text: # 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.
  import argparse
  import contextlib
  import json
  import logging
  import os
  import platform
  from collections import OrderedDict
  from pathlib import Path
  from typing import Any, Dict, Generator, List, Mapping, Optional, Tuple, Union
  
  import torch
  from torch.nn import Module
  from torch.optim import Optimizer
  
  import pytorch_lightning as pl
  from pytorch_lightning.core.optimizer import _get_default_scheduler_config, _init_optimizers_and_lr_schedulers
  from pytorch_lightning.overrides.base import _LightningModuleWrapperBase
  from pytorch_lightning.plugins.environments.cluster_environment import ClusterEnvironment
  from pytorch_lightning.plugins.precision import PrecisionPlugin
  from pytorch_lightning.strategies.ddp import DDPStrategy
  from pytorch_lightning.trainer.states import TrainerFn
  from pytorch_lightning.utilities import GradClipAlgorithmType
  from pytorch_lightning.utilities.apply_func import apply_to_collection
  from pytorch_lightning.utilities.distributed import log, rank_zero_info
  from pytorch_lightning.utilities.enums import _StrategyType, AMPType, PrecisionType
  from pytorch_lightning.utilities.exceptions import MisconfigurationException
  from pytorch_lightning.utilities.imports import _DEEPSPEED_AVAILABLE
  from pytorch_lightning.utilities.model_helpers import is_overridden
  from pytorch_lightning.utilities.seed import reset_seed
  from pytorch_lightning.utilities.types import _PATH, LRSchedulerConfig, LRSchedulerTypeUnion, STEP_OUTPUT
  from pytorch_lightning.utilities.warnings import rank_zero_warn, WarningCache
  
  warning_cache = WarningCache()
  
  if _DEEPSPEED_AVAILABLE:
      import deepspeed
  
  
  def remove_module_hooks(model: torch.nn.Module) -> None:
      # todo (tchaton) awaiting this feature to move upstream to DeepSpeed
      for module in model.modules():
          module._backward_hooks = OrderedDict()
          module._is_full_backward_hook = None
          module._forward_hooks = OrderedDict()
          module._forward_pre_hooks = OrderedDict()
          module._state_dict_hooks = OrderedDict()
          module._load_state_dict_pre_hooks = OrderedDict()
  
  
  class LightningDeepSpeedModule(_LightningModuleWrapperBase):
      def __init__(self, pl_module: "pl.LightningModule", precision: int) -> None:
          super().__init__(pl_module)
          self.precision = precision
  
      def forward(self, *inputs, **kwargs):
          if self.precision == 16:
              inputs = self._move_float_tensors_to_half(inputs)
  
          return super().forward(*inputs, **kwargs)
  
      @staticmethod
      def batch_to(data):
          return data.half()
  
      def _move_float_tensors_to_half(self, batch: Any):
          batch = apply_to_collection(batch, (torch.FloatTensor, torch.cuda.FloatTensor), function=self.batch_to)
          return batch
  
  
  class DeepSpeedStrategy(DDPStrategy):
      distributed_backend = _StrategyType.DEEPSPEED
      DEEPSPEED_ENV_VAR = "PL_DEEPSPEED_CONFIG_PATH"
  
      def __init__(
          self,
          accelerator: Optional["pl.accelerators.accelerator.Accelerator"] = None,
          zero_optimization: bool = True,
          stage: int = 2,
          remote_device: str = "cpu",
          offload_optimizer: bool = False,
          offload_parameters: bool = False,
          offload_params_device: str = "cpu",
          nvme_path: str = "/local_nvme",
          params_buffer_count: int = 5,
          params_buffer_size: int = 1e8,
          max_in_cpu: int = 1e9,
          offload_optimizer_device: str = "cpu",
          optimizer_buffer_count: int = 4,
          block_size: int = 1048576,
          queue_depth: int = 8,
          single_submit: bool = False,
          overlap_events: bool = True,
          thread_count: int = 1,
          pin_memory: bool = False,
          sub_group_size: int = 1e12,
          contiguous_gradients: bool = True,
          overlap_comm: bool = True,
          allgather_partitions: bool = True,
          reduce_scatter: bool = True,
          allgather_bucket_size: int = 2e8,
          reduce_bucket_size: int = 2e8,
          zero_allow_untested_optimizer: bool = True,
          logging_batch_size_per_gpu: Union[str, int] = "auto",
          config: Optional[Union[Path, str, dict]] = None,
          logging_level: int = logging.WARN,
          parallel_devices: Optional[List[torch.device]] = None,
          cluster_environment: Optional[ClusterEnvironment] = None,
          loss_scale: float = 0,
          initial_scale_power: int = 16,
          loss_scale_window: int = 1000,
          hysteresis: int = 2,
          min_loss_scale: int = 1,
          partition_activations: bool = False,
          cpu_checkpointing: bool = False,
          contiguous_memory_optimization: bool = False,
          synchronize_checkpoint_boundary: bool = False,
          load_full_weights: bool = False,
          precision_plugin: Optional[PrecisionPlugin] = None,
      ) -> None:
          """Provides capabilities to run training using the DeepSpeed library, with training optimizations for large
          billion parameter models. `For more information: https://pytorch-
          lightning.readthedocs.io/en/latest/advanced/advanced_gpu.html#deepspeed`.
  
