01: /*
02: * (c) Copyright 2006 by Volker Bergmann. All rights reserved.
03: *
04: * Redistribution and use in source and binary forms, with or without
05: * modification, is permitted under the terms of the
06: * GNU General Public License.
07: *
08: * For redistributing this software or a derivative work under a license other
09: * than the GPL-compatible Free Software License as defined by the Free
10: * Software Foundation or approved by OSI, you must first obtain a commercial
11: * license to this software product from Volker Bergmann.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
14: * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
15: * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
16: * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
17: * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
18: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
20: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
21: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
22: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
23: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24: * POSSIBILITY OF SUCH DAMAGE.
25: */
26:
27: package org.databene.benerator.primitive.number.distribution;
28:
29: import org.databene.benerator.WeightFunction;
30:
31: /**
32: * Exponential function. a * e^bx.<br/>
33: * <br/>
34: * Created: 04.09.2006 23:25:20
35: */
36: public class ExponentialFunction implements WeightFunction {
37:
38: private double a;
39: private double b;
40:
41: public ExponentialFunction(double a, double b) {
42: this .a = a;
43: this .b = b;
44: }
45:
46: public double value(double param) {
47: return a * Math.exp(b * param);
48: }
49:
50: public String toString() {
51: return getClass().getSimpleName() + '[' + a + "*e^(" + b
52: + "x)]";
53: }
54: }
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