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ray-project--ray/python/ray/tune/examples/cifar10_pytorch.py
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2026-07-13 13:17:40 +08:00

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Python

# ruff: noqa
# fmt: off
# __import_begin__
import os
import tempfile
from typing import Dict
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
import torchvision
import torchvision.transforms as transforms
from filelock import FileLock
from torch.utils.data import random_split
import ray
from ray import tune
from ray.tune import Checkpoint
from ray.tune.schedulers import ASHAScheduler
# __import_end__
# __load_data_begin__
DATA_DIR = tempfile.mkdtemp()
def load_data(data_dir):
transform = transforms.Compose([
transforms.ToTensor(),
transforms.Normalize((0.4914, 0.4822, 0.4465), (0.2023, 0.1994, 0.2010)),
])
# We add FileLock here because multiple workers will want to
# download data, and this may cause overwrites since
# DataLoader is not threadsafe.
with FileLock(os.path.expanduser("~/.data.lock")):
trainset = torchvision.datasets.CIFAR10(
root=data_dir, train=True, download=True, transform=transform)
testset = torchvision.datasets.CIFAR10(
root=data_dir, train=False, download=True, transform=transform)
return trainset, testset
# __load_data_end__
def load_test_data():
# Loads a fake dataset for testing so it doesn't rely on external download.
trainset = torchvision.datasets.FakeData(
128, (3, 32, 32), num_classes=10, transform=transforms.ToTensor()
)
testset = torchvision.datasets.FakeData(
16, (3, 32, 32), num_classes=10, transform=transforms.ToTensor()
)
return trainset, testset
# __net_begin__
class Net(nn.Module):
def __init__(self, l1=120, l2=84):
super(Net, self).__init__()
self.conv1 = nn.Conv2d(3, 6, 5)
self.pool = nn.MaxPool2d(2, 2)
self.conv2 = nn.Conv2d(6, 16, 5)
self.fc1 = nn.Linear(16 * 5 * 5, l1)
self.fc2 = nn.Linear(l1, l2)
self.fc3 = nn.Linear(l2, 10)
def forward(self, x):
x = self.pool(F.relu(self.conv1(x)))
x = self.pool(F.relu(self.conv2(x)))
x = x.view(-1, 16 * 5 * 5)
x = F.relu(self.fc1(x))
x = F.relu(self.fc2(x))
x = self.fc3(x)
return x
# __net_end__
# __train_begin__
def train_cifar(config):
net = Net(config["l1"], config["l2"])
device = "cpu"
if torch.cuda.is_available():
device = "cuda:0"
if torch.cuda.device_count() > 1:
net = nn.DataParallel(net)
net.to(device)
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(net.parameters(), lr=config["lr"], momentum=0.9)
# Load existing checkpoint through `get_checkpoint()` API.
if tune.get_checkpoint():
loaded_checkpoint = tune.get_checkpoint()
with loaded_checkpoint.as_directory() as loaded_checkpoint_dir:
model_state, optimizer_state = torch.load(
os.path.join(loaded_checkpoint_dir, "checkpoint.pt")
)
net.load_state_dict(model_state)
optimizer.load_state_dict(optimizer_state)
if config["smoke_test"]:
trainset, testset = load_test_data()
else:
trainset, testset = load_data(DATA_DIR)
test_abs = int(len(trainset) * 0.8)
train_subset, val_subset = random_split(
trainset, [test_abs, len(trainset) - test_abs])
trainloader = torch.utils.data.DataLoader(
train_subset,
batch_size=int(config["batch_size"]),
shuffle=True,
num_workers=0 if config["smoke_test"] else 8,
)
valloader = torch.utils.data.DataLoader(
val_subset,
batch_size=int(config["batch_size"]),
shuffle=True,
num_workers=0 if config["smoke_test"] else 8,
)
for epoch in range(10): # loop over the dataset multiple times
running_loss = 0.0
epoch_steps = 0
for i, data in enumerate(trainloader):
# get the inputs; data is a list of [inputs, labels]
inputs, labels = data
inputs, labels = inputs.to(device), labels.to(device)
# zero the parameter gradients
optimizer.zero_grad()
# forward + backward + optimize
outputs = net(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
# print statistics
running_loss += loss.item()
epoch_steps += 1
if i % 2000 == 1999: # print every 2000 mini-batches
print("[%d, %5d] loss: %.3f" % (epoch + 1, i + 1,
running_loss / epoch_steps))
running_loss = 0.0
# Validation loss
val_loss = 0.0
val_steps = 0
total = 0
correct = 0
for i, data in enumerate(valloader, 0):
with torch.no_grad():
inputs, labels = data
inputs, labels = inputs.to(device), labels.to(device)
outputs = net(inputs)
_, predicted = torch.max(outputs.data, 1)
total += labels.size(0)
correct += (predicted == labels).sum().item()
loss = criterion(outputs, labels)
val_loss += loss.cpu().numpy()
