C# IVRPProblemInstance.EvaluateTour方法代码示例

    public static PotvinEncoding CreateSolution(IVRPProblemInstance instance, IRandom random, bool adhereTimeWindows) {
      PotvinEncoding result = new PotvinEncoding(instance);

      IPickupAndDeliveryProblemInstance pdp = instance as IPickupAndDeliveryProblemInstance;

      List<int> customers = new List<int>();
      for (int i = 1; i <= instance.Cities.Value; i++)
        if (pdp == null || pdp.GetDemand(i) >= 0)
          customers.Add(i);

      customers.Sort((city1, city2) => {
        double angle1 = CalculateAngleToDepot(instance, city1);
        double angle2 = CalculateAngleToDepot(instance, city2);

        return angle1.CompareTo(angle2);
      });

      Tour currentTour = new Tour();
      result.Tours.Add(currentTour);

      int j = random.Next(customers.Count);
      for (int i = 0; i < customers.Count; i++) {
        int index = (i + j) % customers.Count;

        int stopIdx = 0;
        if (currentTour.Stops.Count > 0)
          stopIdx = result.FindBestInsertionPlace(currentTour, customers[index]);
        currentTour.Stops.Insert(stopIdx, customers[index]);

        if (pdp != null) {
          stopIdx = result.FindBestInsertionPlace(currentTour, pdp.GetPickupDeliveryLocation(customers[index]));
          currentTour.Stops.Insert(stopIdx, pdp.GetPickupDeliveryLocation(customers[index]));
        }

        CVRPEvaluation evaluation = instance.EvaluateTour(currentTour, result) as CVRPEvaluation;
        if (result.Tours.Count < instance.Vehicles.Value &&
          ((adhereTimeWindows && !instance.Feasible(evaluation)) || ((!adhereTimeWindows) && evaluation.Overload > double.Epsilon))) {
          currentTour.Stops.Remove(customers[index]);
          if (pdp != null)
            currentTour.Stops.Remove(pdp.GetPickupDeliveryLocation(customers[index]));

          if (currentTour.Stops.Count == 0)
            result.Tours.Remove(currentTour);
          currentTour = new Tour();
          result.Tours.Add(currentTour);

          currentTour.Stops.Add(customers[index]);
          if (pdp != null) {
            currentTour.Stops.Add(pdp.GetPickupDeliveryLocation(customers[index]));
          }
        }
      }

      if (currentTour.Stops.Count == 0)
        result.Tours.Remove(currentTour);

      return result;
    }

    public static PotvinEncoding CreateSolution(IVRPProblemInstance problemInstance, IRandom random,
      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;

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

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

      RemoveUnusedDepots(depots, vehicles);
      Dictionary<int, int> depotAssignment = new Dictionary<int, int>();

      unroutedCustomers = SortCustomers(
        problemInstance, unroutedCustomers, depots, depotAssignment,
        alpha, beta, gamma);

      /////////
      Tour tour = new Tour();
      result.Tours.Add(tour);
      int currentCustomer = unroutedCustomers[0];
      unroutedCustomers.RemoveAt(0);

      int currentDepot = depotAssignment[currentCustomer];
      int currentVehicle = vehicles[currentDepot][0];
      vehicles[currentDepot].RemoveAt(0);
      if (RemoveUnusedDepots(depots, vehicles)) {
        unroutedCustomers = SortCustomers(
        problemInstance, unroutedCustomers, depots, depotAssignment,
        alpha, beta, gamma);
      }

      result.VehicleAssignment[result.Tours.Count - 1] = currentVehicle;

      tour.Stops.Add(currentCustomer);
      if (pdp != null) {
        tour.Stops.Add(pdp.GetPickupDeliveryLocation(currentCustomer));
      }
      ////////

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

        foreach (int unrouted in unroutedCustomers) {
          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) {
              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 && feasible) {
                  customer = unrouted;
                  minimumCost = cost;
                  indexOfMinimumCost = i;
//.........这里部分代码省略.........

    public static void Apply(PotvinEncoding solution, PotvinPDShiftMove move, IVRPProblemInstance problemInstance) {
      bool newTour = false;

      if (move.Tour >= solution.Tours.Count) {
        solution.Tours.Add(new Tour());
        newTour = true;
      }
      Tour tour = solution.Tours[move.Tour];

