;;; random stuff
(let* ((seed0      10013)
       (seed       seed0)
       (multiplier 16807.0d0)
       (modulus    2147483647.0d0))
  (defun reset-seed ()  (setf seed seed0))
  (defun randf      (n) (* n (- 1.0d0 (park-miller-randomizer))))
  (defun randi      (n) (floor (* n (/ (randf 1000.0) 1000))))
  (defun park-miller-randomizer ()
  	"cycle= 2,147,483,646 numbers"
    (setf seed (mod (* multiplier seed) modulus))
    (/ seed modulus))
)

(deftest !rands ()
  (reset-seed)
  (dotimes (i 11) (randf 100))
  (test (randf 100) 8.386648357094572d0)
  (reset-seed)
  (test (randf 100) 92.16345646053713d0))