Refactor: 1/n legacy accelerators and plugins

CHANGELOG.md

@@ -102,6 +102,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - `stat_scores_multiple_classes` is deprecated in favor of `stat_scores` ([#4839](https://github.com/PyTorchLightning/pytorch-lightning/pull/4839))
 
 
+- Moved accelerators and plugins to its `legacy` pkg ([#5645](https://github.com/PyTorchLightning/pytorch-lightning/pull/5645))
+
+
 ### Removed
 
 - Removed deprecated checkpoint argument `filepath` ([#5321](https://github.com/PyTorchLightning/pytorch-lightning/pull/5321))

benchmarks/test_sharded_parity.py

@@ -21,10 +21,10 @@
 import torch
 
 from pytorch_lightning import seed_everything, Trainer
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.sharded_plugin import DDPShardedPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.sharded_plugin import DDPShardedPlugin
 from pytorch_lightning.utilities import _FAIRSCALE_AVAILABLE, _NATIVE_AMP_AVAILABLE
-from tests.backends import DDPLauncher
+from tests.accelerators.legacy import DDPLauncher
 from tests.base.boring_model import BoringModel, RandomDataset
 
 

dockers/tpu-tests/tpu_test_cases.jsonnet

@@ -21,7 +21,10 @@ local tputests = base.BaseTest {
   command: utils.scriptCommand(
     |||
       cd pytorch-lightning
-      coverage run --source=pytorch_lightning -m pytest tests/models/test_tpu.py tests/backends/test_tpu_backend.py pytorch_lightning/utilities/xla_device_utils.py -v
+      coverage run --source=pytorch_lightning -m pytest -v \
+          pytorch_lightning/utilities/xla_device_utils.py \
+          tests/accelerators/legacy/test_tpu_backend.py \
+          tests/models/test_tpu.py
       test_exit_code=$?
       echo "\n||| END PYTEST LOGS |||\n"
       coverage xml

docs/source/advanced/multi_gpu.rst

@@ -580,9 +580,9 @@ Below are the possible configurations we support.
 
 Implement Your Own Distributed (DDP) training
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-If you need your own way to init PyTorch DDP you can override :meth:`pytorch_lightning.plugins.ddp_plugin.DDPPlugin.init_ddp_connection`.
+If you need your own way to init PyTorch DDP you can override :meth:`pytorch_lightning.plugins.legacy.ddp_plugin.DDPPlugin.init_ddp_connection`.
 
-If you also need to use your own DDP implementation, override :meth:`pytorch_lightning.plugins.ddp_plugin.DDPPlugin.configure_ddp`.
+If you also need to use your own DDP implementation, override :meth:`pytorch_lightning.plugins.legacy.ddp_plugin.DDPPlugin.configure_ddp`.
 
 
 ----------
@@ -692,7 +692,7 @@ This should be kept within the ``sequential_module`` variable within your ``Ligh
 
 .. code-block:: python
 
-    from pytorch_lightning.plugins.ddp_sequential_plugin import DDPSequentialPlugin
+    from pytorch_lightning.plugins.legacy.ddp_sequential_plugin import DDPSequentialPlugin
     from pytorch_lightning import LightningModule
 
     class MyModel(LightningModule):

docs/source/extensions/accelerators.rst

@@ -16,7 +16,7 @@ To link up arbitrary hardware, implement your own Accelerator subclass
 
 .. code-block:: python
 
-    from pytorch_lightning.accelerators.accelerator import Accelerator
+    from pytorch_lightning.accelerators.legacy.accelerator import Accelerator
 
         class MyAccelerator(Accelerator):
             def __init__(self, trainer, cluster_environment=None):
@@ -124,59 +124,59 @@ Available Accelerators
 CPU Accelerator
 ===============
 
-.. autoclass:: pytorch_lightning.accelerators.cpu_accelerator.CPUAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.cpu_accelerator.CPUAccelerator
     :noindex:
 
 DDP Accelerator
 ===============
 
-.. autoclass:: pytorch_lightning.accelerators.ddp_accelerator.DDPAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp_accelerator.DDPAccelerator
     :noindex:
 
