Added linalg.inv (#48261)
Summary:
This PR adds `torch.linalg.inv` for NumPy compatibility.
`linalg_inv_out` uses in-place operations on provided `result` tensor.
I modified `apply_inverse` to accept tensor of Int instead of std::vector, that way we can write a function similar to `linalg_inv_out` but removing the error checks and device memory synchronization.
I fixed `lda` (leading dimension parameter which is max(1, n)) in many places to handle 0x0 matrices correctly.
Zero batch dimensions are also working and tested.
Ref https://github.com/pytorch/pytorch/issues/42666
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48261
Reviewed By: ngimel
Differential Revision: D25690129
Pulled By: mruberry
fbshipit-source-id: edb2d03721f22168c42ded8458513cb23dfdc712
