[Rd] Very Long Expressions

Luke Tierney luke at stat.uiowa.edu
Tue Jan 25 21:09:50 CET 2005

On Mon, 24 Jan 2005, Thomas Lumley wrote:

> On Mon, 24 Jan 2005, Prof Brian Ripley wrote:
> > On Mon, 24 Jan 2005, McGehee, Robert wrote:
> >
> > [Instructions to the R developers deleted.]
> >
> >> Secondly, the ?options help (thanks for everyone who reminded me about
> >> this), says that expressions can have values between 25...100000.
> >> 
> >> However, if the original example is set past 4995 on my computers, I
> >> receive a stack overflow.
> >
> > More accurately, you caused a protection stack overflow.
> >
> At one point we were concerned about overflowing the C stack if 
> options(expressions=) were set too high.  I think this was in the days 
> when MacOS had a very small stack, and that things are safer now.
>  	-thomas

I hadn't noticed that they finally kicked the default up to 8M--good.

We still need to be a bit careful since running out of C stack will
cause a protection violation and there is no portabmle way to catch
this.  But we can probably afford to loosen the defaults a bit.


Luke Tierney
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
   Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu

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