为什么对链接计划实体的约束会导致以下分数损坏异常？

Question

我目前正在致力于解决包含取货和送货的 VRP。在当前模型中，

Vehicle

是我的第一个

@PlanningEntity

，包含

@PlanningListVariable

的

LoadJobs

，可以是

PICKUP

或

DROPOFF

类型。每个

LoadJob

都引用它正在传递的

Load

，并且

Load

类都引用它的

PICKUP

和

DROPOFF

LoadJob

。

我编写了以下约束，以确保两个

LoadJobs

都放在同一个

Vehicle

上（当然，尝试传递从未被拾起的负载是没有意义的，并且拿起货物而不交付它）：

fun pickupAndDropoffOnSameVehicle(constraintFactory: ConstraintFactory): Constraint {
    return constraintFactory
        .forEach(LoadJob::class.java)
        .filter { it.load.pickup.vehicle != it.load.dropoff.vehicle }
        .penalizeConfigurable()
        .asConstraint(PICKUP_AND_DROPOFF_ON_SAME_VEHICLE)
}

当我在

FULL_ASSERT

模式下运行时，出现以下异常：

Caused by: java.lang.IllegalStateException: Score corruption (100hard): the workingScore (-19init/-100hard/0medium/-11670soft) is not the uncorruptedScore (-19init/-200hard/0medium/-11670soft) after completedAction (LoadJob(id=DROPOFF-loDKrYTAqF5kIfjFM6n4) {null -> Vehicle(idx=0)[0]}):
Score corruption analysis:
  The corrupted scoreDirector has no ConstraintMatch(s) which are in excess.
  The corrupted scoreDirector has 1 ConstraintMatch(s) which are missing:
    com.cargonexx.vehiclerouting.solver.constraint/pickupAndDropoffOnSameVehicle/[LoadJob(id=PICKUP-loDKrYTAqF5kIfjFM6n4)]=-100hard/0medium/0soft
  Maybe there is a bug in the score constraints of those ConstraintMatch(s).
  Maybe a score constraint doesn't select all the entities it depends on, but finds some through a reference in a selected entity. This corrupts incremental score calculation, because the constraint is not re-evaluated if such a non-selected entity changes.
Shadow variable corruption in the corrupted scoreDirector:
  None
    at org.optaplanner.core.impl.score.director.AbstractScoreDirector.assertScoreFromScratch(AbstractScoreDirector.java:637)
    at org.optaplanner.core.impl.score.director.AbstractScoreDirector.assertWorkingScoreFromScratch(AbstractScoreDirector.java:613)
    at org.optaplanner.core.impl.score.director.AbstractScoreDirector.doAndProcessMove(AbstractScoreDirector.java:204)
    at org.optaplanner.core.impl.heuristic.thread.MoveThreadRunner.run(MoveThreadRunner.java:131)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:577)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
    at java.base/java.lang.Thread.run(Thread.java:1589)

由于错误消息，我猜测这可能是由两个

LoadJobs

通过

Load

类之间的传递关系引起的。我尝试过仅过滤

PICKUP

，然后再过滤同一辆车并加入

LoadJob::class.java

，然后在两个加载作业上过滤相同的

Load

，然后再过滤同一辆车，一切都无济于事.

此异常的原因是什么？如何解决？

Answer 1

这是因为增量分数计算如何与

交互

.filter { it.load.pickup.vehicle != it.load.dropoff.vehicle }

没有选择

pickup

或

dropoff

，因此ConstraintStreams实现（无论是OptaPlanner CS Drools impl，还是Timefold的faster impl），不知道当上车或下车的车辆变量发生变化时，需要将这个约束重新评估（以增量方式实现可扩展性）。

解决方案

类似：

forEach(pickup)
.join(dropoff, equals(getLoad))
.filter(not same vehicle)
.penalize()