QuasiSigmoidDecayFunction (Apache Commons Math 4.0-SNAPSHOT)

java.lang.Object
- org.apache.commons.math4.neuralnet.sofm.util.QuasiSigmoidDecayFunction

All Implemented Interfaces:

LongToDoubleFunction
```
public class QuasiSigmoidDecayFunction
extends Object
implements LongToDoubleFunction
```
Decay function whose shape is similar to a sigmoid.
Class is immutable.

Since:

3.3

- Constructor Summary
  
  Constructors
  Constructor Description
  
  QuasiSigmoidDecayFunction(double initValue, double slope, long numCall)
  Creates an instance.
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  double applyAsDouble(long numCall)
  Computes the value of the learning factor.
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - QuasiSigmoidDecayFunction
```
public QuasiSigmoidDecayFunction(double initValue,
                                 double slope,
                                 long numCall)
```
    Creates an instance. The function f will have the following properties:
    
    f(0) = initValue
    
    numCall is the inflexion point
    
    slope = f'(numCall)
    Parameters:
    
    initValue - Initial value, i.e. applyAsDouble(0).
    
    slope - Value of the function derivative at numCall.
    
    numCall - Inflexion point.
    
    Throws:
    
    IllegalArgumentException - if initValue <= 0, slope >= 0 or numCall <= 0.
- Method Detail
  - applyAsDouble
```
public double applyAsDouble(long numCall)
```
    Computes the value of the learning factor.
    
    Specified by:
    
    applyAsDouble in interface LongToDoubleFunction
    
    Parameters:
    
    numCall - Current step of the training task.
    
    Returns:
    
    the value of the function at numCall.