remove find unused param (#477)

Author: yiheng-wang-nv

modules/dynunet_pipeline/train.py

@@ -52,9 +52,7 @@ def validation(args):
     net = net.to(device)
 
     if multi_gpu_flag:
-        net = DistributedDataParallel(
-            module=net, device_ids=[device], find_unused_parameters=True
-        )
+        net = DistributedDataParallel(module=net, device_ids=[device])
 
     num_classes = len(properties["labels"])
 
@@ -139,9 +137,7 @@ def train(args):
     net = net.to(device)
 
     if multi_gpu_flag:
-        net = DistributedDataParallel(
-            module=net, device_ids=[device], find_unused_parameters=True
-        )
+        net = DistributedDataParallel(module=net, device_ids=[device])
 
     optimizer = torch.optim.SGD(
         net.parameters(),
@@ -193,7 +189,9 @@ def train(args):
 
     train_handlers += [
         ValidationHandler(validator=evaluator, interval=interval, epoch_level=True),
-        StatsHandler(tag_name="train_loss", output_transform=from_engine(["loss"], first=True)),
+        StatsHandler(
+            tag_name="train_loss", output_transform=from_engine(["loss"], first=True)
+        ),
     ]
 
     trainer = DynUNetTrainer(