source: branches/1955_DynamicVehicleRouting/HeuristicLab.PDPSimulation/3.3/Operators/DynPushForwardInsertionCreator.cs @ 17578

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Encodings.PermutationEncoding;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Common;
using HeuristicLab.Problems.VehicleRouting.Interfaces;
using HeuristicLab.Problems.VehicleRouting.ProblemInstances;
using HeuristicLab.Problems.VehicleRouting.Variants;
using HeuristicLab.Problems.VehicleRouting.Encodings.Potvin;
using HeuristicLab.Problems.VehicleRouting;

namespace HeuristicLab.PDPSimulation.Operators {
  [Item("DynPushForwardInsertionCreator", "Creates a randomly initialized VRP solution.")]
  [StorableClass]
  public sealed class DynPushForwardInsertionCreator : PotvinCreator, IStochasticOperator {
    #region IStochasticOperator Members
    public ILookupParameter<IRandom> RandomParameter {
      get { return (LookupParameter<IRandom>)Parameters["Random"]; }
    }
    #endregion

    public IValueParameter<DoubleValue> Alpha {
      get { return (IValueParameter<DoubleValue>)Parameters["Alpha"]; }
    }
    public IValueParameter<DoubleValue> AlphaVariance {
      get { return (IValueParameter<DoubleValue>)Parameters["AlphaVariance"]; }
    }
    public IValueParameter<DoubleValue> Beta {
      get { return (IValueParameter<DoubleValue>)Parameters["Beta"]; }
    }
    public IValueParameter<DoubleValue> BetaVariance {
      get { return (IValueParameter<DoubleValue>)Parameters["BetaVariance"]; }
    }
    public IValueParameter<DoubleValue> Gamma {
      get { return (IValueParameter<DoubleValue>)Parameters["Gamma"]; }
    }
    public IValueParameter<DoubleValue> GammaVariance {
      get { return (IValueParameter<DoubleValue>)Parameters["GammaVariance"]; }
    }

    [StorableConstructor]
    private DynPushForwardInsertionCreator(bool deserializing) : base(deserializing) { }

    public DynPushForwardInsertionCreator()
      : base() {
      Parameters.Add(new LookupParameter<IRandom>("Random", "The pseudo random number generator."));
      Parameters.Add(new ValueParameter<DoubleValue>("Alpha", "The alpha value.", new DoubleValue(0.7)));
      Parameters.Add(new ValueParameter<DoubleValue>("AlphaVariance", "The alpha variance.", new DoubleValue(0.5)));
      Parameters.Add(new ValueParameter<DoubleValue>("Beta", "The beta value.", new DoubleValue(0.1)));
      Parameters.Add(new ValueParameter<DoubleValue>("BetaVariance", "The beta variance.", new DoubleValue(0.07)));
      Parameters.Add(new ValueParameter<DoubleValue>("Gamma", "The gamma value.", new DoubleValue(0.2)));
      Parameters.Add(new ValueParameter<DoubleValue>("GammaVariance", "The gamma variance.", new DoubleValue(0.14)));
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new DynPushForwardInsertionCreator(this, cloner);
    }

    private DynPushForwardInsertionCreator(DynPushForwardInsertionCreator original, Cloner cloner)
      : base(original, cloner) {
    }

    // use the Box-Mueller transform in the polar form to generate a N(0,1) random variable out of two uniformly distributed random variables
    private static double Gauss(IRandom random) {
      double u = 0.0, v = 0.0, s = 0.0;
      do {
        u = (random.NextDouble() * 2) - 1;
        v = (random.NextDouble() * 2) - 1;
        s = Math.Sqrt(u * u + v * v);
      } while (s < Double.Epsilon || s > 1);
      return u * Math.Sqrt((-2.0 * Math.Log(s)) / s);
    }

    private static double N(double mu, double sigma, IRandom random) {
      return mu + (sigma * Gauss(random)); // transform the random variable sampled from N(0,1) to N(mu,sigma)
    }

    private static double GetDistance(int start, int end, IVRPProblemInstance problemInstance, PotvinEncoding solution) {
      double distance = 0.0;

