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cs: fix random-seed to be compatible with Racket

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Fix `random-seed` to set the pseudo-random generator's
state to the same state as traditional Racket.
This commit is contained in:
Matthew Flatt 2019-08-29 19:14:39 -06:00
parent afef3fe900
commit dd5e517e88
1 changed files with 23 additions and 21 deletions
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44
racket/src/cs/rumble/random.ss
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@ -90,15 +90,17 @@
(srand-half! s (bitwise-and (bitwise-arithmetic-shift-right x 16) #xFFFF))) (srand-half! s (bitwise-and (bitwise-arithmetic-shift-right x 16) #xFFFF)))
(define (srand-half! s x) (define (srand-half! s x)
(let* ([x (random-n! x (let* ([u32+ (lambda (a b)
(bitwise-and (+ a b) #xFFFFFFFF))]
[x (random-n! x
(- Im1 1) (- Im1 1)
(lambda (z) (lambda (z)
(pseudo-random-generator-x10-set! (pseudo-random-generator-x10-set!
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (+ 1 (modulo
(+ (inexact->exact (pseudo-random-generator-x10 s)) (u32+ (inexact->exact (pseudo-random-generator-x10 s))
z) z)
(- Im1 1)))))))] (- Im1 1)))))))]
[x (random-n! x [x (random-n! x
Im1 Im1
@ -106,20 +108,20 @@
(pseudo-random-generator-x11-set! (pseudo-random-generator-x11-set!
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (modulo
(+ (inexact->exact (pseudo-random-generator-x11 s)) (u32+ (inexact->exact (pseudo-random-generator-x11 s))
z) z)
Im1))))))] Im1)))))]
[x (random-n! x [x (random-n! x
Im1 Im1
(lambda (z) (lambda (z)
(pseudo-random-generator-x12-set! (pseudo-random-generator-x12-set!
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (modulo
(+ (inexact->exact (pseudo-random-generator-x12 s)) (u32+ (inexact->exact (pseudo-random-generator-x12 s))
z) z)
Im1))))))] Im1)))))]
[x (random-n! x [x (random-n! x
(- Im2 1) (- Im2 1)
(lambda (z) (lambda (z)
@ -127,8 +129,8 @@
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (+ 1 (modulo
(+ (inexact->exact (pseudo-random-generator-x20 s)) (u32+ (inexact->exact (pseudo-random-generator-x20 s))
z) z)
(- Im2 1)))))))] (- Im2 1)))))))]
[x (random-n! x [x (random-n! x
Im2 Im2
@ -136,20 +138,20 @@
(pseudo-random-generator-x21-set! (pseudo-random-generator-x21-set!
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (modulo
(+ (inexact->exact (pseudo-random-generator-x21 s)) (u32+ (inexact->exact (pseudo-random-generator-x21 s))
z) z)
Im2))))))] Im2)))))]
[x (random-n! x [x (random-n! x
Im2 Im2
(lambda (z) (lambda (z)
(pseudo-random-generator-x22-set! (pseudo-random-generator-x22-set!
s s
(exact->inexact (exact->inexact
(+ 1 (modulo (modulo
(+ (inexact->exact (pseudo-random-generator-x22 s)) (u32+ (inexact->exact (pseudo-random-generator-x22 s))
z) z)
Im2))))))]) Im2)))))])
(void))) (void)))
(define (random-n! x Im k) (define (random-n! x Im k)