lightning/tests/callbacks/test_early_stopping.py

207 lines
7.2 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.
import os
import pickle
from unittest import mock
import cloudpickle
import pytest
import torch
from pytorch_lightning import Trainer, seed_everything
from pytorch_lightning.callbacks import EarlyStopping, ModelCheckpoint
from tests.base import EvalModelTemplate
from pytorch_lightning.utilities.exceptions import MisconfigurationException
class EarlyStoppingTestRestore(EarlyStopping):
# this class has to be defined outside the test function, otherwise we get pickle error
def __init__(self, expected_state=None):
super().__init__()
self.expected_state = expected_state
# cache the state for each epoch
self.saved_states = []
def on_train_start(self, trainer, pl_module):
if self.expected_state:
assert self.on_save_checkpoint(trainer, pl_module) == self.expected_state
def on_validation_end(self, trainer, pl_module):
super().on_validation_end(trainer, pl_module)
self.saved_states.append(self.on_save_checkpoint(trainer, pl_module).copy())
def test_resume_early_stopping_from_checkpoint(tmpdir):
"""
Prevent regressions to bugs:
https://github.com/PyTorchLightning/pytorch-lightning/issues/1464
https://github.com/PyTorchLightning/pytorch-lightning/issues/1463
"""
seed_everything(42)
model = EvalModelTemplate()
checkpoint_callback = ModelCheckpoint(dirpath=tmpdir, monitor="early_stop_on", save_top_k=1)
early_stop_callback = EarlyStoppingTestRestore()
trainer = Trainer(
default_root_dir=tmpdir,
checkpoint_callback=checkpoint_callback,
callbacks=[early_stop_callback],
num_sanity_val_steps=0,
max_epochs=4,
)
trainer.fit(model)
checkpoint_filepath = checkpoint_callback.kth_best_model_path
# ensure state is persisted properly
checkpoint = torch.load(checkpoint_filepath)
# the checkpoint saves "epoch + 1"
early_stop_callback_state = early_stop_callback.saved_states[checkpoint["epoch"] - 1]
assert 4 == len(early_stop_callback.saved_states)
assert checkpoint["callbacks"][type(early_stop_callback)] == early_stop_callback_state
# ensure state is reloaded properly (assertion in the callback)
early_stop_callback = EarlyStoppingTestRestore(early_stop_callback_state)
new_trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
resume_from_checkpoint=checkpoint_filepath,
callbacks=[early_stop_callback],
)
with pytest.raises(MisconfigurationException, match=r'.*you restored a checkpoint with current_epoch*'):
new_trainer.fit(model)
@mock.patch.dict(os.environ, {"PL_DEV_DEBUG": "1"})
def test_early_stopping_no_extraneous_invocations(tmpdir):
"""Test to ensure that callback methods aren't being invoked outside of the callback handler."""
model = EvalModelTemplate()
expected_count = 4
trainer = Trainer(
default_root_dir=tmpdir,
callbacks=[EarlyStopping()],
val_check_interval=1.0,
max_epochs=expected_count,
)
trainer.fit(model)
assert len(trainer.dev_debugger.early_stopping_history) == expected_count
@pytest.mark.parametrize(
"loss_values, patience, expected_stop_epoch",
[([6, 5, 5, 5, 5, 5], 3, 4), ([6, 5, 4, 4, 3, 3], 1, 3), ([6, 5, 6, 5, 5, 5], 3, 4),],
)
def test_early_stopping_patience(tmpdir, loss_values, patience, expected_stop_epoch):
"""Test to ensure that early stopping is not triggered before patience is exhausted."""
class ModelOverrideValidationReturn(EvalModelTemplate):
validation_return_values = torch.Tensor(loss_values)
count = 0
def validation_epoch_end(self, outputs):
loss = self.validation_return_values[self.count]
self.count += 1
return {"test_val_loss": loss}
model = ModelOverrideValidationReturn()
early_stop_callback = EarlyStopping(monitor="test_val_loss", patience=patience, verbose=True)
trainer = Trainer(
default_root_dir=tmpdir,
callbacks=[early_stop_callback],
val_check_interval=1.0,
num_sanity_val_steps=0,
max_epochs=10,
)
trainer.fit(model)
assert trainer.current_epoch == expected_stop_epoch
def test_pickling(tmpdir):
early_stopping = EarlyStopping()
early_stopping_pickled = pickle.dumps(early_stopping)
early_stopping_loaded = pickle.loads(early_stopping_pickled)
assert vars(early_stopping) == vars(early_stopping_loaded)
early_stopping_pickled = cloudpickle.dumps(early_stopping)
early_stopping_loaded = cloudpickle.loads(early_stopping_pickled)
assert vars(early_stopping) == vars(early_stopping_loaded)
def test_early_stopping_no_val_step(tmpdir):
"""Test that early stopping callback falls back to training metrics when no validation defined."""
class CurrentModel(EvalModelTemplate):
def training_step(self, *args, **kwargs):
output = super().training_step(*args, **kwargs)
output.update({'my_train_metric': output['loss']}) # could be anything else
return output
model = CurrentModel()
model.validation_step = None
model.val_dataloader = None
stopping = EarlyStopping(monitor='my_train_metric', min_delta=0.1, patience=0)
trainer = Trainer(
default_root_dir=tmpdir,
callbacks=[stopping],
overfit_batches=0.20,
max_epochs=10,
)
result = trainer.fit(model)
assert result == 1, 'training failed to complete'
assert trainer.current_epoch < trainer.max_epochs - 1
def test_early_stopping_functionality(tmpdir):
class CurrentModel(EvalModelTemplate):
def validation_epoch_end(self, outputs):
losses = [8, 4, 2, 3, 4, 5, 8, 10]
val_loss = losses[self.current_epoch]
self.log('abc', torch.tensor(val_loss))
model = CurrentModel()
trainer = Trainer(
default_root_dir=tmpdir,
callbacks=[EarlyStopping(monitor='abc')],
overfit_batches=0.20,
max_epochs=20,
)
trainer.fit(model)
assert trainer.current_epoch == 5, 'early_stopping failed'
def test_early_stopping_functionality_arbitrary_key(tmpdir):
"""Tests whether early stopping works with a custom key and dictionary results on val step."""
class CurrentModel(EvalModelTemplate):
def validation_epoch_end(self, outputs):
losses = [8, 4, 2, 3, 4, 5, 8, 10]
val_loss = losses[self.current_epoch]
return {'jiraffe': torch.tensor(val_loss)}
model = CurrentModel()
trainer = Trainer(
default_root_dir=tmpdir,
callbacks=[EarlyStopping(monitor='jiraffe')],
overfit_batches=0.20,
max_epochs=20,
)
trainer.fit(model)
assert trainer.current_epoch >= 5, 'early_stopping failed'