org.apache.commons.math3.analysis.function

Class Logistic

java.lang.Object

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

All Implemented Interfaces:

DifferentiableUnivariateFunction, UnivariateFunction

public class Logistic
extends Object
implements DifferentiableUnivariateFunction

Generalised logistic function.

Since:

3.0

Version:

$Id$

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
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

Constructors

Constructor and Description
Logistic(double k, double m, double b, double q, double a, double n)

Method Summary

Methods

Modifier and Type	Method and Description
UnivariateFunction	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

Logistic

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

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

public UnivariateFunction derivative()

Returns the derivative of the function

Specified by:

derivative in interface DifferentiableUnivariateFunction

Returns:

the derivative function