diag.disc <-
function (x, centroids, prior, weight) 
{
  if (!missing(weight)) {
    posid <- (weight > 0)
    if (any(posid)) {
      weight <- sqrt(weight[posid])
      centroids <- centroids[posid, , drop = FALSE] * weight
      x <- x[posid, , drop = FALSE] * weight
    }
    else {
      mat <- outer(rep(1, ncol(x)), log(prior), "*")
      dimnames(mat) <- list(NULL, dimnames(centroids)[[2]])
      return(mat)
    }
  }
  dd <- t(x) %*% centroids
  dd0 <- drop(rep(1, nrow(centroids)) %*% (centroids^2))/2 - 
    log(prior)
  names(dd0) <- NULL
  scale(dd, dd0, FALSE)
}