Add rand_ui52 for some generic functions in Base.Random.

JuliaRandom · Nov 29, 2016 · e24994e · e24994e
1 parent e9be24d
commit e24994e
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/src/common.jl b/src/common.jl
@@ -1,4 +1,4 @@
-import Base.Random: rand
+import Base.Random: rand, rand_ui52
 
 """
 ```julia
@@ -11,11 +11,14 @@ abstract AbstractRNG{T<:Number} <: Base.Random.AbstractRNG
 
 typealias BitTypes Union{Bool, Signed, Unsigned}
 
+@inline function rand_ui52(rng::AbstractRNG)
+    rand(rng, UInt64) & Base.significand_mask(Float64)
+end
+
 # see https://github.com/sunoru/RNG.jl/issues/8
 # TODO: find a better approach.
 @inline function rand{T<:Union{UInt64, UInt128}}(rng::AbstractRNG{T}, ::Type{Float64}=Float64)
-    u = rand(rng, UInt64)
-    reinterpret(Float64, Base.exponent_one(Float64) | Base.significand_mask(Float64) & u) - 1.0
+    reinterpret(Float64, Base.exponent_one(Float64) | rand_ui52(rng)) - 1.0
 end
 @inline function rand{T<:Union{UInt8, UInt16, UInt32}}(rng::AbstractRNG{T}, ::Type{Float64}=Float64)
     rand(rng, T) * exp2(-sizeof(T) << 3)

diff --git a/test/generic.jl b/test/generic.jl
@@ -0,0 +1,6 @@
+r = PCG.PCGStateOneseq(123)
+@test randn(r) == -0.4957408739873887
+@test randn(r, Float64, 8) == [
+    -0.38659391873108484, -0.12391575881839223, 0.305709506865529, 1.0234147128314572,
+    1.1925044460767074, 0.8448640519165571, -0.2982275988025108, 0.9615482011555472
+]