          .. warning:: ``DeepSpeedStrategy`` is in beta and subject to change.
  
          Defaults have been set to enable ZeRO-Offload and some have been taken from the link below.
          These defaults have been set generally, but may require tuning for optimum performance based on your model size.
          `For more information: https://www.deepspeed.ai/docs/config-json/#zero-optimizations-for-fp16-training`.
  
          Arguments:
  
              zero_optimization: Enable ZeRO optimization. This is only compatible with precision=16.
  
              stage: Different stages of the ZeRO Optimizer. 0 is disabled,
                  1 is optimizer state partitioning, 2 is optimizer+gradient state partitioning,
                  3 is optimizer+gradient_parameter partitioning using the infinity engine.
  
              remote_device: Device to instantiate the model on initially (``cpu`` or ``nvme``).
  
              offload_optimizer: Enable offloading optimizer memory and computation to CPU or NVMe
                  based on ``offload_optimizer_device``.
  
              offload_parameters: When using ZeRO Stage 3, Enable offloading parameter memory and computation
                  to CPU or NVMe based on ``offload_params_device``.
  
              offload_params_device: When offloading parameters choose the device to offload to, ``cpu`` or ``nvme``.
  
              offload_optimizer_device: When offloading optimizer state choose the device to offload to,
                  ``cpu`` or ``nvme``.
  
              params_buffer_count: Number of buffers in buffer pool for
                  parameter offloading when ``offload_params_device`` is ``nvme``.
  
              params_buffer_size: Size of buffers in buffer pool for parameter offloading
                  when ``offload_params_device`` is ``nvme``.
  
              max_in_cpu: Number of parameter elements to maintain in CPU memory when offloading to NVMe is enabled.
  
              nvme_path: Filesystem path for NVMe device for optimizer/parameter state offloading.
  
              optimizer_buffer_count: Number of buffers in buffer pool for optimizer state offloading
                  when ``offload_optimizer_device`` is set to to ``nvme``.
                  This should be at least the number of states maintained per parameter by the optimizer.
                  For example, Adam optimizer has 4 states (parameter, gradient, momentum, and variance).
  
              block_size: When using NVMe Offloading, the I/O block size in bytes.
  
              queue_depth: When using NVMe Offloading, the I/O queue depth.
  
              single_submit: When using NVMe Offloading,
                  submit requests to storage device as multiple individual requests,
                  as opposed to one block of requests.
  
              overlap_events: When using NVMe Offloading,
                  submit requests to storage device in an overlapped fashion
                  without waiting for completion of earlier requests.
  
              thread_count: When using NVMe Offloading,
                  Intra-request parallelism for each read/write submitted by a user thread.
  
              pin_memory: When using ZeRO stage 3, pin optimizer state memory on CPU.
                  This could boost throughput at the cost of extra memory overhead.
  
              sub_group_size: When using ZeRO stage 3, defines the number of parameters
                  within a sub group to offload at a time.
                  Smaller numbers require more communication, but improve memory efficiency.
  
              contiguous_gradients: Copies gradients to a continuous buffer as they are produced.
                  Avoids memory fragmentation during backwards. Useful when training large models.
  
              overlap_comm: Overlap the reduction (synchronization) of gradients with the backwards computation.
                  This is a speed optimization when training across multiple GPUs/machines.
  
              allgather_partitions: All gather updated parameters at the end of training step,
                  instead of using a series of broadcast collectives.
  
              reduce_scatter: Use reduce/scatter instead of allreduce to average gradients.
  
              allgather_bucket_size: Number of elements to allgather at once.
                  Used to limit the memory required for larger model sizes, with a tradeoff with speed.
  
              reduce_bucket_size: Number of elements to reduce at once.
                  Used to limit the memory required for larger model sizes, with a tradeoff with speed.
  
              zero_allow_untested_optimizer: Allow untested optimizers to be used with ZeRO. Currently only Adam is a
                  DeepSpeed supported optimizer when using ZeRO.
  
