[CP2K:10750] Problem in the preconditioner when using UKS

Daniele Ongari daniele... at gmail.com
Thu Sep 20 12:17:11 CEST 2018


Thank you very much!
The protocol you proposed is a very smart compromise between efficiency and 
robustness.

Daniele

Il giorno mercoledì 19 settembre 2018 15:49:44 UTC+2, jgh ha scritto:
>
> Hi 
>
> yes, these high spin state systems can be tricky to converge. 
> Your system did rather smoothly converge for me with the following 
> protocol: 
>
> - optimize with CG and OUTER_SCF every 10 steps until eps_scf 1.e-4. 
> - restart optimization with DIIS until eps_scf 1.e-7 (is rather slow at 
> the end) 
>
> final energy:  -1170.0452882317 
>
> 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 
> <javascript:> 
> Winterthurerstrasse 190 
> CH-8057 Zürich, Switzerland 
> --------------------------------------------------------------- 
>
> -----cp... at googlegroups.com <javascript:> wrote: ----- 
> To: "cp2k" <cp... at googlegroups.com <javascript:>> 
> From: "Daniele Ongari" 
> Sent by: cp... at googlegroups.com <javascript:> 
> Date: 09/19/2018 12:50PM 
> Subject: [CP2K:10750] Problem in the preconditioner when using UKS 
>
> Dear CP2K developers, 
> I want to report a serious problem with the preconditioner when computing 
> the energy of Fe-MOF-74 with UKS settings. 
> Long story short the energy goes down, it is close to convergence but 
> then, after recomputing the preconditioner in the outer step it starts to 
> diverge: see the image. 
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> Now, I attached the input and the output, but I already tried very 
> different settings: 
> -smearing 
> -diagonalization without smearing 
> -different BS 
> -UKS false (converged, but to a higher energy, forcing the closed shell) 
> - starting magnetization on metals 
> - CG minimizer 
> - lower multiplicity 
> - 2x and 3x replicated unit cell in the shortest dimension 
> - lowering ENERGY_GAP to 0.001 
> These calculation ALL failed (I made 16 attempts in total, changing 
> settings!). 
>
> And at the end the only one working (the 17th attempt, ironically the 
> unlucky number for Italians!) was to use CG minimizer with no outer SCF, 
> hence not recomputing the preconditioner. It converged after ~600 inner 
> steps, to: 
>
>  HOMO - LUMO gap [eV] :    1.917671 
>  HOMO - LUMO gap [eV] :    0.235602 
>
>  ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           
>  -1170.045288008604075 
>
> Please let me know what was the problem, if it is a known issue of the 
> preconditioner and how to circumvent it: for the moment I'm using no outer 
> steps to have a robust convergence, but I know that this may cause the 
> convergence to a local miniimum! 
>
> Thanks a lot! 
>
> Daniele 
> PhD candidate, LSMO, EPFL Sion 
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> [attachment "energy.inp" removed by Jürg Hutter/at/UZH] 
> [attachment "energy.out" removed by Jürg Hutter/at/UZH] 
> [attachment "Fe-MOF-74_h111.subsys" removed by Jürg Hutter/at/UZH] 
>
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