使用pycharm基于pytorch对cifar 10分类,要求准确度达到85以上,并输出分类图像结果
时间: 2023-12-03 22:45:32 浏览: 31
好的,下面我来给你讲解一下具体的实现步骤:
1. 首先,你需要安装 PyTorch 和 torchvision 库,可以使用以下命令进行安装:
```
pip install torch torchvision
```
2. 然后,你需要下载 CIFAR-10 数据集,并将其转换为 PyTorch 可以处理的格式。可以使用以下代码进行下载和转换:
```python
import torchvision.transforms as transforms
from torchvision.datasets import CIFAR10
transform = transforms.Compose(
[transforms.ToTensor(),
transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])
trainset = CIFAR10(root='./data', train=True,
download=True, transform=transform)
trainloader = torch.utils.data.DataLoader(trainset, batch_size=4,
shuffle=True, num_workers=2)
testset = CIFAR10(root='./data', train=False,
download=True, transform=transform)
testloader = torch.utils.data.DataLoader(testset, batch_size=4,
shuffle=False, num_workers=2)
```
3. 接着,你需要定义模型。可以使用以下代码定义一个简单的卷积神经网络模型:
```python
import torch.nn as nn
import torch.nn.functional as F
class Net(nn.Module):
def __init__(self):
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, 120)
self.fc2 = nn.Linear(120, 84)
self.fc3 = nn.Linear(84, 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 = Net()
```
4. 接下来,你需要定义损失函数和优化器。可以使用以下代码定义交叉熵损失函数和随机梯度下降优化器:
```python
import torch.optim as optim
criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(net.parameters(), lr=0.001, momentum=0.9)
```
5. 然后,你需要训练模型。可以使用以下代码进行训练:
```python
for epoch in range(2): # 多批次循环
running_loss = 0.0
for i, data in enumerate(trainloader, 0):
# 获取输入
inputs, labels = data
# 梯度清零
optimizer.zero_grad()
# 正向传播,反向传播,优化
outputs = net(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
# 打印统计信息
running_loss += loss.item()
if i % 2000 == 1999: # 每 2000 批次打印一次
print('[%d, %5d] loss: %.3f' %
(epoch + 1, i + 1, running_loss / 2000))
running_loss = 0.0
print('Finished Training')
```
6. 最后,你需要测试模型并输出分类图像结果。可以使用以下代码进行测试和输出结果:
```python
import matplotlib.pyplot as plt
import numpy as np
# 测试模型
correct = 0
total = 0
with torch.no_grad():
for data in testloader:
images, labels = data
outputs = net(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: %d %%' % (
100 * correct / total))
# 输出分类图像结果
classes = ('plane', 'car', 'bird', 'cat',
'deer', 'dog', 'frog', 'horse', 'ship', 'truck')
def imshow(img):
img = img / 2 + 0.5 # 反归一化
npimg = img.numpy()
plt.imshow(np.transpose(npimg, (1, 2, 0)))
plt.show()
dataiter = iter(testloader)
images, labels = dataiter.next()
# 输出图片
imshow(torchvision.utils.make_grid(images))
# 输出预测结果
print('GroundTruth: ', ' '.join('%5s' % classes[labels[j]] for j in range(4)))
outputs = net(images)
_, predicted = torch.max(outputs, 1)
print('Predicted: ', ' '.join('%5s' % classes[predicted[j]]
for j in range(4)))
```
以上就是基于 PyTorch 对 CIFAR-10 数据集进行分类的完整代码。你可以根据需要进行修改和优化。