      if (problemInstance is DynPDPProblemInstance) {
        distance = (problemInstance as DynPDPProblemInstance).GetDistance(start, end);
      }
      else if (problemInstance.UseDistanceMatrix.Value && problemInstance.DistanceMatrix != null) {
        distance = problemInstance.DistanceMatrix[start, end];
      } else {
        double startX = problemInstance.Coordinates[start, 0];
        double startY = problemInstance.Coordinates[start, 1];

        double endX = problemInstance.Coordinates[end, 0];
        double endY = problemInstance.Coordinates[end, 1];

        distance =
            Math.Sqrt(
              Math.Pow(startX - endX, 2) +
              Math.Pow(startY - endY, 2));
      }

      return distance;
    }

    private static double GetCosts(int customer, int vehicle, IVRPProblemInstance problemInstance,
      Dictionary<int, List<int>> vehicles, Dictionary<int, Tour> vehicleTours, List<bool> vehicleUsed, PotvinEncoding solution,
      double alpha, double beta, double gamma, out bool feasible, out bool existingRoute) {
      int depotCount = 1;
      IMultiDepotProblemInstance mdp = problemInstance as IMultiDepotProblemInstance;
      if (mdp != null) {
        depotCount = mdp.Depots.Value;
      }

      feasible = true;

      double distance = GetDistance(vehicle, customer + depotCount - 1, problemInstance, solution);
      if (vehicleUsed != null) {
        existingRoute = vehicleUsed[vehicle];
      } else {
        existingRoute = true;
      }

      double dueTime = 0;
      if (problemInstance is ITimeWindowedProblemInstance) {
        ITimeWindowedProblemInstance vrptw = problemInstance as ITimeWindowedProblemInstance;
        dueTime = vrptw.DueTime[customer + depotCount - 1];
      }

      if (vehicleTours.ContainsKey(vehicle)) {
        Tour tour = vehicleTours[vehicle];

        IPickupAndDeliveryProblemInstance pdp = problemInstance as IPickupAndDeliveryProblemInstance;
        if (pdp != null && pdp.GetPickupDeliveryLocation(customer) > 0) {
          solution.InsertPair(tour, customer, pdp.GetPickupDeliveryLocation(customer), problemInstance);
        } else {
          tour.Stops.Insert(solution.FindBestInsertionPlace(tour, customer), customer);
        }

        feasible = problemInstance.TourFeasible(tour, solution);

        tour.Stops.Remove(customer);
        if (pdp != null && pdp.GetPickupDeliveryLocation(customer) > 0) {
          tour.Stops.Remove(pdp.GetPickupDeliveryLocation(customer));
        }
      }
      else if (problemInstance is ITimeWindowedProblemInstance) {
        IPickupAndDeliveryProblemInstance pdp = problemInstance as IPickupAndDeliveryProblemInstance;
        ITimeWindowedProblemInstance vrptw = problemInstance as ITimeWindowedProblemInstance;
        double time = vrptw.ReadyTime[vehicle];
        time += distance;
        if (time > dueTime) {
          feasible = false;
        } else {
          time += vrptw.ServiceTime[customer - 1];
          if (pdp != null && pdp.GetPickupDeliveryLocation(customer) > 0) {
            int targetCustomer = pdp.GetPickupDeliveryLocation(customer);
            time += GetDistance(customer + depotCount - 1, targetCustomer + depotCount - 1, problemInstance, solution);
            if (time > vrptw.DueTime[targetCustomer + depotCount - 1]) {
              feasible = false;
            } 

            time += vrptw.ServiceTime[targetCustomer - 1];
            time += GetDistance(targetCustomer + depotCount - 1, vehicle, problemInstance, solution);

            if (time > vrptw.DueTime[vehicle]) {
              feasible = false;
            } 
          } else {
            time += GetDistance(customer + depotCount - 1, vehicle, problemInstance, solution);
            if (time > vrptw.DueTime[vehicle]) {
              feasible = false;
            } 
          }
        }
      }

