/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* 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
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
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* 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 Multiquadric kernel of both examples.
*
* @author Ingo Mierswa
* @version $Id: KernelMultiquadric.java,v 1.3 2008/05/09 19:23:26 ingomierswa Exp $
*/
public class KernelMultiquadric extends Kernel {
private static final long serialVersionUID = -5537408210606781153L;
/** The parameter sigma of the Multiquadric kernel. */
private double sigma = 1.0d;
/** The parameter shift of the multiquadric kernel. */
private double shift = 1.0d;
/** Constructor(s) */
public KernelMultiquadric(double sigma, double shift) {
super();
this.sigma = sigma;
this.shift = shift;
}
public KernelMultiquadric() {
super();
}
public double eval(double[] x, double[] y) {
return Math.sqrt((norm2(x, y) / sigma) + (shift * shift));
}
public String toString() {
return "multiquadric kernel [sigma = " + sigma + ", shift = " + shift + "]";
}
}