public static void ApplyManipulation(IRandom random, PotvinEncoding individual, IVRPProblemInstance instance, bool allowInfeasible) {
int selectedIndex = SelectRandomTourBiasedByLength(random, individual, instance);
if (selectedIndex >= 0) {
Tour route1 = individual.Tours[selectedIndex];
bool performed = false;
int customer1Position = 0;
while (customer1Position < route1.Stops.Count) {
performed = false;
foreach (Tour tour in individual.Tours) {
if (tour != route1) {
for (int customer2Position = 0; customer2Position < tour.Stops.Count; customer2Position++) {
int customer1 = route1.Stops[customer1Position];
int customer2 = tour.Stops[customer2Position];
//customer1 can be feasibly inserted at the location of customer2
tour.Stops[customer2Position] = customer1;
route1.Stops.RemoveAt(customer1Position);
if (instance.TourFeasible(tour, individual)) {
int routeIdx, place;
if (FindInsertionPlace(individual,
customer2, selectedIndex, allowInfeasible, out routeIdx, out place)) {
individual.Tours[routeIdx].Stops.Insert(place, customer2);
//two-level exchange has been performed
performed = true;
break;
} else {
tour.Stops[customer2Position] = customer2;
route1.Stops.Insert(customer1Position, customer1);
}
} else {
tour.Stops[customer2Position] = customer2;
route1.Stops.Insert(customer1Position, customer1);
}
}
}
if (performed)
break;
}
if (!performed)
customer1Position++;
}
}
}
private static bool FindBetterInsertionPlace(
PotvinEncoding individual, IVRPProblemInstance instance, int tour, int city, int length,
out int insertionTour, out int insertionPlace)
{
bool insertionFound = false;
insertionTour = -1;
insertionPlace = 1;
List <int> toBeDeleted = individual.Tours[tour].Stops.GetRange(city, length);
double distance = individual.GetTourLength(individual.Tours[tour]);
individual.Tours[tour].Stops.RemoveRange(city, length);
double removalBenefit = distance - individual.GetTourLength(individual.Tours[tour]);
int currentTour = 0;
while (currentTour < individual.Tours.Count && !insertionFound)
{
int currentCity = 0;
while (currentCity <= individual.Tours[currentTour].Stops.Count && !insertionFound)
{
distance = individual.GetTourLength(individual.Tours[currentTour]);
individual.Tours[currentTour].Stops.InsertRange(currentCity, toBeDeleted);
if (instance.TourFeasible(individual.Tours[currentTour], individual))
{
double lengthIncrease =
individual.GetTourLength(individual.Tours[currentTour]) - distance;
if (removalBenefit > lengthIncrease)
{
insertionTour = currentTour;
insertionPlace = currentCity;
insertionFound = true;
}
}
individual.Tours[currentTour].Stops.RemoveRange(currentCity, length);
currentCity++;
}
currentTour++;
}
individual.Tours[tour].Stops.InsertRange(city, toBeDeleted);
return(insertionFound);
}
private static bool FindBetterInsertionPlace(
PotvinEncoding individual, IVRPProblemInstance instance, int tour, int city, int length,
out int insertionTour, out int insertionPlace) {
bool insertionFound = false;
insertionTour = -1;
insertionPlace = 1;
List<int> toBeDeleted = individual.Tours[tour].Stops.GetRange(city, length);
double distance = individual.GetTourLength(individual.Tours[tour]);
individual.Tours[tour].Stops.RemoveRange(city, length);
double removalBenefit = distance - individual.GetTourLength(individual.Tours[tour]);
int currentTour = 0;
while (currentTour < individual.Tours.Count && !insertionFound) {
int currentCity = 0;
while (currentCity <= individual.Tours[currentTour].Stops.Count && !insertionFound) {
distance = individual.GetTourLength(individual.Tours[currentTour]);
individual.Tours[currentTour].Stops.InsertRange(currentCity, toBeDeleted);
if (instance.TourFeasible(individual.Tours[currentTour], individual)) {
double lengthIncrease =
individual.GetTourLength(individual.Tours[currentTour]) - distance;
if (removalBenefit > lengthIncrease) {
insertionTour = currentTour;
insertionPlace = currentCity;
insertionFound = true;
}
}
individual.Tours[currentTour].Stops.RemoveRange(currentCity, length);