      if (problemInstance is IHeterogenousCapacitatedProblemInstance) {
        IHeterogenousCapacitatedProblemInstance cvrp = problemInstance as IHeterogenousCapacitatedProblemInstance;
        double demand = problemInstance.GetDemand(customer);
        if (demand > cvrp.Capacity[vehicle])
          feasible = false;
      } else if (problemInstance is IHomogenousCapacitatedProblemInstance) {
        IHomogenousCapacitatedProblemInstance cvrp = problemInstance as IHomogenousCapacitatedProblemInstance;
        double demand = problemInstance.GetDemand(customer);
        if (demand > cvrp.Capacity.Value)
          feasible = false;
      }

      double x0 = problemInstance.Coordinates[vehicle, 0];
      double y0 = problemInstance.Coordinates[vehicle, 1];
      double dist;
      if (problemInstance.Coordinates[customer + depotCount - 1, 0] < x0)
        dist = -distance;
      else
        dist = distance;
      double polarAngle = (dist != 0 ? (Math.Asin((problemInstance.Coordinates[customer + depotCount - 1, 1] - y0) / dist) / 360 * dist) : 0);

      if (problemInstance is ITimeWindowedProblemInstance) {
        ITimeWindowedProblemInstance vrptw = problemInstance as ITimeWindowedProblemInstance;

        if (dueTime == double.MaxValue)
          dueTime = 0;
        else {
          dueTime -= vrptw.ReadyTime[vehicle];
        }
      }

      double cost = alpha * distance + // distance 0 <-> City[i]
                   -beta * dueTime + // latest arrival time
                  -gamma * polarAngle; // polar angle

      if (vehicleUsed != null) {
        if (!vehicleUsed[vehicle])
          cost += problemInstance.FleetUsageFactor.Value;
      }

      return cost;
    }

    private static int GetNearestDepot(IVRPProblemInstance problemInstance, List<int> depots, int customer,
      Dictionary<int, List<int>> vehicles, Dictionary<int, Tour> vehicleTours, List<bool> vehicleUsed, PotvinEncoding solution,
      double alpha, double beta, double gamma, out double minCost, out bool bound, out bool bestExistingRoute) {
      int nearest = -1;
      minCost = double.MaxValue;
      bestExistingRoute = false;

      bool bestFeasible = false;
      int feasibleCount = 0;
      foreach (int depot in depots) {
        int vehicle = vehicles[depot][0];

        bool existingRoute;
        bool feasible;
        double cost = GetCosts(
          customer, vehicle,
          problemInstance, vehicles, vehicleTours, vehicleUsed,
          solution, alpha, beta, gamma, out feasible, out existingRoute);

        if (feasible)
          feasibleCount++;

        if ((feasible && !bestFeasible) || 
          (feasible == bestFeasible && existingRoute && !bestExistingRoute) || 
          (feasible == bestFeasible && existingRoute == bestExistingRoute && cost < minCost)) {
          minCost = cost;
          nearest = depot;
          bestFeasible = feasible;
          bestExistingRoute = existingRoute;
        }
      }

      bound = (feasibleCount == 1);

      return nearest;
    }

    private static List<int> SortCustomers(IVRPProblemInstance problemInstance, List<int> customers, List<int> depots,
      Dictionary<int, int> depotAssignment, Dictionary<int, int> customerBinding, 
      Dictionary<int, List<int>> vehicles, Dictionary<int, Tour> vehicleTours, List<bool> vehicleUsed, PotvinEncoding solution,
      double alpha, double beta, double gamma) {
      List<int> sortedCustomers = new List<int>();
      depotAssignment.Clear();
      customerBinding.Clear();

      List<bool> boundList = new List<bool>();
      List<bool> existingRouteList = new List<bool>();
      List<double> costList = new List<double>();

      for (int i = 0; i < customers.Count; i++) {
        double cost;
        bool bound;
        bool existingRoute;
        int depot = GetNearestDepot(problemInstance, depots, customers[i], vehicles, vehicleTours, vehicleUsed, solution,
          alpha, beta, gamma,
          out cost, out bound, out existingRoute);
        depotAssignment[customers[i]] = depot;
        if (bound) {
          customerBinding.Add(customers[i], depot);
        }

        int index = 0;
        while (index < costList.Count &&
          ((!bound && boundList[index]) || 
           (bound == boundList[index] && !existingRoute && existingRouteList[index]) || 
           (bound == boundList[index] && existingRoute == existingRouteList[index] && costList[index] < cost)))
          index++;

