[DFTB-Plus-User] Unreasonably large number of steps in simultaneous geometry and cell optimization
Bálint Aradi
aradi at uni-bremen.de
Sun Dec 5 21:40:56 CET 2021
Dear Alexander Maryewski,
You are absolutely right, the current geometry optimizers of DFTB+ have
often very poor performance when lattice optimization is involved.
We are working on the problem, and hope to merge a pull request with
significantly improved geometry optimisers within the next few days.
Using the new rational function based driver (Rational), I get a
convergence for lattice and atom positions in only 174 steps for your
system. As you are using a development version already, you may be
interested to try it yourself:
https://github.com/dftbplus/dftbplus/pull/862
Some other notes to your input:
- You use the damped electrostatics, specify Hubbard U derivatives, but
did not switch on the third order correction (ThirdOrderFull = Yes). I
guess, that's just by mistake. (If you had not switched off the parser
errors with IgnordedUnprocessedNodes = Yes, you would have obtained an
error message about the superfluous HubbardDerivatives block...)
- The SCC tolerance of 1e-8 is really tight. You can speed up the
calculation by choosing the default value instead. That should still
give forces accurate enough to get a proper geometry convergence and
could spare you a few scc cycles in each step.
Best regards,
Bálint
On 04.12.21 23:11, Alexander Maryewski wrote:
> Dear DFTB+ users and developers,
>
>
> I'm experiencing a problem with unreasonably slow convergence for
> simultaneous geometry & cell optimization. The initial structure for
> optimization (organic molecular crystal) is obtained from PBE relaxation
> with MBD correction in FHI-aims, so it is supposed to be in proximity of
> DFTB minimum; the system itself is quite simple, with no flexible
> dihedral angles. The final structure is essentially identical to the
> initial one, the volume change is very small. However, the relaxation
> takes 3448 geometry steps and 91 lattice steps, which is, in my opinion,
> too much for such negligible change.
>
>
> I'm attaching the initial and final structures, as well as the input
> specification. I must note that changing the relaxation driver to BFGS
> or CG led to even bigger number of steps, while increasing the max step
> size had virtually no effect on number of steps. The problem also
> persists for all other types of dispersion corrections (D3, D4, and
> MBD), as well as for DFTB1, DFTB2, and xTB Hamiltonian. I'm using a
> development version of DFTB+ (commit 65b0275).
>
>
> Thank you in advance for you help!
>
>
> Input:
>
> Geometry = VaspFormat {
> <<< "POSCAR"
> }
>
> Driver = FIRE {
> MovedAtoms = 1:-1
> MaxForceComponent = 1e-4
> LatticeOpt = Yes
> MaxSteps = -1
> MaxAtomStep = 0.94486
> MaxLatticeStep = 0.94486
> }
>
>
> Hamiltonian = DFTB {
> SCC = Yes
> SCCTolerance = 1e-08
> MaxSCCIterations = 2000
> SlaterKosterFiles = Type2FileNames{
> Prefix = /home/amarjewski/Downloads/3ob-3-1/
> Separator = "-"
> Suffix = ".skf"
> }
> HCorrection = Damping {
> Exponent = 4.2
> }
>
>
> HubbardDerivs {
> C = -0.1492
> S = -0.11
> N = -0.1535
> }
> MaxAngularMomentum = {
> C = p
> S = d
> N = p
> }
> KPointsAndWeights = SupercellFolding {
> 2. 0. 0.
> 0. 2. 0.
> 0. 0. 1.
