<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Madhura: this has been discussed zilliions of times in this forum, and has to do with the way symmetry operations are found out by the code. When the symmetry group of the system is non-symmorphic, only those fractional translations that are commensurate with the FFT grid are actually found. This may sound a bit cryptic, and I leave it as such on purpose. You will find much more about this issue by browsing the archives of this mailing list. Hope this helps - SB<div><br><div><div>On Jan 5, 2010, at 12:24 PM, Madhura Marathe wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div> Dear all,<br><br> While performing convergence calculations w.r.t energy cut-off for a bulk<br>system, I found that the number of symmetry operations detected by a code<br>is different depending on the value of ecut. This is very surprising<br>because for the same system, the symmetries should not depend on the ecut<br>value.<br><br> For Ecut = 20, 25, 40, 50 and 55 Ry, the output says -<br>"24 Sym.Ops. (with inversion)";<br>whereas for ecut = 30, 35, 45 and 60 Ry, the output is -<br>"12 Sym.Ops. (no inversion)"<br><br> I have performed the same calculations using versions 4.0.4 and 4.1 with<br>the same results.<br>The input file is as follows -<br>*****<br> &control<br> calculation = 'scf'<br> verbosity = 'high'<br> restart_mode = 'from_scratch',<br> prefix = 'RuGGA',<br> tstress=.true.<br> tprnfor=.true.<br> pseudo_dir = '/home/madhura-data/pseudo/',<br> outdir = '/home/madhura-data/tmp/'<br>/<br> &system<br> ibrav = 4, celldm(1) = 5.1831, celldm(3) = 1.584,<br> nat = 2, ntyp = 1,<br> ecutwfc = 20, ecutrho = 160, # ecutrho = 8*ecutwfc<br> occupations='smearing', smearing='mp',degauss=0.05<br> nbnd = 20<br>/<br> &electrons<br> diagonalization = 'david', mixing_mode = 'plain',<br> mixing_beta = 0.7, conv_thr = 1.0d-12<br>/<br>ATOMIC_SPECIES<br> Ru 101.07 Ru.pbe-n-van.UPF<br>ATOMIC_POSITIONS {crystal}<br> Ru 0.00 0.00 0.00<br> Ru 0.66666667 0.33333333 0.50<br>K_POINTS automatic<br> 8 8 8 0 0 0<br>*****<br><br> Can anybody explain what is happening? Or do I need to file a bug report?<br>Because except for this problem, energies and stress values seem to be<br>converging.<br><br> Thanks and regards,<br> Madhura.<br><br>-- <br>Madhura Marathe,<br>PhD student, TSU,<br>JNCASR, Bangalore.<br>India.<br>Phone No: +91-80-22082835<br>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>http://www.democritos.it/mailman/listinfo/pw_forum<br></div></blockquote></div><br><div>
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"><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">---</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Stefano Baroni - SISSA</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">&</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">DEMOCRITOS National Simulation Center - Trieste</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "><a href="http://stefano.baroni.me">http://stefano.baroni.me</a> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; font-size: 12px; "><br style="font-size: 12px; "></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; font-size: 12px; "><span class="Apple-style-span" style="font-size: 14px; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">La morale est une logique de l'action comme la logique est une morale de la pensée - Jean Piaget</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "><br></span></font></div></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Please, if possible, don't</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">send me MS Word or PowerPoint attachments</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Why? See:</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" color="#0023E9" size="3"><span class="Apple-style-span" style="font-size: 12px; "><a href="http://www.gnu.org/philosophy/no-word-attachments.html">http://www.gnu.org/philosophy/no-word-attachments.html</a></span></font></div><div><font class="Apple-style-span" color="#0023E9" size="3"><span class="Apple-style-span" style="font-size: 12px; "><br class="webkit-block-placeholder"></span></font></div></div></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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