CLI DDP fixes (#135)

ultralytics/hub/utils.py

@@ -5,7 +5,7 @@ import time
 import requests
 
 from ultralytics.hub.config import HUB_API_ROOT
-from ultralytics.yolo.utils import DEFAULT_CONFIG_DICT, LOGGER, RANK, SETTINGS, colorstr, emojis, yaml_load
+from ultralytics.yolo.utils import DEFAULT_CONFIG_DICT, LOGGER, RANK, SETTINGS, colorstr, emojis
 
 PREFIX = colorstr('Ultralytics: ')
 HELP_MSG = 'If this issue persists please visit https://github.com/ultralytics/hub/issues for assistance.'
@@ -49,7 +49,7 @@ def request_with_credentials(url: str) -> any:
 
 
 # Deprecated TODO: eliminate this function?
-def split_key(key: str = '') -> tuple[str, str]:
+def split_key(key=''):
     """
     Verify and split a 'api_key[sep]model_id' string, sep is one of '.' or '_'
 

ultralytics/yolo/utils/torch_utils.py

@@ -29,10 +29,11 @@ WORLD_SIZE = int(os.getenv('WORLD_SIZE', 1))
 @contextmanager
 def torch_distributed_zero_first(local_rank: int):
     # Decorator to make all processes in distributed training wait for each local_master to do something
-    if local_rank not in {-1, 0}:
+    initialized = torch.distributed.is_initialized()  # prevent 'Default process group has not been initialized' errors
+    if initialized and local_rank not in {-1, 0}:
         dist.barrier(device_ids=[local_rank])
     yield
-    if local_rank == 0:
+    if initialized and local_rank == 0:
         dist.barrier(device_ids=[0])