The latest BFGS has a curvature trap which can change the behavior particularly if you have too few k-points. Can you please do
grep -e "! tot" -e bfgs WHATEVER.out (where WHATEVER is relevant) and send it to me, perhaps at my private email (or the full .out file). I am not an expert with QE, but might be able to say something. 2011/4/18 ?????? ????? <max.n.popov at gmail.com>: > Dear QE developers, > > comparing vc-relax calculations between BFGS(4.2.1) and the latest BFGS(from > CVS) I faced? with a following problem: > the newest QE calculates one extra point after achieving convergence > criteria (etot_conv_thr,force_conv_thr,press_conv_thr), > which leads to slightly higher total energy. > > Here are the two latest energies from outputs: > ?????? v.4.2.1???????? ? ? ? ? ? ??? CVS(18.04.2011) > > -242.66342170 Ry?????? -242.66342267 Ry > -242.66342336 Ry?????? -242.66284562 Ry > > One can see that there is a good agreement between the last energy by > v.4.2.1 and next to the last by CVS-version, whereas > the last energy by CVS is higher by ~ 0.5 mRy. > > I tried relax (cell shape fixed) also - it works fine, no extra point > calculation. > > -- > Best regards, Max Popov > Ph.D. student > Materials center Leoben (MCL), Leoben, Austria. > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- Laurence Marks Department of Materials Science and Engineering MSE Rm 2036 Cook Hall 2220 N Campus Drive Northwestern University Evanston, IL 60208, USA Tel: (847) 491-3996 Fax: (847) 491-7820 email: L-marks at northwestern dot edu Web: www.numis.northwestern.edu Chair, Commission on Electron Crystallography of IUCR www.numis.northwestern.edu/ Research is to see what everybody else has seen, and to think what nobody else has thought Albert Szent-Gyorgi
