library(parallel) if(require(boot)) { cd4.rg <- function(data, mle) MASS::mvrnorm(nrow(data), mle$m, mle$v) cd4.mle <- list(m = colMeans(cd4), v = var(cd4)) mc <- getOption("mc.cores", 2) run1 <- function(...) boot(cd4, corr, R = 500, sim = "parametric", ran.gen = cd4.rg, mle = cd4.mle) ## To make this reproducible: set.seed(123, "L'Ecuyer"); mc.reset.stream() res <- mclapply(seq_len(mc), run1) cd4.boot <- do.call(c, res) boot.ci(cd4.boot, type = c("norm", "basic", "perc"), conf = 0.9, h = atanh, hinv = tanh) }