private static int GetNearestDepot(IVRPProblemInstance problemInstance, List <int> depots, int customer,
double alpha, double beta, double gamma, out double minCost)
{
int nearest = -1;
minCost = double.MaxValue;
int depotCount = 1;
IMultiDepotProblemInstance mdp = problemInstance as IMultiDepotProblemInstance;
if (mdp != null)
{
depotCount = mdp.Depots.Value;
}
foreach (int depot in depots)
{
double x0 = problemInstance.Coordinates[depot, 0];
double y0 = problemInstance.Coordinates[depot, 1];
double distance = GetDistance(customer + depotCount - 1, depot, problemInstance);
double dueTime = 0;
if (problemInstance is ITimeWindowedProblemInstance)
{
dueTime = (problemInstance as ITimeWindowedProblemInstance).DueTime[customer + depotCount - 1];
}
if (dueTime == double.MaxValue)
{
dueTime = 0;
}
double x = problemInstance.Coordinates[customer + depotCount - 1, 0];
double y = problemInstance.Coordinates[customer + depotCount - 1, 1];
double cost = alpha * distance + // distance 0 <-> City[i]
-beta * dueTime + // latest arrival time
-gamma * ((Math.Atan2(y - y0, x - x0) + Math.PI) / (2.0 * Math.PI) * distance); // polar angle
if (cost < minCost)
{
minCost = cost;
nearest = depot;
}
}
return(nearest);
}
protected override void EvaluateTour(VRPEvaluation eval, IVRPProblemInstance instance, Tour tour, IVRPEncoding solution)
{
TourInsertionInfo tourInfo = new TourInsertionInfo(solution.GetVehicleAssignment(solution.GetTourIndex(tour)));
eval.InsertionInfo.AddTourInsertionInfo(tourInfo);
double originalQuality = eval.Quality;
IHeterogenousCapacitatedProblemInstance cvrpInstance = instance as IHeterogenousCapacitatedProblemInstance;
DoubleArray demand = instance.Demand;
ITimeWindowedProblemInstance vrptw = instance as ITimeWindowedProblemInstance;
DoubleArray dueTime = vrptw.DueTime;
DoubleArray readyTime = vrptw.ReadyTime;
DoubleArray serviceTimes = vrptw.ServiceTime;
IPickupAndDeliveryProblemInstance pdp = instance as IPickupAndDeliveryProblemInstance;
IntArray pickupDeliveryLocation = pdp.PickupDeliveryLocation;
IMultiDepotProblemInstance mdp = instance as IMultiDepotProblemInstance;
IntArray vehicleAssignment = mdp.VehicleDepotAssignment;
int depots = mdp.Depots.Value;
double time = 0.0;
double waitingTime = 0.0;
double serviceTime = 0.0;
double tardiness = 0.0;
double overweight = 0.0;
double distance = 0.0;
int tourIndex = solution.GetTourIndex(tour);
int vehicle = solution.GetVehicleAssignment(tourIndex);
int depot = vehicleAssignment[vehicle];
double capacity = cvrpInstance.Capacity[vehicle];
double currentLoad = 0.0;
Dictionary <int, bool> stops = new Dictionary <int, bool>();
int pickupViolations = 0;
double tourStartTime = readyTime[0];
time = tourStartTime;
//simulate a tour, start and end at depot
for (int i = 0; i <= tour.Stops.Count; i++)
{
int start = 0;
if (i > 0)
{
start = tour.Stops[i - 1];
}
int end = 0;
if (i < tour.Stops.Count)
{
end = tour.Stops[i];
}
//drive there
double currentDistace = vrptw.GetDistance(start, end, solution);
time += currentDistace;
distance += currentDistace;
double arrivalTime = time;
int endIndex;
if (end == 0)
{
endIndex = depot;
}
else
{
endIndex = end + depots - 1;
}
//check if it was serviced on time
if (time > dueTime[endIndex])
{
tardiness += time - dueTime[endIndex];
}
//wait
double currentWaitingTime = 0.0;
if (time < readyTime[endIndex])
{
