lightning/tests/tests_fabric/utilities/test_load.py

140 lines
4.6 KiB
Python

# Copyright The Lightning AI 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
import torch.nn as nn
from lightning.fabric.utilities.load import (
_lazy_load,
_materialize_tensors,
_move_state_into,
_NotYetLoadedTensor,
)
def test_lazy_load_module(tmp_path):
model0 = nn.Linear(2, 2)
torch.save(model0.state_dict(), tmp_path / "model.pt")
model1 = nn.Linear(2, 2)
checkpoint = _lazy_load(tmp_path / "model.pt")
model1.load_state_dict(checkpoint)
assert isinstance(checkpoint["weight"], _NotYetLoadedTensor)
assert type(model0.weight.data) is torch.Tensor
assert torch.equal(model0.weight, model1.weight)
assert torch.equal(model0.bias, model1.bias)
class ATensor(torch.Tensor):
pass
def test_lazy_load_tensor(tmp_path):
"""Test that lazy load can handle different classes of tensors."""
expected = {
"tensor": torch.rand(2),
"parameter": nn.Parameter(torch.rand(3)),
"subclass": torch.Tensor._make_subclass(ATensor, torch.rand(4)),
}
torch.save(expected, tmp_path / "data.pt")
loaded = _lazy_load(tmp_path / "data.pt")
for t0, t1 in zip(expected.values(), loaded.values()):
assert isinstance(t1, _NotYetLoadedTensor)
t1_materialized = _materialize_tensors(t1)
assert type(t0) == type(t1_materialized)
assert torch.equal(t0, t1_materialized)
def test_lazy_load_mixed_state(tmp_path):
model0 = nn.Linear(2, 2)
optim0 = torch.optim.Adam(model0.parameters())
checkpoint = {
"int": 1,
"dict": {"a": 1, "b": 2},
"list": [1, 2, 3],
"pickled_model": model0,
"model": model0.state_dict(),
"optimizer": optim0.state_dict(),
}
torch.save(checkpoint, tmp_path / "checkpoint.pt")
model1 = nn.Linear(2, 2)
optim1 = torch.optim.Adam(model0.parameters())
loaded_checkpoint = _lazy_load(tmp_path / "checkpoint.pt")
model1.load_state_dict(loaded_checkpoint["model"])
optim1.load_state_dict(loaded_checkpoint["optimizer"])
def test_lazy_load_raises():
with pytest.raises(FileNotFoundError, match="foo' does not exist"):
_lazy_load("foo")
def test_materialize_tensors(tmp_path):
# Single tensor
tensor = torch.tensor([1, 2])
torch.save(tensor, tmp_path / "tensor.pt")
loaded = _lazy_load(tmp_path / "tensor.pt")
materialized = _materialize_tensors(loaded)
assert torch.equal(materialized, tensor)
assert type(tensor) == type(materialized)
# Collection of tensors
collection = {
"tensor": torch.tensor([1, 2]),
"nested": {"int": 1, "list": [torch.tensor([3.0]), torch.tensor([4])]},
}
torch.save(collection, tmp_path / "collection.pt")
loaded = _lazy_load(tmp_path / "collection.pt")
materialized = _materialize_tensors(loaded)
assert torch.equal(materialized["tensor"], collection["tensor"])
assert torch.equal(materialized["nested"]["list"][0], collection["nested"]["list"][0])
assert torch.equal(materialized["nested"]["list"][1], collection["nested"]["list"][1])
assert materialized["nested"]["int"] == 1
def test_move_state_into():
# all keys from the source
source = {"apple": 1, "cocofruit": 2}
destination = {"banana": 100}
_move_state_into(source, destination)
assert source == {}
assert destination == {"apple": 1, "cocofruit": 2, "banana": 100}
# subset of keys from the source
source = {"apple": 1, "cocofruit": 2}
destination = {"banana": 100}
keys = {"apple"}
_move_state_into(source, destination, keys=keys)
assert source == {"cocofruit": 2}
assert destination == {"apple": 1, "banana": 100}
# with stateful objects in destination
class Fruit:
count = 1
def state_dict(self):
return {"count": self.count}
def load_state_dict(self, state_dict):
self.count = state_dict["count"]
source = {"cocofruit": 2, "banana": {"count": 100}}
destination = {"banana": Fruit()}
_move_state_into(source, destination)
assert source == {}
assert destination["cocofruit"] == 2
assert destination["banana"].count == 100