[CP2K:10736] Re: K-Points and Extrapolation

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

Hi Martin

thank you for pointing out these problems. Unfortunately,
it is more complex than I originally anticipated. I will have
to think and work some more on this.

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
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-----cp... at googlegroups.com wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "M. Brehm" 
Sent by: cp... at googlegroups.com
Date: 09/15/2018 12:14PM
Subject: [CP2K:10736] Re: K-Points and Extrapolation

Hi Juerg,

I noticed that you recently implemented several extrapolation methods for use with K points. I was curious and set up a small example calculation. I adapted the regtest "QS/regtest-kp-1/c_2.inp": I increased the cutoff to a reasonable value, switched to Broyden Mixing, moved one of the carbon atoms a little off its lattice position, and made a geometry optimization (with 4 steps) out of it.

Please find attached my test input file as "c_2.inp". For my tests, I used the current CP2k trunk version.

I tried the four allowed values LINEAR_P, USE_GUESS, USE_PREV_P, and USE_PREV_RHO_R as choices for EXTRAPOLATION. Please see attached the four log files which resulted from these four runs.

It seems that all three "true" extrapolation methods do not work as expected. The quality of the extrapolated initial wave function is a lot poorer than the initial guess, with "convergence" values in the order of 20 - 200.

I would be grateful if somebody would have a look what goes wrong in this example.

Thanks and with best regards,
Martin

  
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[attachment "c_2.inp" removed by Jürg Hutter/at/UZH]
[attachment "use_guess.out" removed by Jürg Hutter/at/UZH]
[attachment "linear_p.out" removed by Jürg Hutter/at/UZH]
[attachment "use_prev_p.out" removed by Jürg Hutter/at/UZH]
[attachment "use_prev_rho_r.out" removed by Jürg Hutter/at/UZH]