[R-SIG-Mac] FAQ? Mac distributed/multiple processor solutions?
kjbeath at kagi.com
Thu Dec 6 12:24:32 CET 2007
On 06/12/2007, at 9:13 PM, Prof Brian Ripley wrote:
> On Thu, 6 Dec 2007, Ken Beath wrote:
>> On 05/12/2007, at 5:57 AM, Thomas Lumley wrote:
>>> On Tue, 4 Dec 2007, Rob Forsyth wrote:
>>>> options here. I am working on an iMac G5 and could access (at
>>>> home -
>>>> i.e. not on a LAN) another G5 and a G4. I've come across the R/MPI
>>>> package but would appreciate advice as to how easy this is to set
>>>> (would it actually be simpler to divide the job "manually"?).
>>> With only three computers it would be easiest to divide the job
>> Much easier, and if you have access to a machine with multiple
>> processors, simply duplicate the R process to have the same number as
>> the number of processors, and then run them simultaneously. Not as
>> elegant and maybe not as efficient as other methods, but effective.
> But those processes need to do different things (and record the
> results in
> different files), which is what Thomas means by 'divide the job
> Incidentally, I find it useful to run slightly more R processes than
> number of processors, to ensure full CPU usage when one of the
> is in an I/O wait or hits a swapping trap. (Provided you have ample
> or you will get additional swapping.)
> Even with many processors it may be easisest to do this manually. Our
> geneticists do simulation-based inference by running separate
> runs on up to 100s of processors simultaneously: the scheduler works
> better with independent jobs.
I meant duplicate the R application, using the Finder. I thought it
was unnecessary to mention that it will require a different set of
commands to be run in each copy of R.
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