Optaplanner 从工作 VRP 解决方案中删除客户 [英] Optaplanner remove customer from working VRP solution
问题描述
基于此问题,我尝试了以下操作:>
Based on this question i tried the following:
public void doFactChange() {
Location toBeRemovedLocation = customerToBeRemoved.getLocation();
Location lookUpWorkingObject = (Location) scoreDirector.lookUpWorkingObject(toBeRemovedLocation);
scoreDirector.beforeProblemFactRemoved(lookUpWorkingObject);
routingSolution.getLocationList().remove(lookUpWorkingObject);
scoreDirector.afterProblemFactRemoved(lookUpWorkingObject);
Customer workingCustomer = (Customer) scoreDirector.lookUpWorkingObject(customerToBeRemoved);
for (Customer customer : routingSolution.getCustomerList()) {
while (customer != null) {
if (customer == workingCustomer) {
if (customer.getPreviousStandstill() != null) {
scoreDirector.beforeVariableChanged(customer, "previousStandstill");
customer.getPreviousStandstill().setNextCustomer(customer.getNextCustomer());
scoreDirector.afterVariableChanged(customer, "previousStandstill");
}
scoreDirector.beforeVariableChanged(customer, "nextCustomer");
customer.getNextCustomer().setPreviousStandstill(customer.getPreviousStandstill());
scoreDirector.afterVariableChanged(customer, "nextCustomer");
}
customer = customer.getNextCustomer();
}
}
scoreDirector.beforeEntityRemoved(workingCustomer);
routingSolution.getCustomerList().remove(workingCustomer);
scoreDirector.afterEntityRemoved(workingCustomer);
scoreDirector.triggerVariableListeners();
}
注意:customerToBeRemoved
是在调用 doFactChange()
但我在调用 scoreDirector.triggerVariableListeners
之前收到了以下异常
But I received the following exception even before calling scoreDirector.triggerVariableListeners
java.lang.IllegalStateException: 实体 (Customer--9048381398840634905) 有一个值为 (Customer--9070671076516032025) 的变量 (previousStandstill),其中有一个 sourceVariableName 变量 (nextCustomer),值为 1805185185185153那个实体.验证该 sourceVariableName 变量的输入问题的一致性.
java.lang.IllegalStateException: The entity (Customer--9048381398840634905) has a variable (previousStandstill) with value (Customer--9070671076516032025) which has a sourceVariableName variable (nextCustomer) with a value (Customer-8518512081385427431) which is not that entity. Verify the consistency of your input problem for that sourceVariableName variable.
另一个问题:
我尝试直接删除实体如下:
I tried to remove the entity directly as follows:
public void doFactChange() {
Location toBeRemovedLocation = customerToBeRemoved.getLocation();
Location lookUpWorkingObject = (Location) scoreDirector.lookUpWorkingObject(toBeRemovedLocation);
scoreDirector.beforeProblemFactRemoved(lookUpWorkingObject);
routingSolution.getLocationList().remove(lookUpWorkingObject);
scoreDirector.afterProblemFactRemoved(lookUpWorkingObject);
Customer workingCustomer = (Customer) scoreDirector.lookUpWorkingObject(customerToBeRemoved);
scoreDirector.beforeEntityRemoved(workingCustomer);
routingSolution.getCustomerList().remove(workingCustomer);
scoreDirector.afterEntityRemoved(workingCustomer);
scoreDirector.triggerVariableListeners();
}
这有效吗?
推荐答案
此方法适用于 optaplanner VRP 示例,使用简单、增量和 drl 分数计算器:
This method works fine with optaplanner VRP example using easy, incremental and drl score calculators:
public void removeRandomCustomer()
{
doProblemFactChange(scoreDirector -> {
VehicleRoutingSolution solution = scoreDirector.getWorkingSolution();
int rnd = 4; //select a random customer
if (solution.getCustomerList().size() > rnd)
{
Customer customer = solution.getCustomerList().get(rnd);
scoreDirector.beforeEntityRemoved(customer);
removeCustomer(solution, customer);
scoreDirector.afterEntityRemoved(customer);
scoreDirector.triggerVariableListeners();
}
});
}
private void removeCustomer(VehicleRoutingSolution solution, Customer customer)
{
Standstill anchor = customer.getPreviousStandstill();
Customer nextCustomer = customer.getNextCustomer();
//anchor shouldn't be null in an initialized solution
if (anchor != null)
anchor.setNextCustomer(nextCustomer);
if (nextCustomer != null)
nextCustomer.setPreviousStandstill(anchor);
solution.getCustomerList().remove(customer);
}
具有简单/增量评分的阴影变量的替代方法:
Alternative approach for shadow variables with easy/incremental scoring:
private void removeCustomer(ScoreDirector<VehicleRoutingSolution> scoreDirector, VehicleRoutingSolution solution, Customer removeCustomer)
{
final Customer customer = scoreDirector.lookUpWorkingObject(removeCustomer);
Standstill anchor = customer.getPreviousStandstill();
Customer nextCustomer = customer.getNextCustomer();
//scoreDirector.beforeVariableChanged(anchor, "nextCustomer");
scoreDirector.beforeVariableChanged(customer, "previousStandstill"); //sets anchor.nextCustomer=null
customer.setPreviousStandstill(null);
scoreDirector.afterVariableChanged(customer, "previousStandstill");
//scoreDirector.afterVariableChanged(anchor, "nextCustomer");
if(nextCustomer!=null)
{
//scoreDirector.beforeVariableChanged(customer, "nextCustomer");
scoreDirector.beforeVariableChanged(nextCustomer, "previousStandstill"); //sets customer.nextCustomer=null
nextCustomer.setPreviousStandstill(anchor);
scoreDirector.afterVariableChanged(nextCustomer, "previousStandstill");
//scoreDirector.afterVariableChanged(customer, "nextCustomer");
}
scoreDirector.beforeEntityRemoved(customer);
//clone customer list
ArrayList<Customer> changedList = new ArrayList<>(solution.getCustomerList());
solution.setCustomerList(changedList);
solution.getCustomerList().remove(customer);
scoreDirector.afterEntityRemoved(customer);
scoreDirector.triggerVariableListeners(); //sets customer.vehicle=null, sets all nextCustomer.vehicle=null
}
解决方案现在应该处于有效状态,但您可能必须修复增量评分(简单评分很好,因为 doProblemFactChange()
会自动重新计算),也许通过删除VehicleRoutingIncrementalScoreCalculator.beforeEntityRemoved()
.如果其他一切都失败了,您可以先将客户移到链的末端并将其从那里移除.
The solution should be in a valid state now but you'll probably have to fix the incremental scoring (easy score is fine because doProblemFactChange()
recalculates it automatically), perhaps by removing the retraction in VehicleRoutingIncrementalScoreCalculator.beforeEntityRemoved()
. If everything else fails you could first move the customer to the end of the chain and remove it from there.
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