              logging_batch_size_per_gpu: Config used in DeepSpeed to calculate verbose timing for logging
                  on a per sample per second basis (only displayed if logging=logging.INFO).
                  If set to "auto", the plugin tries to infer this from
                  the train DataLoader's BatchSampler, else defaults to 1.
                  To obtain accurate logs when using datasets that do not support batch samplers,
                  set this to the actual per gpu batch size (trainer.batch_size).
  
              config: Pass in a deepspeed formatted config dict,
                  or path to a deepspeed config: https://www.deepspeed.ai/docs/config-json.
                  All defaults will be ignored if a config is passed in.
  
              logging_level: Set logging level for deepspeed.
  
              loss_scale: Loss scaling value for FP16 training.
                  0.0 results in dynamic loss scaling, otherwise static.
  
              initial_scale_power: Power of the initial dynamic loss scale value. Loss scale is computed
                  by ``2^initial_scale_power``.
  
              loss_scale_window: Window in which to raise/lower the dynamic FP16 loss scaling value.
  
              hysteresis: FP16 Delay shift in Dynamic Loss scaling.
  
              min_loss_scale: The minimum FP16 dynamic loss scaling value.
  
              partition_activations: Enables partition activation when used with ZeRO stage 3 and model parallelism.
                  Still requires you to wrap your forward functions in deepspeed.checkpointing.checkpoint.
                  See `deepspeed tutorial
                  <https://www.deepspeed.ai/tutorials/megatron/#deepspeed-activation-checkpoints-optional>`_.
  
              cpu_checkpointing: Offloads partitioned activations to CPU if ``partition_activations`` is enabled.
  
              contiguous_memory_optimization: Copies partitioned activations so that they are contiguous in memory.
                  Not supported by all models.
  
              synchronize_checkpoint_boundary: Insert :func:`torch.cuda.synchronize` at each checkpoint boundary.
  
              load_full_weights: True when loading a single checkpoint file containing the model state dict
                  when using ZeRO Stage 3. This differs from the DeepSpeed checkpoint which contains shards
                  per worker.
          """
          if not _DEEPSPEED_AVAILABLE:
              raise MisconfigurationException(
                  "To use the DeepSpeed plugin, you must have DeepSpeed installed. pip install deepspeed"
              )
  
          super().__init__(
              accelerator=accelerator,
              parallel_devices=parallel_devices,
              cluster_environment=cluster_environment,
              precision_plugin=precision_plugin,
          )
  
          self.config = self._load_config(config)
          if self.config is None:
              # User has not overridden config, set defaults
              self.config = self._create_default_config(
                  zero_optimization,
                  zero_allow_untested_optimizer,
                  logging_batch_size_per_gpu,
                  offload_optimizer=offload_optimizer,
                  offload_parameters=offload_parameters,
                  nvme_path=nvme_path,
                  offload_params_device=offload_params_device,
                  params_buffer_count=params_buffer_count,
                  params_buffer_size=params_buffer_size,
                  max_in_cpu=max_in_cpu,
                  pin_memory=pin_memory,
                  offload_optimizer_device=offload_optimizer_device,
                  optimizer_buffer_count=optimizer_buffer_count,
                  block_size=block_size,
                  queue_depth=queue_depth,
                  single_submit=single_submit,
                  overlap_events=overlap_events,
                  thread_count=thread_count,
                  partition_activations=partition_activations,
                  cpu_checkpointing=cpu_checkpointing,
                  contiguous_memory_optimization=contiguous_memory_optimization,
                  synchronize_checkpoint_boundary=synchronize_checkpoint_boundary,
                  stage=stage,
                  contiguous_gradients=contiguous_gradients,
                  overlap_comm=overlap_comm,
                  allgather_partitions=allgather_partitions,
                  reduce_scatter=reduce_scatter,
                  allgather_bucket_size=allgather_bucket_size,
                  reduce_bucket_size=reduce_bucket_size,
                  sub_group_size=sub_group_size,
              )
          self._config_initialized = False
          deepspeed.utils.logging.logger.setLevel(logging_level)
  
          self.remote_device = remote_device
          self.load_full_weights = load_full_weights
  
          # default FP16 parameters.
          self.loss_scale = loss_scale
          self.initial_scale_power = initial_scale_power
          self.loss_scale_window = loss_scale_window
          self.hysteresis = hysteresis
          self.min_loss_scale = min_loss_scale
  
      def _load_config(self, config):
          if config is None and self.DEEPSPEED_ENV_VAR in os.environ:
              rank_zero_info(f"Loading DeepSpeed config from set {self.DEEPSPEED_ENV_VAR} environment variable")
              config = os.environ[self.DEEPSPEED_ENV_VAR]
          if isinstance(config, (str, Path)):
              if not os.path.isfile(config):
                  raise MisconfigurationException(
                      f"You passed in a path to a DeepSpeed config but the path does not exist: {config}"
                  )
              with open(config) as f:
                  config = json.load(f)
          return config
  
      def setup_distributed(self):
          reset_seed()
  
