[ase-users] how to avoid calculator reset when generating a SumCalculator

[Michael Walter]

Dear Rochus,

Am Mi., 17. März 2021 um 15:48 Uhr schrieb Rochus Schmid <
rochus.schmid at rub.de>:

> dear michael,
>
> On 3/17/21 3:15 PM, Michael Walter wrote:
>
> Dear Rochus,
>
> Am Mi., 17. März 2021 um 15:01 Uhr schrieb Rochus Schmid via ase-users <
> ase-users at listserv.fysik.dtu.dk>:
>
>> dear ase experts,
>>
>> i am trying to use the SumCalculator from ase.calculators.mixing to add
>> dispersion corrections from Stefan Grimmes DFTD4 calculator to a GPaw
>> calculator. The problem is that the DFT part converges very slowly. I
>> have a restart file with wavefkts and can restart.
>>
>> so if i do something like this
>>
>> dft = GPAW('restart.gpw')
>> system = dft.get_atoms()
>> e_dft = system.get_potential_energy()
>>
>> all is fine. but then i generate a new calculator like this
>>
>> d4 = DFTD4(method='pbe')
>> sumcalc = SumCalculator([dft, d4], atoms=system)
>> e_total = system.get_potential_energy()
>>
>> then the wavefktd from the dft calculator seems to be reset and starts
>> from scratch. how can i prevent this?
>>
>> i can not see that the reset() method of the mixing calculator is
>> directly called, but i assume that in the process of setting the
>> SumCalculator, the atoms object is "reattached" to both calculators dft
>> and d4, and that attaching a "new" atoms object triggers a reset. this
>> makes sense but in my case i know that the atoms are identical and i do
>> not want the info from the SCF to be discarded. what can i do to prevent
>> this to happen?
>>
>> i also guess that it might be possible to "update" the wavefunctions
>> from the info stored in restart.gpw, but this is probably a question for
>> the gpaw-users mailing list.
>>
>> any help/input highliy appreciated.
>>
>
> There is no need for a SumCalculator.
> Please see
> https://wiki.fysik.dtu.dk/gpaw/documentation/xc/vdwcorrection.html
> where the D4_model is applied in the script given.
>
> Regards,
> Michael
>
>
> thanks a lot for your quick reply. i am using the dftd4-python from
> conda-forge. but i also could not see a "D4_model" class on the github
> repo. is it possible that the script refers to an older API? to me it looks
> like in
>
> cc = D4_model(xc='PBE', calc=c)
> s.calc = cc
>
> the D4_model takes a calculator c and attaches D4 by returning a new
> calculator cc, right? however, it seems that this python API is not in the
> current D4 version any more. there is a regular ASE calculator interface as
> well as a raw python API and a QCSchema interface.
> https://github.com/dftd4/dftd4/tree/main/python
>
> is it possible that the script refers to an older version of the D4 code
> or am i missing something here?
>

Yes, it seems the interface was changed. I do not really see how to use
DFTD4 as a correction anymore.
Sorry about that.

Maybe the following works:

dft = GPAW()
d4 = DFTD4(method='pbe')

system.calc  = SumCalculator([dft, d4])
e_total = system.get_potential_energy()

Regards,
Michael


> best regards,
>   rochus
>
>
>
>>
>> greetings,
>>
>>     rochus schmid
>>
>> --
>>
>>
>> Prof. Dr. Rochus Schmid
>> Lehrstuhl für Anorganische Chemie II
>> Computational Materials Chemistry Group
>> Ruhr-Universität Bochum
>> Room NC02/30 (Postbox 9)
>> D-44780 Bochum
>> Tel.:   ++49(234) 32 24166
>> Fax:    ++49(234) 32 14174
>> Email: rochus.schmid at rub.de
>> http://www.rochusschmid.de
>>
>> _______________________________________________
>> ase-users mailing list
>> ase-users at listserv.fysik.dtu.dk
>> https://listserv.fysik.dtu.dk/mailman/listinfo/ase-users
>>
>
>
> --
> ------------------------------------------
> PD Dr Michael Walter
> Addresses:
> - Fraunhofer IWM, Wöhlerstrasse 11, D-79108 Freiburg i. Br., Germany
>   Tel.: +49 761 5142 296
> - FIT Freiburg Centre for Interactive Materials and Bioinspired
> Technologies, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
>   Tel: +49 761 203 95072
> email: Michael.Walter at fmf.uni-freiburg.de
> www:
> http://www.functional-nanosystems.uni-freiburg.de/People/PDWalter/group
> publications: http://scholar.google.com/citations?user=vlmryKEAAAAJ&hl=en
>
>
> --
>
>
> Prof. Dr. Rochus Schmid
> Lehrstuhl für Anorganische Chemie II
> Computational Materials Chemistry Group
> Ruhr-Universität Bochum
> Room NC02/30 (Postbox 9)
> D-44780 Bochum
> Tel.:   ++49(234) 32 24166
> Fax:    ++49(234) 32 14174
> Email: rochus.schmid at rub.dehttp://www.rochusschmid.de
>
>

-- 
------------------------------------------
PD Dr Michael Walter
Addresses:
- Fraunhofer IWM, Wöhlerstrasse 11, D-79108 Freiburg i. Br., Germany
  Tel.: +49 761 5142 296
- FIT Freiburg Centre for Interactive Materials and Bioinspired
Technologies, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
  Tel: +49 761 203 95072
email: Michael.Walter at fmf.uni-freiburg.de
www: http://www.functional-nanosystems.uni-freiburg.de/People/PDWalter/group
publications: http://scholar.google.com/citations?user=vlmryKEAAAAJ&hl=en
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