VASP tips: Energy and force convergence

So long as we tested, the recommended energy and force convergences are 10$^{-8}$ eV and 10$^{-6}$ Å/eV both when finding an equilibrium structure and when obtaining forces in a displaced structure. However it is difficult to have enough force convergence of an equilibrium structure when an input cell is large. In such a case, try using plus-minus setting introduced in Sec. 2.1.3.