pytorch

c60232d8 - [shard] add back init_from_local_shard_and_global_metadata API (#69226)

[shard] add back init_from_local_shard_and_global_metadata API (#69226) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/69226 This add back the previous init_from_local_shards API, but renamed it to init_from_local_shard_and_global_metadata. It's a partial revert of D32147888 (https://github.com/pytorch/pytorch/commit/35712a8eb4eb9109c4c675ad8b3c249bb539af8d). We now provide two APIs: 1. `init_from_local_shards`: user don't need to provide global metadata and we do all_gather under the hood, the other that 2. `init_from_local_shards_and_global_metadata`: user need to explicitly construct ShardedTensorMetadata to use this API, need to ensure correctness on all ranks, as there's no cross-rank communication/validations. All of these two APIs stay private until it stablizes and proof of UX. The second one can only be called on `ShardedTensor` class directly, not included as a package API for now. Test Plan: test_init_from_local_shards_and_global_metadata test_init_from_local_shards_and_global_metadata_invalid_shards Reviewed By: dstaay-fb, pritamdamania87 Differential Revision: D32746882 fbshipit-source-id: bafd26ce16c02e2095907f9e59984a5d775c7df5