[BioC] Adaptive background correction error

[Anja Schiel]

Dear all,
I tried to use the adaptive background correction for a set of 22 arrays
(2 colour). For array no 17 I get the following error

RGb<-backgroundCorrect(RG, method="normexp", offset=50)

Error in fit.normexp(foreground = RG$R[, j], background = RG$Rb[, j]) :
        optim failure: degeneracy of the Nelder-Mead simplex

There is nothing obviously wrong with that array so is it the array
that's causing the problem or something else?
And what is the Nelder-Mead simplex????

I am running R 2.0.1 + Bioconductor under Debian testing and limma
1.8.16

Thanks, Anja


-- 
Anja E. Schiel, Ph.D.
Departments of General Internal Medicine and Human Genetics
Leiden University Medical Center
PO Box 9503
2300 RA Leiden
The Netherlands 
tel: -31-(0)71-5276067
fax: -31-(0)71-5276075