currentCity++;
}
currentTour++;
}
individual.Tours[tour].Stops.InsertRange(city, toBeDeleted);
return insertionFound;
}
protected static bool Repair(IRandom random, PotvinEncoding solution, Tour newTour, IVRPProblemInstance instance, bool allowInfeasible)
{
bool success = true;
//remove duplicates from new tour
for (int i = 0; i < newTour.Stops.Count; i++)
{
for (int j = 0; j < newTour.Stops.Count; j++)
{
if (newTour.Stops[i] == newTour.Stops[j] && i != j)
{
if (random.NextDouble() < 0.5)
{
newTour.Stops[i] = 0;
}
else
{
newTour.Stops[j] = 0;
}
}
}
}
while (newTour.Stops.Contains(0))
{
newTour.Stops.Remove(0);
}
//remove duplicates from old tours
for (int i = 0; i < newTour.Stops.Count; i++)
{
foreach (Tour tour in solution.Tours)
{
if (tour != newTour && tour.Stops.Contains(newTour.Stops[i]))
{
tour.Stops.Remove(newTour.Stops[i]);
}
}
}
//remove empty tours
List <Tour> toBeDeleted = new List <Tour>();
foreach (Tour tour in solution.Tours)
{
if (tour.Stops.Count == 0)
{
toBeDeleted.Add(tour);
}
}
foreach (Tour tour in toBeDeleted)
{
solution.Tours.Remove(tour);
}
if (newTour.Stops.Count > 0 && !allowInfeasible && !instance.TourFeasible(newTour, solution))
{
return(false);
}
//route unrouted vehicles
success = RouteUnrouted(solution, allowInfeasible);
return(success);
}
protected static bool Repair(IRandom random, PotvinEncoding solution, Tour newTour, IVRPProblemInstance instance, bool allowInfeasible) {
bool success = true;
//remove duplicates from new tour
for (int i = 0; i < newTour.Stops.Count; i++) {
for (int j = 0; j < newTour.Stops.Count; j++) {
if (newTour.Stops[i] == newTour.Stops[j] && i != j) {
if (random.NextDouble() < 0.5)
newTour.Stops[i] = 0;
else
newTour.Stops[j] = 0;
}
}
}
while (newTour.Stops.Contains(0))
newTour.Stops.Remove(0);
//remove duplicates from old tours
for (int i = 0; i < newTour.Stops.Count; i++) {
foreach (Tour tour in solution.Tours) {
if (tour != newTour && tour.Stops.Contains(newTour.Stops[i])) {
tour.Stops.Remove(newTour.Stops[i]);
}
}
}
//remove empty tours
List<Tour> toBeDeleted = new List<Tour>();
foreach (Tour tour in solution.Tours) {
if (tour.Stops.Count == 0)
toBeDeleted.Add(tour);
}
foreach (Tour tour in toBeDeleted) {
solution.Tours.Remove(tour);
}
if (newTour.Stops.Count > 0 && !allowInfeasible && !instance.TourFeasible(newTour, solution))
return false;
//route unrouted vehicles
success = RouteUnrouted(solution, allowInfeasible);
return success;
}
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);
}
}
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 void ApplyManipulation(IRandom random, PotvinEncoding individual, IVRPProblemInstance instance, bool allowInfeasible)
{
int selectedIndex = SelectRandomTourBiasedByLength(random, individual, instance);
if (selectedIndex >= 0)
{
Tour route1 = individual.Tours[selectedIndex];
bool performed = false;
int customer1Position = 0;
while (customer1Position < route1.Stops.Count)
{
performed = false;
foreach (Tour tour in individual.Tours)
{
if (tour != route1)
{
for (int customer2Position = 0; customer2Position < tour.Stops.Count; customer2Position++)
{
int customer1 = route1.Stops[customer1Position];
int customer2 = tour.Stops[customer2Position];
//customer1 can be feasibly inserted at the location of customer2
tour.Stops[customer2Position] = customer1;
route1.Stops.RemoveAt(customer1Position);
if (instance.TourFeasible(tour, individual))
{
int routeIdx, place;
if (FindInsertionPlace(individual,
customer2, selectedIndex, allowInfeasible, out routeIdx, out place))
{
individual.Tours[routeIdx].Stops.Insert(place, customer2);
//two-level exchange has been performed
performed = true;
break;
}
else
{
tour.Stops[customer2Position] = customer2;
route1.Stops.Insert(customer1Position, customer1);
}
}
else
{
tour.Stops[customer2Position] = customer2;
route1.Stops.Insert(customer1Position, customer1);
}
}
}
if (performed)
{
break;
}
}
if (!performed)
{
customer1Position++;
}
}
}
}