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1   /*
2    * @(#)DistConstant.java Apr 3, 2003
3    * 
4    * Copyright (c) 2003 Delft University of Technology Jaffalaan 5, 2628 BX Delft,
5    * the Netherlands All rights reserved.
6    * 
7    * This software is proprietary information of Delft University of Technology
8    * The code is published under the General Public License
9    */
10  package nl.tudelft.simulation.jstats.distributions;
11  
12  import nl.tudelft.simulation.jstats.streams.StreamInterface;
13  
14  /***
15   * The Constant distribution. For more information on this distribution see <a
16   * href="http://mathworld.wolfram.com/ContinuousDistribution.html">
17   * http://mathworld.wolfram.com/ContinuousDistribution.html </a>
18   * <p>
19   * (c) copyright 2002-2004 <a href="http://www.simulation.tudelft.nl">Delft
20   * University of Technology </a>, the Netherlands. <br>
21   * See for project information <a href="http://www.simulation.tudelft.nl">
22   * www.simulation.tudelft.nl </a> <br>
23   * License of use: <a href="http://www.gnu.org/copyleft/gpl.html">General Public
24   * License (GPL) </a>, no warranty <br>
25   * 
26   * @author <a href="http://www.tbm.tudelft.nl/webstaf/alexandv/index.htm">
27   *         Alexander Verbraeck </a> <br>
28   *         <a href="http://www.tbm.tudelft.nl/webstaf/peterja/index.htm"> Peter
29   *         Jacobs </a>
30   * @version 1.10 2004-03-22
31   * @since 1.2
32   */
33  public class DistConstant extends DistContinuous
34  {
35  	/*** value is the value of the constant distribution */
36  	private double value;
37  
38  	/***
39  	 * constructs a new constant distribution
40  	 * 
41  	 * @param stream the numberstream
42  	 * @param value the value
43  	 */
44  	public DistConstant(final StreamInterface stream, final double value)
45  	{
46  		super(stream);
47  		this.value = value;
48  	}
49  
50  	/***
51  	 * @see DistContinuous#draw()
52  	 */
53  	public double draw()
54  	{
55  		this.stream.nextDouble();
56  		return this.value;
57  	}
58  
59  	/***
60  	 * @see nl.tudelft.simulation.jstats.distributions.DistContinuous
61  	 *      #probDensity(double)
62  	 */
63  	public double probDensity(final double observation)
64  	{
65  		if (observation == this.value)
66  		{
67  			return 1.0;
68  		}
69  		return 0.0;
70  	}
71  
72  	/***
73  	 * @see java.lang.Object#toString()
74  	 */
75  	public String toString()
76  	{
77  		return "Constant(" + this.value + ")";
78  	}
79  }