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

Fri Apr 6 15:01:07 CEST 2018

Okay, I will give a try to this approach also.

 -ec 0.001 and -fc 5 is enough for the first scf run the MSR1?

regards
Bhamu

On Fri, Apr 6, 2018 at 4:55 PM, Laurence Marks <L-marks at northwestern.edu>
wrote:

> It is more common to somewhat converge using MSR1 first, e.g. -cc 0.1,
> before switching to MSR1a. However, I don't see and clear indication that
> something is wrong in your output. A large value of :FCHECK is not unusual
> in the early stages.
>
> _____
> Professor Laurence Marks
> "Research is to see what everybody else has seen, and to think what nobody
> else has thought", Albert Szent-Gyorgi
> www.numis.northwestern.edu
>
> On Fri, Apr 6, 2018, 5:49 AM Dr. K. C. Bhamu <kcbhamu85 at gmail.com> wrote:
>
>>  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
>>
>
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