I've spent some time playing with their Jupyter notebooks. The most useful (to me, anyway) is their Example_3_classfication.ipynb ([1]). It works as advertised with the parameters selected by the authors, but if we modified the network shape in the second half of the tutorial (Classification formulation) from (2, 2) to (2, 2, 2), it fails to generalize. The training loss gets down to 1e-9, while test loss stays aroun…
Changes:
1. Increased the training set from 1000 to 100k samples. This solved overfitting.
2. In the dataset generation, slightly reduced noise (0.1 -> 0.07) so that classes don't overlap. With an overlap, naturally, it's impossible to hit 100%.
3. Most important & specific to KANs: train for 30 steps with grid=5 (5 segments for each activation function), then 30 steps with grid=10 (and initializing from the previous model), and then 30 steps with grid=20. This is idiomatic to KANs and covered in the Example_1_function_fitting.ipynb: https://github.com/KindXiaoming/pykan/blob/master/tutorials/...
Overall, my impressions are:
- it works!
- the reference implementation is very slow. A GPU implementation is dearly needed.
- it feels like it's a bit too non-linear and training is not as stable as it's with MLP + ReLU.
- Scaling is not guaranteed to work well. Really need to see if MNIST is possible to solve with this approach.
I will definitely keep an eye on this development.