1. Forum
  2. USENET
  3. comp.lang.lisp

  • Re: seeding random number generation different every time I run the program

    From B. Pym@Nobody447095@here-nor-there.org to comp.lang.lisp on Fri Aug 8 07:26:06 2025
    From Newsgroup: comp.lang.lisp

    Pascal J. Bourguignon wrote:

    (loop with repeatitions = 1000000
    with R = 16
    with counts = (make-array 16 :initial-element 0)
    repeat repeatitions
    for x = (random R)
    do (incf (aref counts x))
    finally (return (map 'vector
    (lambda (count) (/ count (float repeatitions 1.0d0)))
    counts)))
    #(0.062412D0 0.062663D0 0.062758D0 0.062578D0 0.062252D0
    0.063027D0 0.06256D0 0.062532D0 0.062121D0 0.062455D0
    0.06234D0 0.062332D0 0.062452D0 0.062679D0 0.062388D0
    0.062451D0)

    Gauche Scheme

    (use srfi-27) ;; random-integer

    (let* ((repetitions 999888)
    (R 16)
    (counts (make-vector R 0)))
    (dotimes (repetitions)
    (inc! (vector-ref counts (random-integer R))))
    (vector-map (lambda (count) (/. count repetitions)) counts))

    #(0.06247299697566128 0.06231297905365401 0.06204594914630439
    0.06241299025490855 0.06288204278879235 0.06297105275790889
    0.06264001568175635 0.06237098555038164 0.06261601299345526
    0.06260501176131726 0.06279903349175107 0.061806922375306036
    0.06269802217848398 0.06236298465428128 0.06279203270766326
    0.06221096762837438)
    --
    The good news is, it's not Lisp that sucks, but Common Lisp. --- Paul Graham --- Synchronet 3.21a-Linux NewsLink 1.2