R/TRIPLEF.R

In biometryhub/RankedSetSampling: Easing the Application of Ranked Set Sampling in Practice

#' Calculate the triple sum
#'
#' @param uv
#' @param H The set size
#' @param n The sample size
#'
#' @return
#' @keywords internal
TRIPLEF <- function(uv, H, n) {
  coef1 <- (-1)^(uv[2] - 1) / (uv[1]^2 * uv[3])
  coef2 <- choose((H - 1), (uv[1] - 1))
  coef3 <- choose((uv[1] - 1), (uv[2] - 1))
  coef4 <- choose(n, uv[3])
  coef5 <- (uv[1] - uv[2])^(n - uv[3])
  ret <- coef1 * coef2 * coef3 * coef4 * coef5
  return(ret)
}