> 0.5 0.5 0.5
> }
> Dispersion = TS {
> RangeSeparation = 1.05
> }
> }
>
> Options {
> WriteResultsTag = Yes
> TimingVerbosity = -1
> }
> ParserOptions {
> IgnoreUnprocessedNodes = Yes
> }
>
>
> Initial structure:
>
> EA0
> 1.0000000000000000
> 0.000000 0.000000 -7.055000
> -0.000000 -10.130900 -0.000000
> -13.452700 0.000000 -0.000000
> C N S
> 32 16 12
> Direct
> 0.020520 0.692620 0.600950
> 0.042030 0.587050 0.180350
> 0.542030 0.412950 0.819650
> 0.042030 0.912950 0.680350
> 0.030900 0.137560 0.263670
> 0.530900 0.862440 0.736330
> 0.530900 0.637560 0.236330
> 0.030900 0.362440 0.763670
> 0.928500 0.241210 0.079410
> 0.428500 0.758790 0.920590
> 0.428500 0.741210 0.420590
> 0.928500 0.258790 0.579410
> 0.997970 0.671140 0.100580
> 0.497970 0.328860 0.899420
> 0.497970 0.171140 0.399420
> 0.997970 0.828860 0.600580
> 0.542030 0.087050 0.319650
> 0.531340 0.943920 0.822090
> 0.031340 0.056080 0.177910
> 0.520520 0.307380 0.399050
> 0.020520 0.807380 0.100950
> 0.972070 0.640130 0.506290
> 0.472070 0.359870 0.493710
> 0.472070 0.140130 0.993710
> 0.520520 0.192620 0.899050
> 0.983790 0.392900 0.586900
> 0.483790 0.607100 0.413100
> 0.483790 0.892900 0.913100
> 0.983790 0.107100 0.086900
> 0.031340 0.443920 0.677910
> 0.972070 0.859870 0.006290
> 0.531340 0.556080 0.322090
> 0.913600 0.774530 0.938670
> 0.884360 0.148230 0.570310
> 0.384360 0.851770 0.429690
> 0.384360 0.648230 0.929690
> 0.884360 0.351770 0.070310
> 0.534960 0.798690 0.663870
> 0.534960 0.701310 0.163870
> 0.034960 0.201310 0.336130
> 0.085280 0.976920 0.749030
> 0.413600 0.225470 0.061330
> 0.585280 0.023080 0.250970
> 0.034960 0.298690 0.836130
> 0.413600 0.274530 0.561330
> 0.085280 0.523080 0.249030
> 0.585280 0.476920 0.750970
> 0.913600 0.725470 0.438670
> 0.990480 0.028080 0.969370
> 0.490480 0.971920 0.030630
> 0.490480 0.528080 0.530630
> 0.990480 0.471920 0.469370
> 0.916110 0.621430 0.983970
> 0.416110 0.121430 0.516030
> 0.916110 0.878570 0.483970
> 0.101330 0.893130 0.206480
> 0.601330 0.106870 0.793520
> 0.601330 0.393130 0.293520
> 0.101330 0.606870 0.706480
> 0.416110 0.378570 0.016030
>
> Final structure:
>
> 60 F
> C N S
> 1 1 0.1618820919E-01 0.6953035972E+00 0.6028292686E+00
> 2 1 0.6054080320E-01 0.5816253594E+00 0.1889168374E+00
> 3 1 0.5605408032E+00 0.4183746406E+00 0.8110831626E+00
> 4 1 0.6054080212E-01 0.9183746373E+00 0.6889168379E+00
> 5 1 0.3894586478E-01 0.1463696753E+00 0.2863807959E+00
> 6 1 0.5389458648E+00 0.8536303247E+00 0.7136192041E+00
> 7 1 0.5389458626E+00 0.6463696788E+00 0.2136192044E+00
> 8 1 0.3894586258E-01 0.3536303212E+00 0.7863807956E+00
> 9 1 0.9194815724E+00 0.2560876082E+00 0.9025739993E-01
> 10 1 0.4194815724E+00 0.7439123918E+00 0.9097426001E+00
> 11 1 0.4194815742E+00 0.7560876117E+00 0.4097426009E+00
> 12 1 0.9194815742E+00 0.2439123883E+00 0.5902573991E+00
> 13 1 0.1005024217E+01 0.6667714686E+00 0.1023961561E+00
> 14 1 0.5050242166E+00 0.3332285314E+00 0.8976038439E+00
> 15 1 0.5050242175E+00 0.1667714722E+00 0.3976038438E+00
> 16 1 0.1005024218E+01 0.8332285278E+00 0.6023961562E+00