 DDP2 Accelerator
 ================
 
-.. autoclass:: pytorch_lightning.accelerators.ddp2_accelerator.DDP2Accelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp2_accelerator.DDP2Accelerator
     :noindex:
 
 DDP CPU HPC Accelerator
 =======================
 
-.. autoclass:: pytorch_lightning.accelerators.ddp_cpu_hpc_accelerator.DDPCPUHPCAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp_cpu_hpc_accelerator.DDPCPUHPCAccelerator
     :noindex:
 
 DDP CPU Spawn Accelerator
 =========================
 
-.. autoclass:: pytorch_lightning.accelerators.ddp_cpu_spawn_accelerator.DDPCPUSpawnAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp_cpu_spawn_accelerator.DDPCPUSpawnAccelerator
     :noindex:
 
 DDP HPC Accelerator
 ===================
 
-.. autoclass:: pytorch_lightning.accelerators.ddp_hpc_accelerator.DDPHPCAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp_hpc_accelerator.DDPHPCAccelerator
     :noindex:
 
 DDP Spawn Accelerator
 =====================
 
-.. autoclass:: pytorch_lightning.accelerators.ddp_spawn_accelerator.DDPSpawnAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.ddp_spawn_accelerator.DDPSpawnAccelerator
     :noindex:
 
 GPU Accelerator
 ===============
 
-.. autoclass:: pytorch_lightning.accelerators.gpu_accelerator.GPUAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.gpu_accelerator.GPUAccelerator
     :noindex:
 
 Horovod Accelerator
 ===================
 
-.. autoclass:: pytorch_lightning.accelerators.horovod_accelerator.HorovodAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.horovod_accelerator.HorovodAccelerator
     :noindex:
 
 TPU Accelerator
 ===============
 
-.. autoclass:: pytorch_lightning.accelerators.tpu_accelerator.TPUAccelerator
+.. autoclass:: pytorch_lightning.accelerators.legacy.tpu_accelerator.TPUAccelerator
     :noindex:

docs/source/extensions/plugins.rst

@@ -19,16 +19,16 @@ For example, to customize your own DistributedDataParallel you could do somethin
 ApexPlugin
 **********
 
-.. autoclass:: pytorch_lightning.plugins.apex.ApexPlugin
+.. autoclass:: pytorch_lightning.plugins.legacy.apex.ApexPlugin
 
 ***************
 NativeAMPPlugin
 ***************
 
-.. autoclass:: pytorch_lightning.plugins.native_amp.NativeAMPPlugin
+.. autoclass:: pytorch_lightning.plugins.legacy.native_amp.NativeAMPPlugin
 
 *********
 DDPPlugin
 *********
 
-.. autoclass:: pytorch_lightning.plugins.ddp_plugin.DDPPlugin
+.. autoclass:: pytorch_lightning.plugins.legacy.ddp_plugin.DDPPlugin

pl_examples/basic_examples/conv_sequential_example.py

@@ -32,7 +32,7 @@
 from pl_examples import cli_lightning_logo
 from pytorch_lightning import Trainer
 from pytorch_lightning.metrics.functional import accuracy
-from pytorch_lightning.plugins.ddp_sequential_plugin import DDPSequentialPlugin
+from pytorch_lightning.plugins.legacy.ddp_sequential_plugin import DDPSequentialPlugin
 from pytorch_lightning.utilities import _BOLTS_AVAILABLE, _FAIRSCALE_PIPE_AVAILABLE
 
 if _BOLTS_AVAILABLE:

pytorch_lightning/accelerators/__init__.py

@@ -11,15 +11,15 @@
 # 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 pytorch_lightning.accelerators.accelerator import Accelerator  # noqa: F401
-from pytorch_lightning.accelerators.cpu_accelerator import CPUAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp2_accelerator import DDP2Accelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp_accelerator import DDPAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp_cpu_hpc_accelerator import DDPCPUHPCAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp_cpu_spawn_accelerator import DDPCPUSpawnAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp_hpc_accelerator import DDPHPCAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.ddp_spawn_accelerator import DDPSpawnAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.dp_accelerator import DataParallelAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.gpu_accelerator import GPUAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.horovod_accelerator import HorovodAccelerator  # noqa: F401
-from pytorch_lightning.accelerators.tpu_accelerator import TPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.cpu_accelerator import CPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp2_accelerator import DDP2Accelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_accelerator import DDPAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_cpu_hpc_accelerator import DDPCPUHPCAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_cpu_spawn_accelerator import DDPCPUSpawnAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_hpc_accelerator import DDPHPCAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_spawn_accelerator import DDPSpawnAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.dp_accelerator import DataParallelAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.gpu_accelerator import GPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.horovod_accelerator import HorovodAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.tpu_accelerator import TPUAccelerator  # noqa: F401

pytorch_lightning/accelerators/legacy/__init__.py

@@ -0,0 +1,25 @@
+# Copyright The PyTorch Lightning team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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 pytorch_lightning.accelerators.legacy.accelerator import Accelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.cpu_accelerator import CPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp2_accelerator import DDP2Accelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_accelerator import DDPAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_cpu_hpc_accelerator import DDPCPUHPCAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_cpu_spawn_accelerator import DDPCPUSpawnAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_hpc_accelerator import DDPHPCAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.ddp_spawn_accelerator import DDPSpawnAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.dp_accelerator import DataParallelAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.gpu_accelerator import GPUAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.horovod_accelerator import HorovodAccelerator  # noqa: F401
+from pytorch_lightning.accelerators.legacy.tpu_accelerator import TPUAccelerator  # noqa: F401

pytorch_lightning/accelerators/accelerator.py → pytorch_lightning/accelerators/legacy/accelerator.py

@@ -19,8 +19,8 @@
 
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities.apply_func import move_data_to_device
 from pytorch_lightning.utilities.parsing import AttributeDict
 

pytorch_lightning/accelerators/accelerator_connector.py → pytorch_lightning/accelerators/legacy/accelerator_connector.py

@@ -17,7 +17,7 @@
 
 from pytorch_lightning import _logger as log
 from pytorch_lightning import accelerators
-from pytorch_lightning.accelerators.accelerator import Accelerator
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator
 from pytorch_lightning.cluster_environments.slurm_environment import SLURMEnvironment
 from pytorch_lightning.cluster_environments.torchelastic_environment import TorchElasticEnvironment
 from pytorch_lightning.utilities import (

pytorch_lightning/accelerators/cpu_accelerator.py → pytorch_lightning/accelerators/legacy/cpu_accelerator.py

@@ -15,7 +15,7 @@
 
 import torch
 
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.utilities import AMPType
 from pytorch_lightning.utilities.exceptions import MisconfigurationException

pytorch_lightning/accelerators/ddp2_accelerator.py → pytorch_lightning/accelerators/legacy/ddp2_accelerator.py

@@ -18,13 +18,13 @@
 from torch.nn.parallel import DistributedDataParallel
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.core.step_result import Result
 from pytorch_lightning.distributed.dist import LightningDistributed
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities import AMPType
 from pytorch_lightning.utilities.distributed import all_gather_ddp_if_available, rank_zero_only, sync_ddp_if_available
 

pytorch_lightning/accelerators/ddp_accelerator.py → pytorch_lightning/accelerators/legacy/ddp_accelerator.py

@@ -24,12 +24,12 @@
 from torch.nn.parallel import DistributedDataParallel
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.distributed.dist import LightningDistributed
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities import _HYDRA_AVAILABLE, AMPType
 from pytorch_lightning.utilities.distributed import (
     all_gather_ddp_if_available,

pytorch_lightning/accelerators/ddp_cpu_hpc_accelerator.py → pytorch_lightning/accelerators/legacy/ddp_cpu_hpc_accelerator.py

@@ -13,9 +13,9 @@
 # limitations under the License
 from typing import Optional
 
-from pytorch_lightning.accelerators.ddp_hpc_accelerator import DDPHPCAccelerator
+from pytorch_lightning.accelerators.legacy.ddp_hpc_accelerator import DDPHPCAccelerator
 from pytorch_lightning.cluster_environments import ClusterEnvironment
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
 
 
 class DDPCPUHPCAccelerator(DDPHPCAccelerator):

pytorch_lightning/accelerators/ddp_cpu_spawn_accelerator.py → pytorch_lightning/accelerators/legacy/ddp_cpu_spawn_accelerator.py

