[CP2K-user] SCF Convergence stuck with ADMM HF?

[Nicholas Winner]

Matt. I did see that the original ADMM paper uses a special optFIT aux 
basis for diamond; however, it doesn't seem to be in /data/ for the newest 
version. Is there somewhere to acquire optFIT? 

On Friday, May 15, 2020 at 4:52:53 AM UTC-7, Matt W wrote:
>
> Also, diamond is actually a pretty nasty system. . It is so dense the 
> number of integrals can grow very rapidly depending on the exponents chosen 
> and the accuracy requirements can be more stringent than for say a 
> molecular system. In the original ADMM paper a special ADMM basis was made 
> for diamond if I recall correctly.
>
> On Friday, May 15, 2020 at 12:43:16 PM UTC+1, Vladimir Rybkin wrote:
>>
>> Dear Nick,
>>
>>
>> 1) you convergence is not so bad already. At least, good enough for most 
>> applications.
>> 2) You Schwarz screening is rather large. Try 10-7 and smaller. Normally, 
>> convergence is sensitive to the accuracy of Hartree-Fock exchange.
>>
>> are you by chance running it on a Cray system?
>>
>> Yours,
>>
>> Vladimir
>>
>> четверг, 14 мая 2020 г., 22:14:09 UTC+2 пользователь Nicholas Winner 
>> написал:
>>>
>>> Hello all,
>>>
>>> I have tried to perform static PBE0 calculation of diamond using the 
>>> ADMM. I have done many of this type of calculation before, but not for this 
>>> system. I have an issue where the reported "convergence" in the SCF loop is 
>>> unchanged for many steps. I initially tried using the DIIS minimizer and OT 
>>> method, but switched to 2PNT CG search to try to improve convergence. This 
>>> helped a tiny amount (convergence got lower, but still stuck). 
>>>
>>> I'm unclear as to what the problem is. I have attached my input and 
>>> output files. Note I stopped this calculation prematurely.
>>>
>>> Drawing your attention to the first inner SCF loop of the output file, I 
>>> can see that SCF step 19-50 all report the same convergence of (0.00000035) 
>>> with no change. What's more, the "total energy" in that loop is listed as -3903.4843979582 
>>> for all steps after 31. So it seems that the energy is extremely well 
>>> converged... better than the EPS_SCF 1e-7 that I listed in the input file.
>>>
>>> I'd like to know if there's any reason why this would be having such a 
>>> hard time converging; diamond is a large band gap material and should have 
>>> very good convergence with OT, especially with CG. Also, am I 
>>> misunderstanding hte numbers reported by the SCF steps? It seems to me the 
>>> total energy is very well converged to within 1e-9 the end of the first SCF 
>>> loop, but convergence is listed as .00000035.
>>>
>>> Any help would be appreciated.
>>>
>>> Best,
>>> Nick
>>>
>>
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