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

[Frederick Stein]

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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