[Wien] lapw1 runs too slow for H2 molecule
Yurko Natanzon
yurko.natanzon at gmail.com
Fri Oct 10 16:57:51 CEST 2008
Dear Laurence,
thank you for your explanation, it helped me a lot. Yes, I used larger
RMT for H atom and smaller for H2 molecule.
Now I see that it is necessary to run convergence tests of total
energy vs RKmax each time I change RMt radii, is it? for example, when
I want to optimize positions of lattice constants I have to reduce
RMTs, so can I also reduce Rkmax proportionally in order to achieve
better performance?
regards,
Yurko
2008/10/10 Laurence Marks <L-marks at northwestern.edu>:
> The reason is your value for RKMAX.
>
> To expand, the largest k-value in lapw1 is determined by
> RKMAX/min(RMT) which for H2 is 7/0.71. Probably when you did H you had
> a larger RMT (probably 2.0), so the largest k was 7/2.0 which is about
> 3 times smaller. Since the size of the matrix you are diagonalizing
> scales roughly as k**3, for H2 you have a matrix about 27 times larger
> so it will probably take at least 50 time longer.
>
> You can approximately use an RKMAX such that RKMAX/min(RMT) is about
> the same, i.e. for your H2 molecule use an RKMAX of 2 or 2.5.
> Unfortunately it is not quite as simple as this and larger RKMAX is
> better.
>
> Note as well that if you want to calculate the atomization energy of
> H2 you MUST use the same RMT and RKMAX for both H and H2, otherwise
> your energies are GIGO.
>
> N.B., running systems with small RMTs with Wien2k, e.g. for H, is not easy.
>
> On Fri, Oct 10, 2008 at 8:23 AM, Yurko Natanzon
> <yurko.natanzon at gmail.com> wrote:
>> Dear wien2k users,
>> I'm running a simple exercise with H2 molecule located in the middle
>> of a cubic box with a=15 Bohr. the H-H bond length is set to about
>> 0.75 Ang and RMT radus is 0.71 (also the smaller values were tested).
>>
>> The problem is that the calculation is too long. It takes 40 minutes
>> for LAPW1 to run:
>> :log
>>> (runsp_lapw) options:
>> Fri Oct 10 11:41:58 CEST 2008> (x) lapw0
>> Fri Oct 10 11:42:21 CEST 2008> (x) lapw1 -c -up
>> Fri Oct 10 12:20:05 CEST 2008> (x) lapw1 -c -dn
>> Fri Oct 10 12:58:24 CEST 2008> (x) lapw2 -c -up
>> Fri Oct 10 12:58:28 CEST 2008> (x) lapw2 -c -dn
>> Fri Oct 10 12:58:31 CEST 2008> (x) lcore -up
>> Fri Oct 10 12:58:31 CEST 2008> (x) lcore -dn
>> Fri Oct 10 12:58:31 CEST 2008> (x) mixer
>> For comparison, the same calculation for one H atom in the box takes
>> 3 seconds (lapw1), for CoO (a=8 Bohr) - just 12 seconds.
>>
>> I used init_lapw -numk 1 -vxc 13
>> I post my in0 and in1 files as well as a struct file:
>> --------------in0
>> TOT 13 (5...CA-LDA, 13...PBE-GGA, 11...WC-GGA)
>> NR2V IFFT (R2V)
>> -1 -1 -1 1.00 min IFFT-parameters, enhancement factor #changed
>> the default values because of IFFT errors
>> ---------------in1c
>> WFFIL (WFPRI, SUPWF)
>> 7.00 10 4 (R-MT*K-MAX; MAX L IN WF, V-NMT
>> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
>> 0 0.30 0.000 CONT 1
>> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
>> 0 0.30 0.000 CONT 1
>> K-VECTORS FROM UNIT:4 -9.0 2.0 7 emin/emax/nband
>> --------------------struct file
>> h2 molecule
>> P LATTICE,NONEQUIV.ATOMS: 2
>> MODE OF CALC=RELA unit=bohr
>> 15.117815 15.117815 15.117815 90.000000 90.000000 90.000000
>> ATOM -1: X=0.45300000 Y=0.50000000 Z=0.50000000
>> MULT= 1 ISPLIT=-2
>> H 1 NPT= 781 R0=0.00010000 RMT= 0.7100 Z: 1.0
>> LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
>> 0.0000000 1.0000000 0.0000000
>> -1.0000000 0.0000000 0.0000000
>> ATOM -2: X=0.54700000 Y=0.50000000 Z=0.50000000
>> MULT= 1 ISPLIT=-2
>> H 1 NPT= 781 R0=0.00010000 RMT= 0.7100 Z: 1.0
>> LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
>> 0.0000000 1.0000000 0.0000000
>> -1.0000000 0.0000000 0.0000000
>> 8 NUMBER OF SYMMETRY OPERATIONS
>> 1 0 0 0.00000000
>> 0-1 0 0.00000000
>> 0 0-1 0.00000000
>> 1
>> 1 0 0 0.00000000
>> 0-1 0 0.00000000
>> 0 0 1 0.00000000
>> 2
>> 1 0 0 0.00000000
>> 0 0-1 0.00000000
>> 0-1 0 0.00000000
>> 3
>> 1 0 0 0.00000000
>> 0 0 1 0.00000000
>> 0-1 0 0.00000000
>> 4
>> 1 0 0 0.00000000
>> 0 0-1 0.00000000
>> 0 1 0 0.00000000
>> 5
>> 1 0 0 0.00000000
>> 0 0 1 0.00000000
>> 0 1 0 0.00000000
>> 6
>> 1 0 0 0.00000000
>> 0 1 0 0.00000000
>> 0 0-1 0.00000000
>> 7
>> 1 0 0 0.00000000
>> 0 1 0 0.00000000
>> 0 0 1 0.00000000
>> 8
>> --------------------
>>
>> With best regards,
>> Yurko
>>
>> --
>> Yurko (aka Yuriy, Iurii, Jurij etc) Natanzon
>> PhD Student
>> Henryk Niewodniczan`ski Institute of Nuclear Physics
>> Polish Academy of Sciences
>> ul. Radzikowskiego 152,
>> 31-342 Krako`w, Poland
>> Email: Yurii.Natanzon at ifj.edu.pl, yurko.natanzon at gmail.com
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>
>
>
> --
> Laurence Marks
> Department of Materials Science and Engineering
> MSE Rm 2036 Cook Hall
> 2220 N Campus Drive
> Northwestern University
> Evanston, IL 60208, USA
> Tel: (847) 491-3996 Fax: (847) 491-7820
> email: L-marks at northwestern dot edu
> Web: www.numis.northwestern.edu
> Chair, Commission on Electron Crystallography of IUCR
> www.numis.northwestern.edu/
> Electron crystallography is the branch of science that uses electron
> scattering to study the structure of matter.
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
--
Yurko (aka Yuriy, Iurii, Jurij etc) Natanzon
PhD Student
Henryk Niewodniczan`ski Institute of Nuclear Physics
Polish Academy of Sciences
ul. Radzikowskiego 152,
31-342 Krako`w, Poland
Email: Yurii.Natanzon at ifj.edu.pl, yurko.natanzon at gmail.com
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