> 17 1 0.5605408021E+00 0.8162536268E-01 0.3110831621E+00
> 18 1 0.5307570847E+00 0.9362083091E+00 0.8076337958E+00
> 19 1 0.3075708471E-01 0.6379169088E-01 0.1923662042E+00
> 20 1 0.5161882092E+00 0.3046964028E+00 0.3971707314E+00
> 21 1 0.1618820762E-01 0.8046963992E+00 0.1028292686E+00
> 22 1 0.9622657415E+00 0.6386852028E+00 0.5001196801E+00
> 23 1 0.4622657415E+00 0.3613147972E+00 0.4998803199E+00
> 24 1 0.4622657378E+00 0.1386852066E+00 0.9998803195E+00
> 25 1 0.5161882076E+00 0.1953036008E+00 0.8971707314E+00
> 26 1 0.9767711350E+00 0.3817261045E+00 0.5960237041E+00
> 27 1 0.4767711350E+00 0.6182738955E+00 0.4039762959E+00
> 28 1 0.4767711330E+00 0.8817261080E+00 0.9039762953E+00
> 29 1 0.9767711330E+00 0.1182738920E+00 0.9602370469E-01
> 30 1 0.3075708476E-01 0.4362083057E+00 0.6923662040E+00
> 31 1 0.9622657378E+00 0.8613147934E+00 0.1196804560E-03
> 32 1 0.5307570848E+00 0.5637916943E+00 0.3076337960E+00
> 33 2 0.9108197374E+00 0.7815481119E+00 0.9219522648E+00
> 34 2 0.8628543644E+00 0.1347135404E+00 0.5859737071E+00
> 35 2 0.3628543644E+00 0.8652864596E+00 0.4140262929E+00
> 36 2 0.3628543630E+00 0.6347135438E+00 0.9140262920E+00
> 37 2 0.8628543630E+00 0.3652864562E+00 0.8597370800E-01
> 38 2 0.5489472848E+00 0.7895246992E+00 0.6367080419E+00
> 39 2 0.5489472805E+00 0.7104753046E+00 0.1367080424E+00
> 40 2 0.4894728477E-01 0.2104753008E+00 0.3632919581E+00
> 41 2 0.1132682966E+00 0.9872521695E+00 0.7577586812E+00
> 42 2 0.4108197374E+00 0.2184518881E+00 0.7804773523E-01
> 43 2 0.6132682966E+00 0.1274783045E-01 0.2422413188E+00
> 44 2 0.4894728050E-01 0.2895246954E+00 0.8632919576E+00
> 45 2 0.4108197421E+00 0.2815481158E+00 0.5780477357E+00
> 46 2 0.1132682994E+00 0.5127478277E+00 0.2577586806E+00
> 47 2 0.6132682994E+00 0.4872521723E+00 0.7422413194E+00
> 48 2 0.9108197421E+00 0.7184518842E+00 0.4219522643E+00
> 49 3 0.9682605312E+00 0.3602122790E-01 0.9694575748E+00
> 50 3 0.4682605312E+00 0.9639787721E+00 0.3054242521E-01
> 51 3 0.4682605362E+00 0.5360212317E+00 0.5305424258E+00
> 52 3 0.9682605362E+00 0.4639787683E+00 0.4694575742E+00
> 53 3 0.9256425787E+00 0.6018522640E+00 0.9799177228E+00
> 54 3 0.4256425811E+00 0.1018522679E+00 0.5200822773E+00
> 55 3 0.9256425811E+00 0.8981477321E+00 0.4799177227E+00
> 56 3 0.9347257894E-01 0.8945740691E+00 0.2184145744E+00
> 57 3 0.5934725789E+00 0.1054259309E+00 0.7815854256E+00
> 58 3 0.5934725786E+00 0.3945740725E+00 0.2815854253E+00
> 59 3 0.9347257856E-01 0.6054259275E+00 0.7184145747E+00
> 60 3 0.4256425786E+00 0.3981477360E+00 0.2008227717E-01
> 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
> 0.3796409345E-10 -0.2823521794E-10 -0.6775993499E+01
> 0.4331511054E-08 -0.1000091620E+02 -0.3952259833E-11
> -0.1248479890E+02 0.7282280671E-08 0.2555546997E-10
>
>
> Best regards,
>
> Alexander A. Maryewski
>
>
> _______________________________________________
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
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>
--
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b-aradi/
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