[Developers] when to schedule steering methods

[Werner Benger]

I tried to reply earlier, but that mail apparently got lost. Wanted to throw in here
the memories of the prototype implementation of CactusNet/http , where the
http service was separated into two scheduling parts:

  - one to accept the request and possibly switch on parameters, e.g. for
    activating an analysis routine - this section is running before the ANALYSIS
    routines are invoked

  - a second one to send back the results, which is similar to an output routine,
    but globally, I think that one was at POSTSTEP, similar to what the current
    CactusConnect/HTTPS is doing.

The reason for this splitup was to enable temporary analysis routines, for
instance one analysis per HTTP client request, instead of having this one
permanently being invoked even if no one is watching the output.

cheers,
	Werner


On Tue, 02 Oct 2007 09:27:40 -0500, Erik Schnetter <schnetter at cct.lsu.edu> wrote:

> On Oct 1, 2007, at 11:39:21, Thomas Radke wrote:
>
>> Hi,
>>
>> Erik and I recently discussed the question of when would be the best
>> time in the schedule tree to call a methods which allows users to
>> interactively steer parameters (as are implemented in Cactus's
>> webserver
>> thorns CactusConnect/HTTPS and AstroGrid/HTTPS).
>> Currently the webserver's worker routine is scheduled at POSTSTEP
>> which
>> means that a parameter value may change after the evolution but before
>> the analysis. Erik argues that this is somewhat inconsistent; a
>> parameter change should become active only after an iteration has
>> finished completely. I "countered" by saying that users might want to
>> change I/O parameters before analysis so that they can turn on/off
>> certain analysis routines if they'd want to.
>>
>> What's other people's opinion on that ?
>>
>> Iff we decide to schedule steering methods at the very end of an
>> iteration, we'd need to introduce a new schedule bin, such as STEER.
>
> I introduced a registration mechanism for Carpet, where thorns can
> register functions which should be called before or after any of the
> scheduled functions.  This will allow certain actions to be taken at
> a more fine-grained level, e.g. allowing to single-step through the
> RHS calculation instead of only through iterations.
>
> -erik
>



-- 
___________________________________________________________________________
Dr. Werner Benger <werner at cct.lsu.edu>               Visualization Research
Laboratory for Creative Arts and Technology (LCAT)
Center for Computation & Technology at Louisiana State University (CCT/LSU)
239 Johnston Hall, Baton Rouge, Louisiana 70803
Tel.: +1 225 578 4809                        Fax.: +1 225 578-5362

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