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Co-authored-by: Adrian Wälchli <[email protected]>

Author: four4fish

pytorch_lightning/plugins/collective/horovod_collective.py

@@ -32,14 +32,14 @@ def __init__(
         self,
         on_gpu: Optional[bool] = False,
         local_rank: int = 0,
-    ):
+    ) -> None:
         self.on_gpu = on_gpu
         self.local_rank = local_rank
 
     def join(self) -> None:
         """Horovod function that indicates that the rank finished processing data.
 
-        All ranks that did not call join() continue to process allreduce operations. This function blocks Python thread
+        All ranks that did not call join() continue to process allreduce operations. This function blocks the Python thread
         until all ranks join.
         """
         if self.on_gpu:

pytorch_lightning/plugins/collective/torch_collective.py

@@ -36,12 +36,12 @@ def __init__(
         device: Optional[Union[str, torch.device]] = torch.device("cpu"),
         device_id: Optional[int] = None,
         world_size: int = 1,
-    ):
-        """.. note::
-
-        DDP and DDPSpawn sync accross multiple nodes/devices, local_reduce = False
-        DP run reduce in on node, local_reduce = True
-        DDP2 behaves like DP in one node, local_reduce = True
+    ) -> None:
+        """
+        Note:
+            DDP and DDPSpawn sync accross multiple nodes/devices, local_reduce = False
+            DP run reduce in on node, local_reduce = True
+            DDP2 behaves like DP in one node, local_reduce = True
 
         local_reduce set in Plugins.setup() functions
         """
@@ -84,6 +84,7 @@ def reduce(
         If local_reduce = True (dp and ddp2), reduces tensor from all local processes.
 
         If local_reduce = False (ddp, ddpspawning and extentions), reduces a tensor from several distributed processes
+        
         Args:
             tensor: the tensor to sync and reduce
             group: the process group to gather results from. Defaults to all processes (world)