Pytorch离线下载并使用torchvision.models预训练模型

原本直接在IDE中执行models.alexnet(pretrained=True)就行了，但是一直报错，搞得我好不难受！

不用说，肯定是由于网络不好导致模型下载失败，能不能离线下载完之后在本地直接使用？答案是肯定的

其实步骤很简单(但是对于新手要命)，就和我们下载软件一样，详细步骤如下：

复制需要下载的模型地址，粘贴到浏览器地址栏中下载，各种模型的下载地址如下：

1. Resnet:
  model_urls = {
      'resnet18': 'https://download.pytorch.org/models/resnet18-5c106cde.pth',
      'resnet34': 'https://download.pytorch.org/models/resnet34-333f7ec4.pth',
      'resnet50': 'https://download.pytorch.org/models/resnet50-19c8e357.pth',
      'resnet101': 'https://download.pytorch.org/models/resnet101-5d3b4d8f.pth',
      'resnet152': 'https://download.pytorch.org/models/resnet152-b121ed2d.pth',
  }

2. inception:
 model_urls = {
      Inception v3 ported from TensorFlow
     'inception_v3_google': 'https://download.pytorch.org/models/inception_v3_google-1a9a5a14.pth',
 }

3. Densenet: 
 model_urls = {
     'densenet121': 'https://download.pytorch.org/models/densenet121-a639ec97.pth',
     'densenet169': 'https://download.pytorch.org/models/densenet169-b2777c0a.pth',
     'densenet201': 'https://download.pytorch.org/models/densenet201-c1103571.pth',
     'densenet161': 'https://download.pytorch.org/models/densenet161-8d451a50.pth',
 }

4. Alexnet:
 model_urls = {
     'alexnet': 'https://download.pytorch.org/models/alexnet-owt-4df8aa71.pth',
}

5. vggnet:
 model_urls = {
     'vgg11': 'https://download.pytorch.org/models/vgg11-bbd30ac9.pth',
     'vgg13': 'https://download.pytorch.org/models/vgg13-c768596a.pth',
     'vgg16': 'https://download.pytorch.org/models/vgg16-397923af.pth',
     'vgg19': 'https://download.pytorch.org/models/vgg19-dcbb9e9d.pth',
     'vgg11_bn': 'https://download.pytorch.org/models/vgg11_bn-6002323d.pth',
     'vgg13_bn': 'https://download.pytorch.org/models/vgg13_bn-abd245e5.pth',
     'vgg16_bn': 'https://download.pytorch.org/models/vgg16_bn-6c64b313.pth',
     'vgg19_bn': 'https://download.pytorch.org/models/vgg19_bn-c79401a0.pth',
 }

这里以Alexnet为例，复制https://download.pytorch.org/models/alexnet-owt-4df8aa71.pth浏览器地址栏中下载

大约233M，慢慢下吧，友情提示一下，在手机上下载每秒几M，在电脑下载每秒几kb，推荐在手机上下载好之后，再发送到电脑上

将下载好的文件剪切到torch缓存文件夹下即可，windos和linux的torch缓存文件夹分别如下：

windows：C:\Users\wang1\.cache\torch\checkpoints (wang1是你的电脑用户名)
linux：/root/.cache/torch/hub/checkpoints/alexnet-owt-4df8aa71.pth

如下所示：

4. 然后执行models.alexnet(pretrained=True)，发现OK，大功告成！