L-BFGS optimizer with fractional diffusion equation

[ginasn]

Hi everyone,

I am working on the space-fractional diffusion equation using the given pinn foward example in the deepxde. I am trying to train using adam as in the code but then train the model using L-BFGS. However it is failing. Below is the error.
When I compile with Adam it works fine. I am relatively new to deep learning and want to know if it would be possible to use the L-BFGS for this equation. Thank you for helping me with this!

[lululxvi]

Interesting... Not sure why.

[ginasn]

Will there be a fix for this? It would be very helpful.

[lululxvi]

You may try the backend paddle.