pytorch

b02c5147 - [PT-D][Sharded Tensor] new init api for local tensor and sharding spec auto inference (#72733)

[PT-D][Sharded Tensor] new init api for local tensor and sharding spec auto inference (#72733) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/72733 To improve the perf cost due to communication in the process of init the sharded tensor. There are two changes in this PR/diff: 1. We create a new API named `_init_from_local_tensor` so that if we have only one local tensor, we can initiate a sharded tensor directly from it. (GH issue: https://github.com/pytorch/pytorch/issues/72092) 2. We create a new API to infer the sharding spec from global meta data, so we don't have to manually set the sharding spec when it's not `EnumerableShardingSpec`. (GH issue: https://github.com/pytorch/pytorch/issues/67244) ghstack-source-id: 149229259 Test Plan: CI Reviewed By: wanchaol Differential Revision: D34132739 fbshipit-source-id: 3a60135761bcc19d6020b6c45cb2979869645ce6 (cherry picked from commit af569325e2794309a4a86e51749642a062a25f6e)