[Pw_forum] 'Tetrahedra' and 'scf'
On Oct 27, 2010, at 23:02 , Eduardo Ariel Menendez Proupin wrote: > I think it would be helpful and appreciated to keep scf with > tetrahedron method it is still working: it is sufficient to comment out a check in PW/ input.f90 . Anyway, I'll set a les restrictive condition > It would also be fine if the program just don't calculate the > forces when the tetrahedron > method is chosen, and give a warning for the beginners "forces are > not variational. > Use other smearing method" beginners don't read warnings, and when they do, they don't understand it ... P. --- Paolo Giannozzi, Dept of Chemistry, Univ. Udine via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
[Pw_forum] 'Tetrahedra' and 'scf'
Hi, I think it would be helpful and appreciated to keep scf with tetrahedron method, at least to make accurate SCF calculations. It would also be fine if the program just don't calculate the forces when the tetrahedron methos is chosen, and give a warning for the beginners "forces are not variational. Use other smearing method" > according to changelog-4.2, the tetrahedron method was forbidden to be used > for scf at *2010-03-25.* > What is the reason? > >forces are not variational, i.e. are not the derivative of the energy. >This shouldn't be a big problem if you do not calculate forces, though. Best regards -- Eduardo Menendez Departamento de Fisica Facultad de Ciencias Universidad de Chile Phone: (56)(2)9787439 URL: http://fisica.ciencias.uchile.cl/~emenendez They did it! -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20101027/8e32b84a/attachment.htm
[Pw_forum] 'Tetrahedra' and 'scf'
Dear Prof. Giannozzi, first of all, I'm sorry for the typo. Thank you for the quick reply too! It is true that Hellmann-Feynman theorem does not work for the tetrahedron method, but for scf it should not be a problem. Should it? 2010/10/27 Paolo Giannozzi > ?? ? wrote: > > > according to changelog-4.2, the tetrahedron method was forbidden to be > > used for scf at *2010-03-25.* > > What is the reason? > > forces are not variational, i.e. are not the derivative of the energy. > This shouldn't be a big problem if you do not calculate forces, though. > > > Probably, the best person to answer the question is Prof. Gianozzi. > > I don't know any Prof. "Gianozzi". Who is he? > > P. > -- > Paolo Giannozzi, Democritos and University of Udine, Italy > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Best regards, Max Popov Ph.D. student Materials center Leoben (MCL), Leoben, Austria. -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20101027/8adb4ded/attachment.htm
[Pw_forum] 'Tetrahedra' and 'scf'
?? ? wrote: > according to changelog-4.2, the tetrahedron method was forbidden to be > used for scf at *2010-03-25.* > What is the reason? forces are not variational, i.e. are not the derivative of the energy. This shouldn't be a big problem if you do not calculate forces, though. > Probably, the best person to answer the question is Prof. Gianozzi. I don't know any Prof. "Gianozzi". Who is he? P. -- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] 'Tetrahedra' and 'scf'
Hi everyone, according to changelog-4.2, the tetrahedron method was forbidden to be used for scf at *2010-03-25.* What is the reason? Probably, the best person to answer the question is Prof. Gianozzi. -- Best regards, Max Popov Ph.D. student Materials center Leoben (MCL), Leoben, Austria. -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20101027/41396cd3/attachment.htm
[Pw_forum] 'Tetrahedra' and 'scf'
On 10/27/10 3:35 PM, Paolo Giannozzi wrote: >> Probably, the best person to answer the question is Prof. Gianozzi. > I don't know any Prof. "Gianozzi". Who is he? The good-humored, but unhelpful, brother. nicola :-) -- - Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
