[BioC] reducing gene number in affybatch objects

[Hinnerk Boriss]

> > for teaching purposes I would like to cut down the number 
> of genes in
> > affybatch objects so that students won't have to wait that long for
> > their computations. Unfortunately, I cannot figure out how 
> to do that.
> > Any hints? Thanks!
> 
> Cutting down the size of an AffyBatch is not straightforward (for the 
> moment, it should be in the future). There are implications if one
> does so (think about the spatial background correction as done
> in mas 5.0). I believe that the "slowest" part is the computation of
> summary expression values. You may want to investigate the use of the
> parameter 'ids' for the method 'computeExprSet' 
> (or 'summary.subset' for the function 'expresso',
> you can ask for the summary of a given set of affyids).

I've played with this, but it doesn't really help much because the
student's computers are a bit on the slow end. 

How was the affybatch.example object created from the Lemon data? If its
not too painful, I could try this approach.

Best,
Hinnerk