Hi Jeff,
This is a great point. There should probably be NCS output in the PDB header.
yes, it's definitely good to have, but can we really say more than something like: REMARK 3 NCS RESTRAINTS: TYPE TORSION ?
2. What is difference between NCS type, global and torsion angle, and when they are preferred over the other?
Global NCS uses Cartesian-based restraints, which force the matching chains to be identical.
Just a minor correction: what you described are NCS *constraints*, and we don't have them in phenix.refine yet. NCS restraints force the coordinates and B-factors (residual B-factors if TLS is used) of NCS related copies to be *similar* (but not necessarily identical). The degree of similarity is determined by a parameter, and this parameter cannot be set such that NCS restraints become NCS constraints. All the best, Pavel