pytorch实现mobile net图像分类cifar10代码

### 回答1：
下面是一个使用PyTorch实现MobileNet模型在CIFAR-10数据集上进行图像分类的代码示例：

import torch
import torch.nn as nn
import torch.optim as optim
import torchvision
import torchvision.transforms as transforms

# 定义MobileNet模型
class MobileNet(nn.Module):
    def __init__(self, num_classes=10):
        super(MobileNet, self).__init__()
        self.features = nn.Sequential(
            nn.Conv2d(3, 32, kernel_size=3, stride=2, padding=1),
            nn.BatchNorm2d(32),
            nn.ReLU(inplace=True),
            nn.Conv2d(32, 64, kernel_size=3, stride=1, padding=1, groups=32),
            nn.BatchNorm2d(64),
            nn.ReLU(inplace=True),
            nn.Conv2d(64, 128, kernel_size=1, stride=1, padding=0),
            nn.BatchNorm2d(128),
            nn.ReLU(inplace=True),
            nn.Conv2d(128, 128, kernel_size=3, stride=2, padding=1, groups=128),
            nn.BatchNorm2d(128),
            nn.ReLU(inplace=True),
            nn.Conv2d(128, 256, kernel_size=1, stride=1, padding=0),
            nn.BatchNorm2d(256),
            nn.ReLU(inplace=True),
            nn.Conv2d(256, 256, kernel_size=3, stride=2, padding=1, groups=256),
            nn.BatchNorm2d(256),
            nn.ReLU(inplace=True),
            nn.Conv2d(256, 512, kernel_size=1, stride=1, padding=0),
            nn.BatchNorm2d(512),
            nn.ReLU(inplace=True),
            nn.Conv2d(512, 512, kernel_size=3, stride=2, padding=1, groups=512),
            nn.BatchNorm2d(512),
            nn.ReLU(inplace=True),
            nn.Conv2d(512, 1024, kernel_size=1, stride=1, padding=0),
            nn.BatchNorm2d(1024),
            nn.ReLU(inplace=True),
            nn.AvgPool2d(kernel_size=2, stride=1),
        )
        self.classifier = nn.Linear(1024, num_classes)

    def forward(self, x):
        x = self.features(x)
        x = x.view(x.size(0), -1)
        x = self.classifier(x)
        return x

# 定义数据预处理
transform = transforms.Compose([
    transforms.RandomCrop(32, padding=4),
    transforms.RandomHorizontalFlip(),
    transforms.ToTensor(),
    transforms.Normalize(mean=[0.4914, 0.4822, 0.4465], std=[0.2023, 0.1994, 0.2010])
])

# 加载数据集
trainset = torchvision.datasets.CIFAR10(root='./data', train=True, download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=64, shuffle=True, num_workers=2)
testset = torchvision.datasets.CIFAR10(root='./data', train=False, download=True, transform=transform)
testloader = torch.utils.data.DataLoader(testset, batch_size=64, shuffle=False, num_workers=2)

# 初始化模型和损失函数
model = MobileNet()
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.1, momentum=0.9, weight_decay=5e-4)

# 训练模型
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
model.to(device)
for epoch in range(10):
    model.train()
    running_loss = 0.0
    for i, (inputs, labels) in enumerate(trainloader):
        inputs, labels = inputs.to(device), labels.to(device)
        optimizer.zero_grad()

        outputs = model(inputs)
        loss = criterion(outputs, labels)
        loss.backward()
        optimizer.step()

        running_loss += loss.item()
        if i % 100 == 99:
            print('[%d, %5d] loss: %.3f' % (epoch + 1, i + 1, running_loss / 100))
            running_loss = 0.0

# 在测试集上评估模型
model.eval()
total = 0
correct = 0
with torch.no_grad():
    for inputs, labels in testloader:
        inputs, labels = inputs.to(device), labels.to(device)
        outputs = model(inputs)
        _, predicted = torch.max(outputs.data, 1)
        total += labels.size(0)
        correct += (predicted == labels).sum().item()

accuracy = 100 * correct / total
print('Accuracy on the test set: %.2f %%' % accuracy)

注意，在运行代码之前，需要确保已经安装了PyTorch和TorchVision库，并且已经下载了CIFAR-10数据集。

### 回答2：
import torch
import torch.nn as nn
import torch.optim as optim
import torchvision
import torchvision.transforms as transforms

