用pytorch写出vgg19
时间: 2023-05-25 18:04:24 浏览: 177
pytorch_gradcam_vgg19.py
以下是一个示例代码,实现了一个VGG19模型:
```
import torch.nn as nn
class VGG19(nn.Module):
def __init__(self):
super(VGG19, self).__init__()
self.features = nn.Sequential(
nn.Conv2d(3, 64, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(64, 64, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=2, stride=2),
nn.Conv2d(64, 128, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(128, 128, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=2, stride=2),
nn.Conv2d(128, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(256, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(256, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(256, 256, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=2, stride=2),
nn.Conv2d(256, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=2, stride=2),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(512, 512, kernel_size=3, padding=1),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=2, stride=2),
)
self.avgpool = nn.AdaptiveAvgPool2d((7, 7))
self.classifier = nn.Sequential(
nn.Linear(512 * 7 * 7, 4096),
nn.ReLU(inplace=True),
nn.Dropout(),
nn.Linear(4096, 4096),
nn.ReLU(inplace=True),
nn.Dropout(),
nn.Linear(4096, 1000),
)
def forward(self, x):
x = self.features(x)
x = self.avgpool(x)
x = x.view(x.size(0), -1)
x = self.classifier(x)
return x
```
该代码中,我们定义了一个名为VGG19的类,它继承自nn.Module。该模型包括了一个包含了卷积层、ReLU激活函数和最大池化层的特征提取器,以及一个三层全连接层的分类器。
特征提取器包括了5个卷积块,每个卷积块包括若干个卷积层和一个最大池化层。其中,第一个卷积块包括了两个卷积层,其余卷积块包括了四个卷积层。每个卷积层都用ReLU激活函数来为网络引入非线性变换,最大池化层用于将特征图的尺寸减半。
分类器包括了三个全连接层,其中前两个都包含了ReLU激活函数和Dropout正则化,最后一个全连接层包含了softmax激活函数,用于将特征向量映射到1000维的输出空间。
在forward函数中,我们首先对输入数据进行特征提取,然后通过adaptive avg pooling对特征图进行平均池化,最后展平特征张量,将其输入到分类器中得到预测结果。
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