lnsc
Class LogisticUnit

java.lang.Object
  |
  +--lnsc.AbstractFunctionalUnit
        |
        +--lnsc.AbstractSimpleUnit
              |
              +--lnsc.LogisticUnit

All Implemented Interfaces:

java.lang.Cloneable, FunctionalUnit, java.io.Serializable

public final class LogisticUnit

extends AbstractSimpleUnit

A sigmoidal logistic unit. Principally used as unit in neural networks. It has the form: f(x) = factor*(1/(1+exp(-(mu-x)/beta)))) + offset or: f(x) = factor*(1/(1+exp(-alpha*(mu-x)))) + offset. mu is called the half-maximum point of the function and beta is called the slope.

Since:

1.0

See Also:

Serialized Form

Nested Class Summary

Nested classes inherited from class lnsc.FunctionalUnit

FunctionalUnit.ProcessPatternResult

Field Summary

Fields inherited from interface lnsc.FunctionalUnit

EMPTY_PATTERN

Constructor Summary

LogisticUnit()
Creates a simple logistic unit with Factor=1.0 and Offset=0.0, Mu=0.0 and Beta=1.0.

LogisticUnit(double newFactor, double newOffset)
Creates a simple logistic unit with given factor and offset and Mu=0.0 and Beta=1.0.

LogisticUnit(double newFactor, double newOffset, double newMu, double newBeta)
Creates a simple logistic unit with given factor, offset, half-maximum point (Mu) and slope (beta).

Method Summary

double	getAlpha() Returns the current value of parameter alpha.
double	getBeta() Returns the current value of parameter beta.
double	getMu() Returns the current value of parameter mu.
void	setAlpha(double newAlpha) Sets the current value of parameter alpha.
void	setBeta(double newBeta) Sets the current value of parameter beta.
void	setMu(double newMu) Sets the current value of parameter mu.
java.lang.String	toString()

Methods inherited from class lnsc.AbstractSimpleUnit

getFactor, getOffset, processPattern, setFactor, setOffset

Methods inherited from class lnsc.AbstractFunctionalUnit

clone, getInputCount, getOutputCount, isDifferentiable, isStateless, isTwiceDifferentiable, processDataSet, reset

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LogisticUnit

public LogisticUnit()

Creates a simple logistic unit with Factor=1.0 and Offset=0.0, Mu=0.0 and Beta=1.0. That is, with output range between 0.0 and 1.0.

LogisticUnit

public LogisticUnit(double newFactor,
                    double newOffset)

Creates a simple logistic unit with given factor and offset and Mu=0.0 and Beta=1.0. That is, with range between Offset and Factor+Offset.

Parameters:

newFactor - Function factor.

newOffset - Function offset.

LogisticUnit

public LogisticUnit(double newFactor,
                    double newOffset,
                    double newMu,
                    double newBeta)

Creates a simple logistic unit with given factor, offset, half-maximum point (Mu) and slope (beta). That is, with range between Offset and Factor+Offset.

Parameters:

newFactor - Function factor.

newOffset - Function offset.

newMu - Half-maximum point.

newBeta - Slope, must be positive.

Method Detail

getAlpha

public final double getAlpha()

Returns the current value of parameter alpha. Alpha = 1/Beta

Returns:

Value of alpha.

getBeta

public final double getBeta()

Returns the current value of parameter beta. Beta is called the slope of the function.

Returns:

Value of beta.

getMu

public final double getMu()

Returns the current value of parameter mu. Mu is the half-maximum point of the logistic function.

Returns:

Value of mu.

setAlpha

public final void setAlpha(double newAlpha)

Sets the current value of parameter alpha. Alpha = 1/Beta

Parameters:

newAlpha - The new value of alpha, must be positive.

setBeta

public final void setBeta(double newBeta)

Sets the current value of parameter beta. Beta is called the slope of the function.

Parameters:

newBeta - The new value of beta, must be positive.

setMu

public final void setMu(double newMu)

Sets the current value of parameter mu. Mu is the half-maximum point of the logistic function.

Parameters:

newMu - The new value of mu.

toString

public java.lang.String toString()

Overrides:

toString in class AbstractSimpleUnit