[Pw_forum] problem with vc-relax
Stefano Baroni
baroni at sissa.it
Wed Jan 7 13:24:21 CET 2009
On Jan 7, 2009, at 1:19 PM, Stefano de Gironcoli wrote:
> 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.
another more exotic possibility is that the energy gain due to a
decreasing stress is larger than the increase due to an increasing
force. I am not sure that the algorithm implemented guarantees that
the individual components of the energy gradients decrease during
along the minimization process.
Stefano B
>
> 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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>
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