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?). <div><br></div><div>Geometry optimization or MD will differ as the atoms can show a reconstruction of longer wavelength.<div>Matt<br><br></div></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Tuesday, February 23, 2021 at 5:00:25 PM UTC GENG YUAN wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear Pierre and Tiziano,<div><br></div><div>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. </div><div><br></div><div>Many thanks,</div><div>Sincerely,</div><div>Geng</div><div><br><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2021年2月23日星期二 UTC-5 上午11:44:54<<a href data-email-masked rel="nofollow">tiz...@chem.uzh.ch</a>> 写道：<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear Pierre, <br> <br>thanks for chiming it, but to clarify for the KP-related statements: <br> <br>* spglib is not needed to build the k-point grid [1] <br>* spglib is used to reduce the number of k-points by considering the <br>time-reversal symmetry (when FULL_GRID is .FALSE. and SYMMETRY is .TRUE.) <br>* it could be used, but this is not implemented yet, to reduce the <br>number of k-points further by considering the space group <br>* correct, some features are not yet implemented for KPs [2] <br> <br>Yet, we consider KP to be ready for general use (within the <br>aforementioned limits). If you find inconsistent results, please get in <br>contact with us, either by opening an issue on [3] or email. <br> <br>Best regards, <br>Tiziano <br> <br>[1] <br><a href="https://github.com/cp2k/cp2k/blob/9e72863af27f901e325a68031569daed26b32cda/src/cryssym.F#L255-L303" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://github.com/cp2k/cp2k/blob/9e72863af27f901e325a68031569daed26b32cda/src/cryssym.F%23L255-L303&source=gmail&ust=1614799033524000&usg=AFQjCNEvs2fz7MwFJWFUYi9hcl9p9MEwZg">https://github.com/cp2k/cp2k/blob/9e72863af27f901e325a68031569daed26b32cda/src/cryssym.F#L255-L303</a> <br>[2] <a href="https://github.com/cp2k/cp2k/issues/225" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://github.com/cp2k/cp2k/issues/225&source=gmail&ust=1614799033524000&usg=AFQjCNEN8pTT334nLDBZlwPD2JwNPU9OMg">https://github.com/cp2k/cp2k/issues/225</a> <br>[3] <a href="https://github.com/cp2k/cp2k/issues/" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://github.com/cp2k/cp2k/issues/&source=gmail&ust=1614799033524000&usg=AFQjCNGbNen4qyzstlbBwtsoZXMAj-hbzQ">https://github.com/cp2k/cp2k/issues/</a> <br> <br>On 2/20/21 10:51 AM, Pierre-André Cazade wrote: <br>> Dear Geng, <br>> <br>> You compiled cp2k without spglib. This is the error message that you are <br>> getting. <br>> <br>> Initially, Spglib was used to build the k-point grid. It is used to <br>> identify the space group of the system and build the smallest k-point <br>> grid based on it. Spglib comes with such a feature. However, Spglib is <br>> not used, in cp2k v8, to conserve the space group throughout the <br>> geometry (GEO_OPT or CELL_OPT) optimization. This has changed in the <br>> last version of the development version (v9) where the space group is <br>> conserved during optimization. It is important to note that in neither <br>> version, the space group symmetry is used to reduce the computational <br>> cost of energy and forces evaluation. <br>> <br>> Coming back to k-points, if you have issues with spglib, you can use the <br>> keyword "SYMMETRY F". This will disable the reduction of the number of <br>> k-points based on symmetry and the call to spglib: <br>> <a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html&source=gmail&ust=1614799033524000&usg=AFQjCNGNhKMw_oAnzwJvZ4khEjC9Y4kYgg">https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html</a> <br>> <<a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html&source=gmail&ust=1614799033524000&usg=AFQjCNGNhKMw_oAnzwJvZ4khEjC9Y4kYgg">https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html</a>> <br>> <br>> Finally, as a user, I would recommend you not to use k-points. Many <br>> features are not compatible with them in cp2k, and they provide <br>> inconsistent results. Use a supercell instead. In both the cell and <br>> topology sections use the keyword MULTIPLE_UNIT_CELL to do so. <br>> <br>> Regards, <br>> Pierre <br>> <br>> <br>> On Sat, Feb 20, 2021 at 12:12 AM GENG YUAN <<a rel="nofollow">yua...