org.apache.commons.math.analysis.function
Class Logit

java.lang.Object
  org.apache.commons.math.analysis.function.Logit

All Implemented Interfaces:

DifferentiableUnivariateRealFunction, UnivariateRealFunction

public class Logit
extends java.lang.Object
implements DifferentiableUnivariateRealFunction

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

Since:

3.0

Version:

$Id$

Nested Class Summary

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

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

UnivariateRealFunction	derivative() Returns the derivative of the function
double	value(double x) Compute the value of the function.

Methods inherited from class java.lang.Object

clone, equals, finalize, 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)

Compute the value of the function.

Specified by:

value in interface UnivariateRealFunction

Parameters:

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

Returns:

the value of the function.

derivative

public UnivariateRealFunction derivative()

Returns the derivative of the function

Specified by:

derivative in interface DifferentiableUnivariateRealFunction

Returns:

the derivative function