R/create_nll_saturated.R

In danilinares/quickpsy: Fits Psychometric Functions for Multiple Groups

#' Creates the saturated negative log-likelihood function
#' \code{create_nll_saturated} Creates the saturatednegative log-likelihood function
#' @keywords internal
create_nll_saturated <- function(averages, binomial_coef) {

  averages <- averages # without this there is a data mask error

  function(p) {

    phi <- p

    phi[phi < .Machine$double.eps] <- .Machine$double.eps
    phi[phi > (1 - .Machine$double.eps)] <- 1 - .Machine$double.eps

    if (binomial_coef) {
      -sum(lchoose(averages$n, averages$k) + averages$k * log(phi) + (averages$n - averages$k) * log(1 - phi))
    }
    else {
      -sum(averages$k * log(phi) + (averages$n - averages$k) * log(1 - phi))
    }


  }
}