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<p>Hello Giovanni,<br>
<br>
thank you very much for the quick reply and the tips. As
requested, here is my execution line: <br>
</p>
<p>export OMP_NUM_THREADS=48.<br>
mpirun -np 10 pw.x -in input/“$INPUT” -nb 1 -nt 2 >
output/"$OUTPUT”<br>
<br>
<br>
I'm trying to run MPI+openMP in a hybrid way, since using pure MPI
has prohibitively increased the use of RAM. Regarding the second
point, I used K_POINTS gamma for the supercell calculations, I
don't know if that's exactly your question. As for ecutwfc and
ecutrho, I used 50 Ry and 400 Ry respectively. Regarding the
fourth point, as these are steps in a finite displacement process,
at least one coordinate will be subtly disturbed, referring to the
displacement of the atom of the method itself, but in fact as you
mentioned, there were other coordinates that were a little
disturbed due to the relaxation I did with vc-relax before
generating the supercell, which changed the atomic positions a
little for these strange coordinates. I'm already testing the
calculation without this relaxation to see if it improves. I'm
still looking for more suggestions to improve the calculation.<br>
<br>
Sincerely,<br>
<br>
M.Sc. Mateus Corradini Lopes<br>
PhD. student<br>
Gleb Wataghin Institute of Physics - Unicamp<br>
<br>
<br>
</p>
<div class="moz-cite-prefix">Em 22/05/2025 16:34, Giovanni Cantele
escreveu:<br>
</div>
<blockquote type="cite"
cite="mid:CAG=KO1H9mpX5G2f=ZAWNodi-zh5tHaLEZjHZ4dSDLouhZWrr9w@mail