ptolemy.actor.lib.conversions
Class DoubleToFix

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.Transformer
                              ptolemy.actor.lib.conversions.Converter
                                  ptolemy.actor.lib.conversions.DoubleToFix

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 DoubleToFix
extends Converter

This actor converts a DoubleToken to a FixToken with a specified precision. Note that this conversion is lossy, in that the output is an approximation of the input. The approximation can be constructed using a variety of rounding and overflow strategies.

The precision of the output is given by the precision parameter, which is an integer matrix of the form [m, n], where the total number of bits in the output is m, of which n are integer bits. The default precision is [16, 2], which means that an output has 16 bits, of which 2 bits represent the integer part.

The rounding strategy is defined by the rounding parameter and defaults to nearest (or half_floor), selecting the nearest representable value. The floor value nearer to minus infinity is used for values half way between representable values. Other strategies such as truncate are described under ptolemy.math.Rounding.

The overflow strategy is defined by the overflow parameter and defaults to saturate (or clip). Out of range values are saturated to the nearest representable value. Other strategies such as modulo are described under ptolemy.math.Overflow.

Since:

Ptolemy II 0.4

Version:

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

Author:

Bart Kienhuis, Contributor: Edward A. Lee, Ed.Willink,

See Also:

FixToken, Overflow, Precision, Rounding, Serialized Form

Accepted Rating:

Green (pwhitake)

Proposed Rating:

Green (pwhitake)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

private FixPointQuantization	_quantization
StringAttribute	overflow The overflow strategy used, such as "saturate" or "modulo".
Parameter	precision The precision of the output fixed-point number, which is represented by a 2-element integer matrix.
StringAttribute	rounding The rounding strategy used, such as "nearest" or "truncate".

Fields inherited from class ptolemy.actor.lib.Transformer

input, output

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

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

Method Summary

void	attributeChanged(Attribute attribute) Override the base class to set locally cached variables.
java.lang.Object	clone(Workspace workspace) Clone the actor into the specified workspace.
void	fire() Read at most one token from the input and output the converted fixed-point value with the precision given by the precision parameter, overflow strategy given by the overflow parameter, and rounding strategy given by the rounding parameter.
boolean	prefire() Return false if the input port has no token, otherwise return what the superclass returns (presumably true).

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, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, initialize, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, postfire, 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, postfire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, initialize, 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

precision

public Parameter precision

The precision of the output fixed-point number, which is represented by a 2-element integer matrix.

overflow

public StringAttribute overflow

The overflow strategy used, such as "saturate" or "modulo".

rounding

public StringAttribute rounding

The rounding strategy used, such as "nearest" or "truncate".

_quantization

private FixPointQuantization _quantization

Constructor Detail

DoubleToFix

public DoubleToFix(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

Override the base class to set locally cached variables.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the parameter value is invalid.

clone

public java.lang.Object clone(Workspace workspace)
                       throws java.lang.CloneNotSupportedException

Clone the actor into the specified workspace.

Overrides:

clone in class AtomicActor

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.

See Also:

NamedObj.exportMoML(Writer, int, String), NamedObj.setDeferringChangeRequests(boolean)

fire

public void fire()
          throws IllegalActionException

Read at most one token from the input and output the converted fixed-point value with the precision given by the precision parameter, overflow strategy given by the overflow parameter, and rounding strategy given by the rounding parameter.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If there is no director.

prefire

public boolean prefire()
                throws IllegalActionException

Return false if the input port has no token, otherwise return what the superclass returns (presumably true).

Specified by:

prefire in interface Executable

Overrides:

prefire in class AtomicActor

Returns:

True if this actor is ready for firing, false otherwise.

Throws:

IllegalActionException - If there is no director.