currentWaitingTime = readyTime[endIndex] - time;
}
double waitTime = readyTime[endIndex] - time;
waitingTime += currentWaitingTime;
time += currentWaitingTime;
double spareTime = dueTime[endIndex] - time;
double arrivalSpareCapacity = capacity - currentLoad;
if (end > 0)
{
//service
double currentServiceTime = serviceTimes[end - 1];
serviceTime += currentServiceTime;
time += currentServiceTime;
//Pickup / deliver
bool validPickupDelivery =
validPickupDelivery =
((demand[end - 1] >= 0) ||
(stops.ContainsKey(pickupDeliveryLocation[end - 1])));
if (validPickupDelivery)
{
currentLoad += demand[end - 1];
}
else
{
pickupViolations++;
}
if (currentLoad > capacity)
{
overweight += currentLoad - capacity;
}
}
double spareCapacity = capacity - currentLoad;
CVRPPDTWInsertionInfo stopInfo = new CVRPPDTWInsertionInfo(start, end, spareCapacity, tourStartTime,
arrivalTime, time, spareTime, waitTime, new List <int>(stops.Keys), arrivalSpareCapacity);
tourInfo.AddStopInsertionInfo(stopInfo);
stops.Add(end, true);
}
eval.Quality += instance.FleetUsageFactor.Value;
eval.Quality += instance.DistanceFactor.Value * distance;
eval.Distance += distance;
eval.VehicleUtilization += 1;
(eval as CVRPEvaluation).Overload += overweight;
double tourPenalty = 0;
double penalty = overweight * cvrpInstance.OverloadPenalty.Value;
eval.Penalty += penalty;
eval.Quality += penalty;
tourPenalty += penalty;
(eval as CVRPTWEvaluation).Tardiness += tardiness;
(eval as CVRPTWEvaluation).TravelTime += time;
penalty = tardiness * vrptw.TardinessPenalty.Value;
eval.Penalty += penalty;
eval.Quality += penalty;
tourPenalty += penalty;
(eval as CVRPPDTWEvaluation).PickupViolations += pickupViolations;
penalty = pickupViolations * pdp.PickupViolationPenalty.Value;
eval.Penalty += penalty;
tourPenalty += penalty;
eval.Quality += penalty;
eval.Quality += time * vrptw.TimeFactor.Value;
tourInfo.Penalty = tourPenalty;
tourInfo.Quality = eval.Quality - originalQuality;
}
protected override double GetTourInsertionCosts(IVRPProblemInstance instance, IVRPEncoding solution, TourInsertionInfo tourInsertionInfo, int index, int customer,
out bool feasible)
{
CVRPPDTWInsertionInfo insertionInfo = tourInsertionInfo.GetStopInsertionInfo(index) as CVRPPDTWInsertionInfo;
double costs = 0;
feasible = tourInsertionInfo.Penalty < double.Epsilon;
bool tourFeasible = true;
ICapacitatedProblemInstance cvrp = instance as ICapacitatedProblemInstance;
double overloadPenalty = cvrp.OverloadPenalty.Value;
ITimeWindowedProblemInstance vrptw = instance as ITimeWindowedProblemInstance;
DoubleArray dueTime = vrptw.DueTime;
DoubleArray readyTime = vrptw.ReadyTime;
DoubleArray serviceTimes = vrptw.ServiceTime;
double tardinessPenalty = vrptw.TardinessPenalty.Value;
IMultiDepotProblemInstance mdp = instance as IMultiDepotProblemInstance;
int depots = mdp.Depots.Value;
IPickupAndDeliveryProblemInstance pdp = instance as IPickupAndDeliveryProblemInstance;
IntArray pickupDeliveryLocation = pdp.PickupDeliveryLocation;
double pickupPenalty = pdp.PickupViolationPenalty.Value;
double startDistance, endDistance;
costs += instance.GetInsertionDistance(insertionInfo.Start, customer, insertionInfo.End, solution, out startDistance, out endDistance);
double demand = instance.GetDemand(customer);
if (demand > insertionInfo.ArrivalSpareCapacity)
{
tourFeasible = feasible = false;
if (insertionInfo.ArrivalSpareCapacity >= 0)
