Dear Paul and Paolo, Thank you very much for your reply. I guess manually fixing will have to do the trick.
And I am specially grateful for link to w2gz site. I started reading texts, there are some really interesting things there. I will feel free to send you an email if I have some questions. I hope this is ok. Best regards, Jelena P.S. If mid-70s were "the bad old days" you should see it now :( No matter what people say, seventies were the golden age after all. Yet, countryside is still beautiful :) On 2016-04-15 05:03, W2AGZ wrote: > Dear J. Pesic, > > I understand your frustration, and Paolo's response is very > cogent...the > Fortran "ones and zeroes" at k(q) near zero need to be tuned "a > priori or a > posteriori" in either lambda.f90 and/or its output. I've dealt with > this > issue over the years attempting to calculate the Eliashberg-McMillan > strong > coupling superconductivity parameters in copper oxide perovskites. > Please > visit www.w2agz.com for relevant publications/presentations and > references. > I've found some success combining algorithms and code from PWSCF, > GIBBS2, > and ELK. > > I visited and spoke at your institute in Belgade back in "the bad old > days" > of the mid-1970s, and recall fondly the hospitality of the faculty > and the > beauty of the contryside. > > Best, -Paul > > -----Original Message----- > From: [email protected] [mailto:[email protected]] > On > Behalf Of yelena > Sent: Thursday, April 14, 2016 6:49 AM > To: [email protected] > Subject: [Pw_forum] electron-phonon calculation problem > > Dear all, > I've been having problem with electron-phonon calculation. I keep > having > negative phonon frequency in gamma point, -0.00007, nowhere else, (so > it is > not "real" instability, but some numerical problem) but it keeps > interfering > with my lambda.x calculation and all i get is NAN for alpha2F and so > on. So > is there any trick to avoid it? This is clearly numerical issue, > because > other modes are positive and phonon dispersion looks as it should be > and > there is no any instability. Can I somewhere manually change that -, > maybe? > I've tried to increase tr2_ph (and decrease it, also) but it keeps > happening > just the same. And tried larger k and q grid. Still the same. > > Best Regards, > PhD Student J.Pesic > Center for Solid State Physics, > Institute of Physics Belgrade, Serbia > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Institute of Physics Belgrade Pregrevica 118, 11080 Belgrade, Serbia http://www.ipb.ac.rs/ _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
