Model parameters being marked as orphan when using KFAC optimizer

[Uernd]

I was trying to use KFAC optimizer to train the FermiNet, a well-designed PINN for solving atoms and molecules. But when I was trying to add the parity constrain to it, I noticed that some of the parameters was labeled as 'orphan', though the calculation was proceeding normally.

I wonder what 'orphan' means, and is this a normal circumstance? Could these parameters labelled as 'orphan' being updated while trainning normally? I mean even though it finally yielded a correct results, there still was a lot of normally-labelled parameters which ensured the model is trainable.

The following picture contains all my changes to FermiNet. I've only modified the networks.py file.

Thank you for your assistance !