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/
