make TaskLocal the default RNG

stdlib/Random/src/RNGs.jl

@@ -569,45 +569,33 @@ function seed!(r::MersenneTwister, seed::Vector{UInt32})
     return r
 end
 
-seed!(r::MersenneTwister=default_rng()) = seed!(r, make_seed())
+seed!() = seed!(default_rng(), make_seed())
+seed!(r::MersenneTwister) = seed!(r, make_seed())
 seed!(r::MersenneTwister, n::Integer) = seed!(r, make_seed(n))
-seed!(seed::Union{Integer,Vector{UInt32}}) = seed!(default_rng(), seed)
+seed!(seed::Union{Integer,Vector{UInt32},Vector{UInt64}}) = seed!(default_rng(), seed)
 
 
 ### Global RNG
 
-const THREAD_RNGs = MersenneTwister[]
-@inline default_rng() = default_rng(Threads.threadid())
-@noinline function default_rng(tid::Int)
-    0 < tid <= length(THREAD_RNGs) || _rng_length_assert()
-    if @inbounds isassigned(THREAD_RNGs, tid)
-        @inbounds MT = THREAD_RNGs[tid]
-    else
-        MT = MersenneTwister()
-        @inbounds THREAD_RNGs[tid] = MT
-    end
-    return MT
-end
-@noinline _rng_length_assert() =  @assert false "0 < tid <= length(THREAD_RNGs)"
+@inline default_rng() = TaskLocal()
+@inline default_rng(tid::Int) = TaskLocal()
 
 function __init__()
-    resize!(empty!(THREAD_RNGs), Threads.nthreads()) # ensures that we didn't save a bad object
     seed!(TaskLocal())
 end
 
-
 struct _GLOBAL_RNG <: AbstractRNG
     global const GLOBAL_RNG = _GLOBAL_RNG.instance
 end
 
-# GLOBAL_RNG currently represents a MersenneTwister
-typeof_rng(::_GLOBAL_RNG) = MersenneTwister
+# GLOBAL_RNG currently uses TaskLocal
+typeof_rng(::_GLOBAL_RNG) = TaskLocal
 
-copy!(dst::MersenneTwister, ::_GLOBAL_RNG) = copy!(dst, default_rng())
-copy!(::_GLOBAL_RNG, src::MersenneTwister) = copy!(default_rng(), src)
+copy!(dst::Xoshiro, ::_GLOBAL_RNG) = copy!(dst, default_rng())
+copy!(::_GLOBAL_RNG, src::Xoshiro) = copy!(default_rng(), src)
 copy(::_GLOBAL_RNG) = copy(default_rng())
 
-seed!(::_GLOBAL_RNG, seed::Vector{UInt32}) = seed!(default_rng(), seed)
+seed!(::_GLOBAL_RNG, seed::Union{Vector{UInt32}, Vector{UInt64}}) = seed!(default_rng(), seed)
 seed!(::_GLOBAL_RNG, n::Integer) = seed!(default_rng(), n)
 seed!(::_GLOBAL_RNG, ::Nothing) = seed!(default_rng(), nothing)
 seed!(::_GLOBAL_RNG) = seed!(default_rng(), nothing)

stdlib/Random/test/runtests.jl

@@ -627,7 +627,7 @@ guardseed() do
     m = MersenneTwister(0)
     @test Random.seed!() === g
     @test Random.seed!(rand(UInt)) === g
-    @test Random.seed!(rand(UInt32, rand(1:10))) === g
+    @test Random.seed!(rand(UInt32, rand(1:8))) === g
     @test Random.seed!(m) === m
     @test Random.seed!(m, rand(UInt)) === m
     @test Random.seed!(m, rand(UInt32, rand(1:10))) === m
@@ -751,28 +751,27 @@ end
     @test Random.seed!(GLOBAL_RNG, 0) === LOCAL_RNG
     @test Random.seed!(GLOBAL_RNG) === LOCAL_RNG
 
