make srand(::MersenneTwister, seed::Vector{UInt32}) copy the seed

JuliaLang · Jun 14, 2016 · dcd8308 · dcd8308
1 parent 14978f3
commit dcd8308
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/base/random.jl b/base/random.jl
@@ -126,7 +126,7 @@ end
 @inline rand_ui2x52_raw(r::MersenneTwister) = rand_ui52_raw(r) % UInt128 << 64 | rand_ui52_raw(r)
 
 function srand(r::MersenneTwister, seed::Vector{UInt32})
- r.seed = seed
+ copy!(resize!(r.seed, length(seed)), seed)
  dsfmt_init_by_array(r.state, r.seed)
  mt_setempty!(r)
  return r

diff --git a/test/random.jl b/test/random.jl
@@ -430,9 +430,17 @@ let seed = rand(UInt32, 10)
  @test s == r
 end
 
-# intialization
+# MersenneTwister initialization with invalid values
 @test_throws DomainError Base.dSFMT.DSFMT_state(zeros(Int32, rand(0:Base.dSFMT.JN32-1)))
 @test_throws DomainError MersenneTwister(zeros(UInt32, 1), Base.dSFMT.DSFMT_state(),
  zeros(Float64, 10), 0)
 @test_throws DomainError MersenneTwister(zeros(UInt32, 1), Base.dSFMT.DSFMT_state(),
  zeros(Float64, Base.Random.MTCacheLength), -1)
+
+# seed is private to MersenneTwister
+let seed = rand(UInt32, 10)
+ r = MersenneTwister(seed)
+ @test r.seed == seed && r.seed !== seed
+ resize!(seed, 4)
+ @test r.seed != seed
+end