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<p>Dear Anindya <br>
</p>
<p>for static pwscf computations the result should be the same no
matter if some symmetry is actually used in the program or not.
The set of k-points used for the Brillouin-zone sum will be
larger when symmetries are discarded right in order to preserve
all the actual symmetries of the system. <br>
</p>
<p>When the symmetries are not enforced explicitely, there can be
some small numerical error which step by step can spoil the
structural relaxation. So i would perform the relaxation using
the use_all_frac options and then use the obtained structure to
perform an scf computation setting use_all_frac = .false. The
total energy obtained in this latter calculation should be the
same as the one obtained in final computation performed at the end
of the relaxation. <br>
</p>
<p>You can then use the scf calculation with use_all_frac = .false.
to startup the phonon calculations. <br>
</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 30/07/2018 11:15, Anindya Bose
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAJXtw3zjGaNLp8mQ00w_8swpgTYwOMhvWXrFVHTVvoMsJrYAWQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=utf-8">
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<div>Dear Dr <span name="Stefano Baroni" class="gmail-gD">Stefano
Baroni,</span></div>
<div><span name="Stefano Baroni" class="gmail-gD">I have tried
this method by using the card <tt>use_all_frac</tt>=.true.,
in relax,scf and I got the correct point group symmetry
however this causing trouble in the phonon and epw
calculations.Is there any trade off which I can make to have
the calculation symmetrically and technically correct for
the higher level computation(like phonon,epw etc).Can't I
have a Graphene script from VNL ATK Quantumwise with all the
possible corrections.I will be waiting for your response.</span></div>
<div><span name="Stefano Baroni" class="gmail-gD"><br>
</span></div>
<div><span name="Stefano Baroni" class="gmail-gD">Thanks and
regards,<br>
Anindya Bose<br>
Research Fellow,<br>
Indian Institute of Information Technology Allahabad.
<br>
</span></div>
<div><span name="Stefano Baroni" class="gmail-gD"></span> <span
class="gmail-go"><span></span></span></div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Jul 27, 2018 at 8:52 PM,
Stefano Baroni <span dir="ltr"><<a
href="mailto:baroni@sissa.it" target="_blank"
moz-do-not-send="true">baroni@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
style="word-wrap:break-word;line-break:after-white-space">Please,
have a look at this note and see if you find a fix.
<div><a
href="http://www.quantum-espresso.org/Doc/pw_user_guide/node21.html#SECTION000600190000000000000"
target="_blank" moz-do-not-send="true">http://www.quantum-espresso.<wbr>org/Doc/pw_user_guide/node21.<wbr>html#<wbr>SECTION000600190000000000000</a><br>
</div>
<div>If you do, please let us know. Regards — SB<br>
<div><br>
<blockquote type="cite">
<div>
<div class="h5">
<div>On 27 Jul 2018, at 12:26, Anindya Bose <<a
href="mailto:anindya@iiita.ac.in"
target="_blank" moz-do-not-send="true">anindya@iiita.ac.in</a>>
wrote:</div>
<br
class="m_-8329151500162924297Apple-interchange-newline">
</div>
</div>
<div>
<div>
<div class="h5">Dear Experts,<br>
Please suggest me a way to resolve this issue.<br>
<br>
Thanks and regards,<br>
Anindya Bose<br>
<br>
On Monday, July 23, 2018, Anindya Bose <<a
href="mailto:anindya@iiita.ac.in"
target="_blank" moz-do-not-send="true">anindya@iiita.ac.in</a>>
wrote:<br>
> Dear Experts,<br>
> I am facing a problem with point group
symmetry error.Actually While doing the
vc-relax and scf calculation of Graphene, my
relax.out and scf.out file gives wrong point
group information D_2h(mmm) rather than
d3h(the correct one) and even my scf.out and
ph.out showing a wrong point group information
C_s(m).<br>
><br>
> The results are enclosed in the
following(relax.out)<br>
> point group C_s (m) <br>
> there are 2 classes<br>
> the character table:<br>
><br>
> E s <br>
> A' 1.00 1.00<br>
> A'' 1.00 -1.00<br>
><br>
> the symmetry operations in each
class and the name of the first element:<br>
><br>
> E 1<br>
> identity <wbr> <br>
> s 2<br>
> inv. 180 deg rotation - cart.
axis [0,0,1] <br>
><br>
><br>
> I have tried a lot to change my structure
but I am still unable to resolve this
issues.If anyone faced the same issue related
to point group symmetry error then please help
me to solve this difficulty.I will be waiting
for the response.<br>
> Thanks and regards,<br>
> Anindya Bose<br>
> Research Fellow,<br>
> Indian Institute of Information
Technology Allahabad.<br>
><br>
</div>
</div>
>
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<div><span
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style="border-collapse:separate;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;line-height:normal;text-indent:0px;border-spacing:0px"><span
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<div><span style="font-size:12px">— </span></div>
<div style="word-wrap:break-word">
<div style="word-wrap:break-word">
<div style="word-wrap:break-word">
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<div>
<div style="margin:0px"><font
class="m_-8329151500162924297Apple-style-span"><span
style="font-size:12px">Stefano
Baroni - Trieste — </span><a
href="http://stefano.baroni.me"
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"
target="_blank"
moz-do-not-send="true">http://stefano.<wbr>baroni.me</a><span
style="font-size:12px"> </span></font></div>
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</span></span></div>
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