Complex numbers: hermitian and unitary

[jpcorb20]

Hello,

Thanks for the great library!

Do you plan to support cases on complex numbers like hermitian, skew-hermitian and unitary?

Thank you

[lezcano]

There is no plan to support those yet, but I'd happily take a PR adding them.

Here you have an example of a PR that adds a new manifold to the library: #31

It's worth noting the limited support of PyTorch when it comes to complex numbers and optimisers though:
pytorch/pytorch#59998
pytorch/pytorch#65711