Add BPR loss to TTSN (#24439)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24439
many literatures mentioned BPR is useful for improving recommendation quality. Add a BPR loss so that we can train TTSN with it. Would like to see if it can improve retrieval models.
reference: https://arxiv.org/pdf/1205.2618.pdf
Reviewed By: dragonxlwang
Differential Revision: D16812513
fbshipit-source-id: 74488c714a37ccd10e0666d225751a845019eb94
