<div dir="ltr"><div><div><div><div>Hello,<br><br></div> Talking about the k points and their units - would it be possible to have an option for 'MACDONALD' scheme of k points where the "kp_shift" would also be given in units of the reciprocal lattice vectors - they are natural due to the algorithm for their construction and easier - or even an option/short-cut that would enable giving Gamma-point centred k point sets, as these are needed in hexagonal cells. Now the shift depends on and thus changes with the chosen number of grid points.<br><br></div> A side note - in the documentation there appears to be a small error, namely the shift is not mentioned together with the 'MACDONALD' scheme, yet the code crashes if one only provides the three integers mentioned in the document (this is correct for the scheme 'MONKHORST-PACK'). And the symmetries apparently always fail with the 'MACDONALD' scheme - as said, this is basically the compulsory scheme in hexagonal cells. And if I may note, I tried to calculate a hexagonal cell together with the 'MACDONALD' method, with a shift adjusted so that Gamma point is included in the set, but I obtain a strange reduction of symmetry in the forces (the three-fold symmetry that is present due to the lattice is not obeyed laterally) - any idea? I know that this is a new feature, maybe I should just be patient. :)<br><br></div> Greetings from Paris,<br><br></div> apsi<br></div><div class="gmail_extra"><br><div class="gmail_quote">2016-11-09 10:14 GMT+01:00 <span dir="ltr"><<a href="mailto:hut...@chem.uzh.ch" target="_blank">hut...@chem.uzh.ch</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi<br> <br> I updated the code for the k-point input. I hope I did catch<br> all the error. I only made some minimal tests, so I am still<br> not sure that it is correct.<br> <br> regards<br> <br> Juerg Hutter<br> <span class="">------------------------------<wbr>------------------------------<wbr>--<br> Juerg Hutter <wbr> Phone : <a href="tel:%2B%2B41%2044%20635%204491" value="+41446354491">++41 44 635 4491</a><br> Institut für Chemie C FAX : <a href="tel:%2B%2B41%2044%20635%206838" value="+41446356838">++41 44 635 6838</a><br> Universität Zürich E-<wbr>mail: <a href="mailto:hut...@chem.uzh.ch">hut...@chem.uzh.ch</a><br> Winterthurerstrasse 190<br> CH-8057 Zürich, Switzerland<br> ------------------------------<wbr>------------------------------<wbr>---<br> <br> -----<a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a> wrote: -----To: cp2k <<a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>><br> From: Eric Hermes<br> Sent by: <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a><br> Date: 11/01/2016 09:35PM<br> Subject: [CP2K:8332] BAND_STRUCTURE k-point unit conversion bug leads to bogus band structures (CP2K 4.1)<br> <br> </span><span class="">Hello,<br> I am working with ASE to develop routines for the various DFT calculators we support for simple, automatic generation of band structures. I have run into a bug in CP2K's SPECIAL_POINT specification, wherein the specified k-points appear to undergo a redundant B_VECTOR -> CART_BOHR unit conversion. What I mean by that is if I pass the k-points as multiples of the reciprocal unit vectors (i.e. UNIT B_VECTOR, SPECIAL_POINT 0.5 0.25 0.75 for the W point of the diamond lattice), this is multiplied by the reciprocal unit cell vector *twice*. If I pass the points in units of 2pi/Bohr (i.e. UNIT CART_BOHR, SPECIAL_POINT 0.049 0.098 0.000 for a primitive Si diamond lattice with lattice constant a=5.4 angstrom), the k-points are multiplied by the reciprocal unit cell vector *anyway*, giving the same results as before. I can "trick" the system into providing the correct result by saying that I am passing the k-points in 2pi/Bohr, but actually passing the k-points in multiples of the reciprocal unit cell vectors (i.e. UNIT CART_BOHR, SPECIAL_POINT 0.5 0.25 0.75). This results in both the output file and the band structure file printing the exact k-points that I specified (i.e. the k-points in multiples of the reciprocal unit vectors), and the resulting band structure matches that of other DFT codes.<br> </span>Here is an example of the input file I am using that expresses the bug: <a href="https://gist.github.com/ehermes/7ef3d7249b99eeafb34bb14e6c51fd48This" rel="noreferrer" target="_blank">https://gist.github.com/<wbr>ehermes/<wbr>7ef3d7249b99eeafb34bb14e6c51fd<wbr>48This</a> input file was generated by (a modified version of) ASE, and it produces the incorrect band structure. If line 31 is changed to read "UNITS CART_BOHR", the resulting band structure is correct and matches the band structure produced by other codes (GPAW, VASP, etc).<br> <div class="HOEnZb"><div class="h5">I have taken a look at the qs_band_structure.F source file, but the origin of the bug is not obvious to me. I suspect it might be related to line 197, which multiplies each kpoint by the transpose of the unit cell vector, but I am not certain.<br> <br> <br> <br> --<br> <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> <br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k%2Bun...@googlegroups.com">cp2k+unsubscribe@googlegroups.<wbr>com</a>.<br> <br> To post to this group, send email to <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>.<br> <br> Visit this group at <a href="https://groups.google.com/group/cp2k" rel="noreferrer" target="_blank">https://groups.google.com/<wbr>group/cp2k</a>.<br> <br> For more options, visit <a href="https://groups.google.com/d/optout" rel="noreferrer" target="_blank">https://groups.google.com/d/<wbr>optout</a>.<br> <br> <br> --<br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k%2Bun...@googlegroups.com">cp2k+unsubscribe@googlegroups.<wbr>com</a>.<br> To post to this group, send email to <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>.<br> Visit this group at <a href="https://groups.google.com/group/cp2k" rel="noreferrer" target="_blank">https://groups.google.com/<wbr>group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" rel="noreferrer" target="_blank">https://groups.google.com/d/<wbr>optout</a>.<br> </div></div></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-<br> Ari Paavo Seitsonen / <a href="mailto:Ari.P.S...@iki.fi" target="_blank">Ari.P.S...@iki.fi</a> / <a href="http://www.iki.fi/~apsi/" target="_blank">http://www.iki.fi/~apsi/</a><br> Ecole Normale Supérieure (ENS), Département de Chimie, Paris<br> Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935<br></div></div></div></div></div></div> </div>