(define random-maker (let* ((multiplier 48271) (modulus 2147483647) (apply-congruence (lambda (current-seed) (let ((candidate (modulo (* current-seed multiplier) modulus))) (if (zero? candidate) modulus candidate)))) (coerce (lambda (proposed-seed) (if (integer? proposed-seed) (- modulus (modulo proposed-seed modulus)) 19860617)))) ;; an arbitrarily chosen birthday (lambda (initial-seed) (let ((seed (coerce initial-seed))) (lambda args (cond ((null? args) (set! seed (apply-congruence seed)) (/ (- modulus seed) modulus)) ((null? (cdr args)) (let* ((proposed-top (ceiling (abs (car args)))) (exact-top (if (inexact? proposed-top) (inexact->exact proposed-top) proposed-top)) (top (if (zero? exact-top) 1 exact-top))) (set! seed (apply-congruence seed)) (inexact->exact (floor (* top (/ seed modulus)))))) ((eq? (cadr args) 'reset) (set! seed (coerce (car args)))) (else (display "random: unrecognized message") (newline)))))))) ;(define random ; (let ((seed (time-nanosecond (current-time)))) ; (display seed) ; (random-maker seed))) (require-library 'sisc/libs/srfi/srfi-19) (import srfi-19) ; stellt current-time usw. bereit (define random (random-maker (time-nanosecond (current-time))))
(define random-test (lambda (n max) (if (= max 0) 'ok (let [(z (random n))] (if (or (< z 0) (> z (- n 1))) (string-append (number->string z) " --> Fehler!") (random-test n (- max 1)))))))
(random-test 10 1000)
ausführen
