/*
* 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.tools.math.similarity.nominal;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.tools.math.similarity.DistanceMeasure;
/**
* A distance measure for nominal values accounting a value of one if two values are unequal.
*
* @author Sebastian Land, Michael Wurst
* @version $Id: NominalDistance.java,v 1.1 2008/08/05 09:40:31 stiefelolm Exp $
*/
public class NominalDistance extends DistanceMeasure {
public double calculateDistance(double[] value1, double[] value2) {
double sum = 0.0;
int counter = 0;
for (int i = 0; i < value1.length; i++) {
if ((!Double.isNaN(value1[i])) && (!Double.isNaN(value2[i]))) {
if (value1[i] != value2[i])
sum = sum + 1.0;
counter++;
}
}
if (counter > 0)
return sum;
else
return Double.NaN;
}
public double calculateSimilarity(double[] value1, double[] value2) {
return -calculateDistance(value1, value2);
}
// doing nothing
public void init(ExampleSet exampleSet) {}
}