R/window.R

In amouchot/nparamEstim: Nonparametric centile curves estimation

#' Window selection function
#'
#' @param x the explanatory variable - numeric
#' @param y the response variable - numeric
#' @param method the bandwidth method choice: CV or plug-in. Default is CV.
#'
#' @return Calculates the window value using cross validation or plug-in method
#' @import np
#' @import KernSmooth
#' @export
#'
#' @examples
#' #create a data frame
#' example<-data.frame(sample(30:42,10,rep=TRUE),sample(800:5000,10,rep=TRUE))
#' colnames(example)<-c("Gestational Age in weeks","Weight in gramms")
#' x<-example$`Gestational Age in weeks`
#' y<-example$`Weight in gramms`
#' #calculate the window value
#' window(x,y)
#'

window<- function(x,y,method="CV") {
  if (method=="CV"){
    bw<-np::npregbw(formula=y~x)
    model<-np::npreg(bws =bw, gradients = TRUE)
    result<-model$bw
  }
  else {
    if(method=="Plug-in"){
      hplug<-KernSmooth::dpill(x,y,gridsize=length(x))
      result<-hplug
    }
    else{
      if(as.numeric(method)>0){
        result = as.numeric(method)
      }
      else{
        message("The method selected is not supported by the function.")
      }
    }
  }
  return(result)
}