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

[Sun Geng]

Dear Prof. Juerg Hutter,
Thank you very much for reply,
I have increased  EPS_SCHWARZ_FORCES  to 1.0e-4, the overall optimization 
efficiency is much faster.
However I am not sure if it is safe option,  is there any  rule of thumb 
for how to set up EPS_SCHWARZ_FORCES ?
Thank you in advance.

Best,
Geng


          &SCREENING
            EPS_SCHWARZ 1.0E-6
            SCREEN_ON_INITIAL_P T
            EPS_SCHWARZ_FORCES 1.0E-4
            SCREEN_P_FORCES T
          &END SCREENING


在2021年1月5日星期二 UTC-8 上午1:53:20<jgh> 写道：

> Hi
>
> Derivative ERI's are only used once (in the gradient calculation) 
> are therefore not stored. Typical cost is 4x for the normal ERIs.
> The advantage for the derivative ERI calculation is, that it
> can be screened much more efficiently. 
> Have a look at the section
>
> CP2K_INPUT / FORCE_EVAL / DFT / XC / HF / SCREENING
>
> EPS_SCHWARZ_FORCES
> SCREEN_P_FORCES
>
> Optimal settings of these Keywords can make a huge difference.
>
> In addition, timings are very dependent on the ADMM basis and
> the radial cutoff if you are using a truncated operator.
>
> regards
>
> Juerg Hutter
> --------------------------------------------------------------
> Juerg Hutter Phone : ++41 44 635 4491 <+41%2044%20635%2044%2091>
> Institut für Chemie C FAX : ++41 44 635 6838 <+41%2044%20635%2068%2038>
> Universität Zürich E-mail: h... at chem.uzh.ch
> Winterthurerstrasse 190
> CH-8057 Zürich, Switzerland
> ---------------------------------------------------------------
>
> -----c... at googlegroups.com wrote: -----
> To: "cp2k" <c... at googlegroups.com>
> From: "Sun Geng" 
> Sent by: c... at googlegroups.com
> Date: 01/04/2021 09:31PM
> Subject: [CP2K:14472] Number of sph. DERIV's calculated on the fly
>
> 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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