[kepler-users] Creating a feedback loop

[Edward A. Lee]

BooleanSwitch is not an SDF actor...
I guess we really ought to throw an exception when it's
used this way, but there are some times when it's useful
to sneak it through... But not this time :-)

You could use the DDF director.

There is a (rather antique) paper on this subject at:

http://ptolemy.eecs.berkeley.edu/publications/papers/88/recurrencesVLSI-III/

Edward

At 10:49 AM 11/13/2007, Kenneth Evans wrote:
>Frank,
>
>I am also having the same problem.  I have attached a simple iterative loop
>of the type you mention as a workflow and as a workflow with a Composite
>actor.  The former more or less works.  (There are comments in the
>Annotation.)  The latter does not work, and I am not sure how to fix it.
>
>It is very simple.  It starts with a specified value and decrements it until
>it reaches another specified value, then quits.
> 
>Perhaps it would be easier for someone to point out how to fix both to make
>them work right.  I did not see any examples of this type of iteration in
>the demos.
>
>Thanks,
>
>        -Ken
>
>-----Original Message-----
>From: kepler-users-bounces at ecoinformatics.org
>[mailto:kepler-users-bounces at ecoinformatics.org] On Behalf Of Frank
>Steinmann
>Sent: Monday, November 12, 2007 2:50 AM
>To: kepler-users at ecoinformatics.org
>Subject: [kepler-users] Creating a feedback loop
>
>Hi,
>
>I am having some problems designing a composite actor containing a 
>feedback loop. What I would like to have is an actor that reads one 
>input token which is used as initial value for the feedback loop, then 
>runs several iterations of the loop (the number of iterations is not 
>known at implementation time), and finally sends one token (the final 
>result of the loop) to the output port.
>Any suggestions how to design such an actor?
>
>Regards,
>Frank
>
>-- 
>Dipl.-Inf. Frank Steinmann
>Knowledge Management Department
>DFKI GmbH
>
>Tel.:    +49 (0)631 20575 - 114
>Sekr.:   +49 (0)631 20575 - 101
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>E-Mail: Frank.Steinmann at dfki.de
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>
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>
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>
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------------ 
Edward A. Lee
Chair of EECS and Robert S. Pepper Distinguished Professor
231 Cory Hall, UC Berkeley, Berkeley, CA 94720-1770
phone: 510-642-0253, fax: 510-642-2845
eal at eecs.Berkeley.EDU, http://www.eecs.berkeley.edu/Faculty/Homepages/lee.html