On Sep 26, 2012, at 19:55 , Tian Lan wrote: > So It means that I cannot exactly copy the setup of scf calculation > to the cp calculation > because in scf I used a much denser k-mesh but cp calculation only > uses the Gamma > point. Then how could I do the best to eliminate this difference in > the MD calculation? > I just find a blowing supercell in MD that otherwise in equilibrium > in scf.
the simplest and fastest test is to compare the results of self- consistent calculations for cp.x (no dynamics, just electronic minimization) and for pw.x for the same data (use card K_POINTS gamma). Compare the energies and the stresses. The choice of nr1b, nr2b, nr3b (if needed) is not completely obvious: you have to find a compromise between speed (incrases for decreasing values), and accuracy, taking into account that accuracy doesn't actually improve if you increase those values beyond some limits (useless long-range oscillations of the augmentation charges is all you see) Paolo --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
