Find the seeds which produce a random sample of 'HELLO' and 'WORLD'

HelloWorld_seed.R

# Monkeys, Shakespeare, typewriters, &c. ----

# Based on Andrew Heiss' https://gist.github.com/andrewheiss/461c749fce2783551f31611d8f0d7548

library(tidyverse)

# Use 9 CPUs
mirai::daemons(9)

# Loop through just enough seeds to find both 'HELLO' and 'WORLD'
# reducted to the appropriate value after finding them
number_of_seeds <- 1.2e7

# Split this up into chunks of 100,000 seeds and loop through all those chunks
# in parallel with the magic of in_parallel() and {mirai}
chunk_size <- 1e5

tictoc::tic()
possible_seeds <- data.frame(seed = 1:number_of_seeds) |>
  mutate(chunk = seed %/% chunk_size) |>
  nest(.by = chunk) |>
  mutate(
    hw = map(
      data,
      in_parallel(\(chunk) {
        # Surprise! mirai workers don't use Mersenne Twister for their PRNG
        # algorithm. They use L’Ecuyer-CMRG, which is specially designed for
        # parallel processing (it seems to space out the X_n locations in the
        # series for good parallelization?):
        #
        # https://tidyverse.org/blog/2025/09/mirai-2-5-0/#reproducible-parallel-rng
        #
        # So without setting the RNG kind to Mersenne Twister, this loop will
        # find seeds that match HEISS, but in the L’Ecuyer-CMRG world, not the
        # Mersenne Twister world.

        # In this case, I'm not worried about statistically valid parallel PRNG
        # series. I want to loop through the Mersenne Twister world to find
        # seeds I can use in regular old set.seed() for regular old random R functions
        RNGkind("Mersenne-Twister", "Inversion", "Rejection")

        purrr::map_lgl(chunk$seed, \(s) {
          set.seed(s)
          word <- paste0(LETTERS[sample(26, 5, replace = TRUE)], collapse = "")
          word == "HELLO" || word == "WORLD"
        })
      })
    )
  ) |>
  unnest(c(data, hw))
tictoc::toc()
#> 16.582 sec elapsed

hw_seeds <- possible_seeds |>
  filter(hw)
#> # A tibble: 2 × 3
#>   chunk     seed hw
#>   <dbl>    <int> <lgl>
#>   1    25  2505587 TRUE
#>   2   111 11135560 TRUE

map_chr(hw_seeds$seed, \(s) {
  withr::with_seed(s, {
    paste0(LETTERS[sample(26, 5, replace = TRUE)], collapse = "")
  })
})
#> [1] "HELLO" "WORLD"