          # determine which process we are and world size
          self.set_world_ranks()
  
          self._init_deepspeed_distributed()
  
          if not self._config_initialized:
              self._format_config()
              self._config_initialized = True
  
      def setup(self, trainer: "pl.Trainer") -> None:
          self.accelerator.setup(trainer)
          self.setup_optimizers(trainer)
          self.setup_precision_plugin()
          self._move_optimizer_state()
          self.init_deepspeed()
          self.barrier()
  
      def _init_deepspeed_distributed(self) -> None:
          if platform.system() != "Windows":
              # do not set env variables on windows, allow deepspeed to control setup
              self._set_node_environment_variables()
              log.info(
                  "initializing deepspeed distributed: "
                  f"GLOBAL_RANK: {self.global_rank}, "
                  f"MEMBER: {self.global_rank + 1}/{self.world_size}"
              )
          deepspeed.init_distributed(self.torch_distributed_backend, distributed_port=self.cluster_environment.main_port)
  
      def _set_node_environment_variables(self) -> None:
          os.environ["MASTER_ADDR"] = self.cluster_environment.main_address
          os.environ["MASTER_PORT"] = str(self.cluster_environment.main_port)
          os.environ["RANK"] = str(self.global_rank)
          os.environ["WORLD_SIZE"] = str(self.world_size)
          os.environ["LOCAL_RANK"] = str(self.local_rank)
  
      @property
      def restore_checkpoint_after_setup(self) -> bool:
          return True
  
      def _setup_model_and_optimizers(self, model: Module, optimizers: List[Optimizer]) -> Tuple[Module, List[Optimizer]]:
          """Setup a model and multiple optimizers together.
  
          Currently only a single optimizer is supported.
  
          Return:
              The model wrapped into a :class:`deepspeed.DeepSpeedEngine` and a list with a single
              deepspeed optimizer.
          """
          if len(optimizers) != 1:
              raise ValueError(
                  f"Currently only one optimizer is supported with DeepSpeed."
                  f" Got {len(optimizers)} optimizers instead."
              )
  
          # train_micro_batch_size_per_gpu is used for throughput logging purposes
          # normally we set this to the batch size, but it is not available here unless the user provides it
          # as part of the config
          self.config.setdefault("train_micro_batch_size_per_gpu", 1)
          self.model, optimizer = self._setup_model_and_optimizer(model, optimizers[0])
          self._set_deepspeed_activation_checkpointing()
          return self.model, [optimizer]
  
      def _setup_model_and_optimizer(
          self, model: Module, optimizer: Optimizer, lr_scheduler: Optional[LRSchedulerTypeUnion] = None
      ):
          """Initialize one model and one optimizer with an optional learning rate scheduler.
  
          This calls :func:`deepspeed.initialize` internally.
          """
          model_parameters = filter(lambda p: p.requires_grad, model.parameters())
          deepspeed_engine, deepspeed_optimizer, _, _ = deepspeed.initialize(
              args=argparse.Namespace(device_rank=self.root_device.index),
              config=self.config,
              model=model,
              model_parameters=model_parameters,  # type: ignore
              optimizer=optimizer,
              lr_scheduler=lr_scheduler,
              dist_init_required=False,
          )
          return deepspeed_engine, deepspeed_optimizer
  
      def init_deepspeed(self):
          # deepspeed handles gradient clipping internally
          if is_overridden("configure_gradient_clipping", self.lightning_module, pl.LightningModule):
              rank_zero_warn(
                  "Since DeepSpeed handles gradient clipping internally, the default"
                  " `LightningModule.configure_gradient_clipping` implementation will not actually clip gradients."
                  " The hook will still be called. Consider setting"
                  " `Trainer(gradient_clip_val=..., gradient_clip_algorithm='norm')`"
                  " which will use the internal mechanism."
              )
  
          if self.lightning_module.trainer.gradient_clip_algorithm == GradClipAlgorithmType.VALUE:
              raise MisconfigurationException("DeepSpeed does not support clipping gradients by value.")
  
