Package 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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Logistic.Parametric	Parametric function where the input array contains the parameters of the logistic function, ordered as follows: k m b q a n

Constructor Summary

Constructors

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

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Details

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 Details

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