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Java > Open Source Codes > org > jfree > data > PowerFunction2D


1 /* ======================================
2  * JFreeChart : a free Java chart library
3  * ======================================
4  *
5  * Project Info: http://www.jfree.org/jfreechart/index.html
6  * Project Lead: David Gilbert (david.gilbert@object-refinery.com);
7  *
8  * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
9  *
10  * This library is free software; you can redistribute it and/or modify it under the terms
11  * of the GNU Lesser General Public License as published by the Free Software Foundation;
12  * either version 2.1 of the License, or (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
15  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16  * See the GNU Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public License along with this
19  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20  * Boston, MA 02111-1307, USA.
21  *
22  * --------------------
23  * PowerFunction2D.java
24  * --------------------
25  * (C) Copyright 2002, 2003, by Object Refinery Limited.
26  *
27  * Original Author: David Gilbert (for Object Refinery Limited);
28  * Contributor(s): -;
29  *
30  * $Id: PowerFunction2D.java,v 1.2 2003/06/04 22:58:28 mungady Exp $
31  *
32  * Changes:
33  * --------
34  * 01-Oct-2002 : Version 1 (DG);
35  *
36  */

37
38 package org.jfree.data;
39
40 /**
41  * A function of the form y = a * x ^ b.
42  *
43  * @author David Gilbert
44  */

45 public class PowerFunction2D implements Function2D {
46
47     /** The 'a' coefficient. */
48     private double a;
49
50     /** The 'b' coefficient. */
51     private double b;
52
53     /**
54      * Creates a new power function.
55      *
56      * @param a the 'a' coefficient.
57      * @param b the 'b' coefficient.
58      */

59     public PowerFunction2D(double a, double b) {
60         this.a = a;
61         this.b = b;
62     }
63
64     /**
65      * Returns the value of the function for a given input ('x').
66      *
67      * @param x the x-value.
68      *
69      * @return the value.
70      */

71     public double getValue(double x) {
72         return a * Math.pow(x, b);
73     }
74
75 }
76
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