-    mt = MersenneTwister(1)
-    @test copy!(mt, GLOBAL_RNG) === mt
-    @test mt == LOCAL_RNG
-    Random.seed!(mt, 2)
-    @test mt != LOCAL_RNG
-    @test copy!(GLOBAL_RNG, mt) === LOCAL_RNG
-    @test mt == LOCAL_RNG
-    mt2 = copy(GLOBAL_RNG)
-    @test mt2 isa typeof(LOCAL_RNG)
-    @test mt2 !== LOCAL_RNG
-    @test mt2 == LOCAL_RNG
+    xo = Xoshiro()
+    @test copy!(xo, GLOBAL_RNG) === xo
+    @test xo == LOCAL_RNG
+    Random.seed!(xo, 2)
+    @test xo != LOCAL_RNG
+    @test copy!(GLOBAL_RNG, xo) === LOCAL_RNG
+    @test xo == LOCAL_RNG
+    xo2 = copy(GLOBAL_RNG)
+    @test xo2 !== LOCAL_RNG
+    @test xo2 == LOCAL_RNG
 
     for T in (Random.UInt52Raw{UInt64},
               Random.UInt2x52Raw{UInt128},
               Random.UInt104Raw{UInt128},
               Random.CloseOpen12_64)
         x = Random.SamplerTrivial(T())
-        @test rand(GLOBAL_RNG, x) === rand(mt, x)
+        @test rand(GLOBAL_RNG, x) === rand(xo, x)
     end
     for T in (Int64, UInt64, Int128, UInt128, Bool, Int8, UInt8, Int16, UInt16, Int32, UInt32)
         x = Random.SamplerType{T}()
-        @test rand(GLOBAL_RNG, x) === rand(mt, x)
+        @test rand(GLOBAL_RNG, x) === rand(xo, x)
     end
 
     A = fill(0.0, 100, 100)
@@ -781,21 +780,21 @@ end
     vB = view(B, :, :)
     I1 = Random.SamplerTrivial(Random.CloseOpen01{Float64}())
     I2 = Random.SamplerTrivial(Random.CloseOpen12{Float64}())
-    @test rand!(GLOBAL_RNG, A, I1) === A == rand!(mt, B, I1) === B
+    @test rand!(GLOBAL_RNG, A, I1) === A == rand!(xo, B, I1) === B
     B = fill!(B, 1.0)
     @test rand!(GLOBAL_RNG, vA, I1) === vA
-    rand!(mt, vB, I1)
+    rand!(xo, vB, I1)
     @test A == B
     for T in (Float16, Float32)
         B = fill!(B, 1.0)
-        @test rand!(GLOBAL_RNG, A, I2) === A == rand!(mt, B, I2) === B
+        @test rand!(GLOBAL_RNG, A, I2) === A == rand!(xo, B, I2) === B
         B = fill!(B, 1.0)
-        @test rand!(GLOBAL_RNG, A, I1) === A == rand!(mt, B, I1) === B
+        @test rand!(GLOBAL_RNG, A, I1) === A == rand!(xo, B, I1) === B
     end
     for T in Base.BitInteger_types
         x = Random.SamplerType{T}()
         B = fill!(B, 1.0)
-        @test rand!(GLOBAL_RNG, A, x) === A == rand!(mt, B, x) === B
+        @test rand!(GLOBAL_RNG, A, x) === A == rand!(xo, B, x) === B
     end
     # issue #33170
     @test Sampler(GLOBAL_RNG, 2:4, Val(1)) isa SamplerRangeNDL

stdlib/Test/src/Test.jl

@@ -1227,8 +1227,6 @@ function testset_beginend(args, tests, source)
         local RNG = default_rng()
         local oldrng = copy(RNG)
         try
-            # RNG is re-seeded with its own seed to ease reproduce a failed test
-            Random.seed!(RNG.seed)
             let
                 $(esc(tests))
             end
@@ -1319,7 +1317,6 @@ function testset_forloop(args, testloop, source)
         local ts
         local RNG = default_rng()
         local oldrng = copy(RNG)
-        Random.seed!(RNG.seed)
         local tmprng = copy(RNG)
         try
             let
@@ -1790,7 +1787,7 @@ end
 
 "`guardseed(f, seed)` is equivalent to running `Random.seed!(seed); f()` and
 then restoring the state of the global RNG as it was before."
-guardseed(f::Function, seed::Union{Vector{UInt32},Integer}) = guardseed() do
+guardseed(f::Function, seed::Union{Vector{UInt64},Vector{UInt32},Integer}) = guardseed() do
     Random.seed!(seed)
     f()
 end