[R] Does R work in 64 bit on apple G5?

[Prof Brian Ripley]

On Wed, 23 Mar 2005, David Ruau wrote:

> I am working with R on 2xG5 1.8Ghz from Apple under 10.3.8
> The G5 chip is 64 bits but does R run in 64 bit or 32 under OS X?
> How can know?

>From the size of the ncells!
32-bit machine:

> gc()
          used (Mb) gc trigger (Mb)
Ncells 144907  3.9     350000  9.4
Vcells  61911  0.5     786432  6.0

64-bit machine:
> gc()
          used (Mb) gc trigger (Mb)
Ncells 141134  7.6     350000 18.7
Vcells  63088  0.5     786432  6.0

The ncells are 28bytes on a 32-bit machine and usually 56 on a 64-bit 
machine (depending on alignment needs).

> I think it run in 32 bits... but not sure...

The precompiled binary is definitely 32-bit.  If you compiled R yourself I 
suspect you would know if you sed a 64-bit compiler (if you had one).

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595