130 lines
5.1 KiB
C#
130 lines
5.1 KiB
C#
// Copyright 2010-2025 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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using System;
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using System.Collections.Generic;
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using Google.OrTools.ConstraintSolver;
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using Google.Protobuf.WellKnownTypes; // Duration
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// [END import]
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/// <summary>
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/// Minimal Vrp using a time limit.
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/// </summary>
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public class Vrp
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{
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// [START solution_printer]
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/// <summary>
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/// Print the solution.
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/// </summary>
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static void PrintSolution(in RoutingIndexManager manager, in RoutingModel routing, in Assignment solution)
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{
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Console.WriteLine($"Objective {solution.ObjectiveValue()}:");
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// Inspect solution.
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long maxRouteDistance = 0;
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for (int i = 0; i < manager.GetNumberOfVehicles(); ++i)
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{
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if (!routing.IsVehicleUsed(solution, i))
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{
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continue;
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}
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Console.WriteLine("Route for Vehicle {0}:", i);
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long routeDistance = 0;
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var index = routing.Start(i);
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while (routing.IsEnd(index) == false)
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{
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Console.Write("{0} -> ", manager.IndexToNode((int)index));
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var previousIndex = index;
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index = solution.Value(routing.NextVar(index));
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routeDistance += routing.GetArcCostForVehicle(previousIndex, index, 0);
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}
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Console.WriteLine("{0}", manager.IndexToNode((int)index));
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Console.WriteLine("Distance of the route: {0}m", routeDistance);
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maxRouteDistance = Math.Max(routeDistance, maxRouteDistance);
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}
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Console.WriteLine("Maximum distance of the routes: {0}m", maxRouteDistance);
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}
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// [END solution_printer]
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public static void Main(String[] args)
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{
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// Instantiate the data problem.
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// [START data]
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int locationNumber = 20;
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int vehicleNumber = 5;
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int depot = 0;
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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 manager = new RoutingIndexManager(locationNumber, vehicleNumber, 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 = new RoutingModel(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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int transitCallbackIndex = routing.RegisterTransitCallback((long fromIndex, long toIndex) =>
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{
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// Convert from routing variable Index to
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// distance matrix NodeIndex.
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var fromNode = manager.IndexToNode(fromIndex);
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var toNode = manager.IndexToNode(toIndex);
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return 1;
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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.SetArcCostEvaluatorOfAllVehicles(transitCallbackIndex);
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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.AddDimension(transitCallbackIndex,
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/*slack=*/0,
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/*horizon=*/3000,
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/*start_cumul_to_zero=*/true, "Distance");
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RoutingDimension distanceDimension = routing.GetMutableDimension("Distance");
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distanceDimension.SetGlobalSpanCostCoefficient(100);
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// [END distance_constraint]
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// Setting first solution heuristic.
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// [START parameters]
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RoutingSearchParameters searchParameters =
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operations_research_constraint_solver.DefaultRoutingSearchParameters();
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searchParameters.FirstSolutionStrategy = FirstSolutionStrategy.Types.Value.PathCheapestArc;
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searchParameters.LocalSearchMetaheuristic = LocalSearchMetaheuristic.Types.Value.GuidedLocalSearch;
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searchParameters.LogSearch = true;
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searchParameters.TimeLimit = new Duration { 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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Assignment solution = routing.SolveWithParameters(searchParameters);
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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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PrintSolution(manager, routing, solution);
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// [END print_solution]
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}
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}
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// [END program]
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