Sparse CSR CPU: add `addmv_out` (#61536)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61536
This PR adds CPU dispatch for `addmv_out` with Sparse CSR matrix.
The implementation uses MKL Sparse library. If it's not available then a
runtime error is thrown.
Since structured_delegate is used we only need to implement the out variant, the in-place and normal variants are autogenerated.
MKL descriptor of sparse matrices is implemented in `at::mkl::sparse::MklSparseCsrDescriptor`.
MKL Sparse doesn't allow switching indices type in runtime, it's
predetermined in build time. Only 32-bit version of MKL was tested
locally, but I expect 64-bit version to work correctly as well.
When indices type of PyTorch CSR tensor doesn't match with MKL's,
indices tensor is converted to MKL compatible type (`int` vs `int64_t`).
cc nikitaved pearu cpuhrsch IvanYashchuk
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D32141787
Pulled By: malfet
fbshipit-source-id: b818a0b186aa227982221c3862a594266a58a2a6
