DFT: the lore of smoothing and tetrahedra is wrong

Smoothing and tetrahedron methods in density functional theory (DFT) codes were developed to improve the robustness and efficiency of DFT codes. Tests we have performed demonstrate that both methods fail to accomplish either assertion. We have run ~20,000 DFT calculations in VASP and Quantum Espresso with various types and amounts of smoothing on 12 metals. The rate of convergence of the total energy for calculations with smoothing is often worse than those without smoothing, and smoothing does not result in a reduction in the number of self-consistency cycles when compared to runs without smoothing. We obtained similar results in comparisons involving tetrahedron methods.