A matrix of gene expression values or an
object of the class simulateGEdata.
exclude
A vector of indices to be excluded from being chosen
as negative controls.
smoothing
A numerical scalar determining the amount of smoothing to be applied.
nc
An integer setting the number of negative controls.
Value
empNegativeControls returns a vector of indicies of
empirically chosen negative controls.
Warning
For simulated data it is advisable to use the known negative controls or
restrict the empirical
choice to the known negative controls by excluding all other genes.
Details
First the mean of all genes (except the excluded genes) is calculated
and genes are accordingly assigned to bins. The bins have the size
of the smoothing parameter. In each bin the function picks a number of negative control
genes proportional to the total number of genes in the bin.
The picked genes in each bin have the lowest inter-quantile ranges of all
genes in the respective bin.