On Nov 25, 2008, at 11:28 , John C. Tull wrote:
I thought Altivec was a ppc-only optimization. I'm pretty sure this
does not apply to Intel systems, but maybe I'm wrong.
The Altivec part was incorrect but the multithreaded BLAS part was
correct. Replace Altivec with your favorite three-letter code for
Intel CPUs ;). [Not that Altivec matters in any way, since it supports
spfp only which R doesn't use ...].
For more parallelization, see snow and pnmath by Luke Tierney.
Cheers,
S
On Nov 24, 2008, at 10:23 PM, Kasper Daniel Hansen wrote:
It depends on the computations you want to do.
R for Mac OS X uses Altivec which is a multithreaded version of
BLAS and lapack. What this means is that for any computations
involving matrix algebra, you do utilize multiple cores. Depending
on what you are trying to compute and how that computation is
implemented, this may prove to be just what you want or it may have
little to no effect.
Kasper
On Nov 25, 2008, at 15:24 , John C. Tull wrote:
Dear R-mac Users:
I'm wanting to leverage an 8-core Intel Mac Pro for all of its
computational glory. Looking over the mail list, it appears that
the conversation on 64-bit builds of R has been about gaining
access to memory beyond the 32-bit limit of 3.5 GB and not about
multiple processors/cores.
Does running 64-bit R only take advantage of one processor core at
a time like the standard 32-bit R, or does it do symmetric
multiprocessing (is this the right terminology?). If no, is there
any possibility of doing this using X-grid or otherwise that
someone can detail? I do have 10.5 Server if I have to go down
that road.
Thanks,
John
--
John C. Tull, Ph.D.
Conservation Director
Nevada Wilderness Project
8550 White Fir Street
Reno, NV 89523 USA
775.746.7851 (office)
775.224.2947 (mobile)
www.wildnevada.org
_______________________________________________
R-SIG-Mac mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-mac
_______________________________________________
R-SIG-Mac mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-mac
_______________________________________________
R-SIG-Mac mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-mac
