Parallel computing in R for dummies--how to optimize an external model?

Hi Scott,

It is difficult to debug your issue without more information.  Would
it be possible to email me code of a simple example?

Cheers,
Jas.

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Jasjeet S. Sekhon                     
                                      
Associate Professor             
Travers Department of Political Science
Survey Research Center          
UC Berkeley                     

http://sekhon.polisci.berkeley.edu/
V: 510-642-9974  F: 617-507-5524
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Waichler, Scott R writes:
 > 
 > I am trying to use the optimizing function genoud() with the snow
 > package on a couple of i686 machines running Redhat Linux WS4 .  I don't
 > know anything about PVM or MPI, so I just followed the directions in
 > snow and rgenoud for the simplest method and started a socket cluster.
 > My function fn for genoud involves updating an input file for a separate
 > numerical model with the latest parameter set from the optimizer,
 > running the (compiled) model on the input file with system(), and
 > processing the output including calculation of objective function.  The
 > whole process works on the localhost machine in one cpu, and I can see
 > that an R session is created in the second, non-localhost machine, but
 > it doesn't seem to be doing anything.  All of the model runs generated
 > by the application of genoud take place in the cpu.  What am I missing?
 > I can see where there would be a conflict in having multiple processors
 > trying to access the same system model input file at once, but I don't
 > see any indication of that type of problem.
 > 
 > Grateful for any help,
 > 
 > Scott Waichler
 > Pacific Northwest National Laboratory
 > scott.waichler at pnl.gov
 > 
 >