[R-sig-ME] Model specification help

Andrew Perrin clists at perrin.socsci.unc.edu
Fri Mar 9 03:41:07 CET 2007

On Thu, 8 Mar 2007, elw at stderr.org wrote:

>> Thank you for this. I will return to it tomorrow and let you know how it 
>> goes. As for the machine it's running on: it's a dual-Xeon 2.8Ghz IBM 
>> eseries server with 6GB RAM, running debian Linux, kernel 2.6.18.  So the 
>> 3GB per-process memory limit applies. I also have access to a shared server 
>> with "twenty-four 1.05 GHz Ultra-Sparc III+ processors and 40 GB of main 
>> memory" running solaris, if that's better.
> Andrew,
> That gets you onto a 64-bit platform, beyond the 32-bit-Intel 4GB memory (3G 
> for user process, 1G for OS kernel) limit, and beyond a bunch of other data 
> size limits.  The memory bandwidth available to you on the Solaris machine is 
> also likely to be much more significant - something that you will find quite 
> pleasant for even some more trivial analyses.  :)
> Much better, certainly!  [And very much like what 'beefy' R code is most 
> frequently run on...]
> W.r.t. the eSeries server you're commonly running on now - if you can have 
> your systems people check to make sure that you have a PAE-enabled linux 
> kernel running, you might be able to muscle past the 3GB mark with a single R 
> process.... with some work.
> [If the machine can actually "see" all 6GB of memory, you probably have a PAE 
> kernel.]
> --e

Ironically enough, I *am* the systems people for the eSeries.... having 
been a unix sysadmin and perl programmer before cutting and running for 
social science :).. The kernel is PAE enabled, but that only helps with 
seeing 6G altogether, not over 3G for a single process. I toyed with the 
idea of whether I could break down the process into several threaded ones, 
but that's way above my head.

(The Solaris cluster is university-run, though.)


Andrew J Perrin - andrew_perrin (at) unc.edu - http://perrin.socsci.unc.edu
Assistant Professor of Sociology; Book Review Editor, _Social Forces_
University of North Carolina - CB#3210, Chapel Hill, NC 27599-3210 USA
New Book: http://www.press.uchicago.edu/cgi-bin/hfs.cgi/00/178592.ctl

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