[Pw_forum] question on electron_dynamics and orthogonalization

Nicola Marzari marzari at MIT.EDU
Thu Mar 30 00:05:57 CEST 2006


> I will play with it a bit more to see if I can isolate the problem. I
> do recall that the stress changes on the order of 0.5 GPa per
> component when I changed either
> emass_cutoff
> or
> nr1b,nr2b,nr3b

The only reason while it would change with emass_cutoff is that
you are not perfectly converged (I think). With enough iterations,
emass_cutoff shouldn't matter; it is just a preconditioning to take
into account that the hamiltonian is diagonally dominanant, in a plane
wave basis set, with the diagonal diverging as G^2.

nr1b... etc: well, let's revisit this as soon as CP is fixed. Paolo
and Carlo have been kindly working on this.


Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu

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