[R] Mathematica now working with Nvidia GPUs --> any plan for R?

[Peter Dalgaard]

Stefan Evert wrote:
> 
> On 19 Nov 2008, at 07:56, Prof Brian Ripley wrote:
> 
>>> I just read an announcement saying that Mathematica is launching a
>>> version working with Nvidia GPUs. It is claimed that it'd make it
>>> ~10-100x faster!
>>> http://www.physorg.com/news146247669.html
>>
>> Well, lots of things are 'claimed' in marketing (and Wolfram is not
>> shy to claim).  I think that you need lots of GPUs, as well as the
>> right problem.
> 
> Which makes me wonder whether R would be able to make use of this
> processing power, since the figures claimed by Wolfram are very probably
> for single-precision floats? (Am I right in thinking that R only works
> with double precision?)
> 
> According to the nVidia Web site, the Tesla architecture is _ten times_
> slower for double-precision operations than for single-precision, which
> makes it seem far less amazing than at first sight.
> 

It wouldn't be rocket science to add a single-precision data type to R,
it is just a large amount of work to get all details right, and noone
has found it worth the trouble.

Probably more of a stumbling block is that GPUs traditionally have had a
rather cavalier attitude to floating-point standards. We have had our
share of problems with compilers that breaks the rules (or users setting
flags like -fast-math that allow rule breakage), and ensuing breakage of
user code and/or "make check", so I don't think it is viable to try and
get the GPU to take on all of  R's computations. Special-purpose
computation, e.g. an R package interfacing to "libgpublas.so" or
whatever,  is always a possibility, but that really goes without saying.

-- 
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