Aggregate with numerous factors

Dear list members,

I am facing some problems using the aggregate() function.
I want to calculate a sum and a mean of one variable over the 
combination of 12 factors with the aggregate() function to avoid loops 
but it doesn't work (or the job is far too long, it exceeds 2 hours). It 
works with a fewer number of factors, so I constructed a factor being 
the levels combination of 7 factors (I need the other ones being on 
their own). I had then 6 factors, but it still doesn't work.
Could someone tell me how to fix the problem or know another function I 
could use ?
Thank you very much,
Joachim Claudet.

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Joachim Claudet

PhD

EPHE - CNRS FRE 2935
52, avenue Paul Alduy
66860 Perpignan cedex
Tel : 33 4 68662055
Fax : 33 4 68503686


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