Added sublist support for torch.einsum (#56625)
Summary:
This PR adds an alternative way of calling `torch.einsum`. Instead of specifying the subscripts as letters in the `equation` parameter, one can now specify the subscripts as a list of integers as in `torch.einsum(operand1, subscripts1, operand2, subscripts2, ..., [subscripts_out])`. This would be equivalent to `torch.einsum('<subscripts1>,<subscripts2>,...,->[<subscript_out>]', operand1, operand2, ...)`
TODO
- [x] Update documentation
- [x] Add more error checking
- [x] Update tests
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56625
Reviewed By: zou3519
Differential Revision: D28062616
Pulled By: heitorschueroff
fbshipit-source-id: ec50ad34f127210696e7c545e4c0675166f127dc
