英文:
Optaplanner constraints for time windows
问题
以下是翻译好的内容：
我正在尝试使用OptaPlanner解决VRP问题。我有多个客户，每个客户都有不同的时间窗口。以下是我的约束提供者：
protected Constraint arrivalAfterDueTime(ConstraintFactory factory) {
return factory.from(TimeWindowedCustomer.class)
.filter(customer -> customer.getArrivalTime() >= customer.getDueTime())
.penalizeLong("arrivalAfterDueTime",
HardSoftLongScore.ONE_HARD,
customer -> customer.getArrivalTime() - customer.getDueTime());
}
protected Constraint arrivalBeforeReadyTime(ConstraintFactory factory) {
return factory.from(TimeWindowedCustomer.class)
.filter(customer -> customer.getArrivalTime() > customer.getReadyTime()
&& customer.getArrivalTime() < customer.getDueTime() )
.penalizeLong("arrivalBeforeReadyTime",
HardSoftLongScore.ONE_HARD,
customer -> customer.getReadyTime() - customer.getArrivalTime());
}
但是在解决方案中，我得到了到达时间早于准备时间的情况。我应该如何修复这个问题？提前谢谢您的帮助。
英文:
I am trying to solve VRP with OptaPlanner. I have multiple customers that have different time windows. Here are my constraint providers
protected Constraint arrivalAfterDueTime(ConstraintFactory factory) {
return factory.from(TimeWindowedCustomer.class)
.filter(customer -> customer.getArrivalTime() >= customer.getDueTime())
.penalizeLong("arrivalAfterDueTime",
HardSoftLongScore.ONE_HARD,
customer -> customer.getArrivalTime() - customer.getDueTime());
}
protected Constraint arrivalBeforeReadyTime(ConstraintFactory factory) {
return factory.from(TimeWindowedCustomer.class)
.filter(customer -> customer.getArrivalTime() > customer.getReadyTime()
&& customer.getArrivalTime() < customer.getDueTime() )
.penalizeLong("arrivalBeforeReadyTime",
HardSoftLongScore.ONE_HARD,
customer -> customer.getReadyTime() - customer.getArrivalTime());
}
But in the solution I get arrival times that are < ready time. How can I fix this? Thank you in advance.
答案1
得分: 1
一般有三种方法来处理提前到达的情况：
- A) 等待直到时间窗口开启，虽然会浪费时间，但不会额外产生惩罚。因此，当车辆在9:30到达，服务时间为0:10，准备时间为10:00时，车辆会在10:10出发（而不是9:40！）。如果您设置了减少车辆总活动时间的一般性约束（或每辆车的最大活动时间与每天任务过多的组合），将自动避免此情况。
- B) 与A)相同，但会额外产生轻微惩罚。如果没有全局约束来减少车辆总活动时间，这可能会很有用。
- C) 与A)相同，但会额外产生严重惩罚。这很危险，因为考虑有两个任务，一个时间窗口是9:00到10:00，另一个是11:00到12:00，它们之间有10分钟的行驶时间，并且没有其他任务，这将阻止一个车辆同时执行这两个任务。
无论如何，使用ConstraintVerifier来单元测试您的约束条件！
英文:
There are generally three approaches when arriving too early:
- A) Wait until the time windows open, losing that time but with no extra penalty. So when it arrives at 9:30, with a service time of 0:10 and ready time of 10:00, the vehicle departs at 10:10 (not 9:40!). This will automatically be avoided if you have a general constraint to reduce the total activity time of vehicles (or a combination of max activity time per vehicle with too many tasks per day).
- B) Same as A), with an extra soft penalty. This can be useful if you don't have a global constraint to reduce the total activity time of vehicles.
- C) Same as A) with an extra hard penalty. This is dangerous because given 2 tasks, one with a time window from 9:00 to 10:00 and one from 11:00 to 12:00, with a 10 minute drive in between, and no other tasks, you're not allowing one vehicle to do both those tasks.
In any case, use ConstraintVerifier to unit test your constraints!
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