直接运行python run.py Downloading http://yann.lecun.com/exdb/mnist/https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz Failed to download (trying next): HTTP Error 503: Service Unavailable Downloading https://ossci-datasets.s3.amazonaws.com/mnist/https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz Failed to download (trying next): HTTP Error 404: Not Found ………… ………… 最后报 RuntimeError: Error downloading https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz 注意到问题是下载网址问题，自动将两个网址拼接起来了，导致网址错误。 操作系统：win10，linux均有此问题 解决方法：自行访问数据集的网址https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz 并将数据集放于如图路径  再将datamodules.__init__.py里的所有内容注释掉，即可。不确定将__init__.py注释掉的其他后果。 
直接运行python run.py
Downloading http://yann.lecun.com/exdb/mnist/https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz
Failed to download (trying next):
HTTP Error 503: Service Unavailable
Downloading https://ossci-datasets.s3.amazonaws.com/mnist/https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz
Failed to download (trying next):
HTTP Error 404: Not Found
…………
…………
最后报
RuntimeError: Error downloading https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz
注意到问题是下载网址问题，自动将两个网址拼接起来了，导致网址错误。
操作系统：win10，linux均有此问题
解决方法：自行访问数据集的网址https://ossci-datasets.s3.amazonaws.com/mnist/train-images-idx3-ubyte.gz
并将数据集放于如图路径
再将datamodules.init.py里的所有内容注释掉，即可。不确定将__init__.py注释掉的其他后果。