Legacy autograd function with non-static forward method is deprecated and will be removed in 1.3.

PyTorch在1.3版本及之后，规定forward方法必须是静态方法。违反了该原则的代码将会在运行时报下列错误：

..\torch\csrc\autograd\python_function.cpp:622: UserWarning: Legacy autograd function with non-static forward method is deprecated and will be removed in 1.3. Please use new-style autograd function with static forward method. (Example:

https://pytorch.org/docs/stable/autograd.html#torch.autograd.Function)

​

解决办法：

将PyTorch降级到1.2版本及以下，因为这个改进直到1.3版本才正式生效；

手动忽略掉UserWarning：

      import warnings

      warnings.filterwarnings("ignore")