RuntimeError: No grad accumulator for a saved leaf!

[diyiiyiii]

Thanks for your excellent work! I meet an error about backward grad issue, does this project support back propagation operation？

[aliutkus]

Hi ! Normally this should, have you pinned thé problem down? Is there an error message?

[pwangcs]

Hi ! Normally this should, have you pinned thé problem down? Is there an error message?

Hi, @aliutkus, I got a same error when I use interp1d to train a network. The error message is as follows,

Traceback (most recent call last):
File "/home/wangping/Codes/DeepOpticsSCI/E2E_train.py", line 296, in
main(E2Enet, optimizer, args)
File "/home/wangping/Codes/DeepOpticsSCI/E2E_train.py", line 260, in main
train(epoch, result_path, model, optimizer, logger, args)
File "/home/wangping/Codes/DeepOpticsSCI/E2E_train.py", line 131, in train
Loss_all.backward()
File "/home/wangping/anaconda3/envs/sci_pytorch/lib/python3.9/site-packages/torch/tensor.py", line 245, in backward
torch.autograd.backward(self, gradient, retain_graph, create_graph, inputs=inputs)
File "/home/wangping/anaconda3/envs/sci_pytorch/lib/python3.9/site-packages/torch/autograd/init.py", line 145, in backward
Variable._execution_engine.run_backward(
File "/home/wangping/anaconda3/envs/sci_pytorch/lib/python3.9/site-packages/torch/autograd/function.py", line 89, in apply
return self._forward_cls.backward(self, *args) # type: ignore
File "/home/wangping/Codes/DeepOpticsSCI/utils.py", line 159, in backward
inputs = ctx.saved_tensors[1:]
RuntimeError: No grad accumulator for a saved leaf!

In my utils.py, code related with interp1d is as

def crf_3d(x): # x : a torch.Tensor with size [batch, H, W]
batch, H, W = x.size()
x = x.view(batch*H, W)
E = torch.linspace(0.0, 1.0, steps= 1024, requires_grad=False).to(x.device)
f0 = parse_emor() # f0 is a numpy.array loaded from the local .txt file
I = torch.from_numpy(f0).to(x.device)
y = interp1d(E, I, x)
y = y.view(batch, H, W)
return y

My codes run under pytorch=1.8.1, Python=3.9.4. Please let me know what's wrong? Thanks in advance.