Efficiency of Generalized Regular k-point grids

Most DFT practitioners use regular grids (Monkhorst-Pack, MP) for integrations in the Brillouin zone. Although regular grids are the natural choice and easy to generate, more general grids whose generating vectors are not merely integer divisions of the reciprocal lattice vectors, are usually more efficient (Wisesa et al., 2016). We demonstrate the efficiency of generalized regular (GR) grids compared to Monkhorst-Pack (MP) and simultaneously commensurate (SC) grids. In the case of metals, for total energy accuracies of one meV/atom, GR grids are 60% faster on average than MP grids and 20% faster than SC grids. GR grids also have greater freedom in choosing the k-point density, enabling the practitioner to achieve a target accuracy with the minimum computational cost