From ripley at stats.ox.ac.uk  Tue Apr 15 08:22:08 2008
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Tue, 15 Apr 2008 07:22:08 +0100 (BST)
Subject: [Rd] option(expressions) and --max-ppsize
In-Reply-To: <4803B875.9020004@telenet.be>
References: <4803B875.9020004@telenet.be>
Message-ID: <alpine.LFD.1.00.0804142131170.4497@gannet.stats.ox.ac.uk>

On Mon, 14 Apr 2008, Tobias Verbeke wrote:

> Dear list,
>
> Is there an exact formula / safe rule of thumb that allows
> one to express the value of --max-ppsize as a function of
> the value of getOption("expressions") ?

There is none: it entirely depends on what you are doing.
But you would expect pp stack usage to be proportional to the number of 
expressions, the problem being what the ratio should be.

The ratio of the defaults was empirically determined, and should be a good 
guide.

However, if you find yourself increasing either then you probably want to 
rethink how you do the calculations in R.

> ?options tells "If you increase it [the expressions option],
> you may also want to start R with a larger protection stack".
>
> Motivation is to determine stack size of a Java vm used
> to launch R with a given --max-ppsize option.

R's expression limit is only vaguely related to its C stack usage
(assuming you mean 'embed R' not 'launch R' -- it is processes that get 
launched in the OS world I inhabit).

>
> Many thanks in advance,
> Tobias
>
> --
>
> Tobias Verbeke - Consultant
> Business & Decision Benelux
> Rue de la r?volution 8
> 1000 Brussels - BELGIUM
>
> +32 499 36 33 15
> tobias.verbeke at businessdecision.com
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>

-- 
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] option(expressions) and --max-ppsize
Prof Brian Ripley