From ripley at stats.ox.ac.uk  Tue Jul 26 10:00:57 2011
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Tue, 26 Jul 2011 09:00:57 +0100
Subject: [Rd] --max-vsize
In-Reply-To: <87sjpzlb3e.fsf@cantab.net>
References: <87sjpzlb3e.fsf@cantab.net>
Message-ID: <alpine.LFD.2.02.1107260854551.17692@gannet.stats.ox.ac.uk>

Point 1 is as documented: you have exceeded the maximum integer and it 
does say that it gives NA.  So the only 'odd' is reporting that you 
did not read the documentation.

Point 2 is R not using the correct units for --max-vsize (it used the 
number of Vcells, as was once documented), and I have fixed.

But I do wonder why you are using --max-vsize: the documentation says 
it is very rarely needed, and I suspect that there are better ways to 
do this.

Also, you ignored the posting guide and did not tell us the 'at a 
minimum' information requested: what OS was this, and was it a 32- or 
64-bit R if a 64-bit OS?

I don't find reporting values of several GB as bytes very useful, but 
then mem.limits() is not useful to me either ....

On Thu, 21 Jul 2011, Christophe Rhodes wrote:

> Hi,
>
> In both R 2.13 and the SVN trunk, I observe odd behaviour with the
> --max-vsize command-line argument:
>
> 1. passing a largeish value (about 260M or greater) makes mem.limits()
>   report NA for the vsize limit; gc() continues to report a value...
>
> 2. ...but that value (and the actual limit) is wrong by a factor of 8.
>
> I attach a patch for issue 2, lightly tested.  I believe that fixing
> issue 1 involves changing the return convention of do_memlimits -- not
> returning a specialized integer vector, but a more general numeric; I
> wasn't confident to do that.
>
>

-- 
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



[Rd] --max-vsize
Prof Brian Ripley