[CP2K-user] [CP2K:11178] general normconserving UPF in CP2K

[hut... at chem.uzh.ch]

Hi

1) if you send the inputs I will try to reproduce the problem

4) I am working on a 'easy' way to generate consistent basis sets.

-> I never made a Hf q4 pseudo.

best regards

Juerg
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----"'Michiel van Setten' via cp2k" <cp... at googlegroups.com> wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "'Michiel van Setten' via cp2k" <cp... at googlegroups.com>
Date: 01/11/2019 04:40PM
Subject: Re: [CP2K:11178] general normconserving UPF in CP2K

Hi Juerg,

Thank for the comments,

concerning 1, If you like I can send you the inputs and the backtrace I get with the nlcc

2) no overhead in the scf is very good news,

3) ok thanks, that confirms my understanding, the factor 4 was include in my comparison to abinit. In this I take the smallest rel_cutoff that gives me a converged result for a given cutoff value. 

4) sorry for the confusion. Here I meant, the PD-UPF calculation with cp2k took more iteration steps than the GTH calculation using cp2k, everything else being the same: same basis, same cutoffs, same mixer / diagonalization. Here I was hoping that a basis set optimized to fit the PseudoDojo potential would improve the convergence. If you have some hints an tips for generating them I would appriciate them.

I just generated a q4 Hf potential with ONCVPSP, for this I would need a new basis set anyways. Did you ever made an attempt for a q4 Hf?

Until now I only ran convergence test on the total energy, so I have no idea yet on the actual relative performance of the pseudo potentials. This afternoon I programmed some scripts to run delta-test with cp2k for the different pseudo-potentials. This should give a better idea on the precision of the fitting procedure. 

Thanks,
Michiel



Op vrijdag 11 januari 2019 14:38:24 UTC+1 schreef jgh:Hi Michiel 
 
> 
>I have run some tests on this topic and would just like to share my experience. 
> 
>I ran the pseudo-dojo 0.4 PBE Si pseudo potential combined with the the molopt GTH DZ basis set. 
> 
>It took me some time and reading the source code to find out how but eventually cp2k ran. I now use 
> 
>    POTENTIAL_FILE_NAME PD04-UPF-POTENTIALS (in the &DFT section)  
> 
>and 
> 
>    &KIND Si 
>      POTENTIAL UPF PD04-UPF-POTENTIALS 
>      BASIS_SET DZVP-MOLOPT-SR-GTH 
>    &END KIND 
> 
 
The POTENTIAL_FILE_NAME should not be necessary. What would you do if there are two different atoms? 
 
>Comparing calculations with the same cutoff and relcutoff, only the psp is different, I observe the following 
> 
>1) I needed to turn of non linear core corrections to prevent cp2k to segfaut in the conversion step 
 
This is probably a bug? I thought NLCC worked but I cannot find an example to proof it. 
 
> 
>2) It seems the gausian fit results in many more gausians than the typical GTH pseudo's 
> - This however does not seem to deteriorate performace: calculate_rho_elec and integrate_v_rspace take more or less the same time per iteration for both psp's  
 
The internal format is similar but not exactly the same as the GTHs. Yes, there are much more Gaussians needed for the fit. 
Performance is not a major concern, as CP2K calculates the PP integrals analytically and adds them to the core Hamiltonian 
at the start of the calculation. During the SCF there is no overhead. 
 
>3) I observe a somewhat improved convergence with cutoff and rel_cutoff, comparable to what I am used to when using this pseudo in abinit 
 
The cutoff in CP2K is related to the density cutoff in abinit, usually 4x the input cutoff. 
rel_cutoff is a CP2K internal accuracy setting for the integrations of Gaussians, there is no relation to any cutoff in abinit. 
 
>4) The electronic convergence systematically takes more steps. 
> - I assume this is caused by the use of basisfunctions not optimized for this pseudo (can someone confirm?) 
 
This is not clear, more steps than in abinit? The number of steps depends on the optimizer. CP2K is rather good for insulators and using 
the OT method. For metals and diagonalization methods you need to find the best setting, defaults are not very good. 
 
>5) in the case of the UPF pseudo I see an additional  read_qs_kind in the timing report, I assume this is the part where the upf is read and fitted. I assume it >should be possible to do this fit once and safe the GTH format. 
 
see above. The fit is not compatible with the GTH format, you cannot just print and reuse it. 
 
Thanks for testing this feature. 
 
best regards 
 
Juerg 
 
 
Any comment is welcome. 
 
Please let me know if someone thinks I'm polluting this channel ;-) 
 
thanks for reading, 
Michiel 
 
Op dinsdag 18 december 2018 09:29:20 UTC+1 schreef jgh:Hi  
  
there is minimal support for general normconserving pseudopotentials from UPF  
in CP2K. The potentials are internally fit to a Gaussian form, similar  
to the GTH pseudos. The accuracy of the fit has not been thoroughly  
tested. It should work for most variants (semi-local, non-local) forms,  
but again only minimal testing has been done.  
There are plans to implement a direct integration of the UPF pp   
sometime next year.   
Another problem will be the available basis sets. You will need  
to generate also those, or rely on the PBE-GTH optimized basis sets.  
  
best regards  
  
Juerg  
--------------------------------------------------------------  
Juerg Hutter                         Phone : ++41 44 635 4491  
Institut für Chemie C                FAX   : ++41 44 635 6838  
Universität Zürich                   E-mail: hut... at chem.uzh.ch  
Winterthurerstrasse 190  
CH-8057 Zürich, Switzerland  
---------------------------------------------------------------  
  
-----"'Michiel van Setten' via cp2k" <cp... at googlegroups.com> wrote: -----  
To: "cp2k" <cp... at googlegroups.com>  
From: "'Michiel van Setten' via cp2k" <cp... at googlegroups.com>  
Date: 12/17/2018 11:40AM  
Subject: [CP2K:11053] general normconserving UPF in CP2K  
  
Dear community,  
  
I have seen some keywords concerning the use of UPF pseudo potentials in CP2K, I however did not manage to figure out if this means cp2k can use general normconserving UPF pseudopotentials.   
  
I would like to make some pseudopotentials with different amounts of valence electrons for some elements. Since I have some experience in generating ONVPSP pseudo potentials, for me the easiest would generate ONCVPSP's and use them in CP2K, either in upf format or, as a second option, via a conversion into HGH format.   
  
If any one has some experience, it would be very welcome, reasons why this would be a bad idea would be equally welcome ;-)  
  
many thanks,  
Michiel van Setten  
  
    
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