ptolemy.actor.lib.comm
Class HadamardCode

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.actor.lib.Source
                              ptolemy.actor.lib.comm.HadamardCode

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable

public class HadamardCode
extends Source

Produce a Hadamard codeword by selecting a row from a Hadamard matrix. The log base 2 of the matrix dimension is given by the log2Length parameter, which should be a non-negative integer smaller than 32. The row index is given by the index parameter or by the associated index port, which should be a non-negative integer smaller than the matrix dimension. If the index changes value when the actor is in the middle of producing a sequence of Hadamard codeword, the actor will take on the new index value, and start to produce the new codeword from the beginning.

A Hadamard matrix is defined in the following way:

H₁ = [1, 1; 1, -1]

H_n+1 = [H_n, H_n; H_n, -H_n]

where n is a positive integer. Therefore, H_n is a 2ⁿ by 2ⁿ square matrix. The codeword length is 2ⁿ.

The actor produces Hadamard codeword in booleans. Therefore, 1 is treated as "true" and -1 is treated as "false".

Since:

Ptolemy II 3.0

Version:

$Id: HadamardCode.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Edward A. Lee and Ye Zhou

See Also:

Serialized Form

Accepted Rating:

Red (cxh)

Proposed Rating:

Red (eal)

Nested Class Summary

Nested classes/interfaces inherited from class ptolemy.kernel.Entity

Entity.ContainedObjectsIterator

Field Summary

private int	_index
private int	_latestIndex
private int	_previousIndex
private boolean[]	_row
private static boolean[]	_row0
private static boolean[]	_row1
private boolean	_rowValueInvalid
PortParameter	index Index of the code to generate.
Parameter	log2Length Log base 2 of the length of the code.

Fields inherited from class ptolemy.actor.lib.Source

output, trigger

Fields inherited from class ptolemy.actor.AtomicActor

_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS

Fields inherited from interface ptolemy.actor.Executable

COMPLETED, NOT_READY, STOP_ITERATING

Constructor Summary

HadamardCode(CompositeEntity container, java.lang.String name)
Construct an actor with the given container and name.

Method Summary

private boolean[]	_calculateRow(int matrixDimension, int index) Calculate Hardmard row given by the Hadamard matrix dimension and the row index.
void	attributeChanged(Attribute attribute) If the attribute being changed is log2Length, then calculate the new Hadamard sequence; if it is index, then verify that is non-negative and check if it is different from the previous value.
void	fire() Read from the associated index port if there is any input.
void	initialize() Initialize the actor by resetting the index counter to begin at the beginning of the Hadamard sequence.
boolean	postfire() Return true, unless stop() has been called, in which case, return false.

Methods inherited from class ptolemy.actor.lib.Source

prefire

Methods inherited from class ptolemy.actor.TypedAtomicActor

_addPort, _fireAt, _fireAt, attributeTypeChanged, clone, newPort, typeConstraintList, typeConstraints

Methods inherited from class ptolemy.actor.AtomicActor

_actorFiring, _actorFiring, addActorFiringListener, addInitializable, clone, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, preinitialize, pruneDependencies, recordFiring, removeActorFiringListener, removeDependency, removeInitializable, setContainer, stop, stopFire, terminate, wrapup

Methods inherited from class ptolemy.kernel.ComponentEntity

_adjustDeferrals, _checkContainer, _getContainedObject, _propagateExistence, getContainer, instantiate, isAtomic, isOpaque, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, propagateExistence, setName

Methods inherited from class ptolemy.kernel.Entity

_description, _exportMoMLContents, _removePort, _validateSettables, connectedPortList, connectedPorts, containedObjectsIterator, getAttribute, getPort, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts, setClassDefinition, uniqueName

Methods inherited from class ptolemy.kernel.InstantiableNamedObj

_setParent, exportMoML, getChildren, getElementName, getParent, getPrototypeList, isClassDefinition, isWithinClassDefinition

Methods inherited from class ptolemy.kernel.util.NamedObj

_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _debug, _debug, _debug, _debug, _debug, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _propagateValue, _recordDecoratedAttributes, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, attributeList, attributeList, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getFullName, getModelErrorHandler, getName, getName, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, propagateValue, propagateValues, removeChangeListener, removeDebugListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, validateSettables, workspace

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface ptolemy.actor.Actor

createReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, newReceiver, outputPortList

Methods inherited from interface ptolemy.actor.Executable

isFireFunctional, isStrict, iterate, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, preinitialize, removeInitializable, wrapup

Methods inherited from interface ptolemy.kernel.util.Nameable

description, getContainer, getDisplayName, getFullName, getName, getName, setName

Methods inherited from interface ptolemy.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Field Detail

index

public PortParameter index

Index of the code to generate. Codes with different indexes are orthogonal. This is an int with default 0. It should not exceed length-1, where length = 2^log2Length.

log2Length

public Parameter log2Length

Log base 2 of the length of the code. This is an integer with default 5. It is required to be greater than 0.

_index

private int _index

_previousIndex

private int _previousIndex

_latestIndex

private int _latestIndex

_row

private boolean[] _row

_row0

private static boolean[] _row0

_row1

private static boolean[] _row1

_rowValueInvalid

private transient boolean _rowValueInvalid

Constructor Detail

HadamardCode

public HadamardCode(CompositeEntity container,
                    java.lang.String name)
             throws NameDuplicationException,
                    IllegalActionException

Construct an actor with the given container and name. The output and trigger ports are also constructed.

Parameters:

container - The container.

name - The name of this actor.

Throws:

IllegalActionException - If the entity cannot be contained by the proposed container.

NameDuplicationException - If the container already has an actor with this name.

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

If the attribute being changed is log2Length, then calculate the new Hadamard sequence; if it is index, then verify that is non-negative and check if it is different from the previous value.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If index is negative or log2Length is not strictly positive.

fire

public void fire()
          throws IllegalActionException

Read from the associated index port if there is any input. The actor compares the new index value with the old one. If the value changes, the actor will interrupt the current output sequence, compute the new Hadamard codeword, and send it to the output in sequence. If the index remains constant when it reaches the end of a Hadamard codeword sequence, the next iteration will restart from the beginning of that codeword.

Specified by:

fire in interface Executable

Overrides:

fire in class Source

Throws:

IllegalActionException - If index is out of range.

initialize

public void initialize()
                throws IllegalActionException

Initialize the actor by resetting the index counter to begin at the beginning of the Hadamard sequence.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If there is no director.

postfire

public boolean postfire()
                 throws IllegalActionException

Description copied from class: AtomicActor

Return true, unless stop() has been called, in which case, return false. Derived classes override this method to define operations to be performed at the end of every iteration of its execution, after one invocation of the prefire() method and any number of invocations of the fire() method. This method typically wraps up an iteration, which may involve updating local state. In derived classes, this method returns false to indicate that this actor should not be fired again.

Specified by:

postfire in interface Executable

Overrides:

postfire in class AtomicActor

Returns:

True if execution can continue into the next iteration.

Throws:

IllegalActionException - Not thrown in this base class.

_calculateRow

private boolean[] _calculateRow(int matrixDimension,
                                int index)

Calculate Hardmard row given by the Hadamard matrix dimension and the row index. The method computes iteratively by degrading the matrix dimension into half, until it reaches H₁.

Parameters:

matrixDimension - Hadamard matrix dimension.

index - Row index.

Returns:

Desired Hadamard row.