# 定义 MobileNet 模型
class MobileNet(nn.Module):
def __init__(self, num_classes=10):
super(MobileNet, self).__init__()
self.model = torchvision.models.mobilenet_v2(pretrained=False)
self.model.classifier[1] = nn.Linear(1280, num_classes)

def forward(self, x):
out = self.model(x)
return out

# 数据预处理
transform_train = transforms.Compose([
transforms.RandomHorizontalFlip(),
transforms.ToTensor(),
transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
])

transform_test = transforms.Compose([
transforms.ToTensor(),
transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
])

# 加载 cifar10 数据集
trainset = torchvision.datasets.CIFAR10(root='./data', train=True,
download=True, transform=transform_train)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=128,
shuffle=True, num_workers=2)

testset = torchvision.datasets.CIFAR10(root='./data', train=False,
download=True, transform=transform_test)
testloader = torch.utils.data.DataLoader(testset, batch_size=100,
shuffle=False, num_workers=2)

# 定义模型和优化器
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
net = MobileNet().to(device)
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(net.parameters(), lr=0.001, momentum=0.9)

# 训练模型
for epoch in range(10):
running_loss = 0.0
for i, data in enumerate(trainloader, 0):
inputs, labels = data[0].to(device), data[1].to(device)
optimizer.zero_grad()

outputs = net(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()

running_loss += loss.item()
if i % 200 == 199:
print('[%d, %5d] loss: %.3f' % (epoch+1, i+1, running_loss / 200))
running_loss = 0.0

print("Finished Training")

# 测试模型
correct = 0
total = 0
with torch.no_grad():
for data in testloader:
images, labels = data[0].to(device), data[1].to(device)
outputs = net(images)
_, predicted = torch.max(outputs.data, 1)
total += labels.size(0)
correct += (predicted == labels).sum().item()

print('Accuracy on test images: %.2f %%' % (100 * correct / total))

### 回答3：
import torch
import torch.nn as nn
import torch.optim as optim
import torchvision
import torchvision.transforms as transforms
from torch.utils.data import DataLoader

# 定义MobileNet网络结构
class MobileNet(nn.Module):
def __init__(self, num_classes=10):
super(MobileNet, self).__init__()
self.model = torchvision.models.mobilenet_v2(pretrained=False)
self.model.classifier[1] = nn.Linear(1280, num_classes)

def forward(self, x):
x = self.model(x)
return x

# 数据预处理
transform = transforms.Compose([
transforms.RandomHorizontalFlip(),
transforms.RandomCrop(32, padding=4),
transforms.ToTensor(),
transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
])

# 加载CIFAR10数据集
trainset = torchvision.datasets.CIFAR10(root='./data', train=True, download=True, transform=transform)
testset = torchvision.datasets.CIFAR10(root='./data', train=False, download=True, transform=transform)
trainloader = DataLoader(trainset, batch_size=128, shuffle=True)
testloader = DataLoader(testset, batch_size=128, shuffle=False)

# 创建MobileNet模型并定义损失函数、优化器
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model = MobileNet().to(device)
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(model.parameters(), lr=0.01, momentum=0.9, weight_decay=0.0005)

# 训练模型
def train(epoch):
model.train()
running_loss = 0.0
for batch_idx, (inputs, targets) in enumerate(trainloader):
inputs, targets = inputs.to(device), targets.to(device)
optimizer.zero_grad()
outputs = model(inputs)
loss = criterion(outputs, targets)
loss.backward()
optimizer.step()
running_loss += loss.item()
if batch_idx % 100 == 99:
print('[%d, %5d] loss: %.3f' % (epoch + 1, batch_idx + 1, running_loss / 100))
running_loss = 0.0

# 测试模型
def test():
model.eval()
correct = 0
total = 0
with torch.no_grad():
for data in testloader:
images, labels = data
images, labels = images.to(device), labels.to(device)
outputs = model(images)
_, predicted = torch.max(outputs.data, 1)
total += labels.size(0)
correct += (predicted == labels).sum().item()
print('Accuracy of the network on the 10000 test images: %.2f %%' % (100 * correct / total))

# 运行训练和测试
for epoch in range(10):
train(epoch)
test()

# 最后输出模型在CIFAR10测试集上的准确率。