On 05/25/2011 02:53 PM, Emine Kucukbenli wrote: > I was thinking that you were trying to optimize the calculation > parameters however with this post I am lost.I will give a generic > answer: > > Before starting to work on a system, you need to optimize the > calculation parameters, much like an experimentalist optimizing their > machine set up before an experiment. > > You need to make sure that what you will get, once you do the desired > calculation, (like a desired experiment) would be sensible data. This > is a preparation scheme_before_ the actual calculations. > > In this preparation process, you need to check the convergence of > energy, and/or forces, pressure etc, basically whatever interests you, > or whatever the interested property is sensitive to. And by > convergence, I mean convergence with respect to calculation > parameters: ecutwfc/rho ; kpoints ; smearing for metals; box size for > isolated systems, convergence thresholds etc ..again, whatever is > relevant. > > Once you know the optimum values for these parameters, you can do some > applications: One of them might be finding the equilibrium lattice > parameter. If so, now you can run a "vc-relax" calculation to get the > zero pressure structure.. > > Hope this made any sense and didnt confuse you even more. > cheers, > emine kucukbenli, phd student, sissa, italy Thanks a lot for your systematic analysis ;-)
Regards -- Hongsheng Zhao<zhaohscas at yahoo.com.cn> School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China
