At 10:50 AM 7/25/2008, Paul Allen wrote:
>I found this answer helpful. I have one follow-up question: You said that you 
>use MoMLParser.parse(String) to open multiple instances. Does using teh 
>MoMLParser.parse(URL) version of that method NOT open multiple instances?

No...  In almost any application, if you open a file that you
already have open, you just see the same instance of the file.
In a text editor, for example, you don't get a new window with a new
copy of the file.  Same for a word processor or an IDE.

If you did get a new window, then things would get very
confusing. You could make a change in one copy, save it,
then make a change in the other copy, save it.  The first change
will have been obliterated.

Thus, it is generally a bug in a tool opens multiple copies of
the same file as separate instances.

Edward


>Brian Hudson wrote: 
>>Do I remember correctly that Ptolemy does not in any way support
>>Java concurrency or multi-threading?
>>
>>
>>This depends on your domain really. PN for example uses quite a bit of 
>>threading.
>>
>>If so, then I would assume that one couldn't safely run 2 models in one JVM, 
>>even if each had its own instances of TypedCompositeActor, Manager, Director, 
>>etc.  If one wanted concurrency, one would run separate JVM's, each with one 
>>model that would have no contact with any other model.  Right?
>>
>>
>>You can safely run multiple models in one JVM. You just need to make sure 
>>that you have two instances of the model in memory. We do this by using the 
>>MoMLParser.parser(String) to open multiple instances of the same model.
>>
>>If (in one JVM) I had a program running that wanted to run several models 
>>(similar to each other), one after the other, how much reuse of Ptolemy 
>>instances makes sense?  Would you recommend nulling all references after each 
>>model run, and instantiating all Ptolemy objects fresh?  Or would it make any 
>>sense to reuse the same TypedCompositeActor, Manager, Director, etc?
>>
>>
>>We do this as well. We have some code that "injects" some actors into a model 
>>before me run it, and we modify several parameters. When the execution has 
>>completed we remove these "injected" actors and reset the parameters. When 
>>running sequential runs on the same model we reuse everything.
>>
>>Does Ptolemy have a way to scrub all actors out of a model, allowing the 
>>creation of new ones?
>>
>>
>>We create all of our "injected" actors in their own composite at the top 
>>level. That we when we want to delete them we can simply delete that one 
>>CompositeEntity.
>>
>>Brian
>>
>>On Fri, Jul 25, 2008 at 12:27 PM, Richard Ware <<mailto:[EMAIL 
>>PROTECTED]>[EMAIL PROTECTED]> wrote:
>>1) Do I remember correctly that Ptolemy does not in any way support
>>Java concurrency or multi-threading?  If so, then I would assume that one
>>couldn't safely run 2 models in one JVM, even if each had its own
>>instances of TypedCompositeActor, Manager, Director, etc.  If one
>>wanted concurrency, one would run separate JVM's, each with one
>>model that would have no contact with any other model.  Right?
>>
>>2)  If (in one JVM) I had a program running that wanted to run
>>several models (similar to each other), one after the other, how much reuse
>>of Ptolemy instances makes sense?  Would you recommend nulling
>>all references after each model run, and instantiating all Ptolemy objects
>>fresh?  Or would it make any sense to reuse the same
>>TypedCompositeActor, Manager, Director, etc?  Regardless of
>>which approach I use, I plan to delete all actors from the first model run
>>and create all actors for the second run fresh, for reasons involving the
>>nature of my simulation.  Does Ptolemy have a way to scrub all actors
>>out of a model, allowing the creation of new ones?
>>
>> I look forward to your clarifications.
>>
>>   Richard Ware
>>
>>
>>
>>
>>
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>
>------------ 
>Edward A. Lee
>Robert S. Pepper Distinguished Professor
>EECS Dept., 545Q Cory Hall, UC Berkeley, Berkeley, CA 94720-1770
>phone: 510-643-3728, fax: 510-642-5745
>[EMAIL PROTECTED], http://www.eecs.berkeley.edu/Faculty/Homepages/lee.html  


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