<div dir="ltr">Dear Stefano<div>Thanks for your mail.</div><div>But what does this error mean? when I try to run the calculation, it ejects this error? How can I get rid of it</div><div><div> Error in routine setup (1):</div><div> Variable cell and EXX not tested!</div></div><div>The input file is as under</div><div><br></div><div><div> &CONTROL</div><div> title = 'CsPbI' ,</div><div> calculation = 'vc-relax' ,</div><div> restart_mode = 'from_scratch' ,</div><div> outdir = '/work/saqlain' ,</div><div> wfcdir = '/work/saqlain' ,</div><div> pseudo_dir = '/home/ibm/proj/proj527/saqlain/psp' ,</div><div> prefix = 'PBE0' ,</div><div> /</div><div> &SYSTEM</div><div> ibrav = 0,</div><div> celldm(1) = 1.8897265,</div><div> nat = 5,</div><div> ntyp = 3,</div><div> ecutwfc = 40 ,</div><div> input_dft = 'PBE0' ,</div><div> occupations = 'smearing' ,</div><div> degauss = 0.001 ,</div><div> smearing = 'marzari-vanderbilt' ,</div><div> ecutfock = 40 ,</div><div> exxdiv_treatment = 'none' ,</div><div> nqx1 = 2 ,</div><div> nqx2 = 2 ,</div><div> nqx3 = 2 ,</div><div> /</div><div> &ELECTRONS</div><div> /</div><div> &IONS</div><div> /</div><div>&CELL</div><div> /</div><div>CELL_PARAMETERS cubic </div><div> 6.382434987 0.000000000 0.000000000 </div><div> 0.000000000 6.382434987 0.000000000 </div><div> 0.000000000 0.000000000 6.382434987 </div><div>ATOMIC_SPECIES</div><div> Cs 132.90000 Cs.pbe-sp-hgh.UPF </div><div> I 126.90000 I.pbe-hgh.UPF </div><div> Pb 207.20000 Pb.pbe-hgh.UPF </div><div>ATOMIC_POSITIONS crystal </div><div> Cs 0.500000000 0.500000000 0.500000000 </div><div> I 0.500000000 0.000000000 0.000000000 </div><div> I 0.000000000 0.500000000 0.000000000 </div><div> I 0.000000000 0.000000000 0.500000000 </div><div> Pb 0.000000000 0.000000000 0.000000000 </div><div>K_POINTS automatic </div><div> 2 2 2 1 1 1 </div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jul 23, 2016 at 6:48 PM, stefano de gironcoli <span dir="ltr"><<a href="mailto:degironc@sissa.it" target="_blank">degironc@sissa.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>On 23/07/2016 14:23, Muhammad Adnan
Saqlain wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Dear S<span style="font-size:12.8px">tefano</span>
<div>thanks for your response.</div>
<div>Can you please guide me (1) Why vc-relax is not allowed in
Q-E 5.4.0?</div>
</div>
</blockquote>
it is.<br>
<blockquote type="cite">
<div dir="ltr">
<div>(2) How would the band gap be effected if I relax the cell
without hybrid scheme and then calculate band gap with hybrid
one?<br>
</div>
<div><br>
</div>
</div>
</blockquote>
it would be the band gap of a different structure. <br>
it would depend on how different the structure would be with a
different functional.<br>
<br>
stefano<br>
<blockquote type="cite">
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Jul 23, 2016 at 1:07 PM,
stefano de gironcoli <span dir="ltr"><<a href="mailto:degironc@sissa.it" target="_blank">degironc@sissa.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>dear Muhammad Adnan Saqlain,<br>
<br>
gamma extrapolation is a way to deal with the ill
defined value of the exchange integral between wfcs at k
and k+q in the limit of q->0.<br>
if you use a truncated coulomb interaction that limit
is not ill defined.<br>
no need to use the gamma_extrapolation option<br>
best,<br>
stefano<br>
<br>
On 23/07/2016 10:00, Muhammad Adnan Saqlain wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Dear Prof Clavijo
<div>I am extremely sorry for my misleading title of
the calculation. Actually, It was a cubic structure
consisting of Cs, Pb and I. I deliberately did not
put the atoms in the calculation. more over I do not
know why the algorithm for cell movement was not
copied it was however present in the input file.</div>
<div><br>
</div>
<div>1. If I try these two options, the </div>
<a name="m_6238181706137199252_m_1337774494978436259_m_4755999124063804085_exxdiv_treatment" style="color:rgb(0,0,0);font-size:12.8px;font-family:arial,helvetica,sans-serif">
<table style="border:2px solid rgb(181,181,0);margin-bottom:10px;table-layout:auto" width="100%">
<tbody>
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<blockquote>
<pre style="white-space:pre-wrap">vcut_spherical : appropriate for cubic and quasi-cubic supercells
vcut_ws : appropriate for strongly anisotropic supercells, see also
ecutvcut.</pre>
</blockquote>
</td>
</tr>
</tbody>
</table>
</a>
<div class="gmail_extra">the program says like this</div>
<div class="gmail_extra">
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%</div>
<div class="gmail_extra"> Error in routine
system_checkin (1):</div>
<div class="gmail_extra"> x_gamma_extrapolation
cannot be used with vcut</div>
<div class="gmail_extra"> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%</div>
<div><br>
</div>
</div>
<div class="gmail_extra">I have no idea how to fix it.
