FuzzyNumberTRIANG.java

/***********************************************************************

	This file is part of KEEL-software, the Data Mining tool for regression, 
	classification, clustering, pattern mining and so on.

	Copyright (C) 2004-2010
	
	F. Herrera (herrera@decsai.ugr.es)
    L. S�nchez (luciano@uniovi.es)
    J. Alcal�-Fdez (jalcala@decsai.ugr.es)
    S. Garc�a (sglopez@ujaen.es)
    A. Fern�ndez (alberto.fernandez@ujaen.es)
    J. Luengo (julianlm@decsai.ugr.es)

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU 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 General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see http://www.gnu.org/licenses/
  
**********************************************************************/

package keel.Algorithms.Fuzzy_Rule_Learning.Shared.Fuzzy;


/** 
* <p> 
* Represents a triangular fuzzy number. The support member with membership value of 1.0 is the center 
* and left and right represent the extremes of the triangular fuzzy number.
* </p>
* 
* <p> 
* @author Written by Luciano S�nchez (University of Oviedo) 20/01/2004
* @author Modified by Enrique A. de la Cal (University of Oviedo) 13/12/2008  
* @version 1.0 
* @since JDK1.4 
* </p> 
*/
public class FuzzyNumberTRIANG extends Fuzzy {
	//The extremes and center of the triangular fuzzy number.
    double left, center, right;
    /** 
     * <p> 
     * A constructor for a triangle fuzzy set, given the extremes. 
     * 
     * </p> 
     * @param l the lower extreme of the triangular fuzzy number.
     * @param c the center element of the triangular fuzzy number.
     * @param r the upper extreme of the triangular fuzzy number.
     */
    public FuzzyNumberTRIANG(double l, double c, double r) {
        left=l; center=c; right=r;
    }
    /** 
     * <p> 
     * A copy constructor for a triangular fuzzy number, given other triangular fuzzy number. 
     * 
     * </p> 
     * @param t to be copied.    
     */
    public FuzzyNumberTRIANG(FuzzyNumberTRIANG t) {
        left=t.left; center=t.center; right=t.right;
    }
    /** 
     * <p> 
     * Copies the FuzzyNumberTRIANG parameter over the present instance. 
     * 
     * </p> 
     * @param t a FuzzyNumberTRIANG object to be copied
     */
    public void Asigna(FuzzyNumberTRIANG t) {
        left=t.left; center=t.center; right=t.right;
    }
    /** 
     * <p> 
     *  Indicates whether some other object is "equal to" this one.
     * 
     * </p>
     * @param b the reference object with which to compare. 
     * @return true if this object is the same as the B argument; false otherwise. 
     */     
    public boolean equals(Fuzzy b) {
        if (!(b instanceof FuzzyNumberTRIANG)) return false;
        FuzzyNumberTRIANG bt=(FuzzyNumberTRIANG) b;
        if (left!=bt.left) return false;
        if (center!=bt.center) return false;
        if (right!=bt.right) return false;
        return true;
    }
    /** 
     * <p> 
     * Creates and returns a copy of this object.
     * 
     * </p>
     * @return a clone of this instance. 
     */     
    public Fuzzy clone() {
        return new FuzzyNumberTRIANG(this);
    }   
    /** 
     * <p> 
     *  Returns the membership level for the individual x.
     *  
     * 
     * </p>
     * @param x the individual which membership is to be calculated. 
     * @return the membership level for individual x. 
     */ 
    public double evaluateMembership(double x) {
        if (x<left) return 0;
        if (x<center) return 1-(center-x)/(center-left);
        if (x<right) return (right-x)/(right-center);
        return 0;
    }
    /** 
     * <p> 
     *  Returns the centroid of the present fuzzy number. 	
     *  
     * </p>
     * @return the centroid of the present fuzzy number. 
     */  
    public double massCentre() {
        return center;
    }
    /** 
     * <p> 
     *  Creates and returns a FuzzyInterval with the extremes of the support set.
     *  
     * </p> 
     * @return an interval with the extremes of the support set. 
     */ 
    public FuzzyInterval support() {
        return new FuzzyInterval(left,right);
    }
    /** 
     * <p> 
     *  Returns a printable version of the instance.   	
     *
     * </p>
     
     * @return a String with a printable version of the triangular fuzzy number. 
     */	
    public String aString() {
        return "TRIAN("+left+","+center+","+right+")";
    }
   }