          accumulation_scheduler = self.lightning_module.trainer.accumulation_scheduler
  
          if accumulation_scheduler.epochs != [0]:
              raise MisconfigurationException(
                  "DeepSpeed currently does not support different `accumulate_grad_batches` at different epochs."
              )
  
          model = LightningDeepSpeedModule(pl_module=self.model, precision=self.precision_plugin.precision)
  
          if self.lightning_module.trainer and self.lightning_module.trainer.training:
              self._initialize_deepspeed_train(model)
          else:
              self._initialize_deepspeed_inference(model)
  
      def _init_optimizers(self) -> Tuple[Optimizer, Optional[List[LRSchedulerConfig]], Optional[int]]:
          optimizers, schedulers, optimizer_frequencies = _init_optimizers_and_lr_schedulers(self.lightning_module)
          if len(optimizers) > 1 or len(schedulers) > 1:
              raise MisconfigurationException(
                  "DeepSpeed currently only supports single optimizer, single optional scheduler."
              )
          return (
              optimizers[0],
              schedulers[0] if schedulers else _get_default_scheduler_config(),
              optimizer_frequencies[0] if optimizer_frequencies else None,
          )
  
      @property
      def zero_stage_3(self) -> bool:
          return self.config.get("zero_optimization") and self.config.get("zero_optimization").get("stage") == 3
  
      def _initialize_deepspeed_train(self, model):
          if "optimizer" in self.config:
              rank_zero_info(
                  "You have specified an optimizer and/or scheduler within the DeepSpeed config."
                  " It is recommended to define it in `LightningModule.configure_optimizers`."
              )
              optimizer, lr_scheduler = None, _get_default_scheduler_config()
          else:
              optimizer, lr_scheduler, _ = self._init_optimizers()
  
          scheduler = lr_scheduler["scheduler"]
          model, deepspeed_optimizer = self._setup_model_and_optimizer(model, optimizer, scheduler)
          self._set_deepspeed_activation_checkpointing()
  
          # although we set these here, deepspeed manages the specific optimizer logic
          self.lightning_module.trainer.optimizers = [deepspeed_optimizer]
  
          deepspeed_scheduler = model.lr_scheduler
          if deepspeed_scheduler is not None:
              # disable deepspeed lr scheduling as lightning manages scheduling
              model.lr_scheduler = None
              lr_scheduler["scheduler"] = deepspeed_scheduler
              self.lr_schedulers = [lr_scheduler]
          self.model = model
  
      @contextlib.contextmanager
      def model_sharded_context(self) -> Generator[None, None, None]:
          if self.zero_stage_3:
              assert self._config_initialized
              dtype = (
                  torch.float16
                  if self.precision_plugin.precision in (PrecisionType.HALF, PrecisionType.MIXED)
                  else torch.float32
              )
              model_parallel_context = deepspeed.zero.Init(
                  remote_device=self.remote_device, pin_memory=True, config_dict_or_path=self.config, dtype=dtype
              )
          else:
              model_parallel_context = super().model_sharded_context()
  
          with model_parallel_context:
              yield
  
      def _set_deepspeed_activation_checkpointing(self):
          if self.config.get("activation_checkpointing"):
              checkpoint_config = self.config["activation_checkpointing"]
              deepspeed.checkpointing.configure(
                  mpu_=None,
                  partition_activations=checkpoint_config.get("partition_activations"),
                  contiguous_checkpointing=checkpoint_config.get("contiguous_memory_optimization"),
                  checkpoint_in_cpu=checkpoint_config.get("cpu_checkpointing"),
                  profile=checkpoint_config.get("profile"),
              )
  
      def _initialize_deepspeed_inference(self, model):
          # todo: Currently DeepSpeed requires optimizers at inference to partition weights correctly
          optimizer, scheduler = None, None
          if "optimizer" not in self.config:
              rank_zero_info(
                  "You have not specified an optimizer or scheduler within the DeepSpeed config."
                  " Using `configure_optimizers` to define optimizer and scheduler."
              )
              optimizer, lr_scheduler, _ = self._init_optimizers()
              scheduler = lr_scheduler["scheduler"]
          inference_config = {
              # todo: this is required for DeepSpeed throughput timers
              "train_micro_batch_size_per_gpu": 1
          }
          if "fp16" in self.config:
              inference_config.update({"fp16": self.config["fp16"]})
          if self.zero_stage_3:
              inference_config.update(
                  {
                      "zero_allow_untested_optimizer": self.config["zero_allow_untested_optimizer"],
                      "zero_optimization": self.config["zero_optimization"],
                  }
              )
          # Remove all module hooks before initializing new model
          remove_module_hooks(model)
          model, _, _, _ = deepspeed.initialize(
              args=argparse.Namespace(device_rank=self.root_device.index),
              config=inference_config,
              model=model,
              optimizer=optimizer,
              lr_scheduler=scheduler,
              model_parameters=[],
              dist_init_required=False,
          )
          self.model = model
  
      @property
      def lightning_module(self):
          # the model may not be wrapped with DeepEngine & LightningDeepSpeedModule if calling this too early
          module = getattr(self.model, "module", self.model)
          return module.module if isinstance(module, LightningDeepSpeedModule) else module
  
      @property
      def distributed_sampler_kwargs(self):
          distributed_sampler_kwargs = dict(num_replicas=self.world_size, rank=self.global_rank)
          return distributed_sampler_kwargs
  
      def setup_optimizers(self, trainer: "pl.Trainer") -> None:
          """Creates optimizers and schedulers.
  
