[kepler-dev] Looping a process in kepler

Norbert Podhorszki pnorbert at cs.ucdavis.edu
Sat Jul 22 19:00:53 PDT 2006

Hi Siva,

You can import the DDF Director into Kepler with
Tools/Instantiate Attribute and typing

Or you can open the suggested Loop demo workflow in Kepler and then 

Best regards

      Norbert Podhorszki
      University of California, Davis
      Department of Computer Science
      1 Shields Ave, 2236 Kemper Hall
      Davis, CA 95616
      (530) 754-8188
      pnorbert at cs.ucdavis.edu

On Wed, 19 Jul 2006, Sivagowri Swaminathan wrote:

> Hi Christopher
> Your email arrived just in time when I was contemplating to send another
> email to the group but was feeling burdened with the thought of expressing
> it.
> Prof. Edward lee sent me a reference file and info regarding the nature of
> SDF domains and looping.
> As you mention that DDF domains are capable of handling the looping concept
> better, I do not think it is available in kepler. I am using kepler.
> What is the best way to loop a process in kepler?
> I found a loop-based workflow in ptolemy and created the same workflow in
> kepler using a PN director.
> http://ptolemy.eecs.berkeley.edu/ptolemyII/ptII5.0/ptII5.0/ptolemy/domains/ddf/demo/Loop/Loop.htm
> I do not want to use a PN director.
> Can you help me with a sample workflow such as the following?
> The workflow consists of a filereader that reads a file. If the contents of
> file contains a string "xyz" then I need to keep reading the file until its
> contents does not contain "xyz".  let us suppose that this file keeps
> changing behind the scene. how to incorporate the looping process?
> How can I import the DDF director into kepler?
> Any suggestions are welcome.
> Thanx
> Siva
>> From: "Christopher Brooks" <cxh at eecs.berkeley.edu>
>> To: "Sivagowri Swaminathan" <sivagowri at hotmail.com>
>> CC: kepler-dev at ecoinformatics.org, Kepler-users at ecoinformatics.org
>> Subject: Re: [kepler-dev] Looping a process in kepler Date: Tue, 18 Jul
>> 2006 20:55:31 -0700
>> Hi Sivagowri,
>> I'm just going over old email.
>> I'm not sure if anyone got back to you on this, but you probably want
>> to use DDF here.
>> In Ptolemy, see $PTII/ptolemy/domains/ddf/demo/IfThenElse/IfThenElse.xml
>> DDF is described as:
>> The Dynamic Dataflow (DDF) domain is a superset of the Synchronous
>> Dataflow (SDF) and Boolean dataflow (BDF) domains. In the SDF domain,
>> an actor consumes and produces a fixed number of tokens per
>> firing. This static information makes possible compile-time
>> scheduling. In the DDF domain, an actor could change the production
>> and consumption rates after each firing. The scheduler makes no
>> attempt to construct a compile-time schedule, neither does it attempt
>> to statically answer questions about deadlock and boundedness, which
>> are fundamentally undecidable. Instead, each actor has a set of
>> sequential firing rules (patterns) and can be fired if one of them is
>> satisfied, i.e., one particular firing pattern forms a prefix of
>> sequences of unconsumed tokens at input ports.  The scheduler
>> dynamically schedules the firing of actors according to some criteria.
>> The canonical actors in the DDF domain include Select and Switch,
>> which consume or produce tokens on different channels based on the
>> token received from the control port.
>> _Christopher
>> --------
>>     Hi all
>>     I am trying to repeat a process using an if-then-else logic and I get
>> struc
>>    k
>>     each time.
>>     Here is the scenario:
>>     I have three processes [ not sure if thats the right word, it can be
>>     considered as modules doing a specific task] in a pipeline, say
>> process A,
>>     B, C.
>>     In process B, if the output is "xyz" I have to repeat process B until
>> I get
>>     the desired output, in which case, the control moves to the next
>> module dow
>>    n
>>     the pipe. Each module/process is a composite actor, having an input
>> port an
>>    d
>>     an output port. I have a SDF director for the main workflow which
>> should be
>>     run only once.
>>     How do I trigger process B again?
>>     I get an error message saying that the "output port drives the same
>> relatio
>>    n
>>     as the external input port, this is not legal in SDF" every time. is
>> SDF
>>     appropriate for workflows such as these?
>>     since I use a pipelined approach, I do not want to use PN director, as
>> each
>>     component will run in its own thread.
>>     can someone give me an example for looping which does not involve
>> integer
>>     for loops.
>>     Thanx
>>     Siva
>>     _______________________________________________
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>>     Kepler-dev at ecoinformatics.org
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>> --------
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