[Carpet] Tracking the puncture with Carpet

[Yosef Zlochower]

Hi,

   I want to evolve d Y^a / dt =  - beta^a (Y) to track the location
of the punctures. With a unigrid code I simply added this as an
evolved array to MoL. However, it seems that this is not simply
done with mesh refinement. Is there some way of knowing if the current
level and component is the finest available resolution for the point 
Y^a. If there is, then I suppose that I could set d Y^a = 0 for all
levels and all components but the right one. I can think of another 
method where I interpolate beta at y^a after the timestep is complete.
Will the interpolator give me beta at the highest refinement level
at point y^a, and if so, how do I get the appropriate dt for this 
refinement level?

Yosef