[c++] Distance-agnostic triplet margin loss (#45377)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45377
This PR adds a C++ implementation of the TripletMarginWithDistanceLoss, for which the Python implementation was introduced in PR #43680. It's based on PR #44072, but I'm resubmitting this to unlink it from Phabricator.
Test Plan: Imported from OSS
Reviewed By: izdeby
Differential Revision: D24003973
fbshipit-source-id: 2d9ada7260a6f27425ff2fdbbf623dad0fb79405