{
costs += (demand - insertionInfo.ArrivalSpareCapacity) * overloadPenalty;
}
else
{
costs += demand * overloadPenalty;
}
}
int destination = pickupDeliveryLocation[customer - 1];
bool validPickup = true;
if (demand < 0 && !insertionInfo.Visited.Contains(destination))
{
tourFeasible = feasible = false;
validPickup = false;
costs += pickupPenalty;
}
double time = 0;
double tardiness = 0;
if (index > 0)
{
time = (tourInsertionInfo.GetStopInsertionInfo(index - 1) as CVRPTWInsertionInfo).LeaveTime;
}
else
{
time = insertionInfo.TourStartTime;
}
time += startDistance;
int customerIndex = customer + depots - 1;
if (time > dueTime[customerIndex])
{
tardiness += time - dueTime[customerIndex];
}
if (time < readyTime[customerIndex])
{
time += readyTime[customerIndex] - time;
}
time += serviceTimes[customer - 1];
time += endDistance;
double additionalTime = time - (tourInsertionInfo.GetStopInsertionInfo(index) as CVRPTWInsertionInfo).ArrivalTime;
for (int i = index; i < tourInsertionInfo.GetStopCount(); i++)
{
CVRPTWInsertionInfo nextStop = tourInsertionInfo.GetStopInsertionInfo(i) as CVRPTWInsertionInfo;
if (demand >= 0)
{
if (nextStop.End == destination)
{
demand = 0;
costs -= pickupPenalty;
if (tourInsertionInfo.Penalty == pickupPenalty && tourFeasible)
{
feasible = true;
}
}
else if (nextStop.SpareCapacity < 0)
{
costs += demand * overloadPenalty;
}
else if (nextStop.SpareCapacity < demand)
{
tourFeasible = feasible = false;
costs += (demand - nextStop.SpareCapacity) * overloadPenalty;
}
}
else if (validPickup)
{
if (nextStop.SpareCapacity < 0)
{
costs += Math.Max(demand, nextStop.SpareCapacity) * overloadPenalty;
}
}
if (additionalTime < 0)
{
//arrive earlier than before
//wait probably
if (nextStop.WaitingTime < 0)
{
double wait = nextStop.WaitingTime - additionalTime;
if (wait > 0)
{
additionalTime += wait;
}
}
else
{
additionalTime = 0;
}
//check due date, decrease tardiness
if (nextStop.SpareTime < 0)
{
costs += Math.Max(nextStop.SpareTime, additionalTime) * tardinessPenalty;
}
}
else
{
//arrive later than before, probably don't have to wait
if (nextStop.WaitingTime > 0)
{
additionalTime -= Math.Min(additionalTime, nextStop.WaitingTime);
}
//check due date
if (nextStop.SpareTime > 0)
{
double spare = nextStop.SpareTime - additionalTime;
if (spare < 0)
{
tardiness += -spare;
}
}
else
{
tardiness += additionalTime;
}
}
}
costs += additionalTime * vrptw.TimeFactor.Value;
if (tardiness > 0)
{
tourFeasible = feasible = false;
}
costs += tardiness * tardinessPenalty;
return(costs);
}
protected override void EvaluateTour(VRPEvaluation eval, IVRPProblemInstance instance, Tour tour, IVRPEncoding solution)
{
TourInsertionInfo tourInfo = new TourInsertionInfo(solution.GetVehicleAssignment(solution.GetTourIndex(tour)));
eval.InsertionInfo.AddTourInsertionInfo(tourInfo);
double originalQuality = eval.Quality;
IHeterogenousCapacitatedProblemInstance cvrpInstance = instance as IHeterogenousCapacitatedProblemInstance;
DoubleArray demand = instance.Demand;
ITimeWindowedProblemInstance vrptw = instance as ITimeWindowedProblemInstance;
DoubleArray dueTime = vrptw.DueTime;
DoubleArray readyTime = vrptw.ReadyTime;
DoubleArray serviceTimes = vrptw.ServiceTime;
IMultiDepotProblemInstance mdp = instance as IMultiDepotProblemInstance;
IntArray vehicleAssignment = mdp.VehicleDepotAssignment;
int depots = mdp.Depots.Value;
