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<DIV><FONT face=Verdana color=#000080 size=2>This maybe relate with FFT
grid. Try to specify parameters 'nr' in inputfile. You can get the reference
value by executing this command in outputfile of ecut
=20,25,...</FONT></DIV>
<DIV><FONT color=#000080>$grep 'FFT grid:' ***.out</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT> </DIV>
<DIV><FONT face=Verdana color=#000080 size=2>Kun Yin, PhD student</FONT></DIV>
<DIV><FONT color=#000080>Nanjing University, China</FONT></DIV>
<DIV><FONT face=Verdana color=#c0c0c0 size=2>2010-01-05 </FONT></DIV><FONT
face=Verdana color=#000080 size=2>
<HR style="WIDTH: 100px" align=left color=#b5c4df SIZE=1>
</FONT>
<DIV><FONT face=Verdana color=#c0c0c0 size=2><SPAN>kyin.cn</SPAN> </FONT></DIV>
<HR color=#b5c4df SIZE=1>
<DIV><FONT face=Verdana size=2><STRONG>发件人：</STRONG> Madhura Marathe
</FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>发送时间：</STRONG> 2010-01-05 12:37:30
</FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>收件人：</STRONG> pw_forum </FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>抄送：</STRONG> </FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>主题：</STRONG> [Pw_forum] ecut dependence
of symmetry operations(?) </FONT></DIV>
<DIV><FONT face=Verdana size=2></FONT> </DIV>
<DIV><FONT face=Verdana size=2>
<DIV> Dear all,</DIV>
<DIV></DIV>
<DIV> While performing convergence calculations w.r.t energy cut-off for a bulk</DIV>
<DIV>system, I found that the number of symmetry operations detected by a code</DIV>
<DIV>is different depending on the value of ecut. This is very surprising</DIV>
<DIV>because for the same system, the symmetries should not depend on the ecut</DIV>
<DIV>value.</DIV>
<DIV></DIV>
<DIV> For Ecut = 20, 25, 40, 50 and 55 Ry, the output says -</DIV>
<DIV>"24 Sym.Ops. (with inversion)";</DIV>
<DIV>whereas for ecut = 30, 35, 45 and 60 Ry, the output is -</DIV>
<DIV>"12 Sym.Ops. (no inversion)"</DIV>
<DIV></DIV>
<DIV> I have performed the same calculations using versions 4.0.4 and 4.1 with</DIV>
<DIV>the same results.</DIV>
<DIV>The input file is as follows -</DIV>
<DIV>*****</DIV>
<DIV> &control</DIV>
<DIV> calculation = 'scf'</DIV>
<DIV> verbosity = 'high'</DIV>
<DIV> restart_mode = 'from_scratch',</DIV>
<DIV> prefix = 'RuGGA',</DIV>
<DIV> tstress=.true.</DIV>
<DIV> tprnfor=.true.</DIV>
<DIV> pseudo_dir = '/home/madhura-data/pseudo/',</DIV>
<DIV> outdir = '/home/madhura-data/tmp/'</DIV>
<DIV>/</DIV>
<DIV> &system</DIV>
<DIV> ibrav = 4, celldm(1) = 5.1831, celldm(3) = 1.584,</DIV>
<DIV> nat = 2, ntyp = 1,</DIV>
<DIV> ecutwfc = 20, ecutrho = 160, # ecutrho = 8*ecutwfc</DIV>
<DIV> occupations='smearing', smearing='mp',degauss=0.05</DIV>
<DIV> nbnd = 20</DIV>
<DIV>/</DIV>
<DIV> &electrons</DIV>
<DIV> diagonalization = 'david', mixing_mode = 'plain',</DIV>
<DIV> mixing_beta = 0.7, conv_thr = 1.0d-12</DIV>
<DIV>/</DIV>
<DIV>ATOMIC_SPECIES</DIV>
<DIV> Ru 101.07 Ru.pbe-n-van.UPF</DIV>
<DIV>ATOMIC_POSITIONS {crystal}</DIV>
<DIV> Ru 0.00 0.00 0.00</DIV>
<DIV> Ru 0.66666667 0.33333333 0.50</DIV>
<DIV>K_POINTS automatic</DIV>
<DIV> 8 8 8 0 0 0</DIV>
<DIV>*****</DIV>
<DIV></DIV>
<DIV> Can anybody explain what is happening? Or do I need to file a bug report?</DIV>
<DIV>Because except for this problem, energies and stress values seem to be</DIV>
<DIV>converging.</DIV>
<DIV></DIV>
<DIV> Thanks and regards,</DIV>
<DIV> Madhura.</DIV>
<DIV></DIV>
<DIV>-- </DIV>
<DIV>Madhura Marathe,</DIV>
<DIV>PhD student, TSU,</DIV>
<DIV>JNCASR, Bangalore.</DIV>
<DIV>India.</DIV>
<DIV>Phone No: +91-80-22082835</DIV>
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