R language calculation TPM, RPKM, DeSeq2 standardization principle

1. Customize the function used to calculate TPM, FPKM

RPKM <- function(x, gene.length){
   
    
     
  lib.size <- sum(x)
  rpm <- (x*1e9)/lib.size
  rpkm <- rpm/gene.length
  return(rpkm)
}

TPM