          Args:
              trainer: the Trainer, these optimizers should be connected to
          """
          if trainer.state.fn not in (TrainerFn.FITTING, TrainerFn.TUNING):
              return
          # Skip initializing optimizers here as DeepSpeed handles optimizers via config.
          # User may have specified config options instead in configure_optimizers, but this is handled
          # via `_initialize_deepspeed_train`
          # empty optimizers, schedulers and frequencies
          self.optimizers = []
          self.lr_schedulers = []
          self.optimizer_frequencies = []
  
      @property
      def handles_gradient_accumulation(self) -> bool:
          """Whether the plugin handles gradient accumulation internally."""
          return True
  
      def _format_config(self):
          if self.config is None:
              raise MisconfigurationException(
                  "To use DeepSpeed you must pass in a DeepSpeed config dict, or a path to a JSON config."
                  " See: https://pytorch-lightning.readthedocs.io/en/latest/advanced/advanced_gpu.html#deepspeed"
              )
          self._format_batch_size_and_grad_accum_config()
          self._format_precision_config()
  
      def _format_batch_size_and_grad_accum_config(self):
          # todo: using lite, we do not support these variables within the config
          if self.lightning_module is None:
              return
  
          if "gradient_accumulation_steps" in self.config:
              raise MisconfigurationException(
                  "Do not set `gradient_accumulation_steps` in the DeepSpeed config"
                  " as this will be set with the `accumulate_grad_batches` argument passed via the Lightning Trainer."
              )
          self.config["gradient_accumulation_steps"] = self.lightning_module.trainer.accumulate_grad_batches
          if "train_micro_batch_size_per_gpu" not in self.config:
              batch_size = self._auto_select_batch_size()
              self.config["train_micro_batch_size_per_gpu"] = batch_size
          if "gradient_clipping" not in self.config:
              self.config["gradient_clipping"] = self.lightning_module.trainer.gradient_clip_val or 0.0
  
      def _auto_select_batch_size(self):
          # train_micro_batch_size_per_gpu is used for throughput logging purposes
          # by default we try to use the batch size of the loader
          batch_size = 1
          train_dl_source = self.lightning_module.trainer._data_connector._train_dataloader_source
          if train_dl_source.is_defined():
              try:
                  train_dataloader = train_dl_source.dataloader()
                  if hasattr(train_dataloader, "batch_sampler"):
                      batch_size = train_dataloader.batch_sampler.batch_size
              # broad exception on purpose as `source.dataloader()` will fail if the dataloader requires `setup`
              # to have been called before
              except Exception:
                  if self.global_rank == 0:
                      deepspeed.utils.logging.logger.warning(
                          "Tried to infer the batch size for internal deepspeed logging from the `train_dataloader()`. "
                          "To ensure DeepSpeed logging remains correct, please manually pass the plugin with the "
                          "batch size, `Trainer(strategy=DeepSpeedStrategy(logging_batch_size_per_gpu=batch_size))`."
                      )
          return batch_size
  
      def _format_precision_config(self) -> None:
          if self.precision_plugin.precision in (PrecisionType.HALF, PrecisionType.MIXED):
              if "fp16" not in self.config and self.precision_plugin.amp_type == AMPType.NATIVE:
                  # FP16 is a DeepSpeed standalone AMP implementation
                  rank_zero_info("Enabling DeepSpeed FP16.")
                  self.config["fp16"] = {
                      "enabled": True,
                      "loss_scale": self.loss_scale,
                      "initial_scale_power": self.initial_scale_power,
                      "loss_scale_window": self.loss_scale_window,
                      "hysteresis": self.hysteresis,
                      "min_loss_scale": self.min_loss_scale,
                  }
              elif "amp" not in self.config and self.precision_plugin.amp_type == AMPType.APEX:
                  rank_zero_info("Enabling DeepSpeed APEX Implementation.")
                  self.config["amp"] = {"enabled": True, "opt_level": self.precision_plugin.amp_level}
  
