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Java > Open Source Codes > 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 }
80
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