        costList.Insert(index, cost);
        boundList.Insert(index, bound);
        existingRouteList.Insert(index, existingRoute);
        sortedCustomers.Insert(index, customers[i]);
      }

      return sortedCustomers;
    }

    private static bool RemoveUnusedDepots(List<int> depots, Dictionary<int, List<int>> vehicles) {
      List<int> toBeRemoved = new List<int>();

      foreach (int depot in depots) {
        if (vehicles[depot].Count == 0)
          toBeRemoved.Add(depot);
      }

      foreach (int depot in toBeRemoved) {
        depots.Remove(depot);
        vehicles.Remove(depot);
      }

      return toBeRemoved.Count > 0;
    }

    private static Dictionary<int, Tour> CreateInitialTours(IVRPProblemInstance problemInstance, Dictionary<int, List<int>> vehicles, PotvinEncoding result) {
      Dictionary<int, Tour> vehicleTours = new Dictionary<int, Tour>();
      IPickupAndDeliveryProblemInstance pdp = problemInstance as IPickupAndDeliveryProblemInstance;

      int currentVehicle;

      for (int i = 1; i <= problemInstance.Cities.Value; i++) {
        if (pdp != null && pdp.GetPickupDeliveryLocation(i) <= 0) {
          currentVehicle = -pdp.GetPickupDeliveryLocation(i);
          foreach (int depot in vehicles.Keys) {
            if (vehicles[depot].Contains(currentVehicle)) {
              vehicles[depot].Remove(currentVehicle);
              vehicles[depot].Insert(0, currentVehicle);
              break;
            }
          }

          Tour tour;

          if (!vehicleTours.ContainsKey(currentVehicle)) {
            tour = new Tour();
            result.Tours.Add(tour);
            vehicleTours[currentVehicle] = tour;
            result.VehicleAssignment[result.Tours.Count - 1] = currentVehicle;
          } else {
            tour = vehicleTours[currentVehicle];
          }

          tour.Stops.Add(i);
        }
      }

      foreach (int vehicle in vehicleTours.Keys) {
        Tour vehicleTour = vehicleTours[vehicle];
        List<int> customers = new List<int>(vehicleTour.Stops);
        vehicleTour.Stops.Clear();

        if (problemInstance is DynPDPProblemInstance &&
          (problemInstance as DynPDPProblemInstance).CurrentPlan != null) {
          PotvinEncoding plan = (problemInstance as DynPDPProblemInstance).CurrentPlan;
          Tour planTour = plan.Tours.Find(t => plan.GetVehicleAssignment(plan.Tours.IndexOf(t)) == vehicle);

          customers.Sort((x, y) => planTour.Stops.IndexOf(x).CompareTo(planTour.Stops.IndexOf(y)));
          foreach (int customer in customers)
            vehicleTour.Stops.Add(customer);
        } else {
          for (int i = 0; i < customers.Count; i++) {
            int stop = result.FindBestInsertionPlace(vehicleTour, customers[i]);
            vehicleTour.Stops.Insert(stop, customers[i]);
          }
        }
      }

      return vehicleTours;
    }

    public static PotvinEncoding CreateSolution(IVRPProblemInstance problemInstance, IRandom random, List<bool> vehicleUsed, 
      double alphaValue = 0.7, double betaValue = 0.1, double gammaValue = 0.2,
      double alphaVariance = 0.5, double betaVariance = 0.07, double gammaVariance = 0.14) {
      PotvinEncoding result = new PotvinEncoding(problemInstance);

      IPickupAndDeliveryProblemInstance pdp = problemInstance as IPickupAndDeliveryProblemInstance;
      IMultiDepotProblemInstance mdp = problemInstance as IMultiDepotProblemInstance;

      if (mdp != null) {
        for (int i = 0; i < result.VehicleAssignment.Length; i++) {
          result.VehicleAssignment[i] = -1;
        }
      }

      double alpha, beta, gamma;
      lock (random) {
        alpha = N(alphaValue, Math.Sqrt(alphaVariance), random);
        beta = N(betaValue, Math.Sqrt(betaVariance), random);
        gamma = N(gammaValue, Math.Sqrt(gammaVariance), random);
      }

