[CP2K-user] [CP2K:13305] SCF Convergence stuck with ADMM HF?

[Nicholas Winner]

Jurg, 

Reducing EPS_SCHWARZ did help quite a bit in the convergence. In your 
original paper with Manuel on the ADMM, diamond was one of the case studies 
and it was stated that: 

Since the condition number of the overlap matrix with the FIT3 basis is 
> unfavorable in the case of bulk C (1.7 × 105), an optimized FIT3 
> (optFIT3) basis has been constructed that served as the ABS for the two 
> wave function fitting methods. optFIT3 was obtained by minimization of the 
> total energy of the PBE 2 × 2 × 2 supercell with respect to the 
> constraint of a well behaved overlap matrix (the final condition number is 
> on the order of 102). This allows for rather loose screening thresholds 
> (10-6)
>
 
Which is why I believed there was no issue with EPS_SCHWARZ 1e-6. As I 
mentioned in response to Matt, I cannot find an aux_basis set in the 
BASIS_ADMM or BASIS_ADMM_MOLOPT files of the name "optFIT3", which is why I 
turned to cFIT3. Is it possible to get this optimized basis? If not, I will 
defer to using 1e-7 for the more ill-conditioned problems.

Best,
Nick

On Friday, May 15, 2020 at 4:42:17 AM UTC-7, jgh wrote:
>
> Hi 
>
> this behaviour usually points towards a lack of overall accuracy 
> in the calculation. In your case, I would decrease 
>
> EPS_DEFAULT   and  EPS_SCHWARZ 
>
> You might also want not to screen HFX on initial P when you start 
> an SCF from an inaccurate initial guess. Screened away integrals 
> are lost for the whole SCF procedure. 
>
> regards 
>
> Juerg Hutter 
>
> -------------------------------------------------------------- 
> Juerg Hutter                         Phone : ++41 44 635 4491 
> Institut für Chemie C                FAX   : ++41 44 635 6838 
> Universität Zürich                   E-mail: h... at chem.uzh.ch 
> <javascript:> 
> Winterthurerstrasse 190 
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> --------------------------------------------------------------- 
>
> -----c... at googlegroups.com <javascript:> wrote: ----- 
> To: "cp2k" <c... at googlegroups.com <javascript:>> 
> From: "Nicholas Winner" 
> Sent by: c... at googlegroups.com <javascript:> 
> Date: 05/14/2020 10:14PM 
> Subject: [CP2K:13305] SCF Convergence stuck with ADMM HF? 
>
> Hello all, 
>
> I have tried to perform static PBE0 calculation of diamond using the ADMM. 
> I have done many of this type of calculation before, but not for this 
> system. I have an issue where the reported "convergence" in the SCF loop is 
> unchanged for many steps. I initially tried using the DIIS minimizer and OT 
> method, but switched to 2PNT CG search to try to improve convergence. This 
> helped a tiny amount (convergence got lower, but still stuck). 
>
> I'm unclear as to what the problem is. I have attached my input and output 
> files. Note I stopped this calculation prematurely. 
>
> Drawing your attention to the first inner SCF loop of the output file, I 
> can see that SCF step 19-50 all report the same convergence of (0.00000035) 
> with no change. What's more, the "total energy" in that loop is listed as 
> -3903.4843979582 for all steps after 31. So it seems that the energy is 
> extremely well converged... better than the EPS_SCF 1e-7 that I listed in 
> the input file. 
>
> I'd like to know if there's any reason why this would be having such a 
> hard time converging; diamond is a large band gap material and should have 
> very good convergence with OT, especially with CG. Also, am I 
> misunderstanding hte numbers reported by the SCF steps? It seems to me the 
> total energy is very well converged to within 1e-9 the end of the first SCF 
> loop, but convergence is listed as .00000035. 
>
> Any help would be appreciated. 
>
> Best, 
> Nick   
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> [attachment "cp2k.inp" removed by Jürg Hutter/at/UZH] 
> [attachment "cp2k.out.orig" removed by Jürg Hutter/at/UZH] 
>
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