Fix copying Diagonal matrices (#374)

Author: rossviljoen

src/host/linalg.jl

@@ -97,6 +97,11 @@ function LinearAlgebra.triu!(A::AbstractGPUMatrix{T}, d::Integer = 0) where T
 end
 
 
+## diagonal
+
+Base.copy(D::Diagonal{T, <:AbstractGPUArray{T, N}}) where {T, N} = Diagonal(copy(D.diag))
+
+
 ## matrix multiplication
 
 function generic_matmatmul!(C::AbstractArray{R}, A::AbstractArray{T}, B::AbstractArray{S}, a::Number, b::Number) where {T,S,R}

test/testsuite/linalg.jl

@@ -79,6 +79,15 @@ end
         @test collect(B) ≈ collect(A) + collect(D)
     end
 
+    @testset "copy diagonal" begin
+        a = AT(rand(Float32, 10))
+        D = Diagonal(a)
+        C = copy(D)
+        @test C isa Diagonal
+        @test C.diag isa AT
+        @test collect(D) == collect(C)
+    end
+
     @testset "$f! with diagonal $d" for (f, f!) in ((triu, triu!), (tril, tril!)),
                                         d in -2:2
         A = randn(10, 10)