[CP2K-user] [CP2K:14801] Warning in cryssym: Symmetry library SPGLIB not available

[Matt W]

You can check. You should get exactly the same results for an energy 
calculation from a supercell calculation (Nx Ny Nz) or using a kpoint grid 
(Nx Ny Nz), I think (this is correct with Monkhorst-Pack?). 

Geometry optimization or MD will differ as the atoms can show a 
reconstruction of longer wavelength.
Matt

On Tuesday, February 23, 2021 at 5:00:25 PM UTC GENG YUAN wrote:

> Dear Pierre and Tiziano,
>
> Thanks for your clarifications, I am now more clearer about the use of 
> k-points and spgilb. So is it fine that I could still run simulations with 
> the k-points setting (with the warning) if my results are consistent or 
> reasonable? As we are currently considering two simulation protocols, one 
> is running simulations with k-points, the other is running without 
> k-points. 
>
> Many thanks,
> Sincerely,
> Geng
>
>
> 在2021年2月23日星期二 UTC-5 上午11:44:54<tiz... at chem.uzh.ch> 写道：
>
>> Dear Pierre, 
>>
>> thanks for chiming it, but to clarify for the KP-related statements: 
>>
>> * spglib is not needed to build the k-point grid [1] 
>> * spglib is used to reduce the number of k-points by considering the 
>> time-reversal symmetry (when FULL_GRID is .FALSE. and SYMMETRY is .TRUE.) 
>> * it could be used, but this is not implemented yet, to reduce the 
>> number of k-points further by considering the space group 
>> * correct, some features are not yet implemented for KPs [2] 
>>
>> Yet, we consider KP to be ready for general use (within the 
>> aforementioned limits). If you find inconsistent results, please get in 
>> contact with us, either by opening an issue on [3] or email. 
>>
>> Best regards, 
>> Tiziano 
>>
>> [1] 
>>
>> https://github.com/cp2k/cp2k/blob/9e72863af27f901e325a68031569daed26b32cda/src/cryssym.F#L255-L303 
>> [2] https://github.com/cp2k/cp2k/issues/225 
>> [3] https://github.com/cp2k/cp2k/issues/ 
>>
>> On 2/20/21 10:51 AM, Pierre-André Cazade wrote: 
>> > Dear Geng, 
>> > 
>> > You compiled cp2k without spglib. This is the error message that you 
>> are 
>> > getting. 
>> > 
>> > Initially, Spglib was used to build the k-point grid. It is used to 
>> > identify the space group of the system and build the smallest k-point 
>> > grid based on it. Spglib comes with such a feature. However, Spglib is 
>> > not used, in cp2k v8, to conserve the space group throughout the 
>> > geometry (GEO_OPT or CELL_OPT) optimization. This has changed in the 
>> > last version of the development version (v9) where the space group is 
>> > conserved during optimization. It is important to note that in neither 
>> > version, the space group symmetry is used to reduce the computational 
>> > cost of energy and forces evaluation. 
>> > 
>> > Coming back to k-points, if you have issues with spglib, you can use 
>> the 
>> > keyword "SYMMETRY F". This will disable the reduction of the number of 
>> > k-points based on symmetry and the call to spglib: 
>> > 
>> https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html 
>> > <
>> https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html> 
>>
>> > 
>> > Finally, as a user, I would recommend you not to use k-points. Many 
>> > features are not compatible with them in cp2k, and they provide 
>> > inconsistent results. Use a supercell instead. In both the cell  and 
>> > topology sections use the keyword MULTIPLE_UNIT_CELL to do so. 
>> > 
>> > Regards, 
>> > Pierre 
>> > 
>> > 
>> > On Sat, Feb 20, 2021 at 12:12 AM GENG YUAN <yua... at gmail.com 
>> > <mailto:yua... at gmail.com>> wrote: 
>> > 
>> > Dear CP2K users, 
>> > 
>> > I am currently performing some geometry optimizations for my 
>> > metallic systems. There is one warning message on my output file 
>> > although my simulations successfully completed with the geometry 
>> > optimization completed. Below is the warning detail: 
>> > **** WARNING in cryssym. F : 163 : : Symmetry library SPGLIB not 
>> > available **** 
>> > I tried to search and what I know now is the Spglib is a library for 
>> > finding and handling crystal symmetries written in C. Another thing 
>> > I notice is that this warning is related to the KPOINT setting. All 
>> > my simulations with KPOINT setting have this warning, while this 
>> > warning is gone for my simulations without KPOINT setting. 
>> > So my questions are: Why is this warning shown in my output file, is 
>> > my KPOINT setting wrong? Will it affect the final energy results and 
>> > how could I get rid of this warning if my simulations still need 
>> > KPOINT settting. I have attached my input file here for your 
>> > reference, any suggestions are welcome! 
>> > 
>> > Many thanks in advance and have a nice weekend! 
>> > Sincerely, 
>> > Geng 
>> > 
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>> > 
>> https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com 
>> > <
>> https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com?utm_medium=email&utm_source=footer>. 
>>
>> > 
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>> > <
>> https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%40mail.gmail.com?utm_medium=email&utm_source=footer>. 
>>
>>
>> -- 
>> Tiziano Müller 
>> University of Zurich 
>> Department of Chemistry 
>> Winterthurerstrasse 190 
>> CH-8057 Zürich 
>>
>> Tel: +41 44 63 54234 
>> www.chem.uzh.ch 
>> tiz... at chem.uzh.ch 
>>
>
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