Package opennlp.tools.ml.maxent.quasinewton

Class NegLogLikelihood

java.lang.Object

opennlp.tools.ml.maxent.quasinewton.NegLogLikelihood

All Implemented Interfaces:

Function

Direct Known Subclasses:

ParallelNegLogLikelihood

public class NegLogLikelihood
extends Object
implements Function

Evaluate negative log-likelihood and its gradient from DataIndexer.

Constructor Summary

Constructors

Constructor	Description
NegLogLikelihood(DataIndexer indexer)

Method Summary

Modifier and Type	Method	Description
int	getDimension()
double[]	getInitialPoint()
double[]	gradientAt(double[] x)	Computes the gradient.
double	valueAt(double[] x)	Computes the negative log-likelihood.

Methods inherited from class java.lang.Object

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

Constructor Detail

NegLogLikelihood

public NegLogLikelihood(DataIndexer indexer)

Parameters:

indexer - The DataIndexer to use as input provider.

Method Detail

getDimension

public int getDimension()

Specified by:

getDimension in interface Function

Returns:

Retrieves the dimension value.

getInitialPoint

public double[] getInitialPoint()

Returns:

Retrieves the initial point as double array.

valueAt

public double valueAt(double[] x)

Computes the negative log-likelihood.

Specified by:

valueAt in interface Function

Parameters:

x - The input.

Returns:

Returns the computed negative log-likelihood.

Throws:

IllegalArgumentException - Thrown if parameters were invalid.

gradientAt

public double[] gradientAt(double[] x)

Computes the gradient.

Specified by:

gradientAt in interface Function

Parameters:

x - The input.

Returns:

Returns the computed gradient.

Throws:

IllegalArgumentException - Thrown if parameters were invalid.