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random-sample: actually use the passed-in prng.

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Found by Eli.
This commit is contained in:
Vincent St-Amour 2016-01-05 20:28:49 -06:00
parent 533c0d16ec
commit 1ce6a49f94
1 changed files with 3 additions and 3 deletions
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6
racket/collects/racket/random.rkt
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@ -35,8 +35,8 @@
[i (in-naturals)])
(cond [(< i n) ; we're not full, sample for sure
(vector-set! samples i elt)]
[(< (random (add1 i)) n) ; we've already seen n items; replace one?
(vector-set! samples (random n) elt)]))
[(< (random (add1 i) prng) n) ; we've already seen n items; replace one?
(vector-set! samples (random n prng) elt)]))
;; did we get enough?
(unless (for/and ([s (in-vector samples)])
(not (eq? s not-there)))
@ -53,7 +53,7 @@
(set! samples (make-vector n elt))]
[else ; independently, maybe replace
(for ([j (in-range n)])
(when (zero? (random (add1 i)))
(when (zero? (random (add1 i) prng))
(vector-set! samples j elt)))]))
(unless samples
(raise-argument-error 'random-sample