[kepler-dev] Sending multiple outputs through same output port

[Christopher Brooks]

Hi Chandrika,
The system you describe is known as a multirate system.
See
Buck, J. and Ha, S. and Lee, E. A. and Messerschmitt, D. G.,
"Multirate signal processing in Ptolemy". ICASSP 1991.

See also the Ptolemy Design document, try volume 1:
http://www.eecs.berkeley.edu/Pubs/TechRpts/2008/EECS-2008-28.pdf
and volume 3:
http://www.eecs.berkeley.edu/Pubs/TechRpts/2008/EECS-2008-37.pdf
and search for multirate.

SDF and DDF can handle multirate systems.  With SDF, you need to
know the rate of firing in advance.  A system that has a JobStatus
actor that fires when the job status data changes would work in
simple SDF systems.  What might not work in SDF would be to
have one input to that actor and to have the actor produce
an unknown number of outputs.  It is possible to construct such
an SDF model, but it is also possible to construct models that
are not scheduleable in SDF.  DDF is a good choice.

See also actors that have a trigger port.  The trigger is usually
used the discrete event (DE) model of computation.

_Christopher


On 5/2/10 5:48 PM, Sivaramakrishnan, Chandrika wrote:
> Hi,
> Can an actor send multiple outputs through the same output port and channel only when using a Continuous director? I am currently using the JobStatus actor to get the status of a running job. I am
> interested in modifying the actor such that it can send an output every time the job status changes. Essentially the actor should get input once but send multiple outputs. I was looking for examples
> and was able to find only those which work with Continuous director - ex Pulse, Clock. My workflow currently uses DDF director and has simple boolean switch and expression actors. Is multiple outputs
> possible with DDF director?
> Thought it would be better to ask here before I try to run my workflow with any of the continuous directors or modify the actor similar to ramp actor - to send next status on trigger input
> Thanks
> Chandrika
>
>
>
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-- 
Christopher Brooks, PMP                       University of California
CHESS Executive Director                      US Mail: 337 Cory Hall
Programmer/Analyst CHESS/Ptolemy/Trust        Berkeley, CA 94720-1774
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