R/ef_quasi_score.R

In wbonat/mglm4twin: Multivariate Generalized linear Models for Twin Data

#' @title Quasi-score function
#' @author Wagner Hugo Bonat
#'
#' @description Compute the quasi-score function, its sensitivy and
#'     variability matrix.
#'
#' @param D A matrix. In general the output from
#'     \code{\link[mglm4twin]{mt_link_function}}.
#' @param inv_C A matrix. In general the output from
#'     \code{\link[mglm4twin]{mt_build_sigma}}.
#' @param y_vec A vector.
#' @param mu_vec A vector.
#' @param W Matrix of weights.
#' @keywords internal
#' @return The quasi-score vector, the Sensivity and variability
#'     matrices.
#' @export

ef_quasi_score <- function(D, inv_C, y_vec, mu_vec, W) {
  res <- y_vec - mu_vec
  t_D <- t(D)
  part1 <- t_D %*% inv_C
  score <- part1 %*% W %*% res
  sensitivity <- -part1 %*% W %*% D
  variability <- part1 %*% W^2 %*% D
  output <- list(Score = score, Sensitivity = sensitivity,
                 Variability = variability)
  return(output)
}