Which is the error message, if there is one. Note that the phonon code at a low symmetry q point requires much more k points than the pw.x code.
Andrea Quoting Mohammad Saghayezhian <m.saghayezhian at gmail.com>: > Dear Andrea, > > Thanks for reply. > > The nkp in my calculation is far less than 40000. As I know, the symmetry > reduces nkp, > therefore for a mesh of 30*30*28 the max nkp is 25200, So if the problem > rooted in max nkp parameter, > above mesh should not make any problem, there are some > tests that I did for checking the valid nkp and cut-off energy: > Cut-off(Ry) , Kpoints: 33, 22*22*18 (OK) > 35, 25*25*22 (OK) > 35, 30*30*26 () > 38, 22*22*18 (OK) > 38, 30*30*26 (Failed) > 40, 30*30*26 (Failed) > All of above number kpoints are lower that nkp max (40000). I also run the > calculation > without npool option to provide higher memory for large cut-off. but still I > wonder why > the last two calculation did not worked! > > Could it be due to optimization deficiency in compilation of ph.x files? > Please take a look at this links: > http://www.democritos.it/pipermail/pw_forum/2005-February/002070.html > http://www.democritos.it/pipermail/pw_forum/2005-February/002074.html > Thanks a lot > > > > On Thu, Fri, 01 Jul 2011 10:01:48 +0200, Andrea Dal Corso wrote: >> Please note that the maximum number of k points is still a parameter in >> QE (presently set to 40000), so to make phonon calculations with a very >> large mesh of k points you have to increase the value of npk in >> Modules/parameters.f90. > > >> HTH, > >> Andrea > > > > On Thu, 2011-06-30 at 11:58 +0330, Mohammad Saghayezhian wrote: >> Dear All, >> >> When I perform the scf calculation with high kp (45 45 45) and cut-off >> (42 Ry), the parallel execution ph.x fails and stops (q-points in >> ph.in: 4 4 3). but lowering the kp (15 15 15) and cut-off (22 Ry) >> solves the problem and the parallel ph.x goes on without any problem. >> Does this mean that I can not calculate phonon spectra with this >> accuracy? >> Also, the calculations are for metals. > -- > ------------------------------------------------------------------- > Mohammad Saghayezhian > Computational Condensed Matter Research Lab > Physics Department, Isfahan University of Technology, Isfahan, Iran > > Tel lab: +98 311 391 3731 Fax Office: +98311 391 3746 > ------------------------------------------------------------------- > ---------------------------------------------------------------- SISSA Webmail https://webmail.sissa.it/ Powered by Horde http://www.horde.org/