R/causalgps_smooth.R

In wxwx1993/GPSmatching: Matching on Generalized Propensity Scores with Continuous Exposures

#' @title
#' Generate kernel function
#'
#' @description
#' Generates kernel function
#'
#' @param t standardized vector (z-score)
#'
#' @return
#' probability distribution
#'
#' @keywords internal
#'
#'
generate_kernel <- function(t){
  stats::dnorm(t)
}

#' @title
#' Helper function
#'
#' @param bw bandwidth value
#' @param matched_w a vector of continuous exposure variable in matched set.
#' @param w_vals a vector of values that you want to calculate the values of
#'  the ERF at.
#'
#' @return
#' return value (TODO)
#' @keywords internal
#'
w_fun <- function(bw,matched_w,w_vals){
    w_avals <- NULL
    for (w_val in w_vals){
      w_std <- (matched_w-w_val)/bw
      kern_std <- generate_kernel(w_std)/bw
      tmp_mean <- mean(w_std^2*kern_std)
      w_avals <- c(w_avals, tmp_mean*(generate_kernel(0)/bw) /
                   (mean(kern_std)*tmp_mean-mean(w_std*kern_std)^2))
  }
  return(w_avals/length(matched_w))
}