R/emalgth.R

In FocusPaka/SIMD: Statistical Inferences with MeDIP-seq Data (SIMD) to infer the methylation level for each CpG site

#sum=1
#' Calculate the probability on condition that the sums equal to 1.
#' @description Calculate the probability on condition that only a single CpG 
#' contributes to a short read. 
#' @param X A matrix about X, the elements in X takes values on {0,1} and
#' satisfy the sums of each row equal to 1.
#' @return y1 The probability when sums equal to 1.
#' @examples 
#' set.seed(123)
#' d <- matrix(0, nrow=200, ncol=50)
#' random_num <- sample(1:50, 200, replace=TRUE)
#' for(i in 1:nrow(d)){
#'     d[i,random_num[i]]<-1
#' }
#' result <- emalgth(d)
#' head(result)
#' @export

emalgth <- function(X)
{
    N <- colSums(X)
    y <- X
    for(i in seq_len(length(N))){
        y[y[, i]!=0, i] <- N[i]
    }
    N1 <- rowSums(y)
    CpGnum <- rep(1, length(X[1, ]))
    N11 <- N1 %o% CpGnum
    y1 <- y/N11
    return(y1)
}