[kepler-dev] How do I create nested loops in Kepler

Christopher Brooks cxh at eecs.berkeley.edu
Thu Jul 7 09:07:25 PDT 2005

Hi Edward,

Feel free to take a look and critique my proposed solution at

I like your solution because it does not use hierarchy and thus
might be more efficient.  However, hierarchy could be useful

One issue with parameterizedLoops is that I'm really using the
input to the inner model as a trigger, much like one would 
in DE.

Also, I was interested in how I would use PN to do something similar,
but did not get very far.  Do you have a PN solution?



    This is a very good question. In fact, I wrote a paper once on this
    E. A. Lee, "Recurrences, Iteration, and Conditionals in Statically
    Scheduled Block Diagram Languages," in VLSI Signal Processing III,
    Ed. R. W. Brodersen and H. S. Moscovitz, IEEE Press, New York, 1988.
    This paper is not on the web, although I could get you a copy if you like..
    For your example, the attached model illustrates one simple technique.
    It also elaborates on it, producing the iteration indices for both
    the outer an inner iterations. There are also much more elaborate
    models one can create using higher-order components, like the
    IterateOverArray actor and many others that we haven't gotten
    around to porting from Ptolemy Classic...
    At 03:58 PM 7/5/2005 -0700, Dan Higgins wrote:
    >Hi All,
    >     I am having great difficulty in figuring out how to handle various
    >looping constructs in Kepler/Ptolemy. So I ask if someone can explain
    >how to handle nested loops (using SDF and/or PN directors)?
    >     For example, assume I want to count from 0 to 3 twice in a row so
    >that the output on a final text display is
    >I've tried various ways using Ramp actors and Composite actors but
    >cannot seem to get this simple case to work.
    >Dan Higgins                                  higgins at nceas.ucsb.edu
    >http://www.nceas.ucsb.edu/    Ph: 805-893-5127
    >National Center for Ecological Analysis and Synthesis (NCEAS)
    >Marine Science Building - Room 3405
    >Santa Barbara, CA 93195
    >Kepler-dev mailing list
    >Kepler-dev at ecoinformatics.org

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