Dear Benilton,

an obvious and possibly naive way to avoid the common memory issues  
in the analysis of 500K chips with oligo,
would be to select a sample of SNPs (likely under a stratified random  
design) from the array before using snprma.
Therefore, my first question is whether or not such a sampling method  
is feasible under oligo.
The "affxparser" library allows to select subset of SNPs but I ignore  
how oligo-package deals with values of a command like readCelUnits 
{affxparser}.
My second question is about the reliability of such a method:
The linear fit you use to perform the normalization is based on the  
whole set of SNPs and the information from the mapping package.
Do you think the preprocessing oligo method remains valid (at least  
for the selected sample) if it is based only on a sample of SNPs.
Thanks for your help.

Best. Olivier


--  
________________________________________________________________________

Olivier G. Nuñez
nunez@est-econ.uc3m.es
Universidad Carlos III de Madrid [ Tel : +34 663 03 69 09 ]
Departamento de Estadistica [ Fax : +34 91 624 98 49 ]
Facultad de Ciencias Sociales
C/ Madrid 126 GETAFE 28903 SPAIN
Web Page: http://www.est-econ.uc3m.es/onunez

________________________________________________________________________


El 24/05/2007, a las 17:48, Benilton Carvalho escribió:

> Dear Olivier,
>
> http://www.biostat.jhsph.edu/~bcarvalh/oligo_1.0.2-1.tar.gz
>
> addresses this problem. Could you please give it a try and let me  
> know if everything ran as expected?
>
> thank you,
>
> b
>


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