lightning/tests/accelerators/test_tpu_backend.py

123 lines
3.9 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 pytest
import torch
from torch import nn
from pytorch_lightning import Trainer
from pytorch_lightning.trainer.states import TrainerState
from pytorch_lightning.utilities import _TPU_AVAILABLE
from tests.helpers.boring_model import BoringModel
from tests.helpers.utils import pl_multi_process_test
class WeightSharingModule(BoringModel):
def __init__(self):
super().__init__()
self.layer_1 = nn.Linear(32, 10, bias=False)
self.layer_2 = nn.Linear(10, 32, bias=False)
self.layer_3 = nn.Linear(32, 10, bias=False)
self.layer_3.weight = self.layer_1.weight
def forward(self, x):
x = self.layer_1(x)
x = self.layer_2(x)
x = self.layer_3(x)
return x
@pytest.mark.skipif(not _TPU_AVAILABLE, reason="test requires TPU machine")
@pl_multi_process_test
def test_resume_training_on_cpu(tmpdir):
""" Checks if training can be resumed from a saved checkpoint on CPU"""
# Train a model on TPU
model = BoringModel()
trainer = Trainer(
checkpoint_callback=True,
max_epochs=1,
tpu_cores=8,
)
trainer.fit(model)
model_path = trainer.checkpoint_callback.best_model_path
# Verify saved Tensors are on CPU
ckpt = torch.load(model_path)
weight_tensor = list(ckpt["state_dict"].values())[0]
assert weight_tensor.device == torch.device("cpu")
# Verify that training is resumed on CPU
trainer = Trainer(
resume_from_checkpoint=model_path,
checkpoint_callback=True,
max_epochs=1,
default_root_dir=tmpdir,
)
trainer.fit(model)
assert trainer.state == TrainerState.FINISHED, f"Training failed with {trainer.state}"
@pytest.mark.skipif(not _TPU_AVAILABLE, reason="test requires TPU machine")
@pl_multi_process_test
def test_if_test_works_after_train(tmpdir):
""" Ensure that .test() works after .fit() """
# Train a model on TPU
model = BoringModel()
trainer = Trainer(max_epochs=1, tpu_cores=8, default_root_dir=tmpdir, fast_dev_run=True)
trainer.fit(model)
assert trainer.test(model) == 1
@pytest.mark.skipif(not _TPU_AVAILABLE, reason="test requires TPU machine")
@pl_multi_process_test
def test_weight_tying_warning(tmpdir, capsys=None):
"""
Ensure a warning is thrown if model parameter lengths do not match
post moving to device.
"""
model = WeightSharingModule()
trainer = Trainer(checkpoint_callback=True, max_epochs=1, tpu_cores=1)
with pytest.warns(UserWarning, match=r'The model layers do not match after moving to the target device.'):
result = trainer.fit(model)
assert result
@pytest.mark.skipif(not _TPU_AVAILABLE, reason="test requires TPU machine")
@pl_multi_process_test
def test_if_weights_tied(tmpdir, capsys=None):
"""
Test if weights are properly tied on `on_post_move_to_device`.
Ensure no warning for parameter mismatch is thrown.
"""
class Model(WeightSharingModule):
def on_post_move_to_device(self):
self.layer_3.weight = self.layer_1.weight
model = Model()
trainer = Trainer(checkpoint_callback=True, max_epochs=1, tpu_cores=1)
with pytest.warns(UserWarning) as warnings:
result = trainer.fit(model)
assert result
assert not list(filter(lambda x: 'The model layers do not match' in str(x), warnings.list))
assert trainer.test(model) == 1