[R] Performance & capacity characteristics of R?

[Prof Brian D Ripley]

On Wed, 4 Aug 1999, Karsten M. Self wrote:

> Prof Brian D Ripley wrote:
> > 
> > R has a workspace size limit of 2048Mb, and on 32-bit machines this cannot
> > be raised more than a tiny amount. I have only run R on a machine with
> > 512Mb of RAM, and on that using objects of more than 100Mb or so slowed it
> > down very considerably.
> 
> Is the 2048 MB limit an artifact of 32 bit address space?  Is R 64-bit
> capable on 64 bit architecture (SPARC, Alpha, etc.)?

(For SPARC you would need to use a 64-bit capable compiler and libraries
too.)  The limit is an artefact of the assumption that ints are
32 bit. There seem to be quite a few ints around for memory sizes. In
principle one could rewrite this to use longs, but at present R runs
into problems well before the workspace limits are hit, and I am
suggesting that for the sort of things R is most useful for a workspace of
100Mb or so suffices.

-- 
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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