[R] Should garbage collection be automatic in R sessions?

[Prof Brian Ripley]

On Wed, 30 Jul 2003, Laurie Sindlinger wrote:

>    I am having problems with memory when running R on my PC.  I do not 
> have many large objects in my workspace, and yet when trying to create a 
> new vector I often encounter this error message:
> 
> > lat <- header$lat[match(profile$id, header$id)]
>  Error: cannot allocate vector of size 4575 Kb
> 
> Since it seems like this may indicate that I don't have enough memory
> available, I tried increasing nsize using mem.limits, but I still get
> this error message. 

See what ?mem.limits says about Windows ...  ?memory.size (and the 
rw-FAQ) may be more use to you.

> Is there a function in R where you can see the size
> of all objects in the workspace?

object.size(ls()), but not all objects using memory are in the workspace.

>   When I tried using gc(), I was then able to create the vector. It
> seems to indicate in the help pages that the garbage collection should
> happen automatically. Does anyone know how often this might take place
> or how I can check if it is occurring during my R sessions? Thanks for
> you help, and I have included info about my system below (I have 1 gbyte
> of memory).

?gcinfo, mentioned on ?mem.limits.

> Windows 2000

which is not the most efficient OS at using large amounts of memory 
(although better than Windows 9x).

-- 
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