[CP2K-user] [CP2K:13207] CELL Optimization - Energy not decreasing
Jan Elsner
janel... at gmail.com
Thu Apr 30 18:06:06 UTC 2020
Dear Juerg,
Ok, cheers for the advice.
Best wishes,
Jan
On Thursday, April 30, 2020 at 5:24:26 PM UTC+1, jgh wrote:
>
> Hi
>
> yes, I cam to the same conclusion. The problem seems to be
> the value for rs where the different formulas have to be switched.
> Changing at line 117 in xc_perdew_wang.fypp the value from
> 1.0 to 0.5 seems to solve most problems.
>
> In addition, you might also want to use a reference cell (see CELL_REF)
> when optimizing cells.
>
> I will update the Trunk version of CP2K soon.
>
> 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
> CH-8057 Zürich, Switzerland
> ---------------------------------------------------------------
>
> -----c... at googlegroups.com <javascript:> wrote: -----
> To: "cp2k" <c... at googlegroups.com <javascript:>>
> From: "Jan Elsner"
> Sent by: c... at googlegroups.com <javascript:>
> Date: 04/30/2020 05:31PM
> Subject: Re: [CP2K:13207] CELL Optimization - Energy not decreasing
>
> Dear all,
>
> I thought I should post an update on this.
>
> It seems that there is a problem with using PW92 as the local correlation
> part of XC functional. When I use VWN instead, the analytical and numerical
> forces are equal. I attach input and output files for DEBUG runs on a
> single H20 molecule using optPBE in combination with PW92 and VWN. In the
> case of PW92, there is a mismatch between analytical and numerical forces.
>
> I note that the same applies for the some of the other functionals listed
> here: https://github.com/cp2k/cp2k/tree/master/data/xc_section (at least,
> I can confirm that optB88 and C09 also give a mismatch between numerical
> and analytical forces using the settings listed here).
>
> Best wishes,
>
> Jan
>
>
>
>
> On Friday, April 24, 2020 at 10:43:00 AM UTC+1, Jan Elsner wrote:
> Dear Juerg,
>
> Many thanks for the quick response! Unfortunately, decreasing EPS_SCF (all
> the way to 1.0E-10) does not solve the problem.
>
> I have done a DEBUG run which results in the following error (see end of
> attached file debug.out): 'Abort: A mismatch between the analytical and the
> numerical stress tensor has been detected. Check the implementation of the
> stress tensor'. I'm not entirely sure how I should proceed from here / what
> the problem is exactly - any insight would be very much appreciated.
>
> If it helps shed some light on the problem, I also attach a figure showing
> Total Energy, RMS Gradient and Cell Volume as a function of optimization
> step (plotted from the original cell.out file I sent). The optimiser seems
> to overshoot the minimum energy configuration.
>
> One other question which comes to mind is whether it's ok to use GTH-PBE
> or GTH-PADE pseudopotentials with optPBE-vdW?
>
> Best wishes,
>
> Jan
>
>
>
>
>
> On Monday, April 20, 2020 at 10:20:34 AM UTC+1, jgh wrote:Hi
>
> I don't know how well a setup as this is tested. However, from
> your output I would guess the problem could be related to your
> SCF convergence. With the methods you are using you have to set
> the convergence criteria much tighter in order to get converged
> energy and forces. I would suggest to use at least 1.E-8.
>
> The ultimate test would be to do a DEBUG run in order to verify
> forces and stress tensor for the setting of options.
>
> 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
> Winterthurerstrasse 190
> CH-8057 Zürich, Switzerland
> ---------------------------------------------------------------
>
> -----c... at googlegroups.com wrote: -----
> To: "cp2k" <c... at googlegroups.com>
> From: "Jan Elsner"
> Sent by: c... at googlegroups.com
> Date: 04/18/2020 08:33PM
> Subject: [CP2K:13145] CELL Optimization - Energy not decreasing
>
> Dear all,
>
> I am trying to run a Cell Optimisation on a periodic molecular crystal
> (beta-resorcinol: C6H6O2, 4 molecules in unit cell) using K-points and BFGS
> as optimiser. I am using the vdW-DF-optPBE functional (
> https://github.com/cp2k/cp2k/commit/74ef05b96a46523a0daf7da04e75804420b5cd5e).
> After 83 optimisation steps, my system does converge to the required MOTION
> thresholds, however from step 7 onwards the total energy increases at every
> step i.e.:
>
> -------- Informations at step = 7 ------------
> Optimization Method = BFGS
> Total Energy = -280.1489665596
> Internal Pressure [bar] = -2667.4573178334
> Real energy change = 0.0001037473
> Predicted change in energy = -0.0001063956
> Scaling factor = 0.0000000000
> Step size = 0.0124910496
> Trust radius = 0.4724315332
> Decrease in energy = NO
> Used time = 60.978
>
> Convergence check :
> Max. step size = 0.0124910496
> Conv. limit for step size = 0.0010000000
> Convergence in step size = NO
> RMS step size = 0.0029192108
> Conv. limit for RMS step = 0.0010000000
> Convergence in RMS step = NO
> Max. gradient = 0.0034738629
> Conv. limit for gradients = 0.0001000000
> Conv. for gradients = NO
> RMS gradient = 0.0006857738
> Conv. limit for RMS grad. = 0.0001000000
> Conv. for gradients = NO
> Pressure Deviation [bar] = -2668.4705678334
> Pressure Tolerance [bar] = 200.0000000000
> Conv. for PRESSURE = NO
> ---------------------------------------------------
>
> The resulting cell-optimised structure is therefore not a minimum in
> energy. I've attached the input and output files. Some points which may (or
> may not) be relevant:
> I did not encounter this problem when using a different functional (PBE +
> D3 instead of optPBE-vdW as used here), but otherwise identical settings.
> I encountered the same issue (energy increasing at every step) using
> CUTOFF/REL_CUTOFF = 800/60
> I initially tried to converge CUTOFF and REL_CUTOFF as in the tutorial (
> https://www.cp2k.org/howto:converging_cutoff), however my single point
> calculations did not converge quite as nicely as in the tutorial - instead
> oscillating with an amplitude of order ~ e-4 Ha (I've attached a figure
> showing this). This is why I use such large CUTOFF/REL_CUTOFF values. I
> note that this was also the case when I ran PBE + D3 calculations, however
> in the latter case my cell optimisation did work.
>
> Any input would be greatly appreciated.
>
> Best wishes,
>
> Jan
>
>
>
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>
>
> [attachment "cell.inp" removed by Jürg Hutter/at/UZH]
> [attachment "cell.out" removed by Jürg Hutter/at/UZH]
> [attachment "E_vs_cutoff.png" removed by Jürg Hutter/at/UZH]
> [attachment "subsys.include" removed by Jürg Hutter/at/UZH]
>
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>
>
> [attachment "pw92.inp" removed by Jürg Hutter/at/UZH]
> [attachment "pw92.out" removed by Jürg Hutter/at/UZH]
> [attachment "vwn.inp" removed by Jürg Hutter/at/UZH]
> [attachment "vwn.out" removed by Jürg Hutter/at/UZH]
>
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