      #region initialization
      List<int> unroutedCustomers = new List<int>();
      for (int i = 1; i <= problemInstance.Cities.Value; i++) {
        if (pdp == null || (problemInstance.GetDemand(i) >= 0) || (pdp.GetPickupDeliveryLocation(i) == i))
          unroutedCustomers.Add(i);
      }

      List<int> depots = new List<int>();
      if (mdp != null) {
        for (int i = 0; i < mdp.Depots.Value; i++) {
          depots.Add(i);
        }
      } else {
        depots.Add(0);
      }

      Dictionary<int, List<int>> vehicles = new Dictionary<int, List<int>>();
      foreach (int depot in depots) {
        vehicles[depot] = new List<int>();

        int vehicleCount = problemInstance.Vehicles.Value;
        if (mdp != null) {
          for (int vehicle = 0; vehicle < mdp.VehicleDepotAssignment.Length; vehicle++) {
            if (mdp.VehicleDepotAssignment[vehicle] == depot) {
              vehicles[depot].Add(vehicle);
            }
          }
        } else {
          for (int vehicle = 0; vehicle < vehicleCount; vehicle++) {
            vehicles[depot].Add(vehicle);
          }
        }

        if (vehicleUsed != null) {
          vehicles[depot].Sort(delegate(int x, int y) {
            if (vehicleUsed[x] && vehicleUsed[y])
              return 0;
            else if (vehicleUsed[x])
              return -1;
            else
              return 1;
          });
        }
      }

      Dictionary<int, Tour> vehicleTours = CreateInitialTours(problemInstance, vehicles, result);
      RemoveUnusedDepots(depots, vehicles);
      #endregion

      #region route unrouted
      if (unroutedCustomers.Count > 0) {
        Tour tour;
        int currentDepot;
        int currentVehicle;
        Dictionary<int, int> depotAssignment = new Dictionary<int, int>();

        //# sort customers globally - start new tour
        Dictionary<int, int> customerBinding = new Dictionary<int, int>();
        unroutedCustomers = SortCustomers(
          problemInstance, unroutedCustomers, depots, depotAssignment, customerBinding, 
          vehicles, vehicleTours, vehicleUsed, result,
          alpha, beta, gamma);

        int currentCustomer = unroutedCustomers[0];
        currentDepot = depotAssignment[currentCustomer];
        currentVehicle = vehicles[currentDepot][0];
        vehicles[currentDepot].RemoveAt(0);
        RemoveUnusedDepots(depots, vehicles);

        if (!vehicleTours.ContainsKey(currentVehicle)) {
          tour = new Tour();
          result.Tours.Add(tour);
          result.VehicleAssignment[result.Tours.Count - 1] = currentVehicle;

          unroutedCustomers.Remove(currentCustomer);
          tour.Stops.Add(currentCustomer);
          if (pdp != null && pdp.GetPickupDeliveryLocation(currentCustomer) != currentCustomer) {
            tour.Stops.Add(pdp.GetPickupDeliveryLocation(currentCustomer));
          }
        } else {
          tour = vehicleTours[currentVehicle];
        }

        while (unroutedCustomers.Count > 0) {
          double minimumCost = double.MaxValue;
          bool bestBoundToRoute = false;
          int customer = -1;
          int indexOfMinimumCost = -1;
          int indexOfMinimumCost2 = -1;

          foreach (int unrouted in unroutedCustomers) {
            bool boundToRoute = customerBinding.ContainsKey(unrouted) && customerBinding[unrouted] == currentDepot;

            VRPEvaluation eval = problemInstance.EvaluateTour(tour, result);
            double originalCosts = eval.Quality;

            for (int i = 0; i <= tour.Stops.Count; i++) {
              tour.Stops.Insert(i, unrouted);
              eval = problemInstance.EvaluateTour(tour, result);
              double tourCost = eval.Quality - originalCosts;

