Compatibility with FillArrays

[st--]

We are trying to provide GPU support for AbstractGPs.jl. In AbstractGPs we make use of FillArrays.jl, which unfortunately results in CPU Matrix results when combined with e.g. a CuArray. Would be great if GPUArrays.jl could provide support for the FillArray types!

[maleadt]

Could you provide an MWE of what doesn't work, and what you would want to work?

[st--]

MWE:

using FillArrays, GPUArrays, CUDA, Test
A = CUDA.rand(3, 3)
@test A isa AbstractGPUArray

@test A + Fill(1.2, 3, 3) isa AbstractGPUArray  # works as expected
@test_broken A + Diagonal(Fill(1.2, 3)) isa AbstractGPUArray  # would expect this to work, too

[st--]

I just became aware of JuliaArrays/FillArrays.jl#165, it might fix this issue? but I haven't checked it yet.

Update: I just tested JuliaArrays/FillArrays.jl#165 but it doesn't affect the MWE above (second test remains broken).

[maleadt]

Sorry for the slow response.

@test_broken A + Diagonal(Fill(1.2, 3)) isa AbstractGPUArray # would expect this to work, too

That's because you nest the Fill in a Diagonal; we can't have dispatch for every combination of nested wrappers. See JuliaGPU/Adapt.jl#21, this needs support in Base (e.g. JuliaLang/julia#31563) for better support.