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

java.lang.Object
  org.apache.commons.math3.analysis.function.Logistic

All Implemented Interfaces:

DifferentiableUnivariateFunction, UnivariateDifferentiableFunction, UnivariateFunction

public class Logistic
extends Object
implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction

Generalised logistic function.

Since:

3.0

Version:

$Id: Logistic.java 7721 2013-02-14 14:07:13Z CardosoP $

Nested Class Summary

static class

Logistic.Parametric Parametric function where the input array contains the parameters of the logit function, ordered as follows: Lower asymptote Higher asymptote

Constructor Summary

Logistic(double k, double m, double b, double q, double a, double n)

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

Logistic

public Logistic(double k,
                double m,
                double b,
                double q,
                double a,
                double n)
         throws NotStrictlyPositiveException

Parameters:

k - If b > 0, value of the function for x going towards +∞. If b < 0, value of the function for x going towards -∞.

m - Abscissa of maximum growth.

b - Growth rate.

q - Parameter that affects the position of the curve along the ordinate axis.

a - If b > 0, value of the function for x going towards -∞. If b < 0, value of the function for x going towards +∞.

n - Parameter that affects near which asymptote the maximum growth occurs.

Throws:

NotStrictlyPositiveException - if n <= 0.

Method Detail

value

public double value(double x)

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.

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)

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

Since:

3.1