## org.apache.commons.math3.analysis.function Class Logistic

```java.lang.Object org.apache.commons.math3.analysis.function.Logistic
```
All Implemented Interfaces:
DifferentiableUnivariateFunction, UnivariateDifferentiableFunction, UnivariateFunction

`public class Logisticextends Objectimplements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction`

Generalised logistic function.

Since:
3.0
Version:
\$Id: Logistic.java 1391927 2012-09-30 00:03:30Z erans \$

Nested Class Summary
`static class` `Logistic.Parametric`
Parametric function where the input array contains the parameters of the logit function, ordered as follows: Lower asymptote Higher asymptote

Constructor Summary
```Logistic(double k, double m, double b, double q, double a, double n)```

Method Summary
` 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.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### Logistic

```public Logistic(double k,
double m,
double b,
double q,
double a,
double n)
throws NotStrictlyPositiveException```
Parameters:
`k` - If `b > 0`, value of the function for x going towards +∞. If `b < 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` - If `b > 0`, value of the function for x going towards -∞. If `b < 0`, value of the function for x going towards +∞.
`n` - Parameter that affects near which asymptote the maximum growth occurs.
Throws:
`NotStrictlyPositiveException` - if `n <= 0`.
Method Detail

### 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.

### derivative

```@Deprecated
public UnivariateFunction derivative()```
Deprecated. as of 3.1, replaced by `value(DerivativeStructure)`

Returns the derivative of the function

Specified by:
`derivative` in interface `DifferentiableUnivariateFunction`
Returns:
the derivative function

### 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 interface `UnivariateDifferentiableFunction`
Parameters:
`t` - function input value
Returns:
function result
Since:
3.1

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