ptolemy.domains.continuous.lib
Class DifferentialSystem

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.kernel.CompositeEntity
                      ptolemy.actor.CompositeActor
                          ptolemy.actor.TypedCompositeActor
                              ptolemy.domains.continuous.lib.DifferentialSystem

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 DifferentialSystem
extends TypedCompositeActor

A differential system in the Continuous domain.

The differential system model implements a system whose behavior is defined by:

 dx/dt = f(x, u, t)
 y = g(x, u, t)
 x(0) = x0
 

where x is the state vector, u is the input vector, and y is the output vector, t is the time. To use this actor, proceed through the following steps:

• For each input in u, create an input port. Each input may have any name, since you will refer to it by name rather than by the symbol u. This actor will automatically create a parameter with the same name as the input port. That parameter will have its value set during execution to match the value of the input. Note that at this time, multiport inputs are not supported.
• Fill in the stateVariableNames parameter, which is an array of strings, with the names of the state variables in x. These names can be anything you like, since you will refer them to by name rather than by the symbol x.
• For each state variable name in stateVariableNames, create a parameter with a value equal to the initial value of that particular state variable.
• Specify an update function (part of f above) for each state variable by creating a parameter named name_dot, where name is the name of the state variable. The value of this parameter should be an expression giving the rate of change of this state variable as a function of any of the state variables, any input, any other actor parameter, and (possibly), the variable t, representing current time.
• For each output in y, create an output port. The output may have any name. This actor will automatically create a parameter with the same name as the output port.
• For each parameter matching an output port, set its value to be an expression giving the output value as a function of the state variables, the inputs, any other actor parameter, and (possibly), the variable t, representing current time.

This actor is a higher-order component. Upon preinitialization, the actor will create a subsystem using integrators and expressions. These are not persistent (they are not exported in the MoML file), and will instead by created each time the actor is preinitialized.

This actor is based on the ptolemy.domain.ct.lib.DifferentialSystem actor by Jie Liu.

Since:

Ptolemy II 7.0

Version:

$Id: DifferentialSystem.java 59167 2010-09-21 17:08:02Z cxh $

Author:

Jie Liu and Edward A. Lee

See Also:

Integrator, Serialized Form

Accepted Rating:

Red (cxh)

Proposed Rating:

Red (liuj)

Nested Class Summary

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

CompositeEntity.ContainedObjectsIterator

Field Summary

private boolean	_upToDate Flag indicating whether the contained model is up to date.
Parameter	stateVariableNames The names of the state variables, in an array of strings.
Parameter	t The value of current time.

Fields inherited from class ptolemy.actor.CompositeActor

_actorFiringListeners, _causalityInterface, _initializables, _notifyingActorFiring, _publishedPorts, _publisherRelations, _stopRequested

Fields inherited from class ptolemy.kernel.CompositeEntity

_levelCrossingLinks

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

DifferentialSystem(CompositeEntity container, java.lang.String name)
Construct the composite actor with a name and a container.

DifferentialSystem(Workspace workspace)
Construct a DifferentialSystem in the specified workspace with no container and an empty string as a name.

Method Summary

protected void	_addPort(Port port) Add a port to this actor.
private void	_checkParameters() Check the dimensions of all parameters and ports.
private void	_init() Initialize the class.
private void	_requestInitialization() Set this composite actor to opaque and request for reinitialization from the director if there is one.
void	attributeChanged(Attribute attribute) If the argument is any parameter other than stateVariableNames t, or any parameter matching an input port, then request reinitialization.
void	fire() Override the base class to first set the value of the parameter t to match current time, then to set the local parameters that mirror input values, and then to fire the contained actors.
void	preinitialize() Create the model inside from the parameter values.

Methods inherited from class ptolemy.actor.TypedCompositeActor

_addEntity, _addRelation, _checkTypesFromTo, _typeConstraintsFromTo, newPort, newRelation, resolveTypes, typeConstraintList, typeConstraints

Methods inherited from class ptolemy.actor.CompositeActor

_actorFiring, _actorFiring, _finishedAddEntity, _getPublishedPort, _setDirector, addActorFiringListener, addInitializable, addPiggyback, clone, connectionsChanged, createReceivers, createSchedule, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inferringWidths, inferWidths, initialize, inputPortList, isFireFunctional, isOpaque, isStrict, iterate, linkToPublishedPort, linkToPublishedPort, needsWidthInference, newInsideReceiver, newReceiver, notifyConnectivityChange, outputPortList, postfire, prefire, recordFiring, registerPublisherPort, removeActorFiringListener, removeInitializable, removePiggyback, requestChange, setContainer, setDirector, setManager, stop, stopFire, terminate, unlinkToPublishedPort, unlinkToPublishedPort, unregisterPublisherPort, wrapup

