burlap.behavior.policy

Class RandomPolicy

java.lang.Object

burlap.behavior.policy.RandomPolicy

All Implemented Interfaces:

EnumerablePolicy, Policy

public class RandomPolicy
extends java.lang.Object
implements Policy, EnumerablePolicy

A uniform random policy for single agent domains. You may set the actions between which it randomly selects by providing a domain (from which the domains primitive actions are copied into an internal list) or from a list of Action objects (from which the action references are copied into an internal list). You may also add additional actions with the addAction(ActionType) method or remove or clear the actions.

Upon action selection, all applicable grounded actions for the state are generated and an action is selected uniformly randomly from them. The policy is not defined if there are no applicable actions.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.List<ActionType>	actionTypes The actions from which selection is performed
protected java.util.Random	rand The random factory used to randomly select actions.

Constructor Summary

Constructors

Constructor and Description
RandomPolicy(java.util.List<ActionType> actionTypes) Initializes by copying all the actions references defined in the provided list into an internal action list for this policy.
RandomPolicy(SADomain domain) Initializes by copying all the primitive actions references defined for the domain into an internal action list for this policy.

Method Summary

Modifier and Type	Method and Description
Action	action(State s) This method will return an action sampled by the policy for the given state.
double	actionProb(State s, Action a) Returns the probability/probability density that the given action will be taken in the given state.
void	addAction(ActionType actionType) Adds an aciton to consider in selection.
void	clearActions() Clears the action list used in action selection.
boolean	definedFor(State s) Specifies whether this policy is defined for the input state.
java.util.Random	getRandomGenerator() Returns the random generator used for action selection.
java.util.List<ActionType>	getSelectionActions() Returns of the list of actions that can be randomly selected.
java.util.List<ActionProb>	policyDistribution(State s) This method will return action probability distribution defined by the policy.
void	removeAction(java.lang.String actionName) Removes an action from consideration.
void	setRandomGenerator(java.util.Random rand) Sets the random generator used for action selection.

Methods inherited from class java.lang.Object

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

Field Detail

actionTypes

protected java.util.List<ActionType> actionTypes

The actions from which selection is performed

rand

protected java.util.Random rand

The random factory used to randomly select actions.

Constructor Detail

RandomPolicy

public RandomPolicy(SADomain domain)

Initializes by copying all the primitive actions references defined for the domain into an internal action list for this policy.

Parameters:

domain - the domain containing all the primitive actions.

RandomPolicy

public RandomPolicy(java.util.List<ActionType> actionTypes)

Initializes by copying all the actions references defined in the provided list into an internal action list for this policy.

Parameters:

actionTypes - the actions to select between.

Method Detail

addAction

public void addAction(ActionType actionType)

Adds an aciton to consider in selection.

Parameters:

actionType - an action to consider in selection

clearActions

public void clearActions()

Clears the action list used in action selection. Note that if no actions are added to this policy after calling this method then the policy will be undefined everywhere.

removeAction

public void removeAction(java.lang.String actionName)

Removes an action from consideration.

Parameters:

actionName - the name of the action to remove.

getSelectionActions

public java.util.List<ActionType> getSelectionActions()

Returns of the list of actions that can be randomly selected.

Returns:

the list of actions that can be randomly selected.

getRandomGenerator

public java.util.Random getRandomGenerator()

Returns the random generator used for action selection.

Returns:

the random generator used for action selection.

setRandomGenerator

public void setRandomGenerator(java.util.Random rand)

Sets the random generator used for action selection.

Parameters:

rand - the random generator used for action selection.

action

public Action action(State s)

Description copied from interface: 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:

action in interface 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

actionProb

public double actionProb(State s,
                         Action a)

Description copied from interface: Policy

Returns the probability/probability density that the given action will be taken in the given state.

Specified by:

actionProb in interface Policy

Parameters:

s - the state of interest

a - the action that may be taken in the state

Returns:

the probability/probability density

policyDistribution

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

Description copied from interface: EnumerablePolicy

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:

policyDistribution in interface EnumerablePolicy

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.

definedFor

public boolean definedFor(State s)

Description copied from interface: Policy

Specifies whether this policy is defined for the input state.

Specified by:

definedFor in interface 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.