Fig. 2: Energy convergence with k-point density.
From: Numerical quality control for DFT-based materials databases

Average (a) and maximum error (b) observed for the elemental solids are shown for two different k-point densities ρk. The calculations were carried out for the elemental solids with exciting, FHI-aims, and GPAW using the PBE xc-functional. A simple summation with a Fermi-function smearing of 100 meV is used for the BZ integration to facilitate comparison between codes.