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 >>>> up >>>> (would it actually be simpler to divide the job "manually"?). >>> >>> With only three computers it would be easiest to divide the job >>> manually. >>> >> >> 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 > manually'. > > Incidentally, I find it useful to run slightly more R processes than > the > number of processors, to ensure full CPU usage when one of the > processes > is in an I/O wait or hits a swapping trap. (Provided you have ample > RAM > 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 > simulation > 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. Ken _______________________________________________ R-SIG-Mac mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-mac
