More graceful way of using `CuTensorMap`

[kshyatt]

const CUDAExt = Base.get_extension(TensorKit, :TensorKitCUDAExt)
@assert !isnothing(CUDAExt)
const CuTensorMap = getglobal(CUDAExt, :CuTensorMap)

This is awful!!!

What if instead, we defined CuTensorMap in src/TensorKit.jl but made it MethodError unless the extension is loaded (which would then provide the actual constructors).

[lkdvos]

I completely agree, but there is actually no way to define a type alias like that in the main package. Do you know in what context you want to use this? Maybe we can provide alternative interfaces to circumvent needing CuTensorMap directly?

[kshyatt]

The struct definition we may not be able to put in the main package, I agree, but we could add the wrapper constructors like CuTensorMap(::TensorMap) etc.

[lkdvos]

Isn't that what adapt(CuArray, t::TensorMap) is supposed to do? We can also add CUDA.cu(::TensorMap) as well

[kshyatt]

cu is a really bad one that’s in theory supposed to convert to Float32

…

On Tue, Jan 20, 2026 at 7:31 PM Lukas Devos ***@***.***> wrote: *lkdvos* left a comment (QuantumKitHub/TensorKit.jl#354) <#354 (comment)> Isn't that what adapt(CuArray, t::TensorMap) is supposed to do? We can also add CUDA.cu(::TensorMap) as well — Reply to this email directly, view it on GitHub <#354 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGKJY2IZUE36JEEJQRFAZL4HZX6PAVCNFSM6AAAAACSIZZNFWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTONZUGM2TEOBSGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>