edu.stanford.nlp.classify

Class GeneralizedExpectationObjectiveFunction<L,F>

java.lang.Object

edu.stanford.nlp.optimization.AbstractCachingDiffFunction

edu.stanford.nlp.classify.GeneralizedExpectationObjectiveFunction<L,F>

All Implemented Interfaces:

DiffFunction, Function, HasInitial

public class GeneralizedExpectationObjectiveFunction<L,F>
extends AbstractCachingDiffFunction

Implementation of Generalized Expectation Objective function for an I.I.D. log-linear model. See Mann and McCallum, ACL 2008 for GE in CRFs. This code, however, is just for log-linear model IMPORTANT: the current implementation is only correct as long as the labeled features passed to GE are binary. However, other features are allowed to be real valued. The original paper also discusses GE only for binary features.

Author:

Ramesh Nallapati (nmramesh@cs.stanford.edu)

Field Summary

Fields inherited from class edu.stanford.nlp.optimization.AbstractCachingDiffFunction

derivative, value

Constructor Summary

Constructors

Constructor and Description
GeneralizedExpectationObjectiveFunction(GeneralDataset<L,F> labeledDataset, java.util.List<? extends Datum<L,F>> unlabeledDataList, java.util.List<F> geFeatures)

Method Summary

Modifier and Type	Method and Description
protected void	calculate(double[] x) Calculate the value at x and the derivative and save them in the respective fields.
int	domainDimension() Returns the number of dimensions in the function's domain
protected int	indexOf(int f, int c)
double[][]	to2D(double[] x)

Methods inherited from class edu.stanford.nlp.optimization.AbstractCachingDiffFunction

clearCache, copy, derivativeAt, ensure, getDerivative, gradientCheck, gradientCheck, initial, lastValue, randomInitial, valueAt

Methods inherited from class java.lang.Object

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

Constructor Detail

GeneralizedExpectationObjectiveFunction

public GeneralizedExpectationObjectiveFunction(GeneralDataset<L,F> labeledDataset,
                                               java.util.List<? extends Datum<L,F>> unlabeledDataList,
                                               java.util.List<F> geFeatures)

Method Detail

domainDimension

public int domainDimension()

Description copied from interface: Function

Returns the number of dimensions in the function's domain

Returns:

the number of domain dimensions

indexOf

protected int indexOf(int f,
                      int c)

to2D

public double[][] to2D(double[] x)

calculate

protected void calculate(double[] x)

Description copied from class: AbstractCachingDiffFunction

Calculate the value at x and the derivative and save them in the respective fields.

Specified by:

calculate in class AbstractCachingDiffFunction

Parameters:

x - The point at which to calculate the function