[Fix] fix local-rank in pytorch2.0 (#728)

tools/train.py

@@ -38,7 +38,10 @@ def parse_args():
         choices=['none', 'pytorch', 'slurm', 'mpi'],
         default='none',
         help='job launcher')
-    parser.add_argument('--local_rank', type=int, default=0)
+    # When using PyTorch version >= 2.0.0, the `torch.distributed.launch`
+    # will pass the `--local-rank` parameter to `tools/train.py` instead
+    # of `--local_rank`.
+    parser.add_argument('--local_rank', '--local-rank', type=int, default=0)
     args = parser.parse_args()
     if 'LOCAL_RANK' not in os.environ:
         os.environ['LOCAL_RANK'] = str(args.local_rank)