]
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#include <algorithm>
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#include <cstdint>
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#include <functional>
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#include <sstream>
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#include <string>
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#include <vector>
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#include "google/protobuf/duration.pb.h"
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#include "ortools/constraint_solver/routing.h"
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#include "ortools/constraint_solver/routing_enums.pb.h"
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#include "ortools/constraint_solver/routing_index_manager.h"
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#include "ortools/constraint_solver/routing_parameters.h"
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// [END import]
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namespace operations_research {
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// [START data_model]
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struct DataModel {
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const std::vector<std::vector<int64_t>> distance_matrix{
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{0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468,
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776, 662},
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{548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674,
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1016, 868, 1210},
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{776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130,
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788, 1552, 754},
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{696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822,
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1164, 560, 1358},
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{582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708,
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1050, 674, 1244},
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{274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514,
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1050, 708},
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{502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514,
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1278, 480},
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{194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662,
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742, 856},
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{308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320,
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1084, 514},
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{194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274,
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810, 468},
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{536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730,
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388, 1152, 354},
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{502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308,
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650, 274, 844},
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{388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536,
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388, 730},
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{354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342,
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422, 536},
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{468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342,
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0, 764, 194},
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{776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388,
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422, 764, 0, 798},
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{662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536,
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194, 798, 0},
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};
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const int num_vehicles = 4;
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const RoutingIndexManager::NodeIndex depot{0};
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};
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// [END data_model]
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//! @brief Print the solution.
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//! @param[in] routing_manager Index manager used.
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//! @param[in] routing_model Routing solver used.
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// [START solution_callback_printer]
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void print_solution(const RoutingIndexManager& routing_manager,
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const RoutingModel& routing_model) {
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LOG(INFO) << "################";
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LOG(INFO) << "Solution objective: " << routing_model.CostVar()->Value();
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int64_t total_distance{0};
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for (int vehicle_id = 0; vehicle_id < routing_manager.num_vehicles();
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++vehicle_id) {
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int64_t index = routing_model.Start(vehicle_id);
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LOG(INFO) << "Route for Vehicle " << vehicle_id << ":";
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int64_t route_distance{0};
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std::stringstream route;
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while (routing_model.IsEnd(index) == false) {
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route << " " << routing_manager.IndexToNode(index).value() << " ->";
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int64_t previous_index = index;
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index = routing_model.NextVar(index)->Value();
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route_distance += routing_model.GetArcCostForVehicle(
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previous_index, index, int64_t{vehicle_id});
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}
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LOG(INFO) << route.str() << routing_manager.IndexToNode(index).value();
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LOG(INFO) << "Distance of the route: " << route_distance << "m";
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total_distance += route_distance;
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}
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LOG(INFO) << "Total distance of all routes: " << total_distance << "m";
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}
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// [END solution_callback_printer]
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// [START solution_callback]
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struct SolutionCallback {
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const RoutingIndexManager& routing_manager;
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const RoutingModel& routing_model;
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const int64_t max_solution;
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SolutionCallback(const RoutingIndexManager& manager,
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const RoutingModel& model, const int64_t max_solution)
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: routing_manager(manager),
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routing_model(model),
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max_solution(max_solution) {
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objectives.reserve(max_solution);
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}
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~SolutionCallback() = default;
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void Run() {
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int64_t objective = routing_model.CostVar()->Value();
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if (objectives.empty() || objective < objectives.back()) {
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objectives.push_back(objective);
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print_solution(routing_manager, routing_model);
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counter++;
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}
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if (counter >= max_solution) {
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routing_model.solver()->FinishCurrentSearch();
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}
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}
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std::vector<int64_t> objectives = {};
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private:
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int64_t counter = 0;
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};
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// [END solution_callback]
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void VrpSolutionCallback() {
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// Instantiate the data problem.
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// [START data]
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DataModel data;
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// [END data]
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// Create Routing Index Manager.
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// [START index_manager]
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RoutingIndexManager routing_manager(data.distance_matrix.size(),
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data.num_vehicles, data.depot);
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// [END index_manager]
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// Create Routing Model.
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// [START routing_model]
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RoutingModel routing_model(routing_manager);
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// [END routing_model]
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// Create and register a transit callback.
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// [START transit_callback]
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const int transit_callback_index = routing_model.RegisterTransitCallback(
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[&data, &routing_manager](int64_t from_index,
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int64_t to_index) -> int64_t {
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// Convert from routing variable Index to distance matrix NodeIndex.
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auto from_node = routing_manager.IndexToNode(from_index).value();
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auto to_node = routing_manager.IndexToNode(to_index).value();
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return data.distance_matrix[from_node][to_node];
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});
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// [END transit_callback]
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// Define cost of each arc.
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// [START arc_cost]
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routing_model.SetArcCostEvaluatorOfAllVehicles(transit_callback_index);
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// [END arc_cost]
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// Add Distance constraint.
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// [START distance_constraint]
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routing_model.AddDimension(transit_callback_index,
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0, // no slack
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3000, // vehicle maximum travel distance
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true, // start cumul to zero
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"Distance");
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routing_model.GetMutableDimension("Distance")
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->SetGlobalSpanCostCoefficient(100);
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// [END distance_constraint]
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// Attach a solution callback.
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// [START attach_callback]
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SolutionCallback solution_callback{routing_manager, routing_model,
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/*max_solution=*/15};
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routing_model.AddAtSolutionCallback(
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std::bind(&SolutionCallback::Run, &solution_callback));
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// [END attach_callback]
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// Setting first solution heuristic.
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// [START parameters]
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RoutingSearchParameters search_parameters = DefaultRoutingSearchParameters();
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search_parameters.set_first_solution_strategy(
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FirstSolutionStrategy::PATH_CHEAPEST_ARC);
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search_parameters.set_local_search_metaheuristic(
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LocalSearchMetaheuristic::GUIDED_LOCAL_SEARCH);
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search_parameters.mutable_time_limit()->set_seconds(5);
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// [END parameters]
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// Solve the problem.
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// [START solve]
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const Assignment* solution =
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routing_model.SolveWithParameters(search_parameters);
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// [END solve]
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// Print solution on console.
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// [START print_solution]
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if (solution != nullptr) {
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LOG(INFO) << "Best objectives: "
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<< std::to_string(solution_callback.objectives.back());
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} else {
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LOG(INFO) << "No solution found.";
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}
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// [END print_solution]
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}
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} // namespace operations_research
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int main(int /*argc*/, char* /*argv*/[]) {
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operations_research::VrpSolutionCallback();
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return EXIT_SUCCESS;
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}
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// [END program]
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