Change BCELoss size mismatch warning into an error (#41426)
Summary:
BCELoss currently uses different broadcasting semantics than numpy. Since previous versions of PyTorch have thrown a warning in these cases telling the user that input sizes should match, and since the CUDA and CPU results differ when sizes do not match, it makes sense to upgrade the size mismatch warning to an error.
We can consider supporting numpy broadcasting semantics in BCELoss in the future if needed.
Closes https://github.com/pytorch/pytorch/issues/40023
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41426
Reviewed By: zou3519
Differential Revision: D22540841
Pulled By: ezyang
fbshipit-source-id: 6c6d94c78fa0ae30ebe385d05a9e3501a42b3652
