R/soft.R

In irinagain/RPackageGithubIllustration: Illustrate variout R package options

#' Soft-thresholding function
#'
#' @param a scalar
#' @param lambda non-negative thresholding parameter
#'
#' @return Soft-thresholded a
#' @export
#'
#' @examples
#' soft(3, 1)
#' soft(-3, 1)
#' soft(-3, 4)
soft <- function(a, lambda){
  return(sign(a) * max(abs(a) - lambda, 0))
}



#' Hard-thresholding function
#'
#' @inheritParams soft
#'
#' @return Hard-thresholded a
#' @export
#'
#' @examples
#' hard(3, 1)
#' hard(-3, 1)
#' hard(-3, 4)
hard <- function(a, lambda){
  return(sign(a) * max(abs(a), 0))
}