[R] Cleaning up the memory

[Prof Brian Ripley]

On Fri, 10 Aug 2007, Monica Pisica wrote:

>
> Hi,
>
> I have 4 huge tables on which i want to do a PCA analysis and a kmean 
> clustering. If i run each table individually i have no problems, but if 
> i want to run it in a for loop i exceed the memory alocation after the 
> second table, even if i save the results as a csv table and i clean up 
> all the big objects with rm command. To me it seems that even if i don't 
> have the objects anymore, the memory these objects used to occupy is not 
> cleared. Is there any way to clear up the memory as well? I don't want 
> to close R and start it up again. Also i am running R under Windows.

See ?gc, which does the clearing.

However, unless you study the memory allocation in detail (which you 
cannot do from R code), you don't actually know that this is the problem. 
More likely is that you have fragmentation of your 32-bit address space: 
see ?"Memory-limits".

Without any idea what memory you have and what 'huge' means, we can only 
make wild guesses.  It might be worth raising the memory limit (the 
--max-mem-size flag).

>
> thanks,
>
> Monica
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-- 
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)
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