Package org.hipparchus.analysis.function

Class Sigmoid

java.lang.Object
org.hipparchus.analysis.function.Sigmoid
All Implemented Interfaces:
UnivariateDifferentiableFunction, UnivariateFunction
public class Sigmoid extends Object implements UnivariateDifferentiableFunction
Sigmoid function. It is the inverse of the logit function. A more flexible version, the generalised logistic, is implemented by the Logistic class.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    Sigmoid.Parametric
    Parametric function where the input array contains the parameters of the sigmoid function, ordered as follows: Lower asymptote Higher asymptote

  • Constructor Summary

    Constructors
    Constructor
    Description
    Sigmoid()
    Usual sigmoid function, where the lower asymptote is 0 and the higher asymptote is 1.
    Sigmoid(double lo, double hi)
    Sigmoid function.

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    value(double x)
    Compute the value of the function.
    <T extends Derivative<T>>
    T
    value(T t)
    Compute the value for the function.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • 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.

  • 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.

    • value

      public <T extends Derivative<T>> T value(T t) throws MathIllegalArgumentException
      Compute the value for the function.
      Specified by:
      value in interface UnivariateDifferentiableFunction
      Type Parameters:
      T - the type of the field elements
      Parameters:
      t - the point for which the function value should be computed
      Returns:
      the value
      Throws:
      MathIllegalArgumentException - if x does not satisfy the function's constraints (argument out of bound, or unsupported derivative order for example)