- class pytorch_lightning.strategies.DDP2Strategy(accelerator=None, parallel_devices=None, cluster_environment=None, checkpoint_io=None, precision_plugin=None, ddp_comm_state=None, ddp_comm_hook=None, ddp_comm_wrapper=None, model_averaging_period=None, process_group_backend=None, **kwargs)¶
DDP2 behaves like DP in one node, but synchronization across nodes behaves like in DDP.
Moves the model to the correct device.
- reduce(collection, *args, **kwargs)¶
Reduces a collection of tensors from all processes. It can be applied to just a single tensor. In DDP2, the reduction here is only across local devices within the node.
- Return type
Reduced tensor values or the same value if it was not or did not contain a tensor.
- property root_device¶
Return the root device.