lightning/pytorch_lightning/loops/epoch/evaluation_epoch_loop.py

235 lines
9.4 KiB
Python

# 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 collections import OrderedDict
from typing import Any, Dict, Iterator, List, Optional, Union
from deprecate import void
from torch import Tensor
from pytorch_lightning.loops.base import Loop
from pytorch_lightning.loops.utilities import _prepare_dataloader_iter
from pytorch_lightning.trainer.progress import Progress
from pytorch_lightning.utilities.fetching import AbstractDataFetcher
from pytorch_lightning.utilities.memory import recursive_detach
from pytorch_lightning.utilities.types import STEP_OUTPUT
class EvaluationEpochLoop(Loop):
"""
This is the loop performing the evaluation. It mainly loops over the given dataloader and runs the validation
or test step (depending on the trainer's current state).
"""
def __init__(self) -> None:
super().__init__()
self.dataloader: Optional[Iterator] = None
self._dl_max_batches: Optional[int] = None
self._num_dataloaders: Optional[int] = None
self.outputs: List[STEP_OUTPUT] = []
self.batch_progress = Progress()
self.dataloader_iter: Optional[Iterator] = None
@property
def done(self) -> bool:
"""Returns ``True`` if the current iteration count reaches the number of dataloader batches."""
return self.batch_progress.current.completed >= self._dl_max_batches
def connect(self, **kwargs: "Loop") -> None:
raise NotImplementedError(f"{self.__class__.__name__} does not connect any child loops.")
def reset(self) -> None:
"""Resets the loop's internal state."""
self._dl_max_batches = None
self._num_dataloaders = None
self.outputs = []
if not self.restarting:
self.batch_progress.current.reset()
def on_run_start(
self, data_fetcher: AbstractDataFetcher, dataloader_idx: int, dl_max_batches: int, num_dataloaders: int
) -> None:
"""Adds the passed arguments to the loop's state if necessary
Args:
data_fetcher: the current data_fetcher wrapping the dataloader
dataloader_idx: index of the current dataloader
dl_max_batches: maximum number of batches the dataloader can produce
num_dataloaders: the total number of dataloaders
"""
void(dataloader_idx)
self._dl_max_batches = dl_max_batches
self._num_dataloaders = num_dataloaders
self.dataloader_iter = _prepare_dataloader_iter(data_fetcher, self.batch_progress.current.ready)
def advance(
self, data_fetcher: AbstractDataFetcher, dataloader_idx: int, dl_max_batches: int, num_dataloaders: int
) -> None:
"""Calls the evaluation step with the corresponding hooks and updates the logger connector.
Args:
dataloader_iter: iterator over the dataloader
dataloader_idx: index of the current dataloader
dl_max_batches: maximum number of batches the dataloader can produce
num_dataloaders: the total number of dataloaders
Raises:
StopIteration: If the current batch is None
"""
void(data_fetcher, dl_max_batches, num_dataloaders)
batch_idx, (batch, _) = next(self.dataloader_iter)
if batch is None:
raise StopIteration
if not self.trainer.data_connector.evaluation_data_fetcher.store_on_device:
with self.trainer.profiler.profile("evaluation_batch_to_device"):
batch = self.trainer.accelerator.batch_to_device(batch, dataloader_idx=dataloader_idx)
self.batch_progress.increment_ready()
# hook
self.on_evaluation_batch_start(batch, batch_idx, dataloader_idx)
self.batch_progress.increment_started()
# lightning module methods
with self.trainer.profiler.profile("evaluation_step_and_end"):
output = self.evaluation_step(batch, batch_idx, dataloader_idx)
output = self.evaluation_step_end(output)
self.batch_progress.increment_processed()
# track loss history
self.on_evaluation_batch_end(output, batch, batch_idx, dataloader_idx)
self.batch_progress.increment_completed()
# log batch metrics
self.trainer.logger_connector.update_eval_step_metrics()
# track epoch level outputs
self.outputs = self._track_output_for_epoch_end(self.outputs, output)
def on_run_end(self) -> List[STEP_OUTPUT]:
"""Returns the outputs of the whole run"""
outputs = self.outputs
# free memory
self.outputs = []
return outputs
def evaluation_step(self, batch: Any, batch_idx: int, dataloader_idx: int) -> Optional[STEP_OUTPUT]:
"""The evaluation step (validation_step or test_step depending on the trainer's state).
