Source for org.jfree.data.function.PowerFunction2D

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   6:  *
   7:  * Project Info:  http://www.jfree.org/jfreechart/index.html
   8:  *
   9:  * This library is free software; you can redistribute it and/or modify it 
  10:  * under the terms of the GNU Lesser General Public License as published by 
  11:  * the Free Software Foundation; either version 2.1 of the License, or 
  12:  * (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but 
  15:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
  16:  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
  17:  * License for more details.
  18:  *
  19:  * You should have received a copy of the GNU Lesser General Public
  20:  * License along with this library; if not, write to the Free Software
  21:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
  22:  * USA.  
  23:  *
  24:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
  25:  * in the United States and other countries.]
  26:  *
  27:  * --------------------
  28:  * PowerFunction2D.java
  29:  * --------------------
  30:  * (C) Copyright 2002-2005, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: PowerFunction2D.java,v 1.3.2.1 2005/10/25 21:31:32 mungady Exp $
  36:  *
  37:  * Changes:
  38:  * --------
  39:  * 01-Oct-2002 : Version 1 (DG);
  40:  *
  41:  */
  42: 
  43: package org.jfree.data.function;
  44: 
  45: 
  46: /**
  47:  * A function of the form y = a * x ^ b.
  48:  */
  49: public class PowerFunction2D implements Function2D {
  50: 
  51:     /** The 'a' coefficient. */
  52:     private double a;
  53: 
  54:     /** The 'b' coefficient. */
  55:     private double b;
  56: 
  57:     /**
  58:      * Creates a new power function.
  59:      *
  60:      * @param a  the 'a' coefficient.
  61:      * @param b  the 'b' coefficient.
  62:      */
  63:     public PowerFunction2D(double a, double b) {
  64:         this.a = a;
  65:         this.b = b;
  66:     }
  67: 
  68:     /**
  69:      * Returns the value of the function for a given input ('x').
  70:      *
  71:      * @param x  the x-value.
  72:      *
  73:      * @return The value.
  74:      */
  75:     public double getValue(double x) {
  76:         return this.a * Math.pow(x, this.b);
  77:     }
  78: 
  79: }