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 1391927 2012-09-30 00:03:30Z erans \$

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