Import MultiheadAttention to PyTorch (#18334)
Summary:
Import MultiheadAttention into the core pytorch framework.
Users now can import MultiheadAttention directly from torch.nn.
See "Attention Is All You Need" for more details related to MultiheadAttention function.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18334
Differential Revision: D14577966
Pulled By: zhangguanheng66
fbshipit-source-id: 756c0deff623f3780651d9f9a70ce84516c806d3
