[gpaw-users] GPAW dev r7883: Spin-pol vdW-DF2 diverges

[Eskil Varenius]

Thanks for the idea!
Yes, I've tried changing eigensolver to 'cg' and played a little with the
mixer settings, but with no improvement. Trouble is, in other calculations
I've sometimes encountered convergence errors which can be solved by
following instructions on the convergence page. But those times the energy
is always close to some value, it just won't converge the last decimals. Or
the log10 error refuses to go below -3. In this case the whole calculation
rapidly blows out of proportion. Energy jumps of several hundred eV for a
single hydrogen atom seems really weird. And the log errors are often
positive between iterations.

Have anyone successfully did a spin-polarised vdW-DF2 calculation? If so, on
what system? I would gladly try it here. Also, if one has a working setup
for spin-polarised vdW-DF2 it would be interesting to see if the hydrogen
atomization example works in that setup.

Best regards,
Eskil


2011/4/25 Duy Le <ttduyle at gmail.com>

> The convergence issues are discussed in:
>
> https://wiki.fysik.dtu.dk/gpaw/documentation/convergence/convergence.html#convergence
> Have you ever tried them? Especially to change the eigensolver and the
> mixing
> --------------------------------------------------
> Duy Le
> PhD Student
> Department of Physics
> University of Central Florida.
>
> "Men don't need hand to do things"
>
>
>
> On Mon, Apr 25, 2011 at 9:32 AM, Eskil Varenius
> <eskil.varenius at gmail.com> wrote:
> > Dear GPAW users and developers,
> > Background
> > I'm a master student at Chalmers, Gothenburg, Sweden. In my thesis work I
> > want to use GPAW to calculate total energies with the vdW-DF functional.
> I
> > also want to use the recent second version, the vdW-DF2. Since the second
> > version is not easily accessible in the current release version of GPAW
> > (r6974) I asked our cluster admins if they could install the lastest
> > dev-version of GPAW (r7883 at time of asking). In this version the
> vdW-DF2
> > is easily accessible. However I encountered a major problem. Since this
> is a
> > dev checkout I want to ask if this problem has been fixed in later
> > dev-versions and if I should ask the cluster admin to upgrade.
> > Problem
> > Spin-polarized calculations with vdW-DF2 doesn't work. It more or less
> > diverges after a few iterations.
> > However, spin-paired calculations with vdW-DF2 seems to work.
> > Spin-paired / polarized calculations with vdW-DF (version 1) seems to
> work
> > fine.
> > Steps to reproduce
> > 1. Install GPAW dev-version 7883.
> > 2. Run example script for hydrogen atomization energies
> > (https://wiki.fysik.dtu.dk/gpaw/tutorials/atomization/atomization.html)
> with
> > xc='vdW-DF2', and a=8.
> > 3. Check the output. For the first hydrogen calculation I got:
> > Number of Valence Electrons:            1
> >                      log10-error:    Total        Iterations:
> >            Time      WFS    Density  Energy       Fermi  Poisson  MagMom
> > iter:   1  20:54:30  -0.3            -1.31548     0      14       +1.0000
> > iter:   2  20:54:30  -1.8            -1.35790     0               +1.0000
> > iter:   3  20:54:30  -2.3            -1.36544     0               +1.0000
> > iter:   4  20:54:49  -2.7   -1.2     -29.93035    0      6        -1.0000
> > iter:   5  20:55:09  -0.4   -0.4     -10.44161    0      6        +1.0000
> > iter:   6  20:55:28  +0.5   -0.2     -26.34328    0      4        -1.0000
> > iter:   7  20:55:46  +1.0   -0.1     -40.33089    0      6        +1.0000
> > iter:   8  20:56:02  +0.8   -0.0     -57.44584    0      6        -1.0000
> > iter:   9  20:56:18  +1.4   -0.0     -56.50579    0      10       +1.0000
> > iter:  10  20:56:37  +1.1   +0.0     -170.18543   0      14       -1.0000
> > iter:  11  20:56:54  +1.9   -0.2     -142.87739   0      8        +1.0000
> > iter:  12  20:57:12  +0.3   -0.5     -116.98545   0      10       -1.0000
> > I would be very grateful if someone could check this at least briefly
> since
> > my thesis work would benefit a lot from beeing able to do spin-polarized
> > vdW-DF2 calculations.
> > Best regards,
> > Eskil Varenius, Chalmers Master Student
> > _______________________________________________
> > gpaw-users mailing list
> > gpaw-users at listserv.fysik.dtu.dk
> > https://listserv.fysik.dtu.dk/mailman/listinfo/gpaw-users
> >
>
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