/*
* 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.som;
/**
* This class provides a distance measure, equivalent to the
* euclidian distance measure.
*
* @author Sebastian Land
* @version $Id: EuclideanDistance.java,v 1.5 2008/06/18 14:28:36 stiefelolm Exp $
*/
public class EuclideanDistance implements DistanceFunction{
private static final long serialVersionUID = 1127224325142026906L;
public double getDistance(double[] point1, double[] point2) {
double distance = 0;
for (int i = 0; i < point1.length; i++){
distance += Math.pow((point1[i] - point2[i]), 2);
}
distance = Math.sqrt(distance);
if (!Double.isNaN(distance)) {
return distance;
} else {
distance = 0;
for (int i = 0; i < point1.length; i++){
double currentDistance = Math.pow((point1[i] - point2[i]), 2);
if (!Double.isNaN(currentDistance)) {
distance += currentDistance;
}
}
return Math.sqrt(distance);
}
}
public double getDistance(int[] point1, int[] point2) {
double distance = 0;
for (int i = 0; i < point1.length; i++){
distance += Math.pow(point1[i] - point2[i], 2);
}
distance = Math.sqrt(distance);
return distance;
}
/** Integer distance calculation regards the wrap around of the net (hypertorus) */
public double getDistance(int[] point1, int[] point2, int[] dimensions) {
double distance = 0;
for (int i = 0; i < point1.length; i++){
int coord1 = (point1[i] < 0)? dimensions[i] + point1[i]:point1[i]; //wrapping around if incoming coordinate is negative
int coord2 = (point2[i] < 0)? dimensions[i] + point2[i]:point2[i];
distance += Math.pow(Math.min(Math.abs(coord1 - coord2),(coord1 + dimensions[i]- coord2) % dimensions[i]), 2);
}
distance = Math.sqrt(distance);
return distance;
}
}