Examples of ptolemy.domains.ct.kernel.CTDirector

ptolemy.domains.ct.kernel.CTDirector
Abstract base class for directors in the CT domain. A CTDirector has a CTScheduler which provides static schedules for firing the actors in different phases of execution in one iteration.
A CTDirector may have more than one ODE solver. In each phase of execution, one ODE solver takes charge of solving the behavior of a model. This solver is called the current ODE solver.
The continuous time (CT) domain is a timed domain. There is a global notion of time that all the actors are aware of. Time is maintained by the director. The method getModelTime() returns the current notion of model time. Time can be set by the setModelTime() method, but this method should not the called by the actors. Time can only be set by directors or their ODE solvers. Because ODE solvers can change time in their fire() methods, we need to record the beginning time of an iteration to support roll back. The _setIterationBeginTime() method is just designed for this purpose. It is called in the prefire() method of each iteration to store the beginning time, and the getIterationBeginTime() returns the lastest stored time.
This base class maintains a list of parameters that may be used by ODE solvers and actors. These parameters are:
startTime: The start time of the simulation. This parameter is effective only if the director is at the top level. The default value is 0.0.
stopTime: The stop time of the simulation. This parameter is effective only if the director is at the top level. The default value is Infinity, which results in execution that does not stop on its own.
initStepSize: The suggested integration step size by the user. This will be the step size for fixed step size ODE solvers if there is no breakpoint. However, it is just a hint. The default value is 0.1
minStepSize: The minimum step size that users want to use in the simulation. The default value is 1e-5.
maxStepSize: The maximum step size that users want to use in the simulation. Usually used to control the simulation speed. The default value is 1.0.
maxIterations: Used only in implicit ODE solvers. This is the maximum number of iterations for finding the fixed point at one time point. The default value is 20.
errorTolerance: This is the local truncation error tolerance, used for controlling the integration accuracy in variable step size ODE solvers. If the local truncation error at some step size control actors are greater than this tolerance, then the integration step is considered to have failed, and should be restarted with a reduced step size. The default value is 1e-4.
valueResolution: This is used to control the convergence of fixed point iterations. If in two successive iterations the difference of the state variables is less than this resolution, then the fixed point is considered to have reached. The default value is 1e-6.
This director maintains a breakpoint table to record all predictable breakpoints that are greater than or equal to the current time. The breakpoints are sorted in their chronological order. Breakpoints at the same time are considered to be identical, and the breakpoint table does not contain duplicate time points. A breakpoint can be inserted into the table by calling the fireAt() method. The fireAt method may be requested by the director, which inserts the stop time of the execution. The fireAt method may also be requested by actors and the requested firing time will be inserted into the breakpoint table. @author Jie Liu, Haiyang Zheng @version $Id: CTDirector.java,v 1.203 2007/12/06 18:21:49 cxh Exp $ @since Ptolemy II 0.2 @Pt.ProposedRating Green (hyzheng) @Pt.AcceptedRating Green (hyzheng)

    /** Return true if this actor is scheduled to fire at the current time.
     *  @return True if this actor is scheduled to fire at the current time.
     *  @exception IllegalActionException If thrown by the super class.
     */
    public boolean prefire() throws IllegalActionException {
        CTDirector director = (CTDirector) getDirector();
        boolean result = (director.getModelTime().compareTo(_nextOutputTime) == 0);
        return result && super.prefire();
    }

     *  @exception IllegalActionException If the director throws it when
     *   scheduling the next firing, or if the length of the values and
     *   offsets parameters don't match.
     */
    public boolean postfire() throws IllegalActionException {
        CTDirector director = (CTDirector) getDirector();
        double periodValue = ((DoubleToken) period.getToken()).doubleValue();


        // Increment to the next phase.
        _phase++;


        if (_phase >= _offsets.length) {
            _phase = 0;
            _cycleStartTime = _cycleStartTime.add(periodValue);
        }


        if (_offsets[_phase] >= periodValue) {
            throw new IllegalActionException(this, "Offset number " + _phase
                    + " with value " + _offsets[_phase]
                    + " must be less than the " + "period, which is "
                    + periodValue);
        }


        _nextOutputTime = _cycleStartTime.add(_offsets[_phase]);
        director.fireAt(this, _nextOutputTime);
        return true;
    }

