Simplify GPU and TPU accelerator (#5024)

Author: rohitgr7

pytorch_lightning/accelerators/gpu_accelerator.py

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Any, Optional, Union
+from typing import Any, Callable, Optional, Union
 
 import torch
 
@@ -66,53 +66,25 @@ def train(self):
         results = self.train_or_test()
         return results
 
-    def training_step(self, args):
+    def _step(self, model_step: Callable, args):
+        args[0] = self.to_device(args[0])
+
         if self.trainer.amp_backend == AMPType.NATIVE:
             with torch.cuda.amp.autocast():
-                output = self.__training_step(args)
+                output = model_step(*args)
         else:
-            output = self.__training_step(args)
+            output = model_step(*args)
 
         return output
 
-    def __training_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.training_step(*args)
-        return output
+    def training_step(self, args):
+        return self._step(self.trainer.model.training_step, args)
 
     def validation_step(self, args):
-        if self.trainer.amp_backend == AMPType.NATIVE:
-            with torch.cuda.amp.autocast():
-                output = self.__validation_step(args)
-        else:
-            output = self.__validation_step(args)
-
-        return output
-
-    def __validation_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.validation_step(*args)
-        return output
+        return self._step(self.trainer.model.validation_step, args)
 
     def test_step(self, args):
-        if self.trainer.amp_backend == AMPType.NATIVE:
-            with torch.cuda.amp.autocast():
-                output = self.__test_step(args)
-        else:
-            output = self.__test_step(args)
-
-        return output
-
-    def __test_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.test_step(*args)
-        return output
+        return self._step(self.trainer.model.test_step, args)
 
     def to_device(self, batch):
         gpu_id = 0

pytorch_lightning/accelerators/tpu_accelerator.py

@@ -14,7 +14,7 @@
 import io
 import os
 import re
-from typing import Any, Optional, Union
+from typing import Any, Callable, Optional, Union
 
 import torch
 import torch.multiprocessing as mp
@@ -145,26 +145,18 @@ def tpu_train_in_process(self, tpu_core_idx: int, model: LightningModule, traine
         # persist info in spawn
         self.transfer_distrib_spawn_state_on_fit_end(model, mp_queue, results)
 
+    def _step(self, model_step: Callable, args):
+        args[0] = self.to_device(args[0])
+        return model_step(*args)
+
     def training_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.training_step(*args)
-        return output
+        return self._step(self.trainer.model.training_step, args)
 
     def validation_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.validation_step(*args)
-        return output
+        return self._step(self.trainer.model.validation_step, args)
 
     def test_step(self, args):
-        batch = args[0]
-        batch = self.to_device(batch)
-        args[0] = batch
-        output = self.trainer.model.test_step(*args)
-        return output
+        return self._step(self.trainer.model.test_step, args)
 
     def process_dataloader(self, dataloader):
         device = xm.xla_device(self.trainer.tpu_id)