Methods inherited from class ptolemy.kernel.CompositeEntity

_adjustDeferrals, _deepOpaqueEntityList, _description, _exportMoMLContents, _recordDecoratedAttributes, _removeEntity, _removeRelation, _validateSettables, allAtomicEntityList, allCompositeEntityList, allowLevelCrossingConnect, classDefinitionList, connect, connect, containedObjectsIterator, deepEntityList, deepGetEntities, deepOpaqueEntityList, deepRelationSet, entityList, entityList, exportLinks, exportMoML, getAttribute, getEntities, getEntity, getPort, getRelation, getRelations, isAtomic, lazyAllAtomicEntityList, lazyAllCompositeEntityList, lazyClassDefinitionList, lazyDeepEntityList, lazyEntityList, lazyRelationList, numberOfEntities, numberOfRelations, numEntities, numRelations, relationList, removeAllEntities, removeAllRelations, setClassDefinition, statistics, uniqueName

Methods inherited from class ptolemy.kernel.ComponentEntity

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

Methods inherited from class ptolemy.kernel.Entity

_removePort, connectedPortList, connectedPorts, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts

Methods inherited from class ptolemy.kernel.InstantiableNamedObj

_setParent, 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, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, attributeList, attributeList, attributeTypeChanged, clone, 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, 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, prefire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, initialize, 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

stateVariableNames

public Parameter stateVariableNames

The names of the state variables, in an array of strings. The default is an ArrayToken of an empty String.

t

public Parameter t

The value of current time. This parameter is not visible in the expression screen except in expert mode. Its value initially is just 0.0, a double, but upon each firing, it is given a value equal to the current time as reported by the director.

_upToDate

private boolean _upToDate

Flag indicating whether the contained model is up to date.

Constructor Detail

DifferentialSystem

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

Construct the composite actor with a name and a container. This constructor creates the ports, parameters, and the icon.

Parameters:

container - The container.

name - The name.

Throws:

NameDuplicationException - If another entity already had this name.

IllegalActionException - If there was an internal problem.

DifferentialSystem

public DifferentialSystem(Workspace workspace)
                   throws IllegalActionException,
                          NameDuplicationException

Construct a DifferentialSystem in the specified workspace with no container and an empty string as a name. You can then change the name with setName(). If the workspace argument is null, then use the default workspace.

Parameters:

workspace - The workspace that will list the actor.

Throws:

IllegalActionException - If the name has a period in it, or the director is not compatible with the specified container.

NameDuplicationException - If the container already contains an entity with the specified name.

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

If the argument is any parameter other than stateVariableNames t, or any parameter matching an input port, then request reinitialization.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the numerator and the denominator matrix is not a row vector.

fire

public void fire()
          throws IllegalActionException

Override the base class to first set the value of the parameter t to match current time, then to set the local parameters that mirror input values, and then to fire the contained actors.

Specified by:

fire in interface Executable

Overrides:

fire in class CompositeActor

Throws:

IllegalActionException - If there is no director, or if the director's fire() method throws it, or if the actor is not opaque.

preinitialize

public void preinitialize()
                   throws IllegalActionException

Create the model inside from the parameter values. This method gets write access on the workspace.

Specified by:

preinitialize in interface Initializable

Overrides:

preinitialize in class CompositeActor

Throws:

IllegalActionException - If there is no director, or if any contained actors throws it in its preinitialize() method.

_addPort

protected void _addPort(Port port)
                 throws IllegalActionException,
                        NameDuplicationException

Add a port to this actor. This overrides the base class to add a parameter with the same name as the port. This parameter is not persistent and is visible only in expert mode. It will be used to mirror the values of the inputs.

Overrides:

_addPort in class TypedCompositeActor

Parameters:

port - The TypedIOPort to add to this actor.

Throws:

IllegalActionException - If the port class is not acceptable to this actor, or the port has no name.

NameDuplicationException - If the port name collides with a name already in the actor.

_checkParameters

private void _checkParameters()
                       throws IllegalActionException

Check the dimensions of all parameters and ports.

Throws:

IllegalActionException - If the dimensions are illegal.

_init

private void _init()
            throws IllegalActionException,
                   NameDuplicationException

Initialize the class.

Throws:

IllegalActionException

NameDuplicationException

_requestInitialization

private void _requestInitialization()

Set this composite actor to opaque and request for reinitialization from the director if there is one.