burlap.behavior.policy

Class BeliefPolicyToPOMDPPolicy

java.lang.Object

burlap.behavior.policy.Policy

burlap.behavior.policy.BeliefPolicyToPOMDPPolicy

public class BeliefPolicyToPOMDPPolicy
extends Policy

This policy takes as input a policy for a belief MDP generated with BeliefMDPGenerator and when queried for an action, first queries the belief MDP policy and then translates its actions to the corresponding POMDP actions that can be executed in a POMDP domain.

Note that this policy is should *not* be used with policies returned by wrapper planning algorithms like BeliefSparseSampling, because these algorithms already manage the conversion between belief MDP and POMDP actions. You should only use this policy if you are manually solving a belief MDP with a standard MDP planner.

Author:

James MacGlashan.

Nested Class Summary

Nested classes/interfaces inherited from class burlap.behavior.policy.Policy

Policy.ActionProb, Policy.GroundedAnnotatedAction, Policy.PolicyUndefinedException

Field Summary

Fields

Modifier and Type	Field and Description
protected Policy	beliefPolicy

Fields inherited from class burlap.behavior.policy.Policy

annotateOptionDecomposition, evaluateDecomposesOptions

Constructor Summary

Constructors

Constructor and Description
BeliefPolicyToPOMDPPolicy(Policy beliefPolicy) Constructs from the input belief MDP policy that should be converted to returning the POMDP actions.

Method Summary

Methods

Modifier and Type	Method and Description
AbstractGroundedAction	getAction(State s) This method will return an action sampled by the policy for the given state.
java.util.List<Policy.ActionProb>	getActionDistributionForState(State s) This method will return action probability distribution defined by the policy.
boolean	isDefinedFor(State s) Specifies whether this policy is defined for the input state.
boolean	isStochastic() Indicates whether the policy is stochastic or deterministic.
protected GroundedAction	unpackPOMDPAction(AbstractGroundedAction beliefAction) Unpacks and returns the pomdp action from an input AbstractGroundedAction that is an instance of BeliefMDPGenerator.GroundedBeliefAction.

Methods inherited from class burlap.behavior.policy.Policy

evaluateBehavior, evaluateBehavior, evaluateBehavior, evaluateBehavior, evaluateBehavior, evaluateMethodsShouldAnnotateOptionDecomposition, evaluateMethodsShouldDecomposeOption, followAndRecordPolicy, followAndRecordPolicy, getDeterministicPolicy, getProbOfAction, getProbOfActionGivenDistribution, getProbOfActionGivenDistribution, sampleFromActionDistribution

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

beliefPolicy

protected Policy beliefPolicy

Constructor Detail

BeliefPolicyToPOMDPPolicy

public BeliefPolicyToPOMDPPolicy(Policy beliefPolicy)

Constructs from the input belief MDP policy that should be converted to returning the POMDP actions.

Parameters:

beliefPolicy - the source belief MDP action.

Method Detail

getAction

public AbstractGroundedAction getAction(State s)

Description copied from class: Policy

This method will return an action sampled by the policy for the given state. If the defined policy is stochastic, then multiple calls to this method for the same state may return different actions. The sampling should be with respect to defined action distribution that is returned by getActionDistributionForState

Specified by:

getAction in class Policy

Parameters:

s - the state for which an action should be returned

Returns:

a sample action from the action distribution; null if the policy is undefined for s

getActionDistributionForState

public java.util.List<Policy.ActionProb> getActionDistributionForState(State s)

Description copied from class: Policy

This method will return action probability distribution defined by the policy. The action distribution is represented by a list of ActionProb objects, each which specifies a grounded action and a probability of that grounded action being taken. The returned list does not have to include actions with probability 0.

Specified by:

getActionDistributionForState in class Policy

Parameters:

s - the state for which an action distribution should be returned

Returns:

a list of possible actions taken by the policy and their probability.

isStochastic

public boolean isStochastic()

Description copied from class: Policy

Indicates whether the policy is stochastic or deterministic.

Specified by:

isStochastic in class Policy

Returns:

true when the policy is stochastic; false when it is deterministic.

isDefinedFor

public boolean isDefinedFor(State s)

Description copied from class: Policy

Specifies whether this policy is defined for the input state.

Specified by:

isDefinedFor in class Policy

Parameters:

s - the input state to test for whether this policy is defined

Returns:

true if this policy is defined for State s, false otherwise.

unpackPOMDPAction

protected GroundedAction unpackPOMDPAction(AbstractGroundedAction beliefAction)

Unpacks and returns the pomdp action from an input AbstractGroundedAction that is an instance of BeliefMDPGenerator.GroundedBeliefAction.

Parameters:

beliefAction - the input BeliefMDPGenerator.GroundedBeliefAction.

Returns:

the input belief action's corresponding POMDP action.