[Rd] R compiled under windows 64 bit???

[Peter Dalgaard BSA]

Uwe Ligges <ligges at statistik.uni-dortmund.de> writes:

> Alex Gracian wrote:
> 
> > Hi,
> > Any plans to realse in Cran binaries for R base & packages, for
> > Windows
> > using 64bit, now that the AMD 64 is coming out?
> 
> No plans, AFAIK.
> Are you volunteering to compile R base (there may be need for some
> adjustments in the code, as well as in the Makefiles) for CRAN?
> The maintainer would need both, an AMD 64 machine, and a 64-bit
> Windows in order to compile.
> I'm volunteering to make the packages, if you'll buy an AMD 64 machine
> + 64-bit Windows for my office. ;-)

You may regret that statement, once you realize that you also need the
entire 64bit toolchain...

> > It seems a perfect match for cost effective high performane number
> > crunching??
> 
> I don't know whether it will be much faster to use the 64bit mode,
> because the internal structure of x86 processors for number crunching
> already has been 80 bit for floating point arithmetics. Additionally,
> you will need more RAM for the same problems which slows down some
> calculations.
> In principle, you can extend the 2GB limit of the R process, though.

Yes. And we do actually bump into that when we try to do something
sufficiently "stupid". Recent case: attempting to fit a polr() to weekly
data for 2500 persons for one year each, including 2500 person levels,
giving a design matrix of ~2.5GB. Some times you do want to try that
sort of thing by brute force and ignorance (of course, raising the
memory limit might just have revealed further obstacles...)

I would say that the perfect match currently is the SuSE Linux product
for AMD-64. I don't think people quite realize how much extra work
goes into maintaining the Windows platform (about as much as the
Unix/Linux variants combined, I'd say), and we basically only do it
because of its market penetration.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907