Class Sigmoid
java.lang.Object
org.apache.commons.math3.analysis.function.Sigmoid
- All Implemented Interfaces:
DifferentiableUnivariateFunction,UnivariateDifferentiableFunction,UnivariateFunction
public class Sigmoid
extends Object
implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction
Sigmoid function.
It is the inverse of the
logit function.
A more flexible version, the generalised logistic, is implemented
by the Logistic class.- Since:
- 3.0
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic classParametric function where the input array contains the parameters of thesigmoid function, ordered as follows: Lower asymptote Higher asymptote -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionDeprecated.doublevalue(double x) Compute the value of the function.Simple mathematical function.
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Constructor Details
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Sigmoid
public Sigmoid()Usual sigmoid function, where the lower asymptote is 0 and the higher asymptote is 1. -
Sigmoid
public Sigmoid(double lo, double hi) Sigmoid function.- Parameters:
lo- Lower asymptote.hi- Higher asymptote.
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Method Details
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derivative
Deprecated.as of 3.1, replaced byvalue(DerivativeStructure)Returns the derivative of the function- Specified by:
derivativein interfaceDifferentiableUnivariateFunction- Returns:
- the derivative function
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value
public double value(double x) Compute the value of the function.- Specified by:
valuein interfaceUnivariateFunction- Parameters:
x- Point at which the function value should be computed.- Returns:
- the value of the function.
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value
Simple mathematical function.UnivariateDifferentiableFunctionclasses compute both the value and the first derivative of the function.- Specified by:
valuein interfaceUnivariateDifferentiableFunction- Parameters:
t- function input value- Returns:
- function result
- Throws:
DimensionMismatchException- if t is inconsistent with the function's free parameters or order- Since:
- 3.1
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value(DerivativeStructure)