double time = 0.0;
double waitingTime = 0.0;
double serviceTime = 0.0;
double tardiness = 0.0;
double delivered = 0.0;
double overweight = 0.0;
double distance = 0.0;
int tourIndex = solution.GetTourIndex(tour);
int vehicle = solution.GetVehicleAssignment(tourIndex);
int depot = vehicleAssignment[vehicle];
double capacity = cvrpInstance.Capacity[vehicle];
for (int i = 0; i < tour.Stops.Count; i++)
{
delivered += instance.GetDemand(tour.Stops[i]);
}
double spareCapacity = capacity - delivered;
double tourStartTime = vrptw.ReadyTime[depot];
time = tourStartTime;
//simulate a tour, start and end at depot
for (int i = 0; i <= tour.Stops.Count; i++)
{
int start = 0;
if (i > 0)
{
start = tour.Stops[i - 1];
}
int end = 0;
if (i < tour.Stops.Count)
{
end = tour.Stops[i];
}
//drive there
double currentDistace = vrptw.GetDistance(start, end, solution);
time += currentDistace;
distance += currentDistace;
double arrivalTime = time;
int endIndex;
if (end == 0)
{
endIndex = depot;
}
else
{
endIndex = end + depots - 1;
}
//check if it was serviced on time
if (time > dueTime[endIndex])
{
tardiness += time - dueTime[endIndex];
}
//wait
double currentWaitingTime = 0.0;
if (time < readyTime[endIndex])
{
currentWaitingTime = readyTime[endIndex] - time;
}
double waitTime = readyTime[endIndex] - time;
waitingTime += currentWaitingTime;
time += currentWaitingTime;
double spareTime = dueTime[endIndex] - time;
//service
double currentServiceTime = 0;
if (end > 0)
{
currentServiceTime = serviceTimes[end - 1];
}
serviceTime += currentServiceTime;
time += currentServiceTime;
CVRPTWInsertionInfo stopInfo = new CVRPTWInsertionInfo(start, end, spareCapacity, tourStartTime, arrivalTime, time, spareTime, waitTime);
tourInfo.AddStopInsertionInfo(stopInfo);
}
eval.Quality += instance.FleetUsageFactor.Value;
eval.Quality += instance.DistanceFactor.Value * distance;
eval.Distance += distance;
eval.VehicleUtilization += 1;
if (delivered > capacity)
{
overweight = delivered - capacity;
}
(eval as CVRPEvaluation).Overload += overweight;
double tourPenalty = 0;
double penalty = overweight * cvrpInstance.OverloadPenalty.Value;
eval.Penalty += penalty;
eval.Quality += penalty;
tourPenalty += penalty;
(eval as CVRPTWEvaluation).Tardiness += tardiness;
(eval as CVRPTWEvaluation).TravelTime += time;
penalty = tardiness * vrptw.TardinessPenalty.Value;
eval.Penalty += penalty;
eval.Quality += penalty;
tourPenalty += penalty;
eval.Quality += time * vrptw.TimeFactor.Value;
tourInfo.Penalty = tourPenalty;
tourInfo.Quality = eval.Quality - originalQuality;
}
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;
indexOfMinimumCost2 = j;
}
}
}
else
{
double cost = tourCost;
bool feasible = problemInstance.Feasible(eval);
if (cost < minimumCost && feasible)
{
customer = unrouted;
minimumCost = cost;
indexOfMinimumCost = i;
}
}
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)
{
tour.Stops.Insert(indexOfMinimumCost2, pdp.GetPickupDeliveryLocation(customer));
}
unroutedCustomers.Remove(customer);
}
else // no feasible customer found
{
tour = new Tour();
result.Tours.Add(tour);
currentCustomer = unroutedCustomers[0];
unroutedCustomers.RemoveAt(0);
currentDepot = depotAssignment[currentCustomer];
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));
}
}
}
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);
}
}
}
return(result);
}