org.apache.commons.math3.analysis.function

Class Logit

java.lang.Object

org.apache.commons.math3.analysis.function.Logit

All Implemented Interfaces:

DifferentiableUnivariateFunction, UnivariateDifferentiableFunction, UnivariateFunction

public class Logit
extends java.lang.Object
implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction

Logit function. It is the inverse of the sigmoid function.

Since:

3.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Logit.Parametric Parametric function where the input array contains the parameters of the logit function, ordered as follows: Lower bound Higher bound

Constructor Summary

Constructors

Constructor and Description
Logit() Usual logit function, where the lower bound is 0 and the higher bound is 1.
Logit(double lo, double hi) Logit function.

Method Summary

Modifier and Type	Method and Description
UnivariateFunction	derivative() Deprecated. as of 3.1, replaced by value(DerivativeStructure)
DerivativeStructure	value(DerivativeStructure t) Simple mathematical function.
double	value(double x) Compute the value of the function.

Methods inherited from class java.lang.Object

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

Constructor Detail

Logit

public Logit()

Usual logit function, where the lower bound is 0 and the higher bound is 1.

Logit

public Logit(double lo,
             double hi)

Logit function.

Parameters:

lo - Lower bound of the function domain.

hi - Higher bound of the function domain.

Method Detail

value

public double value(double x)
             throws OutOfRangeException

Compute the value of the function.

Specified by:

value in interface UnivariateFunction

Parameters:

x - Point at which the function value should be computed.

Returns:

the value of the function.

Throws:

OutOfRangeException

derivative

@Deprecated
public UnivariateFunction derivative()

Deprecated. as of 3.1, replaced by value(DerivativeStructure)

Returns the derivative of the function

Specified by:

derivative in interface DifferentiableUnivariateFunction

Returns:

the derivative function

value

public DerivativeStructure value(DerivativeStructure t)
                          throws OutOfRangeException

Simple mathematical function.

UnivariateDifferentiableFunction classes compute both the value and the first derivative of the function.

Specified by:

value in interface UnivariateDifferentiableFunction

Parameters:

t - function input value

Returns:

function result

Throws:

OutOfRangeException - if parameter is outside of function domain

Since:

3.1