              if (pdp != null && pdp.GetPickupDeliveryLocation(unrouted) != unrouted) {
                for (int j = i + 1; j <= tour.Stops.Count; j++) {
                  bool feasible;
                  double cost = tourCost +
                    problemInstance.GetInsertionCosts(eval, result, pdp.GetPickupDeliveryLocation(unrouted), 0, j, out feasible);
                  if ((cost < minimumCost || (!bestBoundToRoute && boundToRoute)) && (boundToRoute || !bestBoundToRoute) && feasible) {
                    customer = unrouted;
                    minimumCost = cost;
                    indexOfMinimumCost = i;
                    indexOfMinimumCost2 = j;
                    bestBoundToRoute = boundToRoute;
                  }
                }
              } else {
                double cost = tourCost;
                bool feasible = problemInstance.Feasible(eval);
                if ((cost < minimumCost || (!bestBoundToRoute && boundToRoute)) && (boundToRoute || !bestBoundToRoute) && feasible) {
                  customer = unrouted;
                  minimumCost = cost;
                  indexOfMinimumCost = i;
                  bestBoundToRoute = boundToRoute;
                }
              }

              tour.Stops.RemoveAt(i);
            }
          }

          if (indexOfMinimumCost == -1 && vehicles.Count == 0) {
            indexOfMinimumCost = tour.Stops.Count;
            indexOfMinimumCost2 = tour.Stops.Count + 1;
            customer = unroutedCustomers[0];
          }

          // insert customer if found
          if (indexOfMinimumCost != -1) {
            tour.Stops.Insert(indexOfMinimumCost, customer);
            if (pdp != null && pdp.GetPickupDeliveryLocation(customer) != customer) {
              tour.Stops.Insert(indexOfMinimumCost2, pdp.GetPickupDeliveryLocation(customer));
            }
            unroutedCustomers.Remove(customer);
          } else { // no feasible customer found
            //# sort customers globally - start new tour
            unroutedCustomers = SortCustomers(
              problemInstance, unroutedCustomers, depots, depotAssignment, customerBinding,
              vehicles, vehicleTours, vehicleUsed, result,
              alpha, beta, gamma);
            
            currentCustomer = unroutedCustomers[0];
            currentDepot = depotAssignment[currentCustomer];
            currentVehicle = vehicles[currentDepot][0];
            vehicles[currentDepot].RemoveAt(0);
            RemoveUnusedDepots(depots, vehicles);

            if (!vehicleTours.ContainsKey(currentVehicle)) {
              tour = new Tour();
              result.Tours.Add(tour);
              result.VehicleAssignment[result.Tours.Count - 1] = currentVehicle;

              unroutedCustomers.Remove(currentCustomer);
              tour.Stops.Add(currentCustomer);
              if (pdp != null && pdp.GetPickupDeliveryLocation(currentCustomer) != currentCustomer) {
                tour.Stops.Add(pdp.GetPickupDeliveryLocation(currentCustomer));
              }
            } else {
              tour = vehicleTours[currentVehicle];
            }
          }
        }
      }
      #endregion

      #region assign vehicles
      if (mdp != null) {
        List<int> availableVehicles = new List<int>();
        for (int i = 0; i < mdp.Vehicles.Value; i++)
          availableVehicles.Add(i);

        for (int i = 0; i < result.VehicleAssignment.Length; i++) {
          if (result.VehicleAssignment[i] != -1)
            availableVehicles.Remove(result.VehicleAssignment[i]);
        }

        for (int i = 0; i < result.VehicleAssignment.Length; i++) {
          if (result.VehicleAssignment[i] == -1) {
            result.VehicleAssignment[i] = availableVehicles[0];
            availableVehicles.RemoveAt(0);
          }
        }
      }
      #endregion

      return result;
    }

    public override IOperation Apply() {
      List<bool> vehicleUsed = null;
      
      DynPDPProblemInstance instance = ProblemInstance as DynPDPProblemInstance;
      if(instance != null) {
        vehicleUsed = new List<bool>();
        for (int i = 0; i < instance.VehicleUsed.Length; i++) {
          vehicleUsed.Add(instance.VehicleUsed[i]);
        }
      }

      VRPToursParameter.ActualValue = CreateSolution(ProblemInstance, RandomParameter.ActualValue, vehicleUsed,
        Alpha.Value.Value, Beta.Value.Value, Gamma.Value.Value,
        AlphaVariance.Value.Value, BetaVariance.Value.Value, GammaVariance.Value.Value);

      return base.Apply();
    }
  }
}