/*
* 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,
* 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.similarity.attributebased;
/**
* A variant of the Dice coefficient defined for numeric attributes.
*
* @author Michael Wurst
* @version $Id: DiceNumericalSimilarity.java,v 1.5 2008/09/12 10:30:47 tobiasmalbrecht Exp $
*/
public class DiceNumericalSimilarity extends AbstractRealValueBasedSimilarity {
private static final long serialVersionUID = 7556034451164266813L;
public double similarity(double[] e1, double[] e2) {
double wxy = 0.0;
double wx = 0.0;
double wy = 0.0;
for (int i = 0; i < e1.length; i++) {
if ((!Double.isNaN(e1[i])) && (!Double.isNaN(e2[i]))) {
wx = wx + e1[i];
wy = wy + e2[i];
wxy = wxy + e1[i] * e2[i];
}
}
return 2 * wxy / (wx + wy);
}
public boolean isDistance() {
return false;
}
}