[CP2K-user] [CP2K:14472] Number of sph. DERIV's calculated on the fly

[Lucas Lodeiro]

Hi Geng,

Could you bring the input and output files? In my case I ran AIMD with
hybrid functionals adn similar amount of atoms, and the
DERIV's calculations are not so expensive as in your case... but I guess in
your case the atoms has d electrons which makes the calculation more
expensive.

Regards

El lun, 4 ene 2021 a las 17:31, Sun Geng (<gengs... at gmail.com>) escribió:

> Dear CP2K users,
>
> I am using CP2K with the ADMM method for structure optimization.
> The system is an inorganic bulk with around 100 atoms in a cubic box
> 12x12x12 angstrom^3.
> I am able to set up the calculation resulting smooth SCF convergence.
> The "Number of sph. ERI's calculated on the fly" is 0 and hence the SCF
> converges quickly. The first SCF takes about 1800 seconds and the following
> SCF steps take only an impressive 20 seconds. In the end, CP2K can converge
> the SCF in approximate 2500 seconds.
> However, I notice that in between the optimization steps, the derivatives
> of integrals are still calculated on the fly (see the output below), and
> this step appears to be very slow. CP2K did not print how long it took to
> compute the derivatives, but I can tell by checking the updating time in
> the output. My estimation is that it takes more than 2 hours to calculate
> the derivatives.
>
>   HFX_MEM_INFO| Number of cart. primitive DERIV's calculated:
>  11208181891200
>   HFX_MEM_INFO| Number of sph. DERIV's calculated:
> 140954718240
>   HFX_MEM_INFO| Number of sph. DERIV's stored in-core:
>      0
>   HFX_MEM_INFO| Number of sph. DERIV's calculated on the fly:
>  140954718240
>   HFX_MEM_INFO| Total memory consumption DERIV's RAM [MiB]:
>     0
>   HFX_MEM_INFO| Whereof max-vals [MiB]:
>     1
>   HFX_MEM_INFO| Total compression factor DERIV's RAM:
>  0.00
>
>
> Finally, the overall efficiency of CP2K for optimization is much slower
> than that of VASP code for this system (both of them used HSE06
> functional). In VASP, although an SCF step takes 200 seconds and SCF
> converged in 15 steps (resulting in 3000 seconds per optimization step),
> the forces are calculated with negligible cost in VASP.
>
> I wonder are there any tricks in the cp2k inputs that can speed up the
> derivatives of the integrals? Or any pieces of advice that I can use in
> using CP2K/ADMM methods?
> My personal impression is that CP2K/ADMM is not the optimal choice (in
> terms of optimization efficiency) for a small system (maybe within 150~200
> atoms, I did not test though) compared with VASP code. Maybe, for a larger
> system, the overhead of calculating forces in CP2K/ADMM is relatively
> small, and in that case, CP2K/ADMM will be more efficient than VASP? Please
> let me know if this is a realistic point for choosing VASP and CP2K.
>
> Thank you very much in advance!
>
> Best
> Geng
>
>
>
>
>
>
>
>
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