R help - Aug 2003 - The snow package

I have a few questions regarding the snow package:

1) Is fine-grained parallelism even possible with R/snow?

(ie, one task that spawns sub-tasks to do work, with results sent back to the 
parent task).

The example(s) only seem to be totally-independent processing (which can be 
done just as easily
with shell-script wrappers....)


2) If so, is an example available?


3. If not, then it is still worth messing with snow to see if you can get an R 
program to skip through multiple directories, doing the independent processing 
in each to avoid a potential race condition that could occur if multiple R 
process one with one .RData file.

Thanks a lot!
Nisha

njmulakk <njmulakk at uclink.berkeley.edu> writes:
> I have a few questions regarding the snow package:
>
> 1) Is fine-grained parallelism even possible with R/snow?
>
> (ie, one task that spawns sub-tasks to do work, with results sent back to
the
> parent task).
>
> The example(s) only seem to be totally-independent processing (which can be
> done just as easily
> with shell-script wrappers....)
You can use the underlying tools (rpvm or Rmpi) to do it.  I think
sockets, as well, but that might take slightly more thought.
> 2) If so, is an example available?
Not readily packaged up.
> 3. If not, then it is still worth messing with snow to see if you can get
an R
> program to skip through multiple directories, doing the independent
processing
> in each to avoid a potential race condition that could occur if multiple R 
> process one with one .RData file.
Sure.  Or just make sure to load/save to other places besides .RData.

?save will help on that.

best,
-tony

-- 
A.J. Rossini     			
rossini at u.washington.edu            http://www.analytics.washington.edu/ 
Biomedical and Health Informatics   University of Washington
Biostatistics, SCHARP/HVTN          Fred Hutchinson Cancer Research Center
UW   :              FAX=206-543-3461 | moving soon to a permanent office
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