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)

}