Dear Nicola,<div><br><div dir="auto">Thank you for your answer, I am really fond of wannier90, it's a real piece of art.<br><br><div class="gmail_quote"><div dir="ltr">في الأحد، ٤ ديسمبر، ٢٠١٦ ١٣:١٤ Nicola Marzari <<a href="mailto:nicola.marzari@epfl.ch">nicola.marzari@epfl.ch</a>> كتب:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br class="gmail_msg">
<br class="gmail_msg">
Dear Youssef,<br class="gmail_msg">
<br class="gmail_msg">
the vectors seems to me to be the same - Wannier 90 writes those in units<br class="gmail_msg">
of 1/Angstrom, while QE writes them in units of 2 pi/alat, where alat is<br class="gmail_msg">
celldm(1), and it is in Bohr. So e.g. the z component of<br class="gmail_msg">
b2 is 0.457131 1/Ang in Wannier90, and is 0.407234 in QE. Now,<br class="gmail_msg">
<br class="gmail_msg">
0.407234 * 2 * pi / 10.577485 gives 0.2419031 1/Bohr, that is<br class="gmail_msg">
exactly 0.457131 1/Ang (1 Bohr = 0.529177 Ang)<br class="gmail_msg">
<br class="gmail_msg">
nicola<br class="gmail_msg">
<br class="gmail_msg">
<br class="gmail_msg">
On 03/12/2016 21:54, Youssef Aharbil wrote:<br class="gmail_msg">
> Dear All,<br class="gmail_msg">
><br class="gmail_msg">
> I have noticed that the reciprocal vectors computed via wannnier90 and<br class="gmail_msg">
> quantum espresso (QE) are different***, which means that the Kpath and<br class="gmail_msg">
> segment length across the BZ aren't the some for both code though<br class="gmail_msg">
> handling the same crystal structure.<br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
> In order to investigate this issue, I have dug inside the source code of<br class="gmail_msg">
> wannier90 and QE and compared the formula used in each code and finally<br class="gmail_msg">
> realized the root cause, In fact QE divide the reciprocal vectors by an<br class="gmail_msg">
> additional term, the real space vector denominator (den variable in<br class="gmail_msg">
> recips.f90), which isn't the case for wannier90 (utility.F90).<br class="gmail_msg">
><br class="gmail_msg">
> So, I am really confused, I can manually fix this, but I wanted to share<br class="gmail_msg">
> with you.<br class="gmail_msg">
> Any suggestions or clues are most welcome.<br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
> ***<br class="gmail_msg">
> Wannier90 header:<br class="gmail_msg">
><br class="gmail_msg">
> ------<br class="gmail_msg">
> SYSTEM<br class="gmail_msg">
> ------<br class="gmail_msg">
><br class="gmail_msg">
> Lattice Vectors (Ang)<br class="gmail_msg">
> a_1 2.784694 -1.607742 4.581610<br class="gmail_msg">
> a_2 0.000000 3.215484 4.581610<br class="gmail_msg">
> a_3 -2.784694 -1.607742 4.581610<br class="gmail_msg">
><br class="gmail_msg">
> Unit Cell Volume: 123.07314 (Ang^3)<br class="gmail_msg">
><br class="gmail_msg">
> Reciprocal-Space Vectors (Ang^-1)<br class="gmail_msg">
> b_1 1.128164 -0.651347 0.457131<br class="gmail_msg">
> b_2 0.000000 1.302693 0.457131<br class="gmail_msg">
> b_3 -1.128164 -0.651347 0.457131<br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
> QE Header:<br class="gmail_msg">
><br class="gmail_msg">
> celldm(1)= 10.577485 celldm(2)= 0.000000 celldm(3)= 0.000000<br class="gmail_msg">
> celldm(4)= 0.504986 celldm(5)= 0.000000 celldm(6)= 0.000000<br class="gmail_msg">
><br class="gmail_msg">
> crystal axes: (cart. coord. in units of alat)<br class="gmail_msg">
> a(1) = ( 0.497501 -0.287232 0.818530 )<br class="gmail_msg">
> a(2) = ( 0.000000 0.574464 0.818530 )<br class="gmail_msg">
> a(3) = ( -0.497501 -0.287232 0.818530 )<br class="gmail_msg">
><br class="gmail_msg">
> reciprocal axes: (cart. coord. in units 2 pi/alat)<br class="gmail_msg">
> b(1) = ( 1.005024 -0.580251 0.407234 )<br class="gmail_msg">
> b(2) = ( 0.000000 1.160501 0.407234 )<br class="gmail_msg">
> b(3) = ( -1.005024 -0.580251 0.407234 )<br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
> Youssef Aharbil,<br class="gmail_msg">
> Laboratory of Physics and Chemistry of Materials<br class="gmail_msg">
> Faculty of sciences Ben msik, Casablanca<br class="gmail_msg">
> Morocco<br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
><br class="gmail_msg">
> _______________________________________________<br class="gmail_msg">
> Wannier mailing list<br class="gmail_msg">
> <a href="mailto:Wannier@quantum-espresso.org" class="gmail_msg" target="_blank">Wannier@quantum-espresso.org</a><br class="gmail_msg">
> <a href="http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier" rel="noreferrer" class="gmail_msg" target="_blank">http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier</a><br class="gmail_msg">
><br class="gmail_msg">
<br class="gmail_msg">
--<br class="gmail_msg">
----------------------------------------------------------------------<br class="gmail_msg">
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL<br class="gmail_msg">
Director, National Centre for Competence in Research NCCR MARVEL, EPFL<br class="gmail_msg">
<a href="http://theossrv1.epfl.ch/Main/Contact" rel="noreferrer" class="gmail_msg" target="_blank">http://theossrv1.epfl.ch/Main/Contact</a> <a href="http://nccr-marvel.ch/en/project" rel="noreferrer" class="gmail_msg" target="_blank">http://nccr-marvel.ch/en/project</a><br class="gmail_msg">
</blockquote></div></div></div>