Re: [R] Memory/data -last time I promise

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From: Prof Brian D Ripley (ripley@stats.ox.ac.uk)
Date: Wed 25 Jul 2001 - 21:57:06 EST 

Message-id: <Pine.GSO.4.31.0107251249501.10289-100000@auk.stats>

On Wed, 25 Jul 2001, Agustin Lobo wrote:

> On Tue, 24 Jul 2001, Prof Brian Ripley wrote:
>
> >
> > The main problem I see is that your machine seems unable to allocate more
> > than about 450Mb to R, and it has surprisingly little swap space. (This
> > 512Mb Linux machine has 1Gb of swap allocated, and happily allocates 800Mb
> > to R when needed.)
>
>
> Well, this rises an interesting point for me: are there advices on
> how to configure a particular system for best R performance with
> large datasets? I've looked into the R system guide and could not find
> anything (that document is a bit obscure for me, must recognize).
> Do you get the 800 Mb by starting R with a particular option?

No, just the standard options. Basically, under Unix/Linux

1) Make sure the ulimit/limit settings are suitable (look up your shell
documentation).

2) Make sure you do have ample swap space configured: disc space is
really cheap, and with the current non-moving-objects garbage collector,
currently unused large objects can be successfully swapped out. (That was
not true before 1.2.0.)

3) Start R without any options.

So there is no advice, as nothing special is needed.

On *Windows* there is an equivalent of ulimit/limit set and you are likely
to be less successful in running large R workspaces. In some far as I
understand it, this applies to the classic Mac port too. 

-- 
Brian D. Ripley,                  ripley@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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