[R] loop over large dataset

Federico Calboli f.calboli at imperial.ac.uk
Mon Jul 4 15:29:38 CEST 2005

On 4 Jul 2005, at 12:41, Uwe Ligges wrote:

> Federico Calboli wrote:
>> In my absentmindedness I'd forgotten to CC this to the list...  
>> and  BTW, using gc() in the loop increases the runtime...
> If the data size increases, you cannot expect linear run time  
> behaviour, e.g. because gc() is called more frequently. And of  
> course, gc() needs some time, hence you get the expected increase  
> in runtime. This answers you other question as well.

Is then internal gc() calls that increase the runtime from 5 minutes  
to more then 24 hours for a 27x increase in data (given that the code  
is exactely the same)?


Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG

Tel +44 (0)20 75941602   Fax +44 (0)20 75943193

f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com

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