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

java.lang.Object
  extended by org.apache.commons.math3.analysis.function.Logit
All Implemented Interfaces:
DifferentiableUnivariateFunction, UnivariateDifferentiableFunction, UnivariateFunction

public class Logit
extends Object
implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction

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

Since:
3.0
Version:
$Id: Logit.java 1391927 2012-09-30 00:03:30Z erans $

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
 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
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)
             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


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