The gene filter removes genes that are either expressed or absent
(expression value is less than 2) in at least X
The motivation for the gene filter is that ubiquitous and rare genes most
often are not informative for the clustering.
Usage
gene_filter(data, fraction)
Arguments
data
expression matrix
fraction
fraction of cells (1 - X/100), default is 0.06.
Value
filtered expression matrix some genes were removed.