Data type: numb
Enumeration range: 0 -> infinity
Enumeration default: 0
The number of constrained (non-refined or dependent) parameters in the least-squares process. These may be due to symmetry or any other constraint process (e.g. rigid-body refinement). See also _atom_site_constraints and _atom_site_refinement_flags. A general description of constraints may appear in _refine_special_details.