/**
* Copyright 2010 Neuroph Project http://neuroph.sourceforge.net
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.neuroph.nnet.learning;
import org.neuroph.core.Connection;
import org.neuroph.core.NeuralNetwork;
import org.neuroph.core.Neuron;
import org.neuroph.core.learning.SupervisedTrainingElement;
/**
* Supervised hebbian learning rule.
* @author Zoran Sevarac <sevarac@gmail.com>
*/
public class SupervisedHebbianLearning extends LMS {
/**
* The class fingerprint that is set to indicate serialization
* compatibility with a previous version of the class.
*/
private static final long serialVersionUID = 1L;
/**
* Creates new instance of SupervisedHebbianLearning algorithm
*/
public SupervisedHebbianLearning() {
super();
}
/**
* Learn method override without network error and iteration limit
* Implements just one pass through the training set Used for testing -
* debugging algorithm
*
* public void learn(TrainingSet trainingSet) { Iterator
* iterator=trainingSet.iterator(); while(iterator.hasNext()) {
* SupervisedTrainingElement trainingElement =
* (SupervisedTrainingElement)iterator.next();
* this.learnPattern(trainingElement); } }
*/
/**
* Trains network with the pattern from the specified training element
*
* @param trainingElement
* supervised training element which contains input and desired
* output
*/
@Override
protected void learnPattern(SupervisedTrainingElement trainingElement) {
double[] input = trainingElement.getInput();
this.neuralNetwork.setInput(input);
this.neuralNetwork.calculate();
double[] output = this.neuralNetwork.getOutput();
double[] desiredOutput = trainingElement.getDesiredOutput();
double[] patternError = this.getPatternError(output, desiredOutput);
this.updateTotalNetworkError(patternError);
this.updateNetworkWeights(desiredOutput);
}
/**
* This method implements weight update procedure for the whole network for
* this learning rule
*
* @param desiredOutput
* desired network output
*/
@Override
protected void updateNetworkWeights(double[] desiredOutput) {
int i = 0;
for (Neuron neuron : neuralNetwork.getOutputNeurons()) {
this.updateNeuronWeights(neuron, desiredOutput[i]);
i++;
}
}
/**
* This method implements weights update procedure for the single neuron
*
* @param neuron
* neuron to update weights
* desiredOutput
* desired output of the neuron
*/
protected void updateNeuronWeights(Neuron neuron, double desiredOutput) {
for (Connection connection : neuron.getInputConnections()) {
double input = connection.getInput();
double deltaWeight = input * desiredOutput * this.learningRate;
connection.getWeight().inc(deltaWeight);
}
}
}