      def _create_default_config(
          self,
          zero_optimization: bool,
          zero_allow_untested_optimizer: bool,
          logging_batch_size_per_gpu: Union[str, int],
          partition_activations: bool,
          cpu_checkpointing: bool,
          contiguous_memory_optimization: bool,
          synchronize_checkpoint_boundary: bool,
          offload_optimizer: bool,
          offload_parameters: bool,
          nvme_path: str,
          offload_params_device: str,
          params_buffer_count: int,
          params_buffer_size: int,
          max_in_cpu: int,
          offload_optimizer_device: str,
          optimizer_buffer_count: int,
          pin_memory: bool,
          block_size: int,
          queue_depth: int,
          single_submit: bool,
          overlap_events: bool,
          thread_count: int,
          **zero_kwargs,
      ) -> Dict:
          cfg = {
              "activation_checkpointing": {
                  "partition_activations": partition_activations,
                  "cpu_checkpointing": cpu_checkpointing,
                  "contiguous_memory_optimization": contiguous_memory_optimization,
                  "synchronize_checkpoint_boundary": synchronize_checkpoint_boundary,
              },
              "aio": {
                  "block_size": block_size,
                  "queue_depth": queue_depth,
                  "single_submit": single_submit,
                  "overlap_events": overlap_events,
                  "thread_count": thread_count,
              },
          }
          if zero_optimization:
              zero_config = zero_kwargs
  
              if offload_optimizer:
                  zero_config["offload_optimizer"] = {
                      "device": offload_optimizer_device,
                      "nvme_path": nvme_path,
                      "buffer_count": optimizer_buffer_count,
                      "pin_memory": pin_memory,
                  }
              if offload_parameters:
                  zero_config["offload_param"] = {
                      "device": offload_params_device,
                      "nvme_path": nvme_path,
                      "buffer_count": params_buffer_count,
                      "buffer_size": params_buffer_size,
                      "max_in_cpu": max_in_cpu,
                      "pin_memory": pin_memory,
                  }
              cfg = {
                  "zero_allow_untested_optimizer": zero_allow_untested_optimizer,
                  "zero_optimization": zero_config,
                  **cfg,
              }
          if logging_batch_size_per_gpu != "auto":
              cfg = {"train_micro_batch_size_per_gpu": logging_batch_size_per_gpu, **cfg}
          return cfg
  
      @property
      def deepspeed_engine(self):
          return self.model
  
      @property
      def _multi_device(self) -> bool:
          return self.num_processes > 1 or self.num_nodes > 1
  
      def save_checkpoint(self, checkpoint: Dict, filepath: _PATH) -> None:
          """Save model/training states as a checkpoint file through state-dump and file-write.
  
          Args:
              checkpoint: The checkpoint state dictionary
              filepath: write-target file's path
          """
          if self.zero_stage_3 and self._multi_device and self.is_global_zero:
              warning_cache.warn(
                  "When saving the DeepSpeed Stage 3 checkpoint, "
                  "each worker will save a shard of the checkpoint within a directory. "
                  "If a single file is required after training, "
                  "see https://pytorch-lightning.readthedocs.io/en/latest/advanced/advanced_gpu.html#"
                  "deepspeed-zero-stage-3-single-file for instructions."
              )
          # Use deepspeed's internal checkpointing function to handle partitioned weights across processes
          # dump states as a checkpoint dictionary object
          _exclude_keys = ["state_dict", "optimizer_states"]
          checkpoint = {k: v for k, v in checkpoint.items() if k not in _exclude_keys}
          self.deepspeed_engine.save_checkpoint(filepath, client_state=checkpoint)
  
      def load_checkpoint(self, checkpoint_path: _PATH) -> Dict[str, Any]:
          if self.load_full_weights and self.zero_stage_3:
              # Broadcast to ensure we load from the rank 0 checkpoint
              # This doesn't have to be the case when using deepspeed sharded checkpointing
              checkpoint_path = self.broadcast(checkpoint_path)
              return super().load_checkpoint(checkpoint_path)
  
          # Rely on deepspeed to load the checkpoint and necessary information
          from pytorch_lightning.trainer.states import TrainerFn
  
          is_fitting = self.lightning_module.trainer.state.fn == TrainerFn.FITTING
          _, client_state = self.deepspeed_engine.load_checkpoint(
              checkpoint_path, load_optimizer_states=is_fitting, load_lr_scheduler_states=False
          )
          if client_state is None:
              raise MisconfigurationException(
                  "DeepSpeed was unable to load the checkpoint. Ensure you passed in a DeepSpeed compatible checkpoint "
                  "or a single checkpoint file with `Trainer(strategy=DeepSpeedStrategy(load_full_weights=True))`."
              )
          return client_state
  
