[Pw_forum] problem with vc-relax
Stefano de Gironcoli
degironc at sissa.it
Wed Jan 7 13:19:53 CET 2009
loc duong ding wrote:
> Dear all,
>
> I have a problem when I run vc-relax input file.
> The force is increasing when the energy is decreasing.
> I wonder this is the normal case or not.
>
this may indicate that you starter from (close to ) a saddle point and
so you are moving away from a local maximum.
as long as the energy decreases it should be ok.
stefano
>
> Total force = 0.008423 Total SCF correction = 0.001451
> Total force = 0.250397 Total SCF correction = 0.001413
> Total force = 0.050557 Total SCF correction = 0.000845
> Total force = 0.023345 Total SCF correction = 0.000806
> Total force = 0.023806 Total SCF correction = 0.000490
> Total force = 0.012668 Total SCF correction = 0.000976
> Total force = 0.018448 Total SCF correction = 0.000564
> Total force = 0.007273 Total SCF correction = 0.000217
> Total force = 0.009299 Total SCF correction = 0.000773
> Total force = 0.020024 Total SCF correction = 0.000250
> Total force = 0.020090 Total SCF correction = 0.000275
> Total force = 0.019091 Total SCF correction = 0.000327
> Total force = 0.015802 Total SCF correction = 0.000400
> Total force = 0.015637 Total SCF correction = 0.000278
> Total force = 0.016418 Total SCF correction = 0.000350
> Total force = 0.015572 Total SCF correction = 0.000426
> Total force = 0.012873 Total SCF correction = 0.001104
> Total force = 0.010242 Total SCF correction = 0.000505
> Total force = 0.011922 Total SCF correction = 0.000188
> Total force = 0.010932 Total SCF correction = 0.000262
> Total force = 0.009932 Total SCF correction = 0.000551
> Total force = 0.011343 Total SCF correction = 0.000600
> Total force = 0.014450 Total SCF correction = 0.000690
> Total force = 0.014524 Total SCF correction = 0.000966
> Total force = 0.011143 Total SCF correction = 0.000587
> Total force = 0.009504 Total SCF correction = 0.000221
> Total force = 0.011470 Total SCF correction = 0.000335
> Total force = 0.014026 Total SCF correction = 0.000562
> Total force = 0.014418 Total SCF correction = 0.000610
> Total force = 0.014141 Total SCF correction = 0.000876
> Total force = 0.014633 Total SCF correction = 0.000997
> Total force = 0.015387 Total SCF correction = 0.001111
> Total force = 0.015936 Total SCF correction = 0.001014
> Total force = 0.015588 Total SCF correction = 0.000677
> Total force = 0.014659 Total SCF correction = 0.000955
> Total force = 0.013135 Total SCF correction = 0.000591
> Total force = 0.011533 Total SCF correction = 0.000887
> Total force = 0.011797 Total SCF correction = 0.000345
> Total force = 0.011249 Total SCF correction = 0.000261
> Total force = 0.009558 Total SCF correction = 0.000150
> Total force = 0.009430 Total SCF correction = 0.000226
> Total force = 0.009257 Total SCF correction = 0.000241
> Total force = 0.010596 Total SCF correction = 0.000144
> Total force = 0.011993 Total SCF correction = 0.000211
> Total force = 0.012208 Total SCF correction = 0.000626
> Total force = 0.011316 Total SCF correction = 0.000538
> Total force = 0.012541 Total SCF correction = 0.000283
> Total force = 0.013752 Total SCF correction = 0.000313
> Total force = 0.014861 Total SCF correction = 0.000345
> Total force = 0.014663 Total SCF correction = 0.000492
>
>
> ! total energy = -311.65667063 Ry
> ! total energy = -311.53467416 Ry
> ! total energy = -311.65476738 Ry
> ! total energy = -311.65809859 Ry
> ! total energy = -311.65746738 Ry
> ! total energy = -311.65818908 Ry
> ! total energy = -311.65836015 Ry
> ! total energy = -311.65850034 Ry
> ! total energy = -311.65862191 Ry
> ! total energy = -311.65888214 Ry
> ! total energy = -311.65922406 Ry
> ! total energy = -311.65963798 Ry
> ! total energy = -311.66003012 Ry
> ! total energy = -311.66040611 Ry
> ! total energy = -311.66078796 Ry
> ! total energy = -311.66117923 Ry
> ! total energy = -311.66141965 Ry
> ! total energy = -311.66161990 Ry
> ! total energy = -311.66177274 Ry
> ! total energy = -311.66190991 Ry
> ! total energy = -311.66205510 Ry
> ! total energy = -311.66222069 Ry
> ! total energy = -311.66243963 Ry
> ! total energy = -311.66268794 Ry
> ! total energy = -311.66289592 Ry
> ! total energy = -311.66304908 Ry
> ! total energy = -311.66320915 Ry
> ! total energy = -311.66340482 Ry
> ! total energy = -311.66361063 Ry
> ! total energy = -311.66386806 Ry
> ! total energy = -311.66413998 Ry
> ! total energy = -311.66442184 Ry
> ! total energy = -311.66467976 Ry
> ! total energy = -311.66497799 Ry
> ! total energy = -311.66518668 Ry
> ! total energy = -311.66545797 Ry
> ! total energy = -311.66563977 Ry
> ! total energy = -311.66584671 Ry
> ! total energy = -311.66601473 Ry
> ! total energy = -311.66615866 Ry
> ! total energy = -311.66626437 Ry
> ! total energy = -311.66638311 Ry
> ! total energy = -311.66651248 Ry
> ! total energy = -311.66665949 Ry
> ! total energy = -311.66687447 Ry
> ! total energy = -311.66704465 Ry
> ! total energy = -311.66725797 Ry
> ! total energy = -311.66744622 Ry
> ! total energy = -311.66766939 Ry
> ! total energy = -311.66791148 Ry
>
> Another problem is related c_bands eigenvalue. I often get the notice:
>
> Davidson diagonalization with overlap
> c_bands: 1 eigenvalues not converged
> c_bands: 1 eigenvalues not converged
>
>
> But It until runs well. I wonder the result for this calculation is believable or not.
>
> Best regards,
> -----------------------------------------------
> Loc Duong Dinh
> Ms-Ph.D Student
> Sungkyunkwan Advanced Institute of Nanotechnology,
> Sungkyunkwan University,
> Suwon, 440-746, Korea
> Email: mambom1902 at yahoo.com
>
>
>
>
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