noises.py: clean up helper functions

• merge coating_thickness into mirror_struct
• merge precomp_mirror into mirror_struct
• merge precomp_power into ifo_power
• merge precomp_cavity into arm_cavity

precomp is no longer used for these helpers, but they're sufficiently trivial that it doesn't matter whether they are cached.

It's orthogonal to this MR, but I see there are some places we've been using the ETM mirror mass, where the reduced mass should probably be used instead.

This is much cleaner and I like the reorganization. But I think the new mirror_struct, arm_cavity, and ifo_power are just cleaner precomps now. I think you can keep these new definitions and also keep the old calc functions by just renaming the functions.

I think the new cavity and power structs are nice. But you explicitly want to get rid of the use of the precomp functions? I guess there is some simplification here, but I'm not sure what's being saved.

If others are fine with this I will be too.

Yes, I prefer that we don't use precomp gratuitously, but just call the functions in calc unless there's a substantial benefit from caching them.

This change seems fine to me.

approved this merge request

merged

mentioned in commit c765d57a