[CP2K:9611] KEEP_ANGLES not possible in CELL_OPT using BFGS

Krack Matthias (PSI) matthia... at psi.ch
Wed Nov 1 07:36:06 CET 2017


Hi Travis

The bug reported by Tobias concerned only CELL_OPT runs using the optimisation TYPE GEO_OPT (BFGS). The TYPE DIRECT_CELL_OPT works fine with respect to cell constraints in the current release 5.1 as well as in the previous CP2K release 4.1 (and most likely even before).

Best

Matthias

From: cp... at googlegroups.com [mailto:cp... at googlegroups.com] On Behalf Of polla... at gmail.com
Sent: 31 October 2017 20:02
To: cp2k
Subject: Re: [CP2K:9611] KEEP_ANGLES not possible in CELL_OPT using BFGS

I'd have to agree, TYPE GEO_OPT can be a terribly inefficient use of resources. If the geometry in the cell is so poor you need to optimize it before relaxing the cell dimensions, just do a RUNTYPE GEO_OPT to tidy things up and follow up with RUNTYPE CELL_OPT and TYPE DIRECT_CELL_OPT. Or run a short annealing simulation. Sometimes that's even better because you'll generate a distribution of starting points to find the minimum.

To Matthias' point, I'm currently using a version of CP2K 5.0 I downloaded a couple months ago. Switching from TYPE GEO_OPT to TYPE DIRECT_CELL_OPT, I was unable to reproduce your issue. Cell angles stayed at 90 degrees. I made only one other change to the second input file you provided and that was to reduce REL_CUTOFF to 40 Ry to make decent progress on a single node.

I killed the job after 15 minutes. Here's the printout before beginning step 50...


 --------------------------
 OPTIMIZATION STEP:     50
 --------------------------

 CELL| Volume [angstrom^3]:                                               91.561
 CELL| Vector a [angstrom]:       4.286     0.000     0.000    |a| =       4.286
 CELL| Vector b [angstrom]:       0.000     4.787     0.000    |b| =       4.787
 CELL| Vector c [angstrom]:       0.000     0.000     4.462    |c| =       4.462
 CELL| Angle (b,c), alpha [degree]:                                       90.000
 CELL| Angle (a,c), beta  [degree]:                                       90.000
 CELL| Angle (a,b), gamma [degree]:                                       90.000
 CELL| Numerically orthorhombic:                                             YES



-Travis






On Tuesday, October 31, 2017 at 5:51:56 AM UTC-4, Tobias Binninger wrote:
Hi Matthias,

thanks, and thanks a lot for the hint regarding cell optimization.

Best regards,
Tobias
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