norm_cpm: Accessors for the 'norm_cpm' (normalised counts per million) element of an SCESet object.
Description
The norm_cpm element of the arrayData slot in an SCESet object holds
a matrix containing normalised counts-per-million values. It has the same dimensions
as the 'exprs' and 'counts' elements, which hold the transformed expression
data and count data, respectively.