burlap.behavior.functionapproximation.sparse

Class SparseCrossProductFeatures

java.lang.Object

burlap.behavior.functionapproximation.sparse.SparseCrossProductFeatures

All Implemented Interfaces:

SparseStateActionFeatures

public class SparseCrossProductFeatures
extends java.lang.Object
implements SparseStateActionFeatures

A SparseStateActionFeatures implementation that takes as input a SparseStateFeatures object, and turns it into state-action features taking the cross product of the features with the action set. This implementation is lazy and creates state-action features as they are queried. Consequently, the state-action feature indices for an action may not be consecutive.

Author:

James MacGlashan.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	SparseCrossProductFeatures.FeaturesMap

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.Map<Action,SparseCrossProductFeatures.FeaturesMap>	actionFeatures
protected int	nextFeatureId
protected SparseStateFeatures	sFeatures

Constructor Summary

Constructors

Modifier	Constructor and Description
	SparseCrossProductFeatures(SparseStateFeatures sFeatures)
protected	SparseCrossProductFeatures(SparseStateFeatures sFeatures, java.util.Map<Action,SparseCrossProductFeatures.FeaturesMap> actionFeatures, int nextFeatureId)

Method Summary

Modifier and Type	Method and Description
protected int	actionFeature(Action a, int from)
SparseCrossProductFeatures	copy() Returns a deep copy of this features function.
java.util.List<StateFeature>	features(State s, Action a) Returns non-zero state-action features for a given state and action.
int	numFeatures() Returns the total number of features

Methods inherited from class java.lang.Object

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

Field Detail

sFeatures

protected SparseStateFeatures sFeatures

actionFeatures

protected java.util.Map<Action,SparseCrossProductFeatures.FeaturesMap> actionFeatures

nextFeatureId

protected int nextFeatureId

Constructor Detail

SparseCrossProductFeatures

public SparseCrossProductFeatures(SparseStateFeatures sFeatures)

SparseCrossProductFeatures

protected SparseCrossProductFeatures(SparseStateFeatures sFeatures,
                                     java.util.Map<Action,SparseCrossProductFeatures.FeaturesMap> actionFeatures,
                                     int nextFeatureId)

Method Detail

features

public java.util.List<StateFeature> features(State s,
                                             Action a)

Description copied from interface: SparseStateActionFeatures

Returns non-zero state-action features for a given state and action.

Specified by:

features in interface SparseStateActionFeatures

Parameters:

s - the state for which features should be returned

a - the action for which features should be returned

Returns:

the features for state s

copy

public SparseCrossProductFeatures copy()

Description copied from interface: SparseStateActionFeatures

Returns a deep copy of this features function. If the features is dynamic, then changes to one will not affect the other.

Specified by:

copy in interface SparseStateActionFeatures

Returns:

a deep copy of this features function

numFeatures

public int numFeatures()

Description copied from interface: SparseStateActionFeatures

Returns the total number of features

Specified by:

numFeatures in interface SparseStateActionFeatures

Returns:

the total number of features

actionFeature

protected int actionFeature(Action a,
                            int from)