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On 02/08/2014 12:00 PM, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:pw_forum-request@pwscf.org">pw_forum-request@pwscf.org</a>
wrote:
<blockquote cite="mid:mailman.9.1391857202.3668.pw_forum@pwscf.org"
type="cite">
<pre wrap=""><div class="moz-txt-sig">Message: 2
Date: Fri, 07 Feb 2014 16:25:14 +0100
From: Paolo Giannozzi <a moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:paolo.giannozzi@uniud.it"><paolo.giannozzi@uniud.it></a>
Subject: Re: [Pw_forum] Error in routine sym_rho_init_shell "lone
vector" with fixed FFT dimension
To: PWSCF Forum <a moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:pw_forum@pwscf.org"><pw_forum@pwscf.org></a>
Message-ID: <a moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:1391786714.5521.99.camel@fe12lx.fisica.uniud.it"><1391786714.5521.99.camel@fe12lx.fisica.uniud.it></a>
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On Thu, 2014-02-06 at 12:58 +0100, Thomas Gruber wrote:
</div></pre>
<blockquote type="cite" style="color: #000000;">
<pre wrap=""><span class="moz-txt-citetags">> </span>I attached 2 inputs files. One with smaller volume works and one with
<span class="moz-txt-citetags">> </span>greater volume with the corresponding *.out file, which works not. Since
<span class="moz-txt-citetags">> </span>I have already done phonon calculations for 5 different volumes, I don't
<span class="moz-txt-citetags">> </span>want to change the FFT dimension. I fixed it to 48 48 200 and the not
<span class="moz-txt-citetags">> </span>fixed FFT dimension would be 50 50 200.
<span class="moz-txt-citetags">> </span>Any suggestions?
</pre>
</blockquote>
<pre wrap="">it works if you reduce by a little bit "ecutrho" from its default value
4*ecutwfc. The problem is that if you keep the FFT grid fixed, you may
"miss" a few G-vectors. The algorithm that divides G-vectors into shells
of vectors transforming into each other cannot work if a shell is
incomplete. Alternatively: remove symmetry, since such algorithm is
used only for symmetrization of the charge density. I have no better
ideas right now: finding an algorithm that is guaranteed to work if
the FFT grid is not sufficient to accommodate the G-vector sphere
up to G<sup class="moz-txt-sup"><span style="display:inline-block;width:0;height:0;overflow:hidden">^</span>2</sup>< ecutrho may require a serious effort
Paolo
</pre>
</blockquote>
Thanks, that works. If I change the "ecutrho" value than I don't
have to fix the FFT dimension. I fixed the FFT dimension to keep the
energies for all volumes for a QHA calculation comparable and to not
get energy jumps. Would that work if I just reduce the ecutrho in
that amount to keep the G-vectors constant? For my case I would have
to decrease the "ecutrho" from 320 to 290 by 5% volume increase. <br>
<br>
Best regards,<br>
Thomas Gruber<br>
<pre class="moz-signature" cols="72">--
TU Bergakademie Freiberg
Dipl. Chem. Thomas Gruber
Institut für Theoretische Physik
Leipziger Str. 23 / OG. 14
D-09599 Freiberg
Tel: +49 3731 39-2006
Email: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:thomas.gruber@physik.tu-freiberg.de">thomas.gruber@physik.tu-freiberg.de</a>
Webseite: tu-freiberg.de</pre>
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