@tom Great work on the notebook. I already had a repo to do a dual tree DWT in pytorch (https://en.wikipedia.org/wiki/Complex_wavelet_transform 14), and inspired by your code, I have now added support for the DWT and Inverse DWT in 2 dimensions. You can check it out at
https://github.com/fbcotter/pytorch_wavelets 102 (@verified.human sorry for the similar name!)
The repo has tests checking that gradients pass nicely through the dual tree DWT, but I am yet to write tests to check the gradients for the DWT. I would wager they work nicely, but do need to confirm. The perfect reconstruction works, as well as getting the same wavelet coefficients as pywt.