172 lines
7.8 KiB
C#
172 lines
7.8 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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// [END import]
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/// <summary>
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/// Minimal Pickup & Delivery Problem (PDP).
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/// </summary>
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public class VrpPickupDelivery
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{
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// [START data_model]
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class DataModel
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{
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public long[,] DistanceMatrix = {
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{ 0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468, 776, 662 },
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{ 548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674, 1016, 868, 1210 },
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{ 776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130, 788, 1552, 754 },
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{ 696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822, 1164, 560, 1358 },
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{ 582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708, 1050, 674, 1244 },
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{ 274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514, 1050, 708 },
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{ 502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514, 1278, 480 },
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{ 194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662, 742, 856 },
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{ 308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320, 1084, 514 },
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{ 194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274, 810, 468 },
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{ 536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730, 388, 1152, 354 },
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{ 502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308, 650, 274, 844 },
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{ 388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536, 388, 730 },
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{ 354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342, 422, 536 },
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{ 468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342, 0, 764, 194 },
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{ 776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388, 422, 764, 0, 798 },
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{ 662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536, 194, 798, 0 }
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};
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// [START pickups_deliveries]
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public int[][] PickupsDeliveries = {
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new int[] { 1, 6 }, new int[] { 2, 10 }, new int[] { 4, 3 }, new int[] { 5, 9 },
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new int[] { 7, 8 }, new int[] { 15, 11 }, new int[] { 13, 12 }, new int[] { 16, 14 },
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};
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// [END pickups_deliveries]
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public int VehicleNumber = 4;
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public int Depot = 0;
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};
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// [END data_model]
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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 DataModel data, in RoutingModel routing, in RoutingIndexManager manager,
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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 totalDistance = 0;
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for (int i = 0; i < data.VehicleNumber; ++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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totalDistance += routeDistance;
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}
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Console.WriteLine("Total Distance of all routes: {0}m", totalDistance);
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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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DataModel data = new DataModel();
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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 =
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new RoutingIndexManager(data.DistanceMatrix.GetLength(0), data.VehicleNumber, 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 = 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 data.DistanceMatrix[fromNode, toNode];
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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, 0, 3000,
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true, // start cumul to zero
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"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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// Define Transportation Requests.
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// [START pickup_delivery_constraint]
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Solver solver = routing.solver();
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for (int i = 0; i < data.PickupsDeliveries.GetLength(0); i++)
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{
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long pickupIndex = manager.NodeToIndex(data.PickupsDeliveries[i][0]);
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long deliveryIndex = manager.NodeToIndex(data.PickupsDeliveries[i][1]);
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routing.AddPickupAndDelivery(pickupIndex, deliveryIndex);
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solver.Add(solver.MakeEquality(routing.VehicleVar(pickupIndex), routing.VehicleVar(deliveryIndex)));
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solver.Add(solver.MakeLessOrEqual(distanceDimension.CumulVar(pickupIndex),
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distanceDimension.CumulVar(deliveryIndex)));
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}
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// [END pickup_delivery_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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// [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(data, routing, manager, 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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