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paddlepaddle--paddle/test/ai_edited_test/test_ai_optimizer_lr_advanced.py
2026-07-13 12:40:42 +08:00

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Python

# Copyright (c) 2026 PaddlePaddle Authors. All Rights Reserved.
#
# 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.
"""
进阶LR调度器单元测试 / Advanced LR Scheduler Unit Tests
测试目标 / Test Target:
paddle.optimizer.lr 更多调度器 (python/paddle/optimizer/lr.py, 覆盖率约80.5%)
覆盖的模块 / Covered Modules:
- paddle.optimizer.lr.ReduceOnPlateau: 按平台期降低LR
- paddle.optimizer.lr.CosineAnnealingDecay: 余弦退火
- paddle.optimizer.lr.MultiStepDecay: 多步衰减
- paddle.optimizer.lr.PolynomialDecay: 多项式衰减
- paddle.optimizer.lr.LambdaDecay: Lambda衰减
- paddle.optimizer.lr.OneCycleLR: 单循环LR
- paddle.optimizer.lr.LinearWarmup: 线性预热
作用 / Purpose:
覆盖进阶学习率调度策略的代码路径,补充lr_scheduler功能测试。
"""
import unittest
import paddle
from paddle import nn
paddle.disable_static()
def create_optimizer(lr_scheduler):
"""创建使用调度器的优化器 / Create optimizer with scheduler"""
model = nn.Linear(5, 2)
return paddle.optimizer.SGD(
learning_rate=lr_scheduler, parameters=model.parameters()
), model
class TestReduceOnPlateau(unittest.TestCase):
"""测试ReduceOnPlateau调度器 / Test ReduceOnPlateau scheduler"""
def test_basic(self):
"""测试基本ReduceOnPlateau / Test basic ReduceOnPlateau"""
scheduler = paddle.optimizer.lr.ReduceOnPlateau(
learning_rate=0.1, factor=0.5, patience=2
)
opt, model = create_optimizer(scheduler)
# Simulate training
for i in range(5):
x = paddle.randn([4, 5])
y = model(x)
loss_val = y.mean().item()
scheduler.step(loss_val)
def test_reduce_on_plateau_mode_max(self):
"""测试max模式 / Test max mode"""
scheduler = paddle.optimizer.lr.ReduceOnPlateau(
learning_rate=0.1, mode='max', factor=0.5, patience=1
)
scheduler.step(0.5)
scheduler.step(0.3) # No improvement
scheduler.step(0.2) # No improvement, should reduce
def test_cooldown(self):
"""测试cooldown参数 / Test cooldown parameter"""
scheduler = paddle.optimizer.lr.ReduceOnPlateau(
learning_rate=0.1, factor=0.5, patience=1, cooldown=2
)
for i in range(6):
scheduler.step(1.0 / (i + 1))
class TestCosineAnnealingDecay(unittest.TestCase):
"""测试余弦退火调度器 / Test CosineAnnealingDecay scheduler"""
def test_basic(self):
"""测试基本余弦退火 / Test basic cosine annealing"""
scheduler = paddle.optimizer.lr.CosineAnnealingDecay(
learning_rate=0.1, T_max=10
)
opt, model = create_optimizer(scheduler)
for _ in range(12):
x = paddle.randn([4, 5])
y = model(x)
y.mean().backward()
opt.step()
opt.clear_grad()
scheduler.step()
def test_with_eta_min(self):
"""测试带最小LR的余弦退火 / Test cosine annealing with eta_min"""
scheduler = paddle.optimizer.lr.CosineAnnealingDecay(
learning_rate=0.1, T_max=10, eta_min=0.001
)
for _ in range(10):
scheduler.step()
self.assertGreaterEqual(scheduler.get_lr(), 0.001)
class TestMultiStepDecay(unittest.TestCase):
"""测试多步衰减调度器 / Test MultiStepDecay scheduler"""
def test_basic(self):
"""测试基本MultiStepDecay / Test basic MultiStepDecay"""
scheduler = paddle.optimizer.lr.MultiStepDecay(
learning_rate=0.1, milestones=[3, 6], gamma=0.1
)
