Conditional aux halo exchange via aux-field flag

[MikeW097]

Based on the discussion in #53, the main goal of this update is to keep the existing interfaces unchanged to avoid unintended downstream effects in ApesMate while still enabling conditional auxiliary halo communication.

[haraldkl]

I'd prefer it if we could set the flag in the init routine of auxfield, that is we amend that one interface, but the others wouldn't need it anymore. This way the initialization of the type is not spread across multiple parts of the code (hopefully).

[MikeW097]

@haraldkl the tracking is currently initialized after the auxfield, so needHaloComm is determined later based on the selected tracking. would you be OK with a two-step auxfield initialization: init_aux sets defaults, and then a single auxfield_configure_from_tracking (still within auxfield module) sets needHaloComm once after tracking is known?

[haraldkl]

Yes, though in that case it isn't that important, I still think it would be preferable to have function there setting the flag, rather than setting the flag directly.

[MikeW097]

@haraldkl I’ve updated the implementation accordingly by introducing auxfield_configure_from_tracking to set the flag.
Could you please take another look and let me know if this aligns with your expectations?

[haraldkl]

@MikeW097 I did some formatting. Please pull. Would you mind adding your copyright line in the top of the files where you added code? Otherwise that's fine to merge from my point of view. Thanks a lot!

[MikeW097]

@haraldkl Thanks for the review and formatting fixes. I’ve added the copyright line to the files I modified.

[haraldkl]

Perfect, thanks again @MikeW097.