Another approach based on the KKR-CPA formulation of DFT is the S ( 2 ) theory for multicomponent alloys, which evaluates the two-point correlation function, an atomic short-range order parameter, ab initio. The S ( 2 ) theory has been used with success to study the Cantor alloy, CrMnFeCoNi and its derivatives, the refractory HEAs, as well as to examine the influence of a materials' magnetic state on atomic ordering tendencies.