001/* An actor that outputs a random sequence with a Poisson distribution.
002
003 Copyright (c) 2004-2016 The Regents of the University of California.
004 All rights reserved.
005 Permission is hereby granted, without written agreement and without
006 license or royalty fees, to use, copy, modify, and distribute this
007 software and its documentation for any purpose, provided that the above
008 copyright notice and the following two paragraphs appear in all copies
009 of this software.
010
011 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
012 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
013 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
014 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
015 SUCH DAMAGE.
016
017 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
018 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
019 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
020 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
021 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
022 ENHANCEMENTS, OR MODIFICATIONS.
023
024 PT_COPYRIGHT_VERSION_2
025 COPYRIGHTENDKEY
026
027 */
028package ptolemy.actor.lib.colt;
029
030import cern.jet.random.Poisson;
031import ptolemy.actor.parameters.PortParameter;
032import ptolemy.data.BooleanToken;
033import ptolemy.data.DoubleToken;
034import ptolemy.data.IntToken;
035import ptolemy.data.expr.SingletonParameter;
036import ptolemy.data.type.BaseType;
037import ptolemy.kernel.CompositeEntity;
038import ptolemy.kernel.util.IllegalActionException;
039import ptolemy.kernel.util.NameDuplicationException;
040
041///////////////////////////////////////////////////////////////////
042//// Poisson
043
044/**
045 Produce a random sequence with a Poisson distribution.  On each
046 iteration, a new random number is produced.  The output port is of
047 type double.  The values that are generated are independent
048 and identically distributed with the mean given by a port-parameter.
049 In addition, the seed can be
050 specified as a parameter to control the sequence that is generated.
051
052 <p> This actor instantiates a
053 <a href="http://hoschek.home.cern.ch/hoschek/colt/V1.0.3/doc/cern/jet/random/Poisson.html">cern.jet.random.Poisson</a>
054 object with a mean of 1.0 by default.
055
056 @author David Bauer and Kostas Oikonomou, contributor: Edward A. Lee
057 @version $Id$
058 @since Ptolemy II 4.1
059 @Pt.ProposedRating Red (cxh)
060 @Pt.AcceptedRating Red (cxh)
061 */
062public class ColtPoisson extends ColtRandomSource {
063    /** Construct an actor with the given container and name.
064     *  @param container The container.
065     *  @param name The name of this actor.
066     *  @exception IllegalActionException If the actor cannot be contained
067     *   by the proposed container.
068     *  @exception NameDuplicationException If the container already has an
069     *   actor with this name.
070     */
071    public ColtPoisson(CompositeEntity container, String name)
072            throws NameDuplicationException, IllegalActionException {
073        super(container, name);
074
075        output.setTypeEquals(BaseType.INT);
076
077        mean = new PortParameter(this, "mean", new DoubleToken(1.0));
078        mean.setTypeEquals(BaseType.DOUBLE);
079        new SingletonParameter(mean.getPort(), "_showName")
080                .setToken(BooleanToken.TRUE);
081
082        mean.moveToFirst();
083    }
084
085    ///////////////////////////////////////////////////////////////////
086    ////                     ports and parameters                  ////
087
088    /** The mean.
089     *  This has type double, initially with value 1.0.
090     */
091    public PortParameter mean;
092
093    ///////////////////////////////////////////////////////////////////
094    ////                         public methods                    ////
095
096    /** Send a random number with a Poisson distribution to the output.
097     *  This number is only changed in the prefire() method, so it will
098     *  remain constant throughout an iteration.
099     *  @exception IllegalActionException If there is no director.
100     */
101    @Override
102    public void fire() throws IllegalActionException {
103        mean.update();
104        super.fire();
105        output.send(0, new IntToken(_current));
106    }
107
108    ///////////////////////////////////////////////////////////////////
109    ////                         protected methods                 ////
110
111    /** Method that is called after _randomNumberGenerator is changed.
112     */
113    @Override
114    protected void _createdNewRandomNumberGenerator() {
115        _generator = new Poisson(1.0, _randomNumberGenerator);
116    }
117
118    /** Generate a new random number.
119     *  @exception IllegalActionException If parameter values are incorrect.
120     */
121    @Override
122    protected void _generateRandomNumber() throws IllegalActionException {
123        double meanValue = ((DoubleToken) mean.getToken()).doubleValue();
124
125        _current = _generator.nextInt(meanValue);
126    }
127
128    ///////////////////////////////////////////////////////////////////
129    ////                         private variables                 ////
130
131    /** The random number for the current iteration. */
132    private int _current;
133
134    /** The random number generator. */
135    private Poisson _generator;
136}