Fix return value of randn! on empty inputs (#528)

.gitignore

@@ -9,3 +9,6 @@ Manifest.toml
 .*.swp
 .*.swo
 *~
+
+# MacOS generated files
+*.DS_Store

src/host/construction.jl

@@ -10,7 +10,7 @@ Base.convert(::Type{T}, a::AbstractArray) where {T<:AbstractGPUArray} = a isa T
 ## convenience constructors
 
 function Base.fill!(A::AnyGPUArray{T}, x) where T
-    length(A) == 0 && return A
+    isempty(A) && return A
     gpu_call(A, convert(T, x)) do ctx, a, val
         idx = @linearidx(a)
         @inbounds a[idx] = val

src/host/random.jl

@@ -84,6 +84,7 @@ function Random.seed!(rng::RNG, seed::Vector{UInt32})
 end
 
 function Random.rand!(rng::RNG, A::AnyGPUArray{T}) where T <: Number
+    isempty(A) && return A
     gpu_call(A, rng.state) do ctx, a, randstates
         idx = linear_index(ctx)
         idx > length(a) && return
@@ -94,8 +95,8 @@ function Random.rand!(rng::RNG, A::AnyGPUArray{T}) where T <: Number
 end
 
 function Random.randn!(rng::RNG, A::AnyGPUArray{T}) where T <: Number
+    isempty(A) && return A
     threads = (length(A) - 1) ÷ 2 + 1
-    length(A) == 0 && return
     gpu_call(A, rng.state; elements = threads) do ctx, a, randstates
         idx = 2*(linear_index(ctx) - 1) + 1
         U1 = gpu_rand(T, ctx, randstates)

test/testsuite/construction.jl

@@ -102,6 +102,12 @@
 
     @testset "convenience" begin
         for T in eltypes
+            A = AT(rand(T, 0))
+            b = rand(T)
+            fill!(A, b)
+            @test A isa AT{T,1}
+            @test Array(A) == fill(b, 0)
+
             A = AT(rand(T, 3))
             b = rand(T)
             fill!(A, b)

test/testsuite/random.jl

@@ -33,6 +33,12 @@
         fill!(A, true)
         rand!(rng, A)
         @test false in Array(A)
+
+        # AT of length 0
+        B = AT{Float32}(undef, 0)
+        fill!(B, 1f0)
+        rand!(rng, B)
+        @test isempty(Array(B))
     end
 
     @testset "randn" begin  # normally-distributed
@@ -56,5 +62,11 @@
                 randn!(cpu_rng, A)
             end
         end
+
+        # AT of length 0
+        A = AT{Float32}(undef, 0)
+        fill!(A, 1f0)
+        randn!(rng, A)
+        @test isempty(Array(A))
     end
 end