01: /* ===========================================================
02: * JFreeChart : a free chart library for the Java(tm) platform
03: * ===========================================================
04: *
05: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
06: *
07: * Project Info: http://www.jfree.org/jfreechart/index.html
08: *
09: * 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: * A function of the form y = a * x ^ b.
47: */
48: public class PowerFunction2D implements Function2D {
49:
50: /** The 'a' coefficient. */
51: private double a;
52:
53: /** The 'b' coefficient. */
54: private double b;
55:
56: /**
57: * Creates a new power function.
58: *
59: * @param a the 'a' coefficient.
60: * @param b the 'b' coefficient.
61: */
62: public PowerFunction2D(double a, double b) {
63: this .a = a;
64: this .b = b;
65: }
66:
67: /**
68: * Returns the value of the function for a given input ('x').
69: *
70: * @param x the x-value.
71: *
72: * @return The value.
73: */
74: public double getValue(double x) {
75: return this.a * Math.pow(x, this.b);
76: }
77:
78: }
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