001/* Extract maximum element from an array.
002
003 Copyright (c) 2003-2014 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 */
027package ptolemy.actor.lib;
028
029import ptolemy.actor.TypedIOPort;
030import ptolemy.data.ArrayToken;
031import ptolemy.data.IntToken;
032import ptolemy.data.ScalarToken;
033import ptolemy.data.expr.Parameter;
034import ptolemy.data.type.ArrayType;
035import ptolemy.data.type.BaseType;
036import ptolemy.kernel.CompositeEntity;
037import ptolemy.kernel.util.IllegalActionException;
038import ptolemy.kernel.util.InternalErrorException;
039import ptolemy.kernel.util.NameDuplicationException;
040import ptolemy.kernel.util.Workspace;
041
042///////////////////////////////////////////////////////////////////
043//// ArrayMaximum
044
045/**
046 Extract the maximum element from an array.  This actor reads an array
047 from the <i>input</i> port and sends the largest of its elements to the
048 <i>output</i> port.  The index of the largest element is sent to the
049 <i>index</i> output port. If there is more than one entry in the array
050 with the maximum value, then the index of the first such entry
051 is what is produced.
052
053 @author Mark Oliver
054 @version $Id$
055 @since Ptolemy II 3.0.2
056 @Pt.ProposedRating Red (cxh)
057 @Pt.AcceptedRating Red (cxh)
058 */
059public class ArrayMaximum extends Transformer {
060    /** Construct an actor with the given container and name.
061     *  @param container The container.
062     *  @param name The name of this actor.
063     *  @exception IllegalActionException If the actor cannot be contained
064     *   by the proposed container.
065     *  @exception NameDuplicationException If the container already has an
066     *   actor with this name.
067     */
068    public ArrayMaximum(CompositeEntity container, String name)
069            throws NameDuplicationException, IllegalActionException {
070        super(container, name);
071
072        // Create index port
073        index = new TypedIOPort(this, "index", false, true);
074        index.setTypeEquals(BaseType.INT);
075        new Parameter(index, "_showName").setExpression("true");
076
077        // Type constraints.
078        output.setTypeAtLeast(ArrayType.elementType(input));
079    }
080
081    ///////////////////////////////////////////////////////////////////
082    ////                         parameters                        ////
083
084    /** The port producing the index of the largest element.
085     *  This is port has type int.
086     */
087    public TypedIOPort index;
088
089    ///////////////////////////////////////////////////////////////////
090    ////                         public methods                    ////
091
092    /** Override the base class to set type constraints.
093     *  @param workspace The workspace for the new object.
094     *  @return A new instance of ArrayElement.
095     *  @exception CloneNotSupportedException If a derived class contains
096     *   an attribute that cannot be cloned.
097     */
098    @Override
099    public Object clone(Workspace workspace) throws CloneNotSupportedException {
100        ArrayMaximum newObject = (ArrayMaximum) super.clone(workspace);
101        try {
102            newObject.output
103                    .setTypeAtLeast(ArrayType.elementType(newObject.input));
104        } catch (IllegalActionException e) {
105            // Should have been caught before.
106            throw new InternalErrorException(e);
107        }
108        return newObject;
109    }
110
111    /** Consume at most one array from the input port and produce
112     *  the maximum of its elements on the <i>output</i> port and the index
113     *  of that element on the <i>index</i> port.  If there is no token
114     *  on the input, then no output is produced.
115     *  @exception IllegalActionException If there is no director.
116     */
117    @Override
118    public void fire() throws IllegalActionException {
119        super.fire();
120        int indexValue = 0;
121
122        if (input.hasToken(0)) {
123            ArrayToken token = (ArrayToken) input.get(0);
124            ScalarToken currentMax = (ScalarToken) token.getElement(indexValue);
125            ScalarToken temp = null;
126            int i;
127
128            for (i = indexValue + 1; i < token.length(); i++) {
129                temp = (ScalarToken) token.getElement(i);
130
131                if (currentMax.isLessThan(temp).booleanValue() == true) {
132                    indexValue = i;
133                    currentMax = temp;
134                }
135            }
136
137            output.send(0, currentMax);
138            index.broadcast(new IntToken(indexValue));
139        }
140    }
141}