NullPointerException thrown in Policy.followAndRecordPolicy about burlap HOT 3 CLOSED

Okay. A couple of questions. (1) Have you updated to the version that has the planner throw an exception if there is no valid plan? (2) If so, since the planner should have thrown a runtime exception if it didn't find a plan to the goal, I'm guessing the policy is being invoked somewhere where it is undefined. Which Policy object specifically are you using? Is it a SDPlannerPolicy? That specific policy implementation would definitely cause the problem if you query a state for which the planner has no plan (returns null), whereas DDPlannerPolicy will call the planner again for any states for which there is no plan.

I can do two things; (1) make sure the followAndRecordPolicy method throws a more meaningful exception (e.g., policy undefined) and (2) make SDPlannerPolicy throw a similar exception instead of returning null. However, I want to make sure I have it tracked in the right place.

from burlap.

Switching to DDPlannerPolicy helped! And if there is an instance where it can't plan, it will throw the planner exception.

I think gratuitous exceptions will help, especially for people like me who aren't experienced in designing domains.

from burlap.

Awesome :)

So that does probably mean it was queried for a state not in the original plan. I've added the additional exceptions to the Policy followAndRecordPolicy method as well as the getAction method (and corresponding distribution method) for the SDPlannerPolicy. I'll merge with master in a minute.

from burlap.