      Tour oldTour = solution.Tours.Find(t => t.Stops.Contains(move.City));
      oldTour.Stops.Remove(move.City);

      if (problemInstance is IPickupAndDeliveryProblemInstance) {
        IPickupAndDeliveryProblemInstance pdp = problemInstance as IPickupAndDeliveryProblemInstance;

        int location = pdp.GetPickupDeliveryLocation(move.City);
        Tour oldTour2 = solution.Tours.Find(t => t.Stops.Contains(location));
        oldTour2.Stops.Remove(location);

        solution.InsertPair(tour, move.City, location, problemInstance);
      } else {
        int place = solution.FindBestInsertionPlace(tour, move.City);
        tour.Stops.Insert(place, move.City);
      }

      if (newTour) {
        List<int> vehicles = new List<int>();
        for (int i = move.Tour; i < problemInstance.Vehicles.Value; i++) {
          vehicles.Add(solution.GetVehicleAssignment(i));
        }

        double bestQuality = double.MaxValue;
        int bestVehicle = -1;

        int originalVehicle = solution.GetVehicleAssignment(move.Tour);
        foreach (int vehicle in vehicles) {
          solution.VehicleAssignment[move.Tour] = vehicle;

          double quality = problemInstance.EvaluateTour(tour, solution).Quality;
          if (quality < bestQuality) {
            bestQuality = quality;
            bestVehicle = vehicle;
          }
        }

        solution.VehicleAssignment[move.Tour] = originalVehicle;

        int index = -1;
        for (int i = move.Tour; i < solution.VehicleAssignment.Length; i++) {
          if (solution.VehicleAssignment[i] == bestVehicle) {
            index = i;
            break;
          }
        }
        solution.VehicleAssignment[index] = originalVehicle;
        solution.VehicleAssignment[move.Tour] = bestVehicle;
      }

      solution.Repair();
    }

    public void InsertPair(Tour tour, int source, int target, IVRPProblemInstance problemInstance, int positionToAvoid = -1, int positionToAvoid2 = -1) {
      int stops = tour.Stops.Count;
      VRPEvaluation eval = problemInstance.EvaluateTour(tour, this);
      double minCosts = double.MaxValue;
      int sourceLocation = -1;
      int targetLocation = -1;

      for (int i = 0; i <= stops; i++) {
        tour.Stops.Insert(i, source);
        VRPEvaluation tourEval = problemInstance.EvaluateTour(tour, this);
        double sourceCosts = tourEval.Quality - eval.Quality;

        for (int j = i + 1; j <= stops + 1; j++) {
          if (positionToAvoid != i || positionToAvoid2 != j || stops == 0) {
            bool feasible;
            double targetCosts = problemInstance.GetInsertionCosts(tourEval, this, target, 0, j, out feasible);

            double costs = sourceCosts + targetCosts;
            if (costs < minCosts) {
              minCosts = costs;
              sourceLocation = i;
              targetLocation = j;
            }
          }
        }
        tour.Stops.Remove(source);
      }

      tour.Stops.Insert(sourceLocation, source);
      tour.Stops.Insert(targetLocation, target);
    }

    private static PotvinEncoding ReplacePair(PotvinEncoding individual, IVRPProblemInstance instance, int replaced, int replacing, bool allowInfeasible) {
      individual = individual.Clone() as PotvinEncoding;
      IPickupAndDeliveryProblemInstance pdp = instance as IPickupAndDeliveryProblemInstance;

      int replacedDest = pdp.GetPickupDeliveryLocation(replaced);
      int replacedSource, replacedTarget;
      if (pdp.GetDemand(replaced) >= 0) {
        replacedSource = replaced;
        replacedTarget = replacedDest;
      } else {
        replacedSource = replacedDest;
        replacedTarget = replaced;
      }
      Tour replacedSourceTour = individual.Tours.Find(t => t.Stops.Contains(replacedSource));
      Tour replacedTargetTour = individual.Tours.Find(t => t.Stops.Contains(replacedTarget));

      int replacingDest = pdp.GetPickupDeliveryLocation(replacing);
      int replacingSource, replacingTarget;
      if (pdp.GetDemand(replacing) >= 0) {
        replacingSource = replacing;
        replacingTarget = replacingDest;
      } else {
        replacingSource = replacingDest;
        replacingTarget = replacing;
      }
      Tour replacingSourceTour = individual.Tours.Find(t => t.Stops.Contains(replacingSource));
      Tour replacingTargetTour = individual.Tours.Find(t => t.Stops.Contains(replacingTarget));

      replacingSourceTour.Stops.Remove(replacingSource);
      replacingTargetTour.Stops.Remove(replacingTarget);

      replacedSourceTour.Stops[replacedSourceTour.Stops.IndexOf(replacedSource)] = replacingSource;
      if (!allowInfeasible && !instance.TourFeasible(replacedSourceTour, individual))
        return null;

