RFC: Allow cu to operate on Array types

[baggepinnen]

With this pr we have

julia> a = randn(2,2)
2×2 Array{Float64,2}:
 0.393718  -1.0575  
 2.1653    -0.835585

julia> cu(a)
2×2 CuArray{Float32,2,Nothing}:
 0.393718  -1.0575  
 2.1653    -0.835585

julia> cu(typeof(a))
CuArray{Float64,2,P} where P

Would it perhaps be better to have CuArray{Float64,2,Nothing}?

[baggepinnen]

I changed the behaviour to return a concrete type if possible

julia> a = randn(2,2)
2×2 Array{Float64,2}:
 -0.184837  -0.0053234
  0.790932  -1.72842  

julia> cu(a)
2×2 CuArray{Float32,2,Nothing}:
 -0.184837  -0.0053234
  0.790932  -1.72842  

julia> cu(typeof(a))
CuArray{Float64,2,Nothing}

[maleadt]

LGTM
bors r+

[bors]

Build failed

• ci/gitlab/staging

[maleadt]

Re-ran CI, succeeded this time (was a package installation failure across the board).