Unkown parameters in InverseProblem can't go on device

[AleDinve]

Tutorial 7 (Inverse parametric 2D Poisson problem) can't be run on GPU.
Most likely, the unknown parameters are not assigned to the device.

[dario-coscia]

Hi! Thank you for reporting the bug, @annaivagnes any clue?

We could fix the bug in #263 since the PINN class is having a restyle (no breaking compatibility)

[annaivagnes]

Yes, thank you for noticing the bug, the problem is that the torch.nn.Parameters are not assigned to the device. I'll fix it soon and add in #263

[dario-coscia]

Hi @AleDinve ! In #283 @annaivagnes fixed the problem. You can see the changes in #263 and use (the unstable) branch. Soon we will integrate #263 in PINA master.

Thanks again @annaivagnes 🚀