In a similar spirit, Garcia-Lastra and Wesolowski constructed a non-decomposable approximation, dubbed NDSD, that switches between the Thomas-Fermi NAKP and the von Weizsäcker NAKP . The latter is switched on in the vicinity of the nuclei of the frozen subsystems, where it shows the correct behavior and cancels out the Coulomb potential of the nucleus. The switching function used in NDSD uses the reduced density gradient of the frozen electron density to detect regions close to the nuclei. Recently, Wesolowski and co-workers improved on this functional by considering a more general kernel of a differential operator instead of the von Weizsäcker functional and by improving the switching function, resulting in the non-decomposable NDCS approximation as well as a symmetrized version thereof .