pytorch

d6f1346c - Add a new op for converting the dense feature to sparse representation

Add a new op for converting the dense feature to sparse representation Summary: we need this op to avoid the splicing of a dense tensor and then use the Mergesinglescaler op Test Plan: integrated test with dper2 Differential Revision: D22677523 fbshipit-source-id: f4f9a1f06841b0906ec8cbb435482ae0a89e1721