Can you suggest one??</div>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">2. I have now used Q-E 5.4.0,
but this version does not allow vc-relax option with
hybrid one. why is it so? How would the band gap be
effected if I relax the cell without hybrid scheme
and then calculate band gap with hybrid one?</div>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">3. About the ecutoff, I
deliberately used small one as these are just
calculations not the real one.</div>
<div class="gmail_extra">4. I have cubic system, may I
try q-grid like 1*2*3 or it has to be symmetric one?</div>
<div class="gmail_extra"> 5. Can you suggest more
about hybrid calculations?</div>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Jul 22, 2016 at
10:09 PM, Josue Itsman Clavijo Penagos <span dir="ltr"><<a href="mailto:jiclavijop@unal.edu.co" target="_blank">jiclavijop@unal.edu.co</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
<div dir="ltr">Dear, Muhammad Adnan Saqlain,
remember the user documentation for <b style="font-size:13px">exxdiv_treatment</b>: <a name="m_6238181706137199252_m_1337774494978436259_m_4755999124063804085_exxdiv_treatment" style="color:rgb(0,0,0);font-family:arial,helvetica,sans-serif">
<table style="border:2px solid rgb(181,181,0);margin-bottom:10px;table-layout:auto" width="100%">
<tbody>
<tr>
<td colspan="2" align="left" valign="top">
<blockquote>
<pre>Specific for EXX. It selects the kind of approach to be used
for treating the Coulomb potential divergencies at small q vectors.
gygi-baldereschi : appropriate for cubic and <b>quasi-cubic supercells</b>
vcut_spherical : appropriate for cubic and quasi-cubic supercells
vcut_ws : appropriate for strongly anisotropic supercells, see also
ecutvcut.
none : sets Coulomb potential at G,q=0 to 0.0 (required for GAU-PBE)</pre>
</blockquote>
</td>
</tr>
</tbody>
</table>
</a><b>Besides that, </b>I<b> </b>have some
observations and suggestions for you based in
the input file you send, so you can realize
why does QE is failing when trying to simulate
your system:
<div><br>
</div>
<div>1 - Check if you really need to apply
smearing, since this technique is intended
to be useful for metallic systems, and
Anatase is cleary not a metallic system, in
fact, is more a Wide-gap or Insulator -type
system.<br>
<div><br>
</div>
<div>2 - You do want to perform a vc-relax
calculation, but nothing are specified in
the cards &IONS and &CELL. There
is not cell relaxing algorithm specified
(BFGS? MD?)</div>
</div>
<div><br>
</div>
<div>3 - The card &ATOMIC_POSITIONS shows
nothing: No atoms, no cell to relax.</div>
<div><br>
</div>
<div>4 - In the card &SYSTEM , <b>ecutwfc
= 40.</b> This, in my humble opinion, a
very poor cutoff for a serious calculation.
Do a ecutwfc convergence test before attempt
your system.</div>
<div><br>
</div>
<div>5 - Please take in account that a hybrid
calculation is VERY expensive in terms of
computational demand, so if you set up a
vc-relax calculation using hybrid PPS you
must test if <b style="font-size:13px">nqx1
= 1, 2 or 3 really makes a difference.</b></div>
<div><b style="font-size:13px"><br>
</b></div>
<div><b>6 - For some systems, input_dft=HSE is
faster than </b><b>input_dft = "PBE0".
Check if that could be your case.</b></div>
<div><b><br>
</b></div>
<div>By the way, are you sure Anatase has a
cubic crystal structure? Does XCrysden show
the correct structure for your input?</div>
<div><br>
</div>
<div><b>Best regards, </b></div>
<div><b><br>
</b></div>
<div class="gmail_extra"><br>
<div class="gmail_quote">Josué Clavijo, PhD.</div>
<div class="gmail_quote">Assistant Professor</div>
<div class="gmail_quote">Universidad
Nacional de Colombia</div>
<div class="gmail_quote">Departamento de
Química</div>
</div>
</div>
<br>
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<br>
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<span><font color="#888888">
<div><br>
</div>
-- <br>
<div data-smartmail="gmail_signature">
<div dir="ltr">Best Regards
<div>Muhammad Adnan Saqlain
<div><br>
</div>
</div>
</div>
</div>
</font></span></div>
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-- <br>
<div data-smartmail="gmail_signature">
<div dir="ltr">Best Regards
<div>Muhammad Adnan Saqlain
<div><br>
</div>
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