just as a side note, the fact that subsequent SCF steps require less davidson iterations should be seen as an advantage (due to the use of smart iterative diagonalization techniques), rather than a disadvantage. I do not quite understand why you need so many k-points, given the symmetry of SrTiO3, and its insulating character ... SB On Jan 21, 2010, at 2:26 PM, Lorenzo Paulatto wrote:
> On Wed, 20 Jan 2010 20:04:40 +0100, Marcos Ver?ssimo Alves > <marcos.verissimo.alves at gmail.com> wrote: > The time bewteen the end of >> the initialization of the calculation (starting mode="from scratch") >> and end of the first calculation step are much longer than the typical >> times for the subsequent davidson diagonalization steps (between 4-5 >> times longer): > > Dear Marcos, > when performing the first diagonalization the initial trial wavefunctions > used by the algorithm are just a superposition of atomic wavefunctions, > which are only a very rough estimate of the eigenvaleus. On subsequent > steps the initial trial wavefunctions are the ones from the previous scf > step, which are usually quite a good estimate. If after finishing the > calculation you restart it from scratch, but setting startingwfc='file', > you should find that now the first diagonalization step is as fast as the > subsequent ones. > > best regards > > > -- > Lorenzo Paulatto > > *** Note: my affiliation has changed! please send future > correspondence to: <Lorenzo.Paulatto at impmc.upmc.fr> *** > > post-doc @ IMPMC/UPMC - Universit? Paris 6 > phone: +33 (0)1 44 27 74 89 > www: http://www-int.impmc.upmc.fr/~paulatto/ > > previously: > phd student @ SISSA & DEMOCRITOS (Trieste) > phone: +39 040 3787 511 > www: http://people.sissa.it/~paulatto/ > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) La morale est une logique de l'action comme la logique est une morale de la pens?e - Jean Piaget Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100121/d39bb5fb/attachment.htm