opt, model = create_optimizer(scheduler)
init_lr = scheduler.get_lr()
for i in range(8):
x = paddle.randn([4, 5])
y = model(x)
y.mean().backward()
opt.step()
opt.clear_grad()
scheduler.step()
final_lr = scheduler.get_lr()
# LR should have decreased after milestones
self.assertLess(final_lr, init_lr)
class TestPolynomialDecay(unittest.TestCase):
"""测试多项式衰减调度器 / Test PolynomialDecay scheduler"""
def test_basic(self):
"""测试基本PolynomialDecay / Test basic PolynomialDecay"""
scheduler = paddle.optimizer.lr.PolynomialDecay(
learning_rate=0.1, decay_steps=10, end_lr=0.001
)
opt, model = create_optimizer(scheduler)
for _ in range(12):
scheduler.step()
# After decay_steps, lr should approach end_lr
lr = scheduler.get_lr()
self.assertAlmostEqual(lr, 0.001, places=4)
def test_cycle(self):
"""测试循环模式 / Test cycle mode"""
scheduler = paddle.optimizer.lr.PolynomialDecay(
learning_rate=0.1, decay_steps=5, end_lr=0.01, cycle=True
)
for _ in range(12):
scheduler.step()
class TestLambdaDecay(unittest.TestCase):
"""测试Lambda调度器 / Test LambdaDecay scheduler"""
def test_basic(self):
"""测试基本LambdaDecay / Test basic LambdaDecay"""
scheduler = paddle.optimizer.lr.LambdaDecay(
learning_rate=0.1, lr_lambda=lambda epoch: 0.95**epoch
)
opt, model = create_optimizer(scheduler)
for i in range(5):
scheduler.step()
# LR should decrease
self.assertLess(scheduler.get_lr(), 0.1)
def test_warmup_lambda(self):
"""测试预热Lambda / Test warmup lambda"""
warmup_steps = 5
def warmup_fn(step):
if step < warmup_steps:
return step / warmup_steps
return 1.0
scheduler = paddle.optimizer.lr.LambdaDecay(
learning_rate=0.1, lr_lambda=warmup_fn
)
# Before warmup
for _ in range(warmup_steps + 2):
scheduler.step()
class TestLinearWarmup(unittest.TestCase):
"""测试线性预热 / Test LinearWarmup scheduler"""
def test_basic(self):
"""测试基本LinearWarmup / Test basic LinearWarmup"""
scheduler = paddle.optimizer.lr.LinearWarmup(
learning_rate=0.1, warmup_steps=5, start_lr=0.0, end_lr=0.1
)
opt, model = create_optimizer(scheduler)
for i in range(8):
x = paddle.randn([4, 5])
y = model(x)
y.mean().backward()
opt.step()
opt.clear_grad()
scheduler.step()
def test_with_base_scheduler(self):
"""测试配合基础调度器使用 / Test with base scheduler"""
base_scheduler = paddle.optimizer.lr.StepDecay(
learning_rate=0.1, step_size=10, gamma=0.5
)
scheduler = paddle.optimizer.lr.LinearWarmup(
learning_rate=base_scheduler,
warmup_steps=5,
start_lr=0.0,
end_lr=0.1,
)
for _ in range(8):
scheduler.step()
class TestCyclicalLR(unittest.TestCase):
"""测试循环LR / Test cyclical LR"""
def test_exponential_decay(self):
"""测试指数衰减 / Test exponential decay"""
scheduler = paddle.optimizer.lr.ExponentialDecay(
learning_rate=0.1, gamma=0.9
)
init_lr = scheduler.get_lr()
scheduler.step()
new_lr = scheduler.get_lr()
self.assertAlmostEqual(new_lr, init_lr * 0.9, places=5)
def test_inverse_time_decay(self):
"""测试逆时间衰减 / Test inverse time decay"""
scheduler = paddle.optimizer.lr.InverseTimeDecay(
learning_rate=0.1, gamma=0.5
)
init_lr = scheduler.get_lr()
self.assertAlmostEqual(init_lr, 0.1, places=5)
for _ in range(3):
scheduler.step()
if __name__ == '__main__':
unittest.main()