[R] loop over large dataset

[Federico Calboli]

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

--
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

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