# STATS 4CI3 January 23, 2019

gen1 <- function(n, x0, a, b, M) {
# A general linear congruential generator to 
# return n uniform(0,1) random variables with
# initial state x0 from the generator
# X(t+1)=aX(t)+b MOD M

  output <- rep(NA, n)
  for (i in 1:n) {
    output[i] <- (a*x0 +b)%%M
    x0 <- output[i]
  }
  output/M
}

RANDU <- function(n, x0) {
# The RANDU generator to generate n uniform(0,1) random
# numbers with initial state x0
  output <- rep(NA, n)
  M <- 2^31
  for (i in 1:n) {
    output[i] <- (65539*x0)%%M
    x0 <- output[i]
  }
  output/M
}