Class Logistic
- java.lang.Object
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- org.apache.commons.math3.analysis.function.Logistic
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- All Implemented Interfaces:
DifferentiableUnivariateFunction
,UnivariateDifferentiableFunction
,UnivariateFunction
public class Logistic extends java.lang.Object implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction
Generalised logistic function.- Since:
- 3.0
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Logistic.Parametric
Parametric function where the input array contains the parameters of thelogistic function
, ordered as follows: k m b q a n
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Field Summary
Fields Modifier and Type Field Description private double
a
Lower asymptote.private double
b
Growth rate.private double
k
Upper asymptote.private double
m
Abscissa of maximum growth.private double
oneOverN
Parameter that affects near which asymptote maximum growth occurs.private double
q
Parameter that affects the position of the curve along the ordinate axis.
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Constructor Summary
Constructors Constructor Description Logistic(double k, double m, double b, double q, double a, double n)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description UnivariateFunction
derivative()
Deprecated.as of 3.1, replaced byvalue(DerivativeStructure)
double
value(double x)
Compute the value of the function.private static double
value(double mMinusX, double k, double b, double q, double a, double oneOverN)
DerivativeStructure
value(DerivativeStructure t)
Simple mathematical function.
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Field Detail
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a
private final double a
Lower asymptote.
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k
private final double k
Upper asymptote.
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b
private final double b
Growth rate.
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oneOverN
private final double oneOverN
Parameter that affects near which asymptote maximum growth occurs.
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q
private final double q
Parameter that affects the position of the curve along the ordinate axis.
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m
private final double m
Abscissa of maximum growth.
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Constructor Detail
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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
.
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Method Detail
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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.
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derivative
@Deprecated public UnivariateFunction derivative()
Deprecated.as of 3.1, replaced byvalue(DerivativeStructure)
Returns the derivative of the function- Specified by:
derivative
in interfaceDifferentiableUnivariateFunction
- Returns:
- the derivative function
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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.
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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 interfaceUnivariateDifferentiableFunction
- Parameters:
t
- function input value- Returns:
- function result
- Since:
- 3.1
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