Source for org.jfree.data.function.PowerFunction2D

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2007, 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 2002-2007, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * Changes:
  36:  * --------
  37:  * 01-Oct-2002 : Version 1 (DG);
  38:  *
  39:  */
  40: 
  41: package org.jfree.data.function;
  42: 
  43: 
  44: /**
  45:  * A function of the form y = a * x ^ b.
  46:  */
  47: public class PowerFunction2D implements Function2D {
  48: 
  49:     /** The 'a' coefficient. */
  50:     private double a;
  51: 
  52:     /** The 'b' coefficient. */
  53:     private double b;
  54: 
  55:     /**
  56:      * Creates a new power function.
  57:      *
  58:      * @param a  the 'a' coefficient.
  59:      * @param b  the 'b' coefficient.
  60:      */
  61:     public PowerFunction2D(double a, double b) {
  62:         this.a = a;
  63:         this.b = b;
  64:     }
  65: 
  66:     /**
  67:      * Returns the value of the function for a given input ('x').
  68:      *
  69:      * @param x  the x-value.
  70:      *
  71:      * @return The value.
  72:      */
  73:     public double getValue(double x) {
  74:         return this.a * Math.pow(x, this.b);
  75:     }
  76: 
  77: }