`InverseLBFGSOperator` for GPU

[tmigot]

This operator is used in JSOSolvers https://github.com/JuliaSmoothOptimizers/JSOSolvers.jl/blob/5c08163ee594d8f8d7e12a98b14f4ed7cd22424e/src/lbfgs.jl#L87C3-L87C63 but nothing allows GPU computation

[dpo]

The solution is probably #258, but needs to be revisited.

[amontoison]

We would like to run lbfgs from JSOSolvers.jl with @michel2323 on GPU.
What is the issue with InverseLBFGSOperator except the type in the workspace?

[dpo]

Sorry, I don’t understand the question

[amontoison]

Sorry I should reformulate my question. Why is it not working on GPU?
Is it only related to the type of the vectors in the workspace (Vector{T}) ?

[amontoison]

Ok, I investigated, and it requires more than just making the array types generic. :(

We need some GPU kernels because some updates affect only specific coefficients in the vectors.

It's a full day's work.