[Pw_forum] Problem: different output with identical input
Pablo García Risueño
garcia.risueno at gmail.com
Wed Dec 28 14:18:21 CET 2016
Dear professor
Thank you very much for your reply. The differences are important in this
case, my final calculated quantities are very sensitive to these optimized
positions. Should I change any of the ***conv_thr variables, or other
variable, to have the same result for same inputs?
Is there any random number in the algorithm of relax calculations, can we
be sure that different outputs with the same input are not due to any bug?
Thank you very much. Best regards.
2016-12-28 14:10 GMT+01:00 Paolo Giannozzi <p.giannozzi at gmail.com>:
> The differences you find are very small. Nothing to worry about in my
> opinion.
>
> By the way: Davidson diagonalization is typically faster than CG; do not
> specify incompatible options in K_POINTS (gamma or automatic, not both;
> gamma should be used unless you have a good reason not to)
>
> Paolo
>
> Il 28/dic/2016 01:46 PM, "Pablo García Risueño" <garcia.risueno at gmail.com>
> ha scritto:
> >
> > Dear Espresso community
> >
> > I have one problem that is important for me; it is somewhat surprising.
> I run geometry optimization (relax) calculations with pw.x with identical
> input files, and I obtain rather different final coordinates. The problem
> does not happen if ecutwfc is 30, but it does appear for cutoffs of 60, 80
> or 90. Below one can see the exact input file, and examples of the
> difference between the final coordinates for both runs (both run with
> identical input) for given cutoffs.
> >
> > Could anybody give me a clue on the origin of the problem, and how to
> solve it?
> >
> > Thank you very much. Best regards.
> >
> >
> >
> > Input file:
> >
> >
> >
> > &CONTROL
> >
> > calculation = 'relax',
> >
> > restart_mode = 'from_scratch',
> >
> > prefix='',
> >
> > outdir = './',
> >
> > pseudo_dir = '/path_xxx/PP/',
> >
> > forc_conv_thr = 1.0D-6 ,
> >
> > etot_conv_thr = 1.0D-8 ,
> >
> > /
> >
> > &system
> >
> > ibrav = 0, a=18.0,
> >
> > nat= 26, ntyp= 2,
> >
> > ecutwfc = 30d0,
> >
> > nbnd = 100,
> >
> > /
> >
> > &electrons
> >
> > conv_thr = 1.0e-9,
> >
> > mixing_beta = 0.7,
> >
> > mixing_mode = 'plain',
> >
> > diagonalization = 'cg'
> >
> > /
> >
> > &IONS
> >
> > /
> >
> >
> >
> > ATOMIC_SPECIES
> >
> > C 12.0107 C.pz-vbc.UPF
> >
> > H 1.007825035 H.pz-vbc.UPF
> >
> >
> >
> > ATOMIC_POSITIONS { angstrom }
> >
> > C 8.891700e+00 8.891700e+00 8.891700e+00
> >
> > C 9.783400e+00 9.783400e+00 8.000000e+00
> >
> > C 9.783400e+00 8.000000e+00 9.783400e+00
> >
> > C 8.000000e+00 9.783400e+00 9.783400e+00
> >
> > C 8.891700e+00 1.067510e+01 1.067510e+01
> >
> > C 1.067510e+01 1.067510e+01 8.891700e+00
> >
> > C 1.067510e+01 8.891700e+00 1.067510e+01
> >
> > C 9.783400e+00 1.156680e+01 9.783400e+00
> >
> > C 9.783400e+00 9.783400e+00 1.156680e+01
> >
> > C 1.156680e+01 9.783400e+00 9.783400e+00
> >
> > H 8.391700e+00 8.391700e+00 8.391700e+00
> >
> > H 7.500000e+00 1.028340e+01 9.283400e+00
> >
> > H 7.500000e+00 9.283400e+00 1.028340e+01
> >
> > H 9.283400e+00 1.028340e+01 7.500000e+00
> >
> > H 1.028340e+01 9.283400e+00 7.500000e+00
> >
> > H 9.283400e+00 7.500000e+00 1.028340e+01
> >
> > H 1.028340e+01 7.500000e+00 9.283400e+00
> >
> > H 9.283400e+00 1.206680e+01 9.283400e+00
> >
> > H 1.206680e+01 9.283400e+00 9.283400e+00
> >
> > H 9.283400e+00 9.283400e+00 1.206680e+01
> >
> > H 8.391700e+00 1.117510e+01 1.117510e+01
> >
> > H 1.117510e+01 1.117510e+01 8.391700e+00
> >
> > H 1.117510e+01 8.391700e+00 1.117510e+01
> >
> > H 1.028340e+01 1.206680e+01 1.028340e+01
> >
> > H 1.028340e+01 1.028340e+01 1.206680e+01
> >
> > H 1.206680e+01 1.028340e+01 1.028340e+01
> >
> >
> >
> >
> >
> > CELL_PARAMETERS {cubic}
> >
> > 1.00 0.00 0.00
> >
> > 0.00 1.00 0.00
> >
> > 0.00 0.00 1.00
> >
> >
> >
> > K_POINTS {gamma} {automatic}
> >
> > 1 1 1 0 0 0
> >
> >
> >
> >
> >
> > The program is run with
> >
> >
> >
> > mpirun -np 32 /path_xxx/pw.x
> >
> >
> >
> > Final coordinates: The first two rows for ecutwfc=30 for two runs with
> identical input are:
> >
> > ATOMIC_POSITIONS (angstrom)
> > C 8.898432121 8.898432121 8.898432121
> > C 9.783306562 9.783306562 8.019670107
> >
> > ATOMIC_POSITIONS (angstrom)
> > C 8.898432121 8.898432121 8.898432121
> > C 9.783306562 9.783306562 8.019670109
> >
> >
> > Final coordinates: The first two rows for ecutwfc=60 for two runs with
> identical input are:
> >
> > ATOMIC_POSITIONS (angstrom)
> > C 8.904988579 8.904988579 8.904988579
> > C 9.783426086 9.783426086 8.031809869
> >
> > ATOMIC_POSITIONS (angstrom)
> > C 8.904962246 8.904962246 8.904962246
> > C 9.783425401 9.783425401 8.031847251
> >
> > --
> > --
> >
> > Dr. Pablo García Risueño
> >
> > Institut für Physikalische Chemie, Universität Hamburg, Grindelallee
> 117, 20146 Hamburg
> >
> > Tel. +49 040 42 83 84 82 7
> >
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
--
--
Dr. Pablo García Risueño
Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117,
20146 Hamburg
Tel. +49 040 42 83 84 82 7
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