lightning/tests/checkpointing/test_trainer_checkpoint.py

87 lines
2.9 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
from copy import deepcopy
import torch
import pytorch_lightning as pl
from pytorch_lightning import seed_everything, Trainer
from pytorch_lightning.callbacks import ModelCheckpoint
from tests.helpers import BoringModel
def test_finetuning_with_resume_from_checkpoint(tmpdir):
"""
This test validates that generated ModelCheckpoint is pointing to the right best_model_path during test
"""
seed_everything(3)
checkpoint_callback = ModelCheckpoint(monitor='val_loss', dirpath=tmpdir, filename="{epoch:02d}", save_top_k=-1)
class ExtendedBoringModel(BoringModel):
def configure_optimizers(self):
optimizer = torch.optim.SGD(self.layer.parameters(), lr=0.001)
lr_scheduler = torch.optim.lr_scheduler.StepLR(optimizer, step_size=1)
return [optimizer], [lr_scheduler]
def validation_step(self, batch, batch_idx):
output = self.layer(batch)
loss = self.loss(batch, output)
self.log("val_loss", loss, on_epoch=True, prog_bar=True)
model = ExtendedBoringModel()
model.validation_epoch_end = None
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
limit_train_batches=12,
limit_val_batches=6,
limit_test_batches=12,
callbacks=[checkpoint_callback],
logger=False,
)
trainer.fit(model)
assert os.listdir(tmpdir) == ['epoch=00.ckpt']
best_model_paths = [checkpoint_callback.best_model_path]
results = []
for idx in range(3, 6):
# load from checkpoint
trainer = pl.Trainer(
default_root_dir=tmpdir,
max_epochs=idx,
limit_train_batches=12,
limit_val_batches=12,
limit_test_batches=12,
resume_from_checkpoint=best_model_paths[-1],
progress_bar_refresh_rate=0,
)
trainer.fit(model)
trainer.test()
results.append(deepcopy(trainer.callback_metrics))
best_model_paths.append(trainer.checkpoint_callback.best_model_path)
for idx in range(len(results) - 1):
assert results[idx]["val_loss"] > results[idx + 1]["val_loss"]
for idx, best_model_path in enumerate(best_model_paths):
if idx == 0:
assert best_model_path.endswith(f"epoch=0{idx}.ckpt")
else:
assert f"epoch={idx + 1}" in best_model_path