Package org.apache.commons.math4.neuralnet.sofm

Class KohonenUpdateAction

java.lang.Object

org.apache.commons.math4.neuralnet.sofm.KohonenUpdateAction

All Implemented Interfaces:

UpdateAction

public class KohonenUpdateAction
extends Object
implements UpdateAction

Update formula for Kohonen's Self-Organizing Map.
The update method modifies the features w of the "winning" neuron and its neighbours according to the following rule: wnew = wold + α e(-d / σ) * (sample - wold) where

• α is the current learning rate,
• σ is the current neighbourhood size, and
• d is the number of links to traverse in order to reach the neuron from the winning neuron.

This class is thread-safe as long as the arguments passed to the constructor are instances of thread-safe classes.
Each call to the update method will increment the internal counter used to compute the current values for

• the learning rate, and
• the neighbourhood size.

Consequently, the function instances that compute those values (passed to the constructor of this class) must take into account whether this class's instance will be shared by multiple threads, as this will impact the training process.

Since:

3.3

Constructor Summary

Constructors

Constructor	Description
KohonenUpdateAction(DistanceMeasure distance, LearningFactorFunction learningFactor, NeighbourhoodSizeFunction neighbourhoodSize)

Method Summary

Modifier and Type	Method	Description
long	getNumberOfCalls()	Retrieves the number of calls to the update method.
void	update(Network net, double[] features)	Updates the network in response to the sample features.

Methods inherited from class java.lang.Object

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

Constructor Detail

KohonenUpdateAction

public KohonenUpdateAction(DistanceMeasure distance,
                           LearningFactorFunction learningFactor,
                           NeighbourhoodSizeFunction neighbourhoodSize)

Parameters:

distance - Distance function.

learningFactor - Learning factor update function.

neighbourhoodSize - Neighbourhood size update function.

Method Detail

update

public void update(Network net,
                   double[] features)

Updates the network in response to the sample features.

Specified by:

update in interface UpdateAction

Parameters:

net - Network.

features - Training data.

getNumberOfCalls

public long getNumberOfCalls()

Retrieves the number of calls to the update method.

Returns:

the current number of calls.