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 ClassesModifier and TypeClassDescriptionstatic class
Parametric function where the input array contains the parameters of thelogistic function
, ordered as follows: k m b q a n -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final double
Lower asymptote.private final double
Growth rate.private final double
Upper asymptote.private final double
Abscissa of maximum growth.private final double
Parameter that affects near which asymptote maximum growth occurs.private final double
Parameter that affects the position of the curve along the ordinate axis. -
Constructor Summary
Constructors -
Method Summary
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Field Details
-
a
private final double aLower asymptote. -
k
private final double kUpper asymptote. -
b
private final double bGrowth rate. -
oneOverN
private final double oneOverNParameter that affects near which asymptote maximum growth occurs. -
q
private final double qParameter that affects the position of the curve along the ordinate axis. -
m
private final double mAbscissa of maximum growth.
-
-
Constructor Details
-
Logistic
public Logistic(double k, double m, double b, double q, double a, double n) throws NotStrictlyPositiveException - Parameters:
k
- Ifb > 0
, value of the function for x going towards +∞. Ifb < 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
- Ifb > 0
, value of the function for x going towards -∞. Ifb < 0
, value of the function for x going towards +∞.n
- Parameter that affects near which asymptote the maximum growth occurs.- Throws:
NotStrictlyPositiveException
- ifn <= 0
.
-
-
Method Details
-
value
public double value(double x) Compute the value of the function.- Specified by:
value
in interfaceUnivariateFunction
- Parameters:
x
- Point at which the function value should be computed.- Returns:
- the value of the function.
-
derivative
Deprecated.as of 3.1, replaced byvalue(DerivativeStructure)
Returns the derivative of the function- Specified by:
derivative
in interfaceDifferentiableUnivariateFunction
- Returns:
- the derivative function
-
value
private static double value(double mMinusX, double k, double b, double q, double a, double oneOverN) - Parameters:
mMinusX
-m - x
.k
-k
.b
-b
.q
-q
.a
-a
.oneOverN
-1 / n
.- Returns:
- the value of the function.
-
value
Simple mathematical function.UnivariateDifferentiableFunction
classes compute both the value and the first derivative of the function.- Specified by:
value
in interfaceUnivariateDifferentiableFunction
- Parameters:
t
- function input value- Returns:
- function result
- Since:
- 3.1
-
value(DerivativeStructure)