for step, (images, labels) in tqdm(enumerate(train_loader), total=len(train_loader)):
时间: 2023-10-07 19:06:37 浏览: 72
这段代码使用了Python中的`enumerate()`函数,它可以将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列,同时列出数据和数据下标。在这里,`enumerate(train_loader)`返回一个迭代器对象,每次迭代会返回一个元组`(step, (images, labels))`,其中`step`表示当前迭代的次数,`(images, labels)`表示从`train_loader`中取出的一个batch的样本和标签。然后使用`tqdm()`函数将这个迭代器包装起来,实现进度条的显示,其中`total=len(train_loader)`表示总共需要迭代`len(train_loader)`次。最终,这段代码会遍历整个`train_loader`,每次取出一个batch的数据进行训练。
相关问题
import torch import torch.nn as nn import torch.optim as optim import numpy as np from torch.autograd import Variable from torchvision.datasets import ImageFolder from torchvision.transforms import transforms from torch.utils.data import DataLoader # 定义超参数 num_epochs = 10 batch_size = 32 learning_rate = 0.001 # 定义数据转换方式 transform = transforms.Compose([ transforms.Resize((32, 32)), transforms.ToTensor(), transforms.Normalize(mean=[0.5], std=[0.5]) ]) # 加载数据集 train_dataset = ImageFolder(root='./ChineseStyle/train/', transform=transform) train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True) test_dataset = ImageFolder(root='./ChineseStyle/test/', transform=transform) test_loader = DataLoader(test_dataset, batch_size=batch_size, shuffle=True) # 定义卷积神经网络结构 class Net(nn.Module): def init(self): super(Net, self).init() self.conv1 = nn.Conv2d(in_channels=3, out_channels=6, kernel_size=5, stride=1, padding=2) self.pool = nn.MaxPool2d(kernel_size=2, stride=2) self.conv2 = nn.Conv2d(in_channels=6, out_channels=32, kernel_size=5, stride=1, padding=2) self.fc1 = nn.Linear(in_features=32 * 8 * 8, out_features=128) self.fc2 = nn.Linear(in_features=128, out_features=15) def forward(self, x): x = self.pool(torch.relu(self.conv1(x))) x = self.pool(torch.relu(self.conv2(x))) x = x.view(-1, 32 * 8 * 8) x = torch.relu(self.fc1(x)) x = self.fc2(x) return x # 实例化卷积神经网络 net = Net() # 定义损失函数和优化器 criterion = nn.CrossEntropyLoss() optimizer = optim.Adam(net.parameters(), lr=learning_rate) # 训练模型 for epoch in range(num_epochs): for i, (images, labels) in enumerate(train_loader): # 将输入和标签转换为变量 images = Variable(images) labels = Variable(labels) # 将梯度清零 optimizer.zero_grad() # 向前传递 outputs = net(images) # 计算损失函数 loss = criterion(outputs, labels) # 反向传播和优化 loss.backward() optimizer.step() # 打印统计信息 if (i + 1) % 100 == 0: print('Epoch [%d/%d], Step [%d/%d], Loss: %.4f' % (epoch + 1, num_epochs, i + 1, len(train_dataset) // batch_size, loss.item())) # 测试模型 correct = 0 total = 0 for images, labels in test_loader: # 向前传递 outputs = net(Variable(images)) # 获取预测结果 _, predicted = torch.max(outputs.data, 1) # 更新统计信息 total += labels.size(0) correct += (predicted == labels).sum() # 计算准确率 print('Accuracy of the network on the test images: %d %%' % (100 * correct / total))有没有测试到测试集
是的,代码中有对测试集的测试。在训练模型之后,通过测试集的数据来检验模型的准确率。具体代码如下:
```
# 测试模型
correct = 0
total = 0
for images, labels in test_loader:
# 向前传递
outputs = net(Variable(images))
# 获取预测结果
_, predicted = torch.max(outputs.data, 1)
# 更新统计信息
total += labels.size(0)
correct += (predicted == labels).sum()
# 计算准确率
print('Accuracy of the network on the test images: %d %%' % (100 * correct / total))
```
def train(dev, data_loader_train, data_loader_test, in_dim, h_dim, n_layers, n_classes, n_epochs, l_rate): model_trained = RNN(in_dim, h_dim, n_layers, n_classes).to(dev) criterion = nn.CrossEntropyLoss().to(dev) optimizer = torch.optim.Adam(model_trained.parameters(), lr=l_rate) rate_list = [] # 损失函数采用交叉熵、优化器采用的是Adam、训练过程中,逐epoch逐step,输出训练得到的损失函数loss情况,同时每个epoch结束,用测试数据进行测试,计算当前模型的分类准确率 # total_step = len(data_loader_train) for epoch in range(n_epochs): for i, (images, labels) in enumerate(data_loader_train): image = images.float().to(dev) image = image.permute(0, 2, 1) labels = labels.long().to(dev) outputs = model_trained(image) loss = criterion(outputs, labels) optimizer.zero_grad() loss.backward() optimizer.step() # if (i + 1) % 5 == 0: # print('Epoch [{}/{}], Step [{}/{}], Loss: {:.4f}' # .format(epoch + 1, num_epochs, i + 1, total_step, loss.item())) rate_correct = test(model_trained, data_loader_test, epoch) # 每迭代一轮,都测试并输出当前模型的识别准确率 rate_list.append(rate_correct) torch.save(model_trained.state_dict(), 'savemodel.dic') return rate_list
这是一个使用PyTorch实现的RNN(循环神经网络)模型的训练函数,其中使用了交叉熵损失函数和Adam优化器进行训练。函数的输入包括设备(GPU或CPU)、训练数据加载器、测试数据加载器、输入维度、隐藏层维度、层数、类别数、训练轮数和学习率。函数在训练过程中会输出每个epoch的损失函数loss,并使用测试数据计算当前模型的分类准确率。最后,函数会返回每个epoch的分类准确率的列表,并将训练好的模型保存到本地。