/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.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, 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.
*
* You should have received a copy of the GNU Affero General Public License 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
*/
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();
}
@Override
public double eval(double[] x, double[] y) {
return Math.sqrt((norm2(x, y) / sigma) + (shift * shift));
}
@Override
public String toString() {
return "multiquadric kernel [sigma = " + sigma + ", shift = " + shift + "]";
}
}