/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
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*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
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*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
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* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.learner.functions.kernel.rvm.kernel;
/**
* Returns the value of the Gaussian combination kernel of both examples.
*
* @author Ingo Mierswa
* @version $Id: KernelGaussianCombination.java,v 1.3 2008/05/09 19:23:26 ingomierswa Exp $
*/
public class KernelGaussianCombination extends Kernel {
private static final long serialVersionUID = -8071778790596969872L;
/** The parameter sigma1 of the Gaussian combination kernel. */
private double sigma1 = 1.0d;
/** The parameter sigma2 of the Gaussian combination kernel. */
private double sigma2 = 0.0d;
/** The parameter sigma3 of the Gaussian combination kernel. */
private double sigma3 = 2.0d;
/** Constructor(s) */
public KernelGaussianCombination(double sigma1, double sigma2, double sigma3) {
super();
this.sigma1 = sigma1;
this.sigma2 = sigma2;
this.sigma3 = sigma3;
}
public KernelGaussianCombination() {
super();
}
public double eval(double[] x, double[] y) {
double norm2 = norm2(x, y);
double exp1 = sigma1 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma1);
double exp2 = sigma2 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma2);
double exp3 = sigma3 == 0.0d ? 0.0d : Math.exp((-1) * norm2 / sigma3);
return exp1 + exp2 - exp3;
}
public String toString() {
return "gaussian combination kernel [sigma1 = " + sigma1 + ", sigma2 = " + sigma2 + ", sigma3 = " + sigma3 + "]";
}
}