Function takes raw counts of NGS data and normalize to CPM, RPKM or TPM.
normalizeGeneCounts(counts, TxDb, method)
counts A data frame with gene ID in rownames and sample ID in colnames
TxDb GenomicFeatures
object created from the same gtf as counts object
method Should be "CPM", "RPKM" or "TPM"
CPM <- normalizeCounts(counts, TxDb, method = "CPM")