is the pytorch backend differentiable? about fdtd

[flaport]

Hey @ni-chen ,

this has been on my todo list for too long, currently there are a few in-place operations preventing this... However, I don't think it should be too difficult to change, I expect the simulator to work slower, however...

Maybe when I find the time I might finally give it a shot soon. This would obviously be an awesome feature to have.

[ni-chen]

Thanks for your reply.
I believe it would be of great interest for many applications. @flaport

[simenhu]

Would you be able to point to the places where the changes would have to be made? Could see if I could try to make a PR on it if it's not a very big change?

Would the general approach of preallocating the field tensors and write to a new index instead of updating an already populated tensor be the general solution you are thinking of?