[CP2K-user] [CP2K:19108] Re: diamond with TC-LRC + ADMM very slow

['Frederick Stein' via cp2k]

Dear Martin,

>From your PBE0 output file, I see that most integrals are calculated on the 
fly indicating that your machine does not have enough memory to store all 
integrals. This increases the compute time significantly. What you could 
try is to
1) replace the pFIT3 with the cpFIT3 basis set to reduce the number of 
contracted basis functions
2) increase the EPS_DEFAULT parameter to reduce the number of matrix 
elements and number of integrals to calculate (only if your accuracy 
demands are still met)

HTH,
Frederick
Martin Konôpka schrieb am Donnerstag, 13. Juli 2023 um 11:49:05 UTC+2:

> Dear CP2K experts,
>
> I tried to use PBE0 functional with the TC-LRC + ADMM technique to 
> calculate bulk diamond in a (110)-oriented cell. First however I used PBE 
> (with the same grids etc) to produce a good initial guess for 
> wavefunctions. The PBE calculation on 14 cores took about 249 sec per 
> electronic iteration. Then I started PBE0 on 18 cores. It took 9909 sec 
> (the 2nd iteration), which is unexpectedly long time. You can see attached 
> my I/O files. BTW, concurrently with the PBE calculation, another 
> calculation was running on the remaining 4 cores of the machine. Without 
> that additional load and using all 18 cores, the time would drop to 194 sec 
> only (PBE).
>
> I have a some experience with using the TC-LRC + ADMM technique for TiO2 
> systems and also for some organic molecules. In those cases PBE0 was always 
> just about 2-3 times slower than PBE. Now I see the enormous ratio and do 
> not understand the reason.
>
> Also, I was surprised by huge memory consumption by the PBE0 calculation: 
> Over 200 GB in total. Still, it fit in the available memory (256 GB DDR4)  
> and the machine remained perfectly responsive. Isn't there some problem 
> with the basis sets that I used for carbon?
>
> The cp2k version that I used was 9.1, the "factory" one provided by the 
> package manager on ubuntu 22.04. I am using also Intel MKL installed 
> through the package manager. I launched the calculation in a screen session 
> by the command
>      mpirun -np 18 cp2k.popt -i cp2k.inp -o cp2k.out
> The machine is a single-socket one with hyperthreading off.
>
> Thanks for your opinions and for your work on bulding the CP2K code.
>
> Sincerely
> Martin Konôpka.
>

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