@gmail.com</a> <br>> <mailto:<a rel="nofollow">yua...@gmail.com</a>>> wrote: <br>> <br>> Dear CP2K users, <br>> <br>> I am currently performing some geometry optimizations for my <br>> metallic systems. There is one warning message on my output file <br>> although my simulations successfully completed with the geometry <br>> optimization completed. Below is the warning detail: <br>> **** WARNING in cryssym. F : 163 : : Symmetry library SPGLIB not <br>> available **** <br>> I tried to search and what I know now is the Spglib is a library for <br>> finding and handling crystal symmetries written in C. Another thing <br>> I notice is that this warning is related to the KPOINT setting. All <br>> my simulations with KPOINT setting have this warning, while this <br>> warning is gone for my simulations without KPOINT setting. <br>> So my questions are: Why is this warning shown in my output file, is <br>> my KPOINT setting wrong? Will it affect the final energy results and <br>> how could I get rid of this warning if my simulations still need <br>> KPOINT settting. I have attached my input file here for your <br>> reference, any suggestions are welcome! <br>> <br>> Many thanks in advance and have a nice weekend! <br>> Sincerely, <br>> Geng <br>> <br>> -- <br>> You received this message because you are subscribed to the Google <br>> Groups "cp2k" group. <br>> To unsubscribe from this group and stop receiving emails from it, <br>> send an email to <a rel="nofollow">cp...@googlegroups.com</a> <br>> <mailto:<a rel="nofollow">cp...@googlegroups.com</a>>. <br>> To view this discussion on the web visit <br>> <a href="https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%2540googlegroups.com&source=gmail&ust=1614799033524000&usg=AFQjCNGLQlYL65R3UVgCwiQYdkiUw5u1pA">https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com</a> <br>> <<a href="https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com?utm_medium=email&utm_source=footer" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1614799033524000&usg=AFQjCNGGuiyCWVon_dsTGpS4g8acm7m3tw">https://groups.google.com/d/msgid/cp2k/b4437744-a691-4841-bbe2-34fc7fd64855n%40googlegroups.com?utm_medium=email&utm_source=footer</a>>. <br>> <br>> -- <br>> You received this message because you are subscribed to the Google <br>> Groups "cp2k" group. <br>> To unsubscribe from this group and stop receiving emails from it, send <br>> an email to <a rel="nofollow">cp...@googlegroups.com</a> <br>> <mailto:<a rel="nofollow">cp...@googlegroups.com</a>>. <br>> To view this discussion on the web visit <br>> <a href="https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%40mail.gmail.com" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%2540mail.gmail.com&source=gmail&ust=1614799033524000&usg=AFQjCNGWOe1A_odJF7bUsFKtYc_PvNII-g">https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%40mail.gmail.com</a> <br>> <<a href="https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%40mail.gmail.com?utm_medium=email&utm_source=footer" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%2540mail.gmail.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1614799033524000&usg=AFQjCNHUUtZ86Sj6OOOhXX0qDHVVZxiIQA">https://groups.google.com/d/msgid/cp2k/CAFnf9goHrDu9y4HFyFkuNQbukv43aqy3gwWAckgzO1pTaXcf8w%40mail.gmail.com?utm_medium=email&utm_source=footer</a>>. <br> <br>-- <br>Tiziano Müller <br>University of Zurich <br>Department of Chemistry <br>Winterthurerstrasse 190 <br>CH-8057 Zürich <br> <br>Tel: +41 44 63 54234 <br><a href="http://www.chem.uzh.ch" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=http://www.chem.uzh.ch&source=gmail&ust=1614799033525000&usg=AFQjCNEeoEeHRIG5okd3RvUJGZ96c6E3Zw">www.chem.uzh.ch</a> <br><a rel="nofollow">tiz...@chem.uzh.ch</a> <br></blockquote></div></div></blockquote></div>