ptolemy.actor.lib

## Class RecursiveLattice

• All Implemented Interfaces:
java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable
Direct Known Subclasses:
VariableRecursiveLattice

```public class RecursiveLattice
extends Transformer```
A recursive (all-pole) filter with a lattice structure. The coefficients of such a filter are called "reflection coefficients." Recursive lattice filters are typically used as synthesis filters for random processes because it is easy to ensure that they are stable. A recursive lattice filter is stable if its reflection coefficients are all less than unity in magnitude. To get the reflection coefficients for a linear predictor for a particular random process, you can use the LevinsonDurbin actor. The inputs and outputs are of type double.

The default reflection coefficients correspond to the following transfer function:

```                           1
H(z) =  --------------------------------------
1 - 2z-1 + 1.91z-2 - 0.91z-3 + 0.205z-4
```

The structure of the filter is as follows:

```      y[0]          y[1]                 y[n-1]           y[n]
X(n) ---(+)->--o-->----(+)->--o--->-- ... ->--(+)->--o--->---o--->  Y(n)
\   /          \   /                  \   /        |
+Kn /        +Kn-1 /                  +K1 /         |
X              X                      X          |
-Kn \        -Kn-1 \                  -K1 \         V
/   \          /   \                  /   \        |
(+)-<--o--[z]--(+)-<--o--[z]- ... -<--(+)-<--o--[z]--/
w[1]           w[2]                   w[n]
```
where the [z] are unit delays and the (+) are adders and "y" and "w" are variables representing the state of the filter.

The reflection (or partial-correlation (PARCOR)) coefficients should be specified right to left, K1 to Kn as above. Using exactly the same coefficients in the Lattice actor will result in precisely the inverse transfer function.

Note that the definition of reflection coefficients is not quite universal in the literature. The reflection coefficients in reference [2] are the negative of the ones used by this actor, which correspond to the definition in most other texts, and to the definition of partial-correlation (PARCOR) coefficients in the statistics literature. The signs of the coefficients used in this actor are appropriate for values given by the LevinsonDurbin actor.

References

[1] J. Makhoul, "Linear Prediction: A Tutorial Review", Proc. IEEE, Vol. 63, pp. 561-580, Apr. 1975.

[2] S. M. Kay, Modern Spectral Estimation: Theory & Application, Prentice-Hall, Englewood Cliffs, NJ, 1988.

Since:
Ptolemy II 1.0
Version:
\$Id: RecursiveLattice.java 70402 2014-10-23 00:52:20Z cxh \$
Author:
Edward A. Lee, Christopher Hylands, Steve Neuendorffer
`IIR`, `LevinsonDurbin`, `Lattice`, `VariableRecursiveLattice`
Accepted Rating:
 Yellow (cxh)
Proposed Rating:
 Yellow (cxh)

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

`Entity.ContainedObjectsIterator`
• ### Field Summary

Fields
Modifier and Type Field and Description
`Parameter` `reflectionCoefficients`
The reflection coefficients.
• ### Fields inherited from class ptolemy.actor.lib.Transformer

`input, output`
• ### Fields inherited from class ptolemy.actor.TypedAtomicActor

`_typesValid`
• ### Fields inherited from class ptolemy.actor.AtomicActor

`_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested`
• ### Fields inherited from class ptolemy.kernel.util.NamedObj

`_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _deferChangeRequests, _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

Constructors
Constructor and Description
```RecursiveLattice(CompositeEntity container, java.lang.String name)```
Construct an actor with the given container and name.
• ### Method Summary

All Methods
Modifier and Type Method and Description
`void` `attributeChanged(Attribute attribute)`
If the argument is the reflectionCoefficients parameter, then reallocate the arrays to use.
`java.lang.Object` `clone(Workspace workspace)`
Clone the actor into the specified workspace.
`void` `fire()`
Consume one input token, if there is one, and produce one output token.
`void` `initialize()`
Initialize the state of the filter.
`boolean` `postfire()`
Update the backward and forward prediction errors that were generated in fire() method.
`boolean` `prefire()`
Check to see if this actor is ready to fire.
• ### Methods inherited from class ptolemy.actor.TypedAtomicActor

