Make copyto!(A,I) work for rectangular matrices (#28790)

* Make copyto!(A,I) work for rectangular matrices * add tests for `copyto!` add tests for `copyto!(::Matrix, ::UniformScaling)` * fix whitespace
JuliaLang · Aug 22, 2018 · 6a2dcc6 · 6a2dcc6
1 parent 85cc84f
commit 6a2dcc6
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diff --git a/stdlib/LinearAlgebra/src/uniformscaling.jl b/stdlib/LinearAlgebra/src/uniformscaling.jl
@@ -207,10 +207,9 @@ isapprox(A::AbstractMatrix, J::UniformScaling; kwargs...) = isapprox(J, A; kwarg
 
 function copyto!(A::AbstractMatrix, J::UniformScaling)
  @assert !has_offset_axes(A)
- size(A,1)==size(A,2) || throw(DimensionMismatch("a UniformScaling can only be copied to a square matrix"))
  fill!(A, 0)
  λ = J.λ
- for i = 1:size(A,1)
+ for i = 1:min(size(A,1),size(A,2))
  @inbounds A[i,i] = λ
  end
  return A

diff --git a/stdlib/LinearAlgebra/test/uniformscaling.jl b/stdlib/LinearAlgebra/test/uniformscaling.jl
@@ -86,6 +86,13 @@ let
  @test cond(J) == (λ ≠ zero(λ) ? one(real(λ)) : oftype(real(λ), Inf))
  end
 
+ @testset "copyto!" begin
+ A = Matrix{Int}(undef, (3,3))
+ @test copyto!(A, I) == one(A)
+ B = Matrix{ComplexF64}(undef, (1,2))
+ @test copyto!(B, J) == [λ zero(λ)]
+ end
+
  @testset "binary ops with matrices" begin
  B = bitrand(2, 2)
  @test B + I == B + Matrix(I, size(B))