Package cc.mallet.fst.semi_supervised

Class CRFOptimizableByEntropyRegularization

java.lang.Object

cc.mallet.fst.semi_supervised.CRFOptimizableByEntropyRegularization

All Implemented Interfaces:

Optimizable, Optimizable.ByGradientValue, java.io.Serializable

public class CRFOptimizableByEntropyRegularization
extends java.lang.Object
implements Optimizable.ByGradientValue, java.io.Serializable

A CRF objective function that is the entropy of the CRF's predictions on unlabeled data. References: Feng Jiao, Shaojun Wang, Chi-Hoon Lee, Russell Greiner, Dale Schuurmans "Semi-supervised conditional random fields for improved sequence segmentation and labeling" ACL 2006 Gideon Mann, Andrew McCallum "Efficient Computation of Entropy Gradient for Semi-Supervised Conditional Random Fields" HLT/NAACL 2007

Author:

Gaurav Chandalia, Gregory Druck

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface cc.mallet.optimize.Optimizable

Optimizable.ByBatchGradient, Optimizable.ByCombiningBatchGradient, Optimizable.ByGISUpdate, Optimizable.ByGradient, Optimizable.ByGradientValue, Optimizable.ByHessian, Optimizable.ByValue, Optimizable.ByVotedPerceptron

Field Summary

Fields

Modifier and Type	Field	Description
protected double[]	cachedGradient
protected double	cachedValue
protected CRF	crf
protected InstanceList	data
protected CRF.Factors	expectations
protected Transducer.Incrementor	incrementor
protected double	scalingFactor

Constructor Summary

Constructors

Constructor	Description
CRFOptimizableByEntropyRegularization(CRF crf, InstanceList ilist)	Initializes the structures (sets the scaling factor to 1.0).
CRFOptimizableByEntropyRegularization(CRF crf, InstanceList ilist, double scalingFactor)	Initializes the structures.

Method Summary

Modifier and Type	Method	Description
void	computeExpectations()	Resets, computes and fills expectations from all instances, also updating the entropy value.
int	getNumParameters()
double	getParameter(int index)
void	getParameters(double[] buffer)
double	getScalingFactor()
double	getValue()
void	getValueGradient(double[] buffer)
void	setParameter(int index, double value)
void	setParameters(double[] buffer)
void	setScalingFactor(double scalingFactor)

Methods inherited from class java.lang.Object

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

Field Detail

expectations

protected CRF.Factors expectations

incrementor

protected Transducer.Incrementor incrementor

data

protected InstanceList data

crf

protected CRF crf

scalingFactor

protected double scalingFactor

cachedValue

protected double cachedValue

cachedGradient

protected double[] cachedGradient

Constructor Detail

CRFOptimizableByEntropyRegularization

public CRFOptimizableByEntropyRegularization(CRF crf,
                                             InstanceList ilist,
                                             double scalingFactor)

Initializes the structures.

CRFOptimizableByEntropyRegularization

public CRFOptimizableByEntropyRegularization(CRF crf,
                                             InstanceList ilist)

Initializes the structures (sets the scaling factor to 1.0).

Method Detail

getScalingFactor

public double getScalingFactor()

setScalingFactor

public void setScalingFactor(double scalingFactor)

computeExpectations

public void computeExpectations()

Resets, computes and fills expectations from all instances, also updating the entropy value.

Analogous to CRFOptimizableByLabelLikelihood.getExpectationValue.

getValue

public double getValue()

Specified by:

getValue in interface Optimizable.ByGradientValue

getValueGradient

public void getValueGradient(double[] buffer)

Specified by:

getValueGradient in interface Optimizable.ByGradientValue

getNumParameters

public int getNumParameters()

Specified by:

getNumParameters in interface Optimizable

getParameters

public void getParameters(double[] buffer)

Specified by:

getParameters in interface Optimizable

setParameters

public void setParameters(double[] buffer)

Specified by:

setParameters in interface Optimizable

getParameter

public double getParameter(int index)

Specified by:

getParameter in interface Optimizable

setParameter

public void setParameter(int index,
                         double value)

Specified by:

setParameter in interface Optimizable