pytorch

e18a2219 - Implement scatter reductions (CUDA), remove divide/subtract (#41977)

Implement scatter reductions (CUDA), remove divide/subtract (#41977) Summary: Fixes https://github.com/pytorch/pytorch/issues/33394 . This PR does two things: 1. Implement CUDA scatter reductions with revamped GPU atomic operations. 2. Remove support for divide and subtract for CPU reduction as was discussed with ngimel . I've also updated the docs to reflect the existence of only multiply and add. Pull Request resolved: https://github.com/pytorch/pytorch/pull/41977 Reviewed By: mruberry Differential Revision: D23748888 Pulled By: ngimel fbshipit-source-id: ea643c0da03c9058e433de96db02b503514c4e9c