val_steps += 1
# Here we save a checkpoint. It is automatically registered with
# Ray Tune and will potentially be accessed through in ``get_checkpoint()``
# in future iterations.
# Note to save a file like checkpoint, you still need to put it under a directory
# to construct a checkpoint.
with tempfile.TemporaryDirectory() as temp_checkpoint_dir:
path = os.path.join(temp_checkpoint_dir, "checkpoint.pt")
torch.save(
(net.state_dict(), optimizer.state_dict()), path
)
checkpoint = Checkpoint.from_directory(temp_checkpoint_dir)
tune.report(
{"loss": (val_loss / val_steps), "accuracy": correct / total},
checkpoint=checkpoint,
)
print("Finished Training")
# __train_end__
# __test_acc_begin__
def test_best_model(config: Dict, checkpoint: "Checkpoint", smoke_test=False):
best_trained_model = Net(config["l1"], config["l2"])
device = "cuda:0" if torch.cuda.is_available() else "cpu"
best_trained_model.to(device)
with checkpoint.as_directory() as checkpoint_dir:
checkpoint_path = os.path.join(checkpoint_dir, "checkpoint.pt")
model_state, optimizer_state = torch.load(checkpoint_path)
best_trained_model.load_state_dict(model_state)
if smoke_test:
_, testset = load_test_data()
else:
_, testset = load_data(DATA_DIR)
testloader = torch.utils.data.DataLoader(
testset, batch_size=4, shuffle=False, num_workers=2)
correct = 0
total = 0
with torch.no_grad():
for data in testloader:
images, labels = data
images, labels = images.to(device), labels.to(device)
outputs = best_trained_model(images)
_, predicted = torch.max(outputs.data, 1)
total += labels.size(0)
correct += (predicted == labels).sum().item()
print("Best trial test set accuracy: {}".format(correct / total))
# __test_acc_end__
# __main_begin__
def main(num_samples=10, max_num_epochs=10, gpus_per_trial=2, smoke_test=False):
config = {
"l1": tune.sample_from(lambda _: 2 ** np.random.randint(2, 9)),
"l2": tune.sample_from(lambda _: 2 ** np.random.randint(2, 9)),
"lr": tune.loguniform(1e-4, 1e-1),
"batch_size": tune.choice([2, 4, 8, 16]),
"smoke_test": smoke_test,
}
scheduler = ASHAScheduler(
max_t=max_num_epochs,
grace_period=1,
reduction_factor=2)
tuner = tune.Tuner(
tune.with_resources(
tune.with_parameters(train_cifar),
resources={"cpu": 2, "gpu": gpus_per_trial},
),
tune_config=tune.TuneConfig(
metric="loss",
mode="min",
num_samples=num_samples,
scheduler=scheduler
),
param_space=config,
)
results = tuner.fit()
best_result = results.get_best_result("loss", "min")
print("Best trial config: {}".format(best_result.config))
print("Best trial final validation loss: {}".format(
best_result.metrics["loss"]))
print("Best trial final validation accuracy: {}".format(
best_result.metrics["accuracy"]))
test_best_model(best_result.config, best_result.checkpoint, smoke_test=smoke_test)
# __main_end__
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser()
parser.add_argument(
"--smoke-test", action="store_true", help="Finish quickly for testing")
parser.add_argument(
"--ray-address",
help="Address of Ray cluster for seamless distributed execution.",
required=False)
args, _ = parser.parse_known_args()
if args.smoke_test:
ray.init(num_cpus=2)
main(num_samples=1, max_num_epochs=1, gpus_per_trial=0, smoke_test=True)
else:
ray.init(args.ray_address)
# Change this to activate training on GPUs
main(num_samples=10, max_num_epochs=10, gpus_per_trial=0)