LBFGS inherit from torch.optim.LBFGS

[towzeur]

Hello!

I noticed that the file kan/LBFGS.py appears to be almost identical to the one in PyTorch (https://github.com/pytorch/pytorch/blob/main/torch/optim/lbfgs.py). The only differences seem to be the addition of tolerance_ys and the removal of complex parameter counting.

To maintain consistency and streamline maintenance, it might be preferable to directly inherit from the Torch class.

I've made a commit that does just that, reducing the code to 100 lines. Please review and let me know your thoughts.

Thank you!