From e3b5ea9797c9efc179d48eadf866561eb9cdebd8 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Wed, 13 Dec 2017 16:34:10 +0100
Subject: prog: fix an unfortunate case of non-determinism

We used the math/rand global prng in biasedRand historically.
Fix that.
---
 prog/rand.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'prog')

diff --git a/prog/rand.go b/prog/rand.go
index 839c6d1c3..b99399c9d 100644
--- a/prog/rand.go
+++ b/prog/rand.go
@@ -103,7 +103,7 @@ func (r *randGen) randRangeInt(begin uint64, end uint64) uint64 {
 // probability of n-1 is k times higher than probability of 0.
 func (r *randGen) biasedRand(n, k int) int {
 	nf, kf := float64(n), float64(k)
-	rf := nf * (kf/2 + 1) * rand.Float64()
+	rf := nf * (kf/2 + 1) * r.Float64()
 	bf := (-1 + math.Sqrt(1+2*kf*rf/nf)) * nf / kf
 	return int(bf)
 }
-- 
cgit mrf-deployment