optimization functions need an elegant copy method for creating the returned model

[bwpriest]

We are currently using deepcopy, which is unnecessarily heavy (especially once we start using heteroscedastic noise). What we need is a copy method that does something like

def copy_model(model: MuyGPS) -> MuyGPS:
    ret = MuyGPS()
    # for all fixed parameters of model, set ret's corresponding references to those objects (no copying)
    # for all free parameters of model, copy ret's corresponding members to those objects (copying)

[alecmdunton]

Are we going to pursue this approach still or go with the other optimization model where we just write over the input MuyGPS model?

[bwpriest]

I think we agreed to overwrite the model. We don't need to address this for the current release, though.

[bwpriest]

This is mostly addressed by v0.7.0, although we might improve on this later.