`_containedTypeConstraints, _customTypeConstraints, _defaultTypeConstraints, _fireAt, _fireAt, attributeTypeChanged, clone, isBackwardTypeInferenceEnabled, newPort, typeConstraintList, typeConstraints`
• ### Methods inherited from class ptolemy.actor.AtomicActor

`_actorFiring, _actorFiring, _declareDelayDependency, addActorFiringListener, addInitializable, 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

`_addPort, _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, _containedDecorators, _copyChangeRequestList, _debug, _debug, _debug, _debug, _debug, _executeChangeRequests, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _notifyHierarchyListenersAfterChange, _notifyHierarchyListenersBeforeChange, _propagateValue, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, addHierarchyListener, attributeDeleted, attributeList, attributeList, decorators, 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, notifyOfNameChange, propagateValue, propagateValues, removeAttribute, removeChangeListener, removeDebugListener, removeHierarchyListener, 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

• #### reflectionCoefficients

`public Parameter reflectionCoefficients`
The reflection coefficients. This is an array of doubles with default value {0.804534, -0.820577, 0.521934, -0.205}. These are the reflection coefficients for the linear predictor of a particular random process.
• ### Constructor Detail

• #### RecursiveLattice

```public RecursiveLattice(CompositeEntity container,
java.lang.String name)
throws NameDuplicationException,
IllegalActionException```
Construct an actor with the given container and name.
Parameters:
`container` - The container.
`name` - The name of this actor.
Throws:
`IllegalActionException` - If the actor 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 argument is the reflectionCoefficients parameter, then reallocate the arrays to use.
Overrides:
`attributeChanged` in class `NamedObj`
Parameters:
`attribute` - The attribute that changed.
Throws:
`IllegalActionException` - If the base class throws it.
• #### clone

```public java.lang.Object clone(Workspace workspace)
throws java.lang.CloneNotSupportedException```
Clone the actor into the specified workspace.
Overrides:
`clone` in class `TypedAtomicActor`
Parameters:
`workspace` - The workspace for the new object.
Returns:
A new actor.
Throws:
`java.lang.CloneNotSupportedException` - If a derived class contains an attribute that cannot be cloned.
`NamedObj.exportMoML(Writer, int, String)`, `NamedObj.setDeferringChangeRequests(boolean)`
• #### fire

```public void fire()
throws IllegalActionException```
Consume one input token, if there is one, and produce one output token. If there is no input, then produce no output.
Specified by:
`fire` in interface `Executable`
Overrides:
`fire` in class `AtomicActor<TypedIOPort>`
Throws:
`IllegalActionException` - If there is no director.
• #### initialize

```public void initialize()
throws IllegalActionException```
Initialize the state of the filter.
Specified by:
`initialize` in interface `Initializable`
Overrides:
`initialize` in class `AtomicActor<TypedIOPort>`
Throws:
`IllegalActionException` - If a derived class throws it.
• #### postfire

```public boolean postfire()
throws IllegalActionException```
Update the backward and forward prediction errors that were generated in fire() method.
Specified by:
`postfire` in interface `Executable`
Overrides:
`postfire` in class `AtomicActor<TypedIOPort>`
Returns:
False if the number of iterations matches the number requested.
Throws:
`IllegalActionException` - If there is no director.
• #### prefire

```public boolean prefire()
throws IllegalActionException```
Check to see if this actor is ready to fire.
Specified by:
`prefire` in interface `Executable`
Overrides:
`prefire` in class `AtomicActor<TypedIOPort>`
Returns:
True if this actor is ready for firing, false otherwise.
Throws:
`IllegalActionException` - If there is no director.