What is the suggested way to implement an autograd version of nn.functional.conv1d?

[penguinshin]

Suppose I want to use fftconv_fwd to implement nn.functional.conv1d - how would I go about doing this? Is there already a function in safari that operates on pytorch tensors and computes a differentiable version of both the convolution as well as the concatenation of the filters? In particular, I'm looking for > 100K kernel size