double xyz or TVector3?
The NOvA Geometry is coded to represent 3 vectors almost exclusively as arrays of doubles while the RecoBase classes use ROOT's TVector3 almost exclusively. I think it would be best in the long run to pick a standard. The issues as I see them:
- TVector3 provides lots of nice functionality at the expense of C++ overhead
- arrays of doubles make for faster code but frequently require one to reinvent some of the TVector3 functionality