      @property
      def lightning_restore_optimizer(self) -> bool:
          # managed by DeepSpeed
          if self.load_full_weights and self.zero_stage_3 and self.lightning_module.trainer.state.fn == TrainerFn.FITTING:
              rank_zero_warn(
                  "A single checkpoint file has been given. This means optimizer states cannot be restored."
                  " If you'd like to restore these states, you must provide a path to the originally saved DeepSpeed"
                  " checkpoint. When using ZeRO 3, the original path should be a directory."
              )
          return False
  
      def load_model_state_dict(self, checkpoint: Mapping[str, Any]) -> None:
          # override to do nothing, deepspeed engine already loaded the weights in `load_checkpoint()`
          if self.load_full_weights and self.zero_stage_3:
              self.model_to_device()
              self._restore_zero_state(checkpoint)
  
      def _restore_zero_state(self, ckpt: Mapping[str, Any]) -> None:
          """Overrides the normal load_state_dict behaviour in PyTorch to ensure we gather parameters that may be
          sharded across processes before loading the state dictionary when using ZeRO stage 3. This is then
          automatically synced across processes.
  
          Args:
              ckpt: The ckpt file.
          """
  
          def load(module: torch.nn.Module, prefix=""):
  
              missing_keys = []
              unexpected_keys = []
              error_msgs = []
              state_dict = ckpt["state_dict"]
  
              # copy state_dict so _load_from_state_dict can modify it
              metadata = getattr(state_dict, "_metadata", None)
              state_dict = state_dict.copy()
              if metadata is not None:
                  state_dict._metadata = metadata
  
              local_metadata = {} if metadata is None else metadata.get(prefix[:-1], {})
              # because zero3 puts placeholders in model params, this context
              # manager gathers (unpartitions) the params of the current layer, then loads from
              # the state dict and then re-partitions them again
              with deepspeed.zero.GatheredParameters(list(module.parameters(recurse=False)), modifier_rank=0):
                  if self.is_global_zero:
                      module._load_from_state_dict(
                          state_dict=state_dict,
                          prefix=prefix,
                          local_metadata=local_metadata,
                          strict=True,
                          missing_keys=missing_keys,
                          unexpected_keys=unexpected_keys,
                          error_msgs=error_msgs,
                      )
  
              for name, child in module._modules.items():
                  if child is not None:
                      load(child, prefix + name + ".")
  
          load(self.lightning_module, prefix="")
  
      def load_optimizer_state_dict(self, checkpoint: Mapping[str, Any]) -> None:
          # override to do nothing, deepspeed engine already loaded the states in `load_checkpoint()`
          pass
  
      @classmethod
      def register_strategies(cls, strategy_registry: Dict) -> None:
          strategy_registry.register("deepspeed", cls, description="Default DeepSpeed Strategy")
          strategy_registry.register("deepspeed_stage_1", cls, description="DeepSpeed with ZeRO Stage 1 enabled", stage=1)
          strategy_registry.register("deepspeed_stage_2", cls, description="DeepSpeed with ZeRO Stage 2 enabled", stage=2)
          strategy_registry.register(
              "deepspeed_stage_2_offload",
              cls,
              description="DeepSpeed ZeRO Stage 2 and CPU Offload",
              stage=2,
              offload_optimizer=True,
          )
          strategy_registry.register("deepspeed_stage_3", cls, description="DeepSpeed ZeRO Stage 3", stage=3)
          strategy_registry.register(
              "deepspeed_stage_3_offload",
              cls,
              description="DeepSpeed ZeRO Stage 3 and CPU Offload",
              stage=3,
              offload_optimizer=True,
              offload_parameters=True,
          )
          strategy_registry.register(
              "deepspeed_stage_3_offload_nvme",
              cls,
              description="DeepSpeed ZeRO Stage 3 and NVMe Offload",
              stage=3,
              offload_optimizer=True,
              offload_parameters=True,
              remote_device="nvme",
              offload_params_device="nvme",
              offload_optimizer_device="nvme",
          )
  
      def validation_step(self, *args, **kwargs) -> Optional[STEP_OUTPUT]:
          with self.precision_plugin.val_step_context():
              return self.model(*args, **kwargs)
  
      def test_step(self, *args, **kwargs) -> Optional[STEP_OUTPUT]:
          with self.precision_plugin.test_step_context():
              return self.model(*args, **kwargs)
  
      def predict_step(self, *args, **kwargs) -> STEP_OUTPUT:
          with self.precision_plugin.predict_step_context():
              return self.model(*args, **kwargs)
  