On Mon, 13 Nov 2006, Cyrille Barreteau wrote: CB> In fact I have looked in more details at the results of pw.x calculations CB> and there is a funny behaviour. The restarted calculations converges towards CB> a totally different scf solution with a total magnetization 1mu_B larger CB> than the previous "crashed" calculation. I guess there are several magnetic CB> solutions and I "jumped" from one solution to the other.. Funny..
hmmmm.... interesting. that could explain the geometry optimizer getting 'stuck' even if you use a large enough cutoff and tight enough wavefunction convergence. since you always restart from the previous wavefunction, there is a high tendency to stick to a similar state, even if it is not the optimal one anymore. did you restart from the previous wavefunction/density or with a new (atomic or random) wavefunction? sadly, this kind of situation is one of the problems that can happen, sometimes rather unexpectedly (it happened to me in a CP dynamics only after several ps simulation time when the system seemed equilibrated and i switched the thermostats for production run). how about adding a (paranioa) flag to pw.x that allows to do a final wavefunction optimization from an initial wfc (either random or atomic) at the last step of a geometry optimization and then compare the energies/eigenvalues and warn if the differences are large (the flag could be a floating point number with 0.0 meaning no check)? cheers, axel. CB> CB> cyrille CB> CB> CB> > Dear Kostya and Axel CB> > CB> > I have restarted my job with the last coordinates and CB> > the geometry optimization converged in just one scf cycle!! CB> > CB> > ========================================================== CB> > BFGS Geometry Optimization CB> > CB> > bfgs converged in 1 scf cycles and 0 bfgs steps CB> > CB> > End of BFGS Geometry Optimization CB> > ============================================= CB> > So I guess the previous "crashed run" did converge correctely CB> > toward the right optimal atomic configuration!! CB> > CB> > thanks CB> > CB> > cyrille CB> > CB> >> On Fri, 10 Nov 2006, Konstantin Kudin wrote: CB> >> CB> >> kostya, CB> >> CB> >> KK> It is not clear why the job should have a hard crash like this CB> >> instead CB> >> KK> of either terminating gracefully, recovering from the condition CB> >> in some CB> >> KK> way, or at least printing the very thing that you say, i.e. that CB> >> KK> "optimization terminated due to noise in the forces, increase CB> >> cutoff", CB> >> KK> or something else similar. CB> >> CB> >> i agree. after this issue has come up quite a few times in the last CB> >> months, it may be worth putting in the effort CB> >> and changing the code, so that it a) exits gracefully, CB> >> b) has a few more options on how to handle the resets, CB> >> e.g. force a minimum number of steps between two resets, CB> >> or have a small(!) randomization of coordinates. CB> >> CB> >> that just leaves the usual problem: who is going to do it? CB> >> anybody in the market for making a lot of people happy? CB> >> CB> >> KK> Actually, in my experience just restarting the job with the last CB> >> KK> coordinates has a very good chance to advance further, and even CB> >> find a CB> >> KK> lower energy structure since the BFGS will be started from scratch. CB> >> CB> >> hmmm. if you see the latter, then perhaps the reset is not CB> >> a complete reset and there may be a bug (unless you have CB> >> a 'randomization' of the coordinates due to limited CB> >> accuracy when reading in the so far optimized coordinates). CB> >> CB> >> cheers, CB> >> axel. CB> >> CB> >> KK> KK> Kostya CB> >> KK> KK> KK> KK> --- Axel Kohlmeyer <akohlmey at cmm.chem.upenn.edu> wrote: CB> >> KK> KK> > On Fri, 10 Nov 2006, Cyrille Barreteau wrote: CB> >> KK> > KK> > CB> Dear Pwscf users CB> >> KK> > KK> > dear cyrille, CB> >> KK> > KK> > did you check the mailing list archives? CB> >> KK> > KK> > IIRC, this error seems to happen if you try to CB> >> KK> > optimize the geometry too tightly for the CB> >> KK> > given convergence of the wavefunction or CB> >> KK> > when you suffer from 'ripples' due to a CB> >> KK> > too small density cutoff. CB> >> KK> > KK> > salut, CB> >> KK> > axel. CB> >> KK> > KK> > CB> I am trying to relax an iron cluster (cubocathedron) and CB> >> KK> > CB> pw.x systematicaly ends with the following error: CB> >> KK> > CB> KK> > CB> KK> > CB> >> KK> CB> >> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% CB> >> CB> >> KK> > CB> from bfgs : error # 1 CB> >> KK> > CB> bfgs history already reset at previous step CB> >> KK> > CB> KK> > CB> >> KK> CB> >> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% CB> >> CB> >> KK> > CB> KK> > CB> stopping ... CB> >> KK> > CB> 2 CB> >> KK> > CB> KK> > CB> KK> > CB> You can find the input and output files CB> >> on the following web CB> >> KK> > site: CB> >> KK> > CB> KK> > CB> CB> >> KK> > CB> >> KK> CB> >> http://www-drecam.cea.fr/Images/Pisp/cbarreteau/temporaire/cuboctahedron_relax.in CB> >> CB> >> KK> > CB> CB> >> KK> > CB> >> KK> CB> >> http://www-drecam.cea.fr/Images/Pisp/cbarreteau/temporaire/cuboctahedron_relax.out CB> >> CB> >> KK> > CB> KK> > CB> KK> > CB> thanks in advance for any constructive CB> >> comment :-) CB> >> KK> > CB> KK> > CB> cyrille CB> >> KK> > CB> KK> > CB> KK> > KK> > -- KK> > CB> >> KK> CB> >> ======================================================================= CB> >> KK> > Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu KK> > CB> >> http://www.cmm.upenn.edu CB> >> KK> > Center for Molecular Modeling -- University of Pennsylvania CB> >> KK> > Department of Chemistry, 231 S.34th Street, Philadelphia, PA CB> >> KK> > 19104-6323 CB> >> KK> > tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: CB> >> KK> > 1-215-898-5425 CB> >> KK> > CB> >> KK> CB> >> ======================================================================= CB> >> KK> > If you make something idiot-proof, the universe creates a better CB> >> KK> > idiot. CB> >> KK> > KK> > _______________________________________________ CB> >> KK> > Pw_forum mailing list CB> >> KK> > Pw_forum at pwscf.org CB> >> KK> > http://www.democritos.it/mailman/listinfo/pw_forum CB> >> KK> > KK> KK> KK> KK> KK> CB> >> ____________________________________________________________________________________ CB> >> CB> >> KK> Cheap talk? CB> >> KK> Check out Yahoo! Messenger's low PC-to-Phone call rates. CB> >> KK> http://voice.yahoo.com CB> >> KK> _______________________________________________ CB> >> KK> Pw_forum mailing list CB> >> KK> Pw_forum at pwscf.org CB> >> KK> http://www.democritos.it/mailman/listinfo/pw_forum CB> >> KK> CB> >> CB> >> CB> > CB> > CB> CB> CB> -- ======================================================================= Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
