simulation-io-demo

sim-demo.R

library(data.table)

dir <- "~/output/sim"
dir.create(dir, showWarnings = FALSE, recursive = TRUE)

params <- expand.grid(
  n = c(100, 1000, 10000),
  mean = c(0.1, 0.2, 0.3),
  sd = c(0.5, 1, 1.5))

sim <- function(n, mean, sd) {
  x <- rnorm(n, 0, 1)
  y <- rnorm(n, mean, sd)
  t_test <- t.test(x, y)
  w_test <- wilcox.test(x, y)
  list(t_test = t_test, w_test = w_test)
}

res <- lapply(1:nrow(params), function(id) {
  param <- params[id,]
  name <- paste0(names(param), "_", param, collapse = "_")
  outfile <- file.path(dir, sprintf("%s.rds", name))
  if (file.exists(outfile)) {
    return(readRDS(outfile))
  }
  cat(id, ": ", paste0(names(param), ": ", param, collapse = ", "), "\n", sep = "")
  data <- do.call(sim, param)
  out <- list(id = id, param = param, data = data)
  tmpfile <- paste0(outfile, ".tmp")
  saveRDS(out, tmpfile, compress = TRUE)
  file.rename(tmpfile, outfile)
})

files <- list.files(dir, "\\.rds$", full.names = TRUE)
output <- lapply(files, readRDS)
test_stats <- rbindlist(lapply(output, function(x) {
  with(x, cbind(id, param, 
    t_stat = data$t_test$statistic, 
    w_stat = data$w_test$statistic,
    t_pvalue = data$t_test$p.value,
    w_pvalue = data$w_test$p.value))
}))