Nonetype

[xinjiTian]

File "main_simmim_pt.py", line 302, in train_one_epoch
G1R = torch.autograd.grad(L1, param[0].clone(), retain_graph=True, create_graph=True)
File "D:\txj\envs\swin2\lib\site-packages\torch\autograd_init_.py", line 236, in grad
inputs, allow_unused, accumulate_grad=False)
RuntimeError: One of the differentiated Tensors appears to not have been used in the graph. Set allow_unused=True if this is the desired behavior.