     *  derivative.
     *  @exception IllegalActionException If the token cannot be sent.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        CTDirector director = (CTDirector) getDirector();


        if (director.isDiscretePhase()) {
            if ((input.hasToken(0) && (!derivative.hasToken(0)))
                    || (!input.hasToken(0) && derivative.hasToken(0))) {
                throw new IllegalActionException(this,
                        " No synchronized inputs.");
            }


            if (input.hasToken(0) && derivative.hasToken(0)) {
                _value = ((DoubleToken) input.get(0)).doubleValue();
                _derivative = ((DoubleToken) derivative.get(0)).doubleValue();
                _time = director.getModelTime();


                if (_debugging) {
                    _debug(getFullName(), " get inputs: (" + _value, ", "
                            + _derivative + ").");
                }
            }
        }


        double timeInterval = director.getModelTime().subtract(_time)
                .getDoubleValue();
        output.send(0, new DoubleToken(_value + (timeInterval * _derivative)));
    }

        // override how this is done.
        _updateTentativeValues();


        // In initialize() method, we already ensured that the director is
        // a CTDirector.
        CTDirector director = (CTDirector) getDirector();


        if (director.isDiscretePhase()) {
            // Get the current time and period.
            Time currentTime = director.getModelTime();
            double periodValue = ((DoubleToken) period.getToken())
                    .doubleValue();


            // Use Time.NEGATIVE_INFINITY to indicate that no refire
            // event should be scheduled because we aren't at a phase boundary.

     *  @exception IllegalActionException If the hasToken() query failed
     *  or tokens cannot be sent from the output.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        CTDirector director = (CTDirector) getDirector();


        // FIXME: do we need to constraint that the current execution phase is
        // CTExecutionPhase.GENERATING_EVENTS_PHASE?
        if (director.isDiscretePhase() && hasCurrentEvent()) {
            trigger.get(0);


            for (int i = 0; i < Math.min(input.getWidth(), output.getWidth()); i++) {
                if (input.hasToken(i)) {
                    output.send(i, input.get(i));

     *  call.
     *  @exception IllegalActionException If the token cannot be sent.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        CTDirector director = (CTDirector) getDirector();


        if (director.isDiscretePhase()) {
            if (input.hasToken(0)) {
                _lastToken = input.get(0);


                CTDirector dir = (CTDirector) getDirector();
                _debug(getFullName() + " receives an event at: "
                        + dir.getModelTime() + " with token "
                        + _lastToken.toString());
            }
        }


        output.send(0, _lastToken);


        if (_debugging) {
            _debug("Consuming a trigger token: " + _thisTrigger);
        }


        CTDirector director = (CTDirector) getDirector();


        if (director.getExecutionPhase() == CTExecutionPhase.GENERATING_EVENTS_PHASE) {
            if (_debugging && _verbose) {
                _debug("This is a discrete phase execution.");
            }


            // There are two conditions when an event is generated.

    /** Return the refined step size if there is a missed event,
     *  otherwise return the current step size.
     *  @return The refined step size.
     */
    public double refinedStepSize() {
        CTDirector dir = (CTDirector) getDirector();
        double refinedStep = dir.getCurrentStepSize();


        if (_eventMissed) {
            // The refined step size is a linear interpolation.
            // NOTE: we always to get a little overshoot to make sure the
            // level crossing happens. The little overshoot chosen here
            // is half of the error toelrance.
            refinedStep = ((Math.abs(_lastTrigger - _level) + (_errorTolerance / 2)) * dir
                    .getCurrentStepSize())
                    / Math.abs(_thisTrigger - _lastTrigger);


            if (_debugging) {
                _debug(getFullName() + " Event Missed: refined step to "
                        + refinedStep + " at " + dir.getModelTime());
            }
        }


        return refinedStep;
    }

     *  current time.
     *  @exception IllegalActionException If the transfer of tokens failed.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        CTDirector director = (CTDirector) getDirector();


        if ((director.getExecutionPhase() == CTExecutionPhase.GENERATING_EVENTS_PHASE)
                && hasCurrentEvent()) {
            for (int i = 0; i < Math.min(input.getWidth(), output.getWidth()); i++) {
                if (input.hasToken(i)) {
                    Token token = input.get(i);
                    output.send(i, token);

    /** Return true if there is a current event. In other words, the current
     *  time is one of the sampling times.
     *  @return If there is a discrete event to emit.
     */
    public boolean hasCurrentEvent() {
        CTDirector director = (CTDirector) getDirector();


        if (director.getModelTime().compareTo(_nextSamplingTime) == 0) {
            _hasCurrentEvent = true;


            if (_debugging && _verbose) {
                _debug(getFullName(), " has an event at: "
                        + director.getModelTime() + ".");
            }
        } else {
            _hasCurrentEvent = false;
        }

Examples of ptolemy.domains.ct.kernel.CTDirector

Related Classes of ptolemy.domains.ct.kernel.CTDirector