? 2011?8?21? ??4:36?Lo_wan_2005XW <lo_wan_2005 at hotmail.com>??? > Dear developer and users: > > Exactly follow the userguide, I am trying to calculate the phonon. > > Firstly I make a self-consistent calculation with > > K_POINTS automatic > 8 8 8 0 0 0 > > After the calculation convergent, I start the ph.x calculation. But the > calculation is extremely slow, thus I goto > the output-file, and find a strange thing. > > For some q-qoint, I find; > number of k points= 1024 Marzari-Vanderbilt smearing, width (Ry)= 0.0500 > > 8*8*8=512. If you set the spin polarized scf calculation, I think the number of total k points should multiply 2 again, so there are 1024 kpoints.
> > I understand that phonon may break some symmetry, but how it can go to > 1024-k-point when I use 8-8-8 mesh? > > I already use "start_q=X, last_q=X, recover=.true.," to separate q-point. I > also use parallel to speed up the calculation. > But it is still extremely slow. My system has only 12 atoms per unit cell, > and it seems that some q-point > (where it requires 1024 k-points) may need one month! > > I don't know if there is other method to speed up the calculation? > > 1,To make sure pwscf can find all symmetry operation in scf calculation. 2, To reduce the number of k points, ecut energy~ Hope it helps! > > Thanks! > > Xiangang Wan > > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- Y. C. Cheng Department of Physics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110821/37fa470b/attachment.htm