[CP2K-user] WARNINGS: The Kohn Sham matrix is not 100% occupied. & The cutoff radius is larger than half the minimal cell dimension

[katarína stančiaková]

Dear Vladimir and Frederick,
thank you for your help. I changed interaction potential to TRUNCATED and 
also omega to 0.15. In 4 days (on 48 cores) I was able to get at least the 
first  SCF optimization. When I look at the output file, I see that the 
first step of the SCF cycle takes almost all time and the other steps takes 
about 1 second each. Is this normal? I don't have much experience with 
these functionals so I don't know what kind of timings I should expect, but 
4 days on 48 cores for a system of approx 20 atoms and 1 SCF cycle seems 
quite a lot to me....

Thank you
Kind regards,
Katarina

Dňa utorok, 20. novembra 2018 13:42:46 UTC+1 Frederick Stein napísal(-a):
>
> Dear Katarina,
>
> if you really need a shortrange potential, you either use a larger value 
> for omega or a larger supercell. Maybe you should look for some variants of 
> HSE with larger omega.
>
> The cutoff radius of the potential is not related to the cutoff radius 
> that cp2k assumes here. The cutoff is chosen such that the potential at 
> that radius equals eps_schwarz (see function erfc_cutoff in file 
> hfx_types.F of the code, if interested). The cutoff (for your system around 
> 32.8 A) should be printed somewhere ("HFX_INFO| Cutoff Radius") but I do 
> not know why it is not printed, here.
>
> I hope I could help you.
>
> Frederick 
>
> Am Montag, 19. November 2018 22:30:50 UTC+1 schrieb katarína stančiaková:
>>
>> Dear CP2K users,
>> I am trying to run HSE06 energy calculation, however, I always got the 
>> following warning and I've never been able to get even one step of SCF 
>> cycle within 48 hours (a periodic system of 22 atoms running on 48 cores).  
>>
>> *** WARNING in hfx_types.F:1343 :: Periodic Hartree Fock calculation      
>> ***
>>  *** requested with use of a truncated or shortrange potential. The 
>> cutoff ***
>>  *** radius is larger than half the minimal cell dimension. This may 
>> lead  ***
>>  *** to unphysical total energies. Reduce the cutoff radius in order 
>> to    ***
>>  *** avoid possible 
>> problems.                                              ***
>>
>> To speed up the calculation I am using restart WF from PBE functional, 
>> but the same issues appear when I don't use it.  I've tested input files 
>> for various CUTOFF_RADIUS values (even very small ones), but without any 
>> result. Does anyone know how to solve this issue? 
>>
>> Input files are attached
>> Thank you for any help!
>>
>> Katarina
>>
>> Dňa pondelok, 30. januára 2017 12:50:28 UTC+1 donaldducksdaughter 
>> napísal(-a):
>>>
>>>
>>>  *** WARNING in hfx_types.F:1342 :: Periodic Hartree Fock calculation    
>>>   ***
>>>
>>>  *** requested with use of a truncated or shortrange potential. The 
>>> cutoff ***
>>>
>>>  *** radius is larger than half the minimal cell dimension. This may 
>>> lead  ***
>>>
>>>  *** to unphysical total energies. Reduce the cutoff radius in order to  
>>>   ***
>>>
>>>  *** avoid possible problems.    
>>>
>>>
>>>
>>>  *** WARNING in hfx_energy_potential.F:600 :: The Kohn Sham matrix is 
>>> not  ***
>>>
>>>  *** 100% occupied. This may result in incorrect Hartree-Fock results. 
>>> Try ***
>>>
>>>  *** to decrease EPS_PGF_ORB and EPS_FILTER_MATRIX in the QS section. 
>>> For  ***
>>>
>>>  *** more information see FAQ: https://www.cp2k.org/faq:hfx_eps_warning  
>>>   ***
>>>
>>>
>>>
>>> Dear all,
>>>
>>>
>>> I'm desperately trying to implement B3LYP on my system and to run a 
>>> geometry optimisation. The calculations take horribly long (over two weeks) 
>>> and still haven't finished. My error file is empty, however I seem to get 
>>> the above two warnings, no matter what I do.
>>>
>>>
>>> With respect to the first truncated potential warning, I'm using this 
>>> truncated potential, because I have received an earlier warning telling me 
>>> to use it and read about it on the cp2k/groups website. I'm using a cutoff 
>>> of 15.0 angstrom with a box size of 30.0, which should be exactly half and 
>>> fine. I'm uncertain whether I should just ignore it, because of the 
>>> responses given in 
>>>
>>>
>>> https://groups.google.com/forum/#!searchin/cp2k/The$20cutoff$20***$20$20***$20radius$20is$20larger$20than$20half$20the$20minimal$20cell$20dimension.$20This$20may$20lead$20$20***$20$20***$20to$20unphysical$20total$20energies.$20Reduce$20the$20cutoff$20radius$20in$20order$20to$20$20$20$20***$20$20***$20avoid$20possible$20problems.$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20$20%7Csort:relevance/cp2k/g1sFck3SYF8/pVS-MPF-GQAJ. 
>>> If I can ignore it, I reckon I should be using smaller auxiliary basis 
>>> sets, as in cFIT types, rather than DZVP ones. Would that give me the same 
>>> result? Additionally, I have already changed all my admms to shorter range 
>>> basis sets to reduce the BSSE.
>>>
>>>
>>> Regarding the second warning, I have already lowered the EPS Default 
>>> from 1.0E-10 to 1.0E-12, but I'm still getting the same error. Also 
>>> changing the poisson solver to WAVELET for my cubic 30x30x30 box would 
>>> still give me the KS matrix as not 100 % occupied. 
>>> https://groups.google.com/forum/#!searchin/cp2k/hfx_energy_potential%7Csort:relevance/cp2k/Xog7jpV5eRk/o254NK-8NGwJ
>>>
>>>
>>> Any experience or help will be appreciated.
>>>
>>>
>>> Many thanks in advance
>>>
>>>
>>> Julia
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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