[BioC] se.exprs in Affy

[Mary Putt]

I am curious about how to use se.exprs (R version 1.70, . My
understanding is that it can be used with an exprSet to access the
model-based standard errors. In particular the code I have used is:

#rma.ctl is an exprSet generated by normalizing an AffyBatch object
("control") with rma. My understanding is that this object contains
model-based #expression values for each gene and each subject on the
chip

>rma.ctl<-rma(control)
>rma.ctl
Expression Set (exprSet) with 
        22283 genes
        8 samples
                 phenoData object with 1 variables and 8 cases
         varLabels
                batch: batch
> exprs.rma<-exprs(rma.ctl)
> dim(exprs.rma)
[1] 22283     8
> exprs.rma[1,]
C:\\cappola/C1.CEL C:\\cappola/C2.CEL C:\\cappola/C3.CEL
C:\\cappola/C4.CEL 
          6.231048           6.372506           6.115754          
6.147328 
C:\\cappola/R1.CEL C:\\cappola/R2.CEL C:\\cappola/R3.CEL
C:\\cappola/R4.CEL 
          6.352380           6.283031           6.426585          
6.207264 
> se.exprs.rma<-se.exprs(rma.ctl)
> dim(se.exprs)
[1] 22283     8
> se.exprs.rma[1,]
[1] NA NA NA NA NA NA NA NA

I don't understand why the se.exprs.rma matrix is empty? Thanks in
advance, Mary Putt
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mputt.vcf
Type: text/x-vcard
Size: 173 bytes
Desc: Card for mary putt
Url : https://www.stat.math.ethz.ch/pipermail/bioconductor/attachments/20030624/588d52c7/mputt.bin