/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 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.tools.math.som;

import java.io.Serializable;

/**
 * This interface defines the methods of an distance measure class. 
 * All three methods should return the same distance if equivalent inputs are
 * given. The third method should regard the wrap around, as if there were no bounds,
 * instead point (0,0) should be neighbour of point (n,n)!
 * 
 * @author Sebastian Land
 */
public interface DistanceFunction extends Serializable {
	
	 /**
	  * This method returns the distance between point1 and point2. 
	  * The dimenson of the points is represented by the length of the
	  * arrays. This method should return the same value as the method 
	  * below, if points are equivalent!
	  */
	public double getDistance(double[] point1, double[] point2);
	
	 /**
	  * This method returns the distance between point1 and point2. 
	  * The dimenson of the points is represented by the length of the
	  * arrays. This method should return the same value as the method 
	  * above, if points are equivalent!
	  */
	public double getDistance(int[] point1, int[] point2);
	
	/**
	 *	This method returns the distance between point1 and point2.
	 *  The dimsion of the points is represented by the length of the
	 *  arrays. This method has to be aware of the size of each dimension!
	 *  Points on the border are neighbours to the point at the opposite site!
	 *  As example: (0, x) is neighbour of (dimensions[0], x), too. Hence, the
	 *  resulting distance is 1. 
	 */
	public double getDistance(int[] point1, int[] point2, int[] dimensions);
}