public class Sigmoid extends java.lang.Object implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction
logit
function.
A more flexible version, the generalised logistic, is implemented
by the Logistic
class.Modifier and Type | Class and 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
|
Modifier and Type | Field and Description |
---|---|
private double |
hi
Higher asymptote.
|
private double |
lo
Lower asymptote.
|
Constructor and Description |
---|
Sigmoid()
Usual sigmoid function, where the lower asymptote is 0 and the higher
asymptote is 1.
|
Sigmoid(double lo,
double hi)
Sigmoid function.
|
Modifier and Type | Method and Description |
---|---|
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.
|
private static double |
value(double x,
double lo,
double hi) |
private final double lo
private final double hi
public Sigmoid()
public Sigmoid(double lo, double hi)
lo
- Lower asymptote.hi
- Higher asymptote.@Deprecated public UnivariateFunction derivative()
value(DerivativeStructure)
derivative
in interface DifferentiableUnivariateFunction
public double value(double x)
value
in interface UnivariateFunction
x
- Point at which the function value should be computed.private static double value(double x, double lo, double hi)
x
- Value at which to compute the sigmoid.lo
- Lower asymptote.hi
- Higher asymptote.x
.public DerivativeStructure value(DerivativeStructure t) throws DimensionMismatchException
UnivariateDifferentiableFunction
classes compute both the
value and the first derivative of the function.
value
in interface UnivariateDifferentiableFunction
t
- function input valueDimensionMismatchException
- if t is inconsistent with the
function's free parameters or order