/*
 * Encog(tm) Core v3.0 - Java Version
 * http://www.heatonresearch.com/encog/
 * http://code.google.com/p/encog-java/
 
 * Copyright 2008-2011 Heaton Research, Inc.
 *
 * 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.
 *   
 * For more information on Heaton Research copyrights, licenses 
 * and trademarks visit:
 * http://www.heatonresearch.com/copyright
 */
package org.encog.neural.pattern;

import org.encog.engine.network.activation.ActivationFunction;
import org.encog.ml.MLMethod;
import org.encog.neural.som.SOM;

/**
 * A self organizing map is a neural network pattern with an input and output
 * layer. There is no hidden layer. The winning neuron, which is that neuron
 * with the higest output is the winner, this winning neuron is often used to
 * classify the input into a group.
 * 
 * @author jheaton
 * 
 */
public class SOMPattern implements NeuralNetworkPattern {

	/**
	 * The number of input neurons.
	 */
	private int inputNeurons;

	/**
	 * The number of output neurons.
	 */
	private int outputNeurons;

	/**
	 * Add a hidden layer. SOM networks do not have hidden layers, so this will
	 * throw an error.
	 * 
	 * @param count
	 *            The number of hidden neurons.
	 */
	public final void addHiddenLayer(final int count) {
		throw new PatternError( "A SOM network does not have hidden layers." );
	}

	/**
	 * Clear out any hidden neurons.
	 */
	public void clear() {
	}

	/**
	 * Generate the RSOM network.
	 * 
	 * @return The neural network.
	 */
	public final MLMethod generate() {
		SOM som = new SOM(this.inputNeurons,this.outputNeurons);
		som.reset();
		return som;
	}

	/**
	 * Set the activation function. A SOM uses a linear activation function, so
	 * this method throws an error.
	 * 
	 * @param activation
	 *            The activation function to use.
	 */
	public final void setActivationFunction(final ActivationFunction activation) {
		throw new PatternError( "A SOM network can't define an activation function.");

	}

	/**
	 * Set the input neuron count.
	 * 
	 * @param count
	 *            The number of neurons.
	 */
	public final void setInputNeurons(final int count) {
		this.inputNeurons = count;

	}

	/**
	 * Set the output neuron count.
	 * 
	 * @param count
	 *            The number of neurons.
	 */
	public final void setOutputNeurons(final int count) {
		this.outputNeurons = count;
	}
}
