[Wien] [Warning message: Sum of forces not small, possible numerical issues]

[Dr. K. C. Bhamu]

 Thank you Prof. Lyudmila for the inlined reply.

I shall mention the optimization process: I am using  run_lapw ............
-it -min to relax the structure with TETRA (default), rmt 3, kpt 50
(4x4x2), PBE. Organometallic system (Hybrideperovskite).

I am not sure whether my scf is going well or not because I do not see any
such message.
My main concern is about too much time (~40 minutes on 16 core) for one scf
cycle and this warning.


Could you please have a look at my further queries:


06.04.2018 10:09, Dr. K. C. Bhamu wrote:

> :WARN
>> :WARNING Sum of forces not small, possible numerical issues
>>
> I'd look attentively around this place in the scf.
>


I do not find anything in scf with this statment or part of this statment.
Also, as per my excersie, nothing is mentioned in mailing list for such
warnings.



>
> below is constructive output from six scf cycles:
>>
> All looks good, though I do not know what is :ADIST. Something connected
> with MSR1a option.
>
>> :ADIST   Largest Distance  1.71E+02 mau for atom  18
>> :ADIST   Largest Distance  1.67E+02 mau for atom  32
>> :ADIST   Largest Distance  1.20E+02 mau for atom  32
>> :ADIST   Largest Distance  5.87E+01 mau for atom  32
>>
>
:ADIST represents the distance between atoms (Pg number 212 UG). Atom 18
and 32 are H.  in the 12th Cycle :FGL is positive for both and is around
~40mRyd/au.


>
> Too large forces appear and movement of the atoms becomes too large.
>
>>         TOTAL FORCE WITH RESPECT TO THE GLOBAL COORDINATE SYSTEM:
>> :FGL018:  18.ATOM              -228.797027515  -110.869626478
>>
>
> I think that mixer is very clever program, so this possibility is taken
> into account, and it wiil correctly treat this data.
>

results from :FGL and hence from :FCHECK is varying. In first cycle the
total forces from :FCHECK was very small and in the 8th Cycle total forces
are too high. The average totla force on each atom is


results from FCHECk and FR are below (in 12th scf cycle):
FCHECK *.scf

> :FCHECK:   Sum of forces        -69.940627520    74.707201466
256.655266254
> :FCHECK:   Sum of forces        -64.560329574    73.360823345
231.480485436
> :FCHECK:   Sum of forces        -48.034175166    65.104093472
166.986223927
> :FCHECK:   Sum of forces        -35.064695164    59.878383059
106.378782186
> :FCHECK:   Sum of forces          1.658948381    44.163592598
-28.823131541
> :FCHECK:   Sum of forces         -1.715900623    54.670180112
-38.208248369
> :FCHECK:   Sum of forces        -44.599628242    84.665399276
 80.309287437
> :FCHECK:   Sum of forces       -104.389046420   114.231138278
298.688183293
> :FCHECK:   Sum of forces       -146.872184802   138.002715039
506.089724144
> :FCHECK:   Sum of forces       -139.929513824   116.740866115
514.542253158
> :FCHECK:   Sum of forces        -44.458957001    53.512685999
 90.795768329
> :FCHECK:   Sum of forces        -21.346540908    53.389897235
 -190.728160314


:FR *.scf

> :FRMSA: (mRyd/au) 684.75( 18)  482.59 RMS (au) 2.11E-03 MAX 3.34E-03
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au) 666.97( 18)  473.06 RMS (au) 6.32E-03 MAX 1.00E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au) 620.05( 18)  446.96 RMS (au) 7.70E-03 MAX 1.22E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au) 564.83( 18)  415.40 RMS (au) 2.26E-02 MAX 3.60E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au) 410.77( 18)  314.76 RMS (au) 3.10E-02 MAX 5.00E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au) 228.80( 18)  169.19 RMS (au) 3.10E-02 MAX 5.00E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  65.91( 17)   47.66 RMS (au) 1.16E-02 MAX 2.21E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  57.84(  9)   41.34 RMS (au) 9.47E-03 MAX 1.98E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  76.92( 35)   55.05 RMS (au) 7.92E-03 MAX 2.08E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  68.91( 21)   60.53 RMS (au) 8.58E-03 MAX 1.53E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  59.32( 25)   53.55 RMS (au) 7.45E-03 MAX 1.32E-02
:F-cond.(mRyd/au)    2.00 F
> :FRMSA: (mRyd/au)  64.13( 13)   54.92 RMS (au) 6.46E-03 MAX 1.04E-02
:F-cond.(mRyd/au)    2.00 F
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20180406/c4a54f11/attachment.html>