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

Dr. K. C. Bhamu kcbhamu85 at gmail.com
Wed Apr 18 08:55:41 CEST 2018


Dear Prof. Marks and Peter,

Sorry for the delay in reply.

I followed your suggestions and did a simple scf.

Now I see forces are less than 5mRyd/au or negative on most of the atoms
except on three "H" atom in CH3NH3PbI3 structure where I am getting ~12
mRyd/au.

 I am mentioning :. FOR013 for atom number 13 along with fcheck

[bhamu at bhamu-pmc]$grep :FGL013 *.scf
:FOR013:  13.ATOM        169.039        -30.643        -61.735
-154.351 partial forces
:FOR013:  13.ATOM        159.798        -28.662        -58.657
-145.853 partial forces
:FOR013:  13.ATOM        138.173        -23.942        -51.530
-125.949 partial forces
:FOR013:  13.ATOM         44.735         -6.229        -18.200
-40.388 partial forces
:FOR013:  13.ATOM         84.208         15.271         30.149
77.128 partial forces
:FOR013:  13.ATOM         99.047         16.328         36.983
90.421 partial forces
:FOR013:  13.ATOM         85.965         13.872         32.473
78.378 partial forces
:FOR013:  13.ATOM         54.272          8.865         20.913
49.290 partial forces
:FOR013:  13.ATOM         34.760          5.776         13.677
31.429 partial forces
:FOR013:  13.ATOM         23.617          4.046          9.520
21.231 partial forces
:FOR013:  13.ATOM         16.518          2.821          6.948
14.718 partial forces
:FOR013:  13.ATOM         24.506          3.900          9.821
22.110 partial forces
:FOR013:  13.ATOM      13.442215       2.158986       5.152247      *12.226458
total forces*

[bhamu at bhamu-pmc]$grep :FCHECK *.scf
:FCHECK:   Sum of forces         13.692019325    -3.440247228
-23.934499318
[bhamu at bhamu-pmc]$


So, I have some further queries:

(1) I should not to force minimization (MSR1a/ -min/min_lapw) and only -fc
2 may be okay with proper convergence parameters. Please correct me if I am
wrong.

(2) As I am using TEMPS so I am not able to grep :GAP.  How to grep :GAP?

(3) I tested some scfs for the present case and scf with -fc xx -it
switches is faster (in my case speed is double) than simple scf (-ec xx -cc
yy). Why?

(4) May I just set the proper convergence parameters in scf dir already
having conversed structure with crude convergence parameters (ec 0.1 -cc
0.1 -fc 10 -it) and start scf?


Kind regards

Bhamu







On Fri, Apr 6, 2018 at 6:58 PM, Laurence Marks <L-marks at northwestern.edu>
wrote:

> My opinion.
>
> Use *TEMPS* not *TEMP*. It won't matter much but I consider it more
> rigorous. I normally use TEMPS  0.0018 which is room temperature. (I have
> rarely seen large values help, I think that is a relic of old mixers.)
>
> :FCHECK can be positive or negative, that does not matter. It should
> become small as the forces and charge density converges. (Of course using a
> centro-symmetric structure is better if possible.)
>
> On Fri, Apr 6, 2018 at 8:18 AM, Dr. K. C. Bhamu <kcbhamu85 at gmail.com>
> wrote:
>
>>
>> Thanks Prof. Peter,
>>
>> There are some more queries.
>>
>> For the present system, ~3-3.5 is best-reported rmt.  Prof. Oleg reported
>> 3.5 in his Sci. Rep. paper while in one of my earlier case I used 3 which
>> was fine to me. So I kept rmt 3 in the present case.
>>
>> Yes, I  am using 16 core here.
>>
>> The strategy told by Prof. Lawrence is similar to yours. So definitely, I
>> will run a crude convergence before structure optimization (after getting
>> the final conclusion from present scf).
>>
>> What should I do if :FCHECK are negative? can it be or I should worry? I
>> see :FCHECK is oscillating (see below).
>>
>>  In all test case of the present calculation, should increase LVNS from 4
>> to 6 in case.in1(c)? or in final. I never tested it so do not know how it
>> will affect the calculation.
>>
>>
>>
>> *Can I use TEMP 0.002 instead of TETRA? *
>> If I am not wrong, them in case of MSR1a the :FOR will work after final
>> 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
>> :FCHECK:   Sum of forces        -62.241454337    85.443479855
>> -99.767209873
>> :FCHECK:   Sum of forces        -33.315408954    60.975140246
>> 18.014683106
>> :FCHECK:   Sum of forces         22.819602947   -13.223462643
>> 257.628716681
>> :FCHECK:   Sum of forces        -30.714958092    40.048468655
>> 258.360331510
>>
>>
>>
>> regards
>>
>> Bhamu
>>
>> On Fri, Apr 6, 2018 at 5:01 PM, Peter Blaha <pblaha at theochem.tuwien.ac.at
>> > wrote:
>>
>>> To be efficient you should:
>>>
>>> Start with an RKmax 0f 2.5 or 3.75 instead of 3 (check later)
>>>
>>> Reduce k-points to 2x2x1 (check later).
>>>
>>> run -it -p  -fc 10   # crude convergence before structure optimization !
>>>                      # -p because you want to use the 16 cores. You have
>>> to define a suitable .machines file ! Are you sure you are using more than
>>> 1 core right now ???
>>>
>>> Once this is converged, check forces (are they so big that you need to
>>> relax ? and :FCHECK. If :FCHECK is still large at the end, probalby your
>>> spheres are not ok. And in addition you should increase LVNS from 4 to 6 in
>>> case.in1(c).
>>>
>>> save, and only then start a run -p -it -min
>>>
>>>
>>> On 04/06/2018 12:49 PM, Dr. K. C. Bhamu 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
>>>>
>>>>
>>>> _______________________________________________
>>>> Wien mailing list
>>>> Wien at zeus.theochem.tuwien.ac.at
>>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=Ssu8eHykcWqBhB9T2t6jD4Tn1GEt06GCIoKnF0YbnyE&e=>
>>>> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wi
>>>> en at zeus.theochem.tuwien.ac.at/index.html
>>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=LDn968a-Anlib6twYHmRJZ9-uNbOMukqSPdtAV8Ixb4&e=>
>>>>
>>>>
>>> --
>>>
>>>                                       P.Blaha
>>> ------------------------------------------------------------
>>> --------------
>>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>>> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
>>> Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.wien2k.at&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=7q7c69Ufut8K1Z7JT1E42aHK9lQcdBBU7ZXdWiCWOI8&e=>
>>> WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.imc.tuwien.ac.at_TC-5FBlaha&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=GQa-jwz0v77GtvLqQRj65tkYCxPbXX-3QZafOot1q14&e=>
>>> ------------------------------------------------------------
>>> --------------
>>> _______________________________________________
>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=Ssu8eHykcWqBhB9T2t6jD4Tn1GEt06GCIoKnF0YbnyE&e=>
>>> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wi
>>> en at zeus.theochem.tuwien.ac.at/index.html
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=A6iJTbTHf0lhqMCsGHNPkGtwiBn4dmvW1RF2Z7w2NBM&s=LDn968a-Anlib6twYHmRJZ9-uNbOMukqSPdtAV8Ixb4&e=>
>>>
>>
>>
>
>
> --
> 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 ; Corrosion in 4D:
> MURI4D.numis.northwestern.edu
> Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent
> Co-Editor, Acta Cryst A
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/
> wien at zeus.theochem.tuwien.ac.at/index.html
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20180418/4c800a6a/attachment.html>


More information about the Wien mailing list