[CP2K-user] [CP2K:16897] Slow force calculation step timing using hybrid functionals

[Augustin Bussy]

Hi Branislav,

your input file is in principle correct. The main issue is that the 
DZVP-MOLOPT-GTH basis set is really not optimized for HFX type 
calculations. Therefore, a lot of time is spent calculating 4-center 
integrals, and even more time is spent on 4-center derivatives.

I see 3 ways that you can improve your timings:

1) Use a basis set that is better suited. For example, Pople style 
all-electron basis sets such as 6-31G* (requires a switch to GAPW)

2) Use a RI approximation for the HFX: add  &RI &END to the &HF section 
(this requires CP2K 9.1 or more recent)

3) Use the ADMM method 
(https://manual.cp2k.org/cp2k-9_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/AUXILIARY_DENSITY_MATRIX_METHOD.html)

I think solution 1) is the easiest.  I also suggest that you use the 
FULL_ALL preconditioner for OT. It performs better than FULL_S_INVERSE 
for smaller system (in that case, you also need to remove the ENERGY_GAP 
keyword).

Hope that helps. Best,

Augustin

On 4/26/22 16:10, Бранислав Миловановић wrote:
> Dear CP2K users,
>
> I'm experiencing problems when using hybrid functionals such as B3LYP 
> or M062X and while optimizing simple test system (hydrogen bonded 
> acetic acid dimer).
>
> SCF convergence appears to be fast and normal but the Force 
> calculation step is extremely slow. Maybe I made some mistake in the 
> input file?
>
> I attached my input files and output file (B3LYP).
> Also, I don't really understand the timings at the end output file.
>
> Thanks in advance!
> Branislav
> -- 
> You received this message because you are subscribed to the Google 
> Groups "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send 
> an email to cp2k+unsubscribe at googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/cp2k/e568c56a-bfea-411c-9274-119d735cc83cn%40googlegroups.com 
> <https://groups.google.com/d/msgid/cp2k/e568c56a-bfea-411c-9274-119d735cc83cn%40googlegroups.com?utm_medium=email&utm_source=footer>.

-- 
Augustin Bussy
Postdoctoral researcher
Hutter Group
University of Zurich

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/d0f2f44c-56f7-a938-6e45-b3cdf988bc6a%40chem.uzh.ch.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20220427/bb236d81/attachment-0001.htm>