[gpaw-users] GPAW versions

[Jens Jørgen Mortensen]

On Fri, 2010-11-12 at 15:42 +0100, Christian Glinsvad wrote:
> Jens Jørgen Mortensen wrote:
> >> On Wed, 2010-11-10 at 19:34 -0800, Monica Garcia Mota wrote:
> >> Hi, 
> >>
> >> I have calculated oxygen adsorption energy on TiO2 using two
> >> different GPAW versions: 0.7.6383 and 0.7.2.6974. The absolute
> >> energy values for TiO2 surface and O-TiO2 are shifted up 0.37 eV
> >> with the new GPAW version.
> >> 
> >> I’m using Dipole correction in my calculations. Does it work in
> >> both GPAW versions in the same way?
> >>
> >> Thanks,
> >>
> >> Monica Garcia
> 
> There's no difference in the way the dipole correction is implemented
> between revision 6383 and 6974, as far as I can tell, nor did we fix any
> major bugs. We did however do a bit of restructuring:
> 6383:6974 diff: 
> https://trac.fysik.dtu.dk/projects/gpaw/changeset?new=trunk%406974&old=trunk%406383
> 6383:6974 timeline: 
> https://trac.fysik.dtu.dk/projects/gpaw/timeline?from=08%2F13%2F10&daysback=112
> 
> > On Thu, 2010-11-11 at 09:02 +0100, Jens Jørgen Mortensen wrote:
> >
> > Thanks, I got your text files and it does look very strange. I'll see
> > if I can figure out what the problem is.
> > 
> > The text files didn't make it to the mailing list because they were
> > too big, but I have them on casimir in /tmp, so those of you in
> > Lyngby can find them there.
> > 
> > Jens Jørgen
> 
> I looked through them and did a side-by-side comparison (jens: there are
> 4 files matching /tmp/O*.txt so I assume you meant the two largest?).

No.  You should compare the last configuration of O-TiO2v072-DP.txt with
the configuration in O-TiO2v076-DP.txt.  The configurations are
identical, but give different energies.

JJ

>  It
> appears to me that you're getting slightly different geometries during
> the QN relaxation and you probably just need to tighten your convergence
> criteria as 'density' and 'energy' have influence on force evaluation.
> 
> Additionally, it strikes me that you've run these with quite different
> parallelization options, which may explain the difference in "entropy"
> that led to the two calculations to diverge a bit.
> 
> It's also curious to me that the forces at the end of the relaxation are
> quite large for the atoms I assume are fixed, and there are quite many
> of them. Just be warned that atom fixation can lead to an oblong minima
> in the potential energy landscape and therefor also convergence issues.
> 
> Regards
> Christian Glinsvad
> 
> >>
> >> Here is my script:
> >>
> >> import os,sys 
> >> import numpy as np
> >> from math import *
> >> from gpaw import GPAW
> >> from ase import Atoms 
> >> from ase import Atom
> >> from ase.constraints import FixAtoms
> >> from ase.optimize import QuasiNewton
> >> from ase.visualize import *
> >> from ase.io import *
> >> from ase.data import reference_states as _refstate
> >> from ase.lattice.tetragonal import SimpleTetragonalFactory
> >> from gpaw.mixer import Mixer
> >> from gpaw.poisson import PoissonSolver
> >> from gpaw.dipole_correction import DipoleCorrectionPoissonSolver
> >>
> >>
> >> slab=read('OonCUS-TiO2-2.gpw')
> >>
> >> name = 'OonCUS-TiO2-pru'
> >>
> >> calc_name=name + '.txt'
> >> traj_name=name + '.traj'
> >> log_name=name + '.log'
> >> gpwdat = name + '.gpw'
> >>
> >>
> >> mask=[atom.tag<1 for atom in slab]
> >> slab.set_constraint(FixAtoms(mask=mask))
> >>
> >>
> >> p = PoissonSolver()
> >> mixer=Mixer(0.1, 5, weight=50.0)
> >> calc = GPAW(h=0.2,
> >>             kpts=(4, 4, 1),     # k-points
> >> 	    xc = 'RPBE',
> >>             #eigensolver='cg',
> >>             txt=calc_name,
> >>             convergence = { 'energy' : 0.001,  #default is 0.0005?
> >>                             'density' : 1.0e-3, # default is 1.0e-4
> >>                             'eigenstates' : 1.0e-9}, #default
> >>             nbands=-20,
> >>             width=0.10,
> >>             verbose=True,
> >>             mixer=mixer,
> >>             poissonsolver=DipoleCorrectionPoissonSolver(p,2))
> >>
> >> calc.attach(calc.write, 1,gpwdat)         
> >>
> >> slab.set_calculator(calc)
> >> traj = PickleTrajectory(traj_name,'w',slab)
> >> qn = QuasiNewton(slab,logfile = log_name)
> >> qn.attach(traj) 
> >> qn.run(fmax=0.05)
> >> calc.write(gpwdat)
> >>
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