R/log_lik.R

In RNAdecay: Maximum Likelihood Decay Modeling of RNA Degradation Data

#' log likelihood
#'
#' Calculates the log likelihood value from the sum of the squared errors, sigma2, and the total number of data points.
#'
#' @param x is the minimum SSE from the slsqp() fitting
#' @param y is sigma2 cooresponding to the minimum SSE
#' @param n is the total number of observations of a single gene (e.g., 8 time points X 4 replicates X 4 treatments/genotypes = 128)
#'
#' @return returns Log Likelihood
#'
#' @export
#'
#' @keywords internal
#'
#' @examples
#' log_lik(1,1/128,128)


log_lik <- function(x, y, n) {
  -(n / 2) * log(2 * pi * y) - (1 / (2 * y)) * x
}