[R] help with random numbers and Rmpi

A.J. Rossini rossini at blindglobe.net
Mon Dec 15 09:59:47 CET 2003


Whoops.  Exhaustion alert.  The point is that R gets started up on the
remote hosts, but you need to initialize the library on them.  So you
don't have to manually start up R on the remote hosts, but you do have
to tell the remote sessions what to compute (including loading any
libraries, etc).

best,
-tony 


rossini at blindglobe.net (A.J. Rossini) writes:

> Faheem Mitha <faheem at email.unc.edu> writes:
>
>> On Sun, 14 Dec 2003, A.J. Rossini wrote:
>>
>>>
>>> Did you make sure that you loaded the library that contains the C
>>> code on the remote hosts?
>>
>> No, I only loaded the library on the local node (master).
>>
>> However, I'm not sure how I should do so. If I simply start up R on the
>> remote hosts and load up the library, I presume this would not be any use,
>> since the master spawns its own R slaves?
>
> No, it would be of use.  The approach is to  run multiple independent
> processes -- this is the general "message-passing" paradigm, and holds
> true regardless of the particular API being used.  So each R process
> has to be appropriately initialized.   SNOW is taking care of the RNG,
> but you've got to do everything else.
>
>> So, the question would be how to get the R slaves to load up the library
>> and I don't see any obvious way of doing this (using snow functions).
>>
>> I must be missing something. Do I need to work at a lower level?
>
> Yes, and no.
>
> Re-read the CPH-statcomp lab, and look at the bootstrap example, which
> solves the same problem.
>
> Look carefully -- it has to initialize the library on each node.
> If you are just loading the library manually, just do it on each node;
> if you are using libraries, just do that.
>
> best,
> -tony
>
> -- 
> 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 (Tu/Th/F): 206-616-7630 FAX=206-543-3461 | Voicemail is unreliable
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-- 
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 (Tu/Th/F): 206-616-7630 FAX=206-543-3461 | Voicemail is unreliable
FHCRC  (M/W): 206-667-7025 FAX=206-667-4812 | use Email

CONFIDENTIALITY NOTICE: This e-mail message and any attachme...{{dropped}}




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