repicea.stats.model.glm

Class LinkFunction

java.lang.Object

repicea.math.AbstractMathematicalFunction

repicea.math.AbstractMathematicalFunctionWrapper

repicea.stats.model.glm.LinkFunction

All Implemented Interfaces:

java.io.Serializable, DerivableMathematicalFunction, EvaluableFunction<java.lang.Double>

public final class LinkFunction
extends AbstractMathematicalFunctionWrapper
implements java.io.Serializable

The LinkFunction class is essential to any generalized linear model. It contains a single parameter, which is a LinearStatisticalExpression instance. The two available link functions are the logit and the log link functions.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LinkFunction.Type

Field Summary

Fields inherited from class repicea.math.AbstractMathematicalFunction

parameterBounds

Constructor Summary

Constructors

Constructor and Description
LinkFunction(LinkFunction.Type type) Public constructor.
LinkFunction(LinkFunction.Type type, AbstractMathematicalFunction eta) Public constructor.

Method Summary

Modifier and Type	Method and Description
Matrix	getGradient() This method returns a vector that contains the first derivatives of the function with respect to its parameters.
Matrix	getHessian() This method returns a matrix that contains the second derivatives of the function with respect to its parameters.
LinkFunction.Type	getType() Provides the type of link function.
java.lang.Double	getValue() This method provides the result of the function evaluation.

Methods inherited from class repicea.math.AbstractMathematicalFunctionWrapper

getBeta, getNumberOfParameters, getNumberOfVariables, getOriginalFunction, getParameterValue, getVariableValue, setBeta, setBounds, setParameterValue, setVariableValue, setX

Methods inherited from class java.lang.Object

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

Constructor Detail

LinkFunction

public LinkFunction(LinkFunction.Type type)

Public constructor. The default nested function is linear.

Parameters:

type - a Type enum variable that defines the type of link function

Throws:

java.security.InvalidParameterException - if type is null

LinkFunction

public LinkFunction(LinkFunction.Type type,
                    AbstractMathematicalFunction eta)

Public constructor.

Parameters:

type - a Type enum variable that defines the type of link function

eta - an AbstractMathematicalFunction instance

Throws:

java.security.InvalidParameterException - if type is null

Method Detail

getType

public LinkFunction.Type getType()

Provides the type of link function.

Returns:

a Type enum variable

getValue

public java.lang.Double getValue()

Description copied from interface: EvaluableFunction

This method provides the result of the function evaluation.

Specified by:

getValue in interface EvaluableFunction<java.lang.Double>

Specified by:

getValue in class AbstractMathematicalFunctionWrapper

Returns:

a P instance

getGradient

public Matrix getGradient()

Description copied from interface: DerivableMathematicalFunction

This method returns a vector that contains the first derivatives of the function with respect to its parameters.

Specified by:

getGradient in interface DerivableMathematicalFunction

Specified by:

getGradient in class AbstractMathematicalFunctionWrapper

Returns:

a Matrix instance

getHessian

public Matrix getHessian()

Description copied from interface: DerivableMathematicalFunction

This method returns a matrix that contains the second derivatives of the function with respect to its parameters.

Specified by:

getHessian in interface DerivableMathematicalFunction

Specified by:

getHessian in class AbstractMathematicalFunctionWrapper

Returns:

a Matrix instance