  A high-throughput benchmarking technique for testing the performance of
different exchange-correlation functionals and pseudopotentials is proposed and
applied to bulk SnS. It is shown that, contrary to the popular view that the
local density approximation can best describe layered materials, a semilocal
pseudopotential with a functional having a gradient dependence better described
lattice vectors and `tetragonicity' of the lattice. We classify the
pseudopotentials based on this value and show that the participation ratio of
maximally localized Wannier functions follows the theory which states that more
distorted structures have higher anti-bonding hybridization as stabilizing
factor. In order to classify pseudopotentials, the local and nonlocal potential
contributions to the dynamical Born effective charges are taken for each
pseudopotential. Finally, a strategy is proposed for learning
exchange-correlation functionals based on the distinction between short and
long range parts of the Kohn-Sham potential.
