R/ptppn.R

In PSDistr: Distributions Derived from Normal Distribution

#' @title Two-Piece Power Normal Distribution
#'
#' @description
#' Density, distribution function, quantile function and random generation
#' for the two-piece power normal distribution with parameters teta, s1, s2 and c.
#'
#' @param x real argument
#' @param teta position parameter
#' @param s1 positive scale parameter
#' @param s2 positive scale parameter
#' @param c shape parameter (c>=1)
#' @return The function returns the value of the cumulative distribution function for the two-piece power normal distribution.
#' @rdname ptppn
#'
#' @details
#' Probability density function
#' see formula (4) in the article
#' Cumulative distribution function
#' see formula (5)
#' Quantile functon
#' see formula (10)
#' Random number generator
#' see formula (21)
#'
#' @author
#' Piotr Sulewski, \email{piotr.sulewski@upsl.edu.pl}, Pomeranian UNiwersity in Slupsk.
#'
#' @references
#' {Sulewski, P. (2021). \emph{Two-Piece Power Normal Distribution,} Communications in Statistics - Theory and Method 50(11), 2619-2639.}
#'
#' @examples
#' dtppn(2,1,1,1,2)
#' ptppn(2,1,1,1,2)
#' qtppn(0.5,1,1,1,2)
#' rtppn(10,1,1,1,2)
#'
#' @export

ptppn <- function(x, teta, s1, s2, c) {
  pnorm <- NULL
  if (s1 > 0 & s2 > 0 & c >= 1)
  {
    return(ifelse(x < teta, pnorm(-((teta - x) / s1) ^ c, 0, 1),
                  pnorm(((x - teta) / s2) ^ c, 0, 1)))
  }
  else
  {
    return('s1>0 and s2>0 and c>=1')
  }
}