[R-SIG-Mac] Does 64-bit R use multiple cores?

[John C. Tull]

I thought Altivec was a ppc-only optimization. I'm pretty sure this  
does not apply to Intel systems, but maybe I'm wrong.

John

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)
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>>
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>