@@ -20,12 +20,12 @@
 from torch.nn.parallel import DistributedDataParallel
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.distributed.dist import LightningDistributed
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities import AMPType
 from pytorch_lightning.utilities.distributed import (
     all_gather_ddp_if_available,

pytorch_lightning/accelerators/ddp_hpc_accelerator.py → pytorch_lightning/accelerators/legacy/ddp_hpc_accelerator.py

@@ -19,12 +19,12 @@
 from torch.nn.parallel import DistributedDataParallel
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.distributed.dist import LightningDistributed
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities import AMPType
 from pytorch_lightning.utilities.distributed import all_gather_ddp_if_available, rank_zero_only, sync_ddp_if_available
 

pytorch_lightning/accelerators/ddp_spawn_accelerator.py → pytorch_lightning/accelerators/legacy/ddp_spawn_accelerator.py

@@ -21,12 +21,12 @@
 from torch.nn.parallel import DistributedDataParallel
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.distributed import LightningDistributed
-from pytorch_lightning.plugins.ddp_plugin import DDPPlugin
-from pytorch_lightning.plugins.rpc_plugin import RPCPlugin
+from pytorch_lightning.plugins.legacy.ddp_plugin import DDPPlugin
+from pytorch_lightning.plugins.legacy.rpc_plugin import RPCPlugin
 from pytorch_lightning.utilities import AMPType
 from pytorch_lightning.utilities.cloud_io import atomic_save
 from pytorch_lightning.utilities.cloud_io import load as pl_load

pytorch_lightning/accelerators/dp_accelerator.py → pytorch_lightning/accelerators/legacy/dp_accelerator.py

@@ -16,7 +16,7 @@
 import torch
 from torch import optim
 
-from pytorch_lightning.accelerators.accelerator import Accelerator
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.core.step_result import Result

pytorch_lightning/accelerators/gpu_accelerator.py → pytorch_lightning/accelerators/legacy/gpu_accelerator.py

@@ -15,7 +15,7 @@
 
 import torch
 
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.distributed.dist import LightningDistributed
 from pytorch_lightning.utilities import AMPType

pytorch_lightning/accelerators/horovod_accelerator.py → pytorch_lightning/accelerators/legacy/horovod_accelerator.py

@@ -17,7 +17,7 @@
 import torch
 from torch.optim.lr_scheduler import _LRScheduler
 
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.utilities import _HOROVOD_AVAILABLE, AMPType, DeviceType
 from pytorch_lightning.utilities.distributed import rank_zero_only

pytorch_lightning/accelerators/tpu_accelerator.py → pytorch_lightning/accelerators/legacy/tpu_accelerator.py

@@ -21,7 +21,7 @@
 from torch.optim import Optimizer
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.accelerators.accelerator import Accelerator, ReduceOp
+from pytorch_lightning.accelerators.legacy.accelerator import Accelerator, ReduceOp
 from pytorch_lightning.cluster_environments import ClusterEnvironment
 from pytorch_lightning.core import LightningModule
 from pytorch_lightning.utilities import (

pytorch_lightning/cluster_environments/cluster_environment.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from pytorch_lightning.plugins.plugin import LightningPlugin
+from pytorch_lightning.plugins.legacy.plugin import LightningPlugin
 
 
 class ClusterEnvironment(LightningPlugin):

pytorch_lightning/plugins/apex.py → pytorch_lightning/plugins/legacy/apex.py

@@ -17,7 +17,7 @@
 from torch.optim.optimizer import Optimizer
 
 from pytorch_lightning.core.lightning import LightningModule
-from pytorch_lightning.plugins.precision_plugin import PrecisionPlugin
+from pytorch_lightning.plugins.legacy.precision_plugin import PrecisionPlugin
 from pytorch_lightning.utilities import _APEX_AVAILABLE, AMPType
 from pytorch_lightning.utilities.distributed import rank_zero_warn