Args:
batch: The current batch to run through the step.
batch_idx: The index of the current batch
dataloader_idx: the index of the dataloader producing the current batch
Returns:
the outputs of the step
"""
# configure step_kwargs
step_kwargs = self._build_kwargs(batch, batch_idx, dataloader_idx)
if self.trainer.testing:
self.trainer.lightning_module._current_fx_name = "test_step"
with self.trainer.profiler.profile("test_step"):
output = self.trainer.accelerator.test_step(step_kwargs)
else:
self.trainer.lightning_module._current_fx_name = "validation_step"
with self.trainer.profiler.profile("validation_step"):
output = self.trainer.accelerator.validation_step(step_kwargs)
return output
def evaluation_step_end(self, *args: Any, **kwargs: Any) -> Optional[STEP_OUTPUT]:
"""Calls the `{validation/test}_step_end` hook"""
hook_name = "test_step_end" if self.trainer.testing else "validation_step_end"
output = self.trainer.call_hook(hook_name, *args, **kwargs)
return output
def on_evaluation_batch_start(self, batch: Any, batch_idx: int, dataloader_idx: int) -> None:
"""Calls the ``on_{validation/test}_batch_start`` hook.
Args:
batch: The current batch to run through the step
batch_idx: The index of the current batch
dataloader_idx: The index of the dataloader producing the current batch
Raises:
AssertionError: If the number of dataloaders is None (has not yet been set).
"""
self.trainer.logger_connector.on_batch_start()
assert self._num_dataloaders is not None
self.trainer.logger_connector.on_evaluation_batch_start(batch, batch_idx, dataloader_idx, self._num_dataloaders)
if self.trainer.testing:
self.trainer.call_hook("on_test_batch_start", batch, batch_idx, dataloader_idx)
else:
self.trainer.call_hook("on_validation_batch_start", batch, batch_idx, dataloader_idx)
def on_evaluation_batch_end(
self, output: Optional[STEP_OUTPUT], batch: Any, batch_idx: int, dataloader_idx: int
) -> None:
"""The ``on_{validation/test}_batch_end`` hook.
Args:
output: The output of the performed step
batch: The input batch for the step
batch_idx: The index of the current batch
dataloader_idx: Index of the dataloader producing the current batch
"""
hook_name = "on_test_batch_end" if self.trainer.testing else "on_validation_batch_end"
self.trainer.call_hook(hook_name, output, batch, batch_idx, dataloader_idx)
self.trainer.logger_connector.on_batch_end()
def _build_kwargs(self, batch: Any, batch_idx: int, dataloader_idx: int) -> Dict[str, Union[Any, int]]:
"""Helper function to build the arguments for the current step
Args:
batch: The current batch to run through the step
batch_idx: the index of the current batch
dataloader_idx: the index of the dataloader producing the current batch
Returns:
the keyword arguments to pass to the step function
"""
# make dataloader_idx arg in validation_step optional
step_kwargs = OrderedDict([("batch", batch), ("batch_idx", batch_idx)])
multiple_val_loaders = not self.trainer.testing and self._num_dataloaders > 1
multiple_test_loaders = self.trainer.testing and self._num_dataloaders > 1
if multiple_test_loaders or multiple_val_loaders:
step_kwargs["dataloader_idx"] = dataloader_idx
return step_kwargs
def _track_output_for_epoch_end(
self, outputs: List[STEP_OUTPUT], output: Optional[STEP_OUTPUT]
) -> List[STEP_OUTPUT]:
if output is not None:
if isinstance(output, dict):
output = recursive_detach(output, to_cpu=self.trainer.move_metrics_to_cpu)
elif isinstance(output, Tensor) and output.is_cuda and self.trainer.move_metrics_to_cpu:
output = output.cpu()
outputs.append(output)
return outputs