      replacedTargetTour.Stops[replacedTargetTour.Stops.IndexOf(replacedTarget)] = replacingTarget;
      if (!allowInfeasible && !instance.TourFeasible(replacedTargetTour, individual))
        return null;

      double bestQuality = double.MaxValue;
      int bestTour = -1;
      int bestPositionSource = -1;
      int bestPositionTarget = -1;

      int routeToAvoid = individual.Tours.IndexOf(replacingSourceTour);

      for (int tourIdx = 0; tourIdx < individual.Tours.Count; tourIdx++) {
        if (tourIdx != routeToAvoid) {
          Tour tour = individual.Tours[tourIdx];
          VRPEvaluation eval = instance.EvaluateTour(tour, individual);
          individual.InsertPair(tour, replacedSource, replacedTarget, instance);
          VRPEvaluation evalNew = instance.EvaluateTour(tour, individual);

          double delta = evalNew.Quality - eval.Quality;

          if (delta < bestQuality &&
              (instance.Feasible(evalNew) || allowInfeasible)) {
            bestQuality = delta;
            bestTour = tourIdx;
            bestPositionSource = tour.Stops.IndexOf(replacedSource);
            bestPositionTarget = tour.Stops.IndexOf(replacedTarget);
          }

          tour.Stops.Remove(replacedSource);
          tour.Stops.Remove(replacedTarget);
        }
      }

      if (bestTour != -1) {
        if (bestPositionTarget < bestPositionSource) {
          individual.Tours[bestTour].Stops.Insert(bestPositionTarget, replacedTarget);
          individual.Tours[bestTour].Stops.Insert(bestPositionSource, replacedSource);
        } else {
          individual.Tours[bestTour].Stops.Insert(bestPositionSource, replacedSource);
          individual.Tours[bestTour].Stops.Insert(bestPositionTarget, replacedTarget);
        }

        return individual;
      } else {
        return null;
      }
    }

    public static bool PairwiseMove(PotvinEncoding individual, IVRPProblemInstance instance, int city, bool allowInfeasible) {
      bool success;

      IPickupAndDeliveryProblemInstance pdp = instance as IPickupAndDeliveryProblemInstance;

      if (pdp != null) {
        Tour route1 = individual.Tours.Find(t => t.Stops.Contains(city));
        int i = route1.Stops.IndexOf(city);

        int dest = pdp.GetPickupDeliveryLocation(city);
        Tour destRoute = individual.Tours.Find(t => t.Stops.Contains(dest));
        int j = destRoute.Stops.IndexOf(dest);

        route1.Stops.Remove(city);
        destRoute.Stops.Remove(dest);

        int routeToAvoid = -1;
        if (route1 == destRoute)
          routeToAvoid = individual.Tours.IndexOf(route1);

        int source, target;
        if (instance.GetDemand(city) >= 0) {
          source = city;
          target = dest;
        } else {
          source = dest;
          target = city;
        }

        double bestQuality = double.MaxValue;
        int bestTour = -1;
        int bestPositionSource = -1;
        int bestPositionTarget = -1;

        for (int tourIdx = 0; tourIdx < individual.Tours.Count; tourIdx++) {
          if (tourIdx != routeToAvoid) {
            Tour tour = individual.Tours[tourIdx];
            VRPEvaluation eval = instance.EvaluateTour(tour, individual);
            individual.InsertPair(tour, source, target, instance);
            VRPEvaluation evalNew = instance.EvaluateTour(tour, individual);

            double delta = evalNew.Quality - eval.Quality;

            if (delta < bestQuality &&
               (instance.Feasible(evalNew) || allowInfeasible)) {
              bestQuality = delta;
              bestTour = tourIdx;
              bestPositionSource = tour.Stops.IndexOf(source);
              bestPositionTarget = tour.Stops.IndexOf(target);
            }

            tour.Stops.Remove(source);
            tour.Stops.Remove(target);
          }
        }

        if (bestTour >= 0) {
          if (bestPositionTarget < bestPositionSource) {
            individual.Tours[bestTour].Stops.Insert(bestPositionTarget, target);
            individual.Tours[bestTour].Stops.Insert(bestPositionSource, source);
          } else {
            individual.Tours[bestTour].Stops.Insert(bestPositionSource, source);
            individual.Tours[bestTour].Stops.Insert(bestPositionTarget, target);
          }

          success = true;
        } else {
          if (j < i) {
            destRoute.Stops.Insert(j, dest);
            route1.Stops.Insert(i, city);
          } else {
            route1.Stops.Insert(i, city);
            destRoute.Stops.Insert(j, dest);
          }

          success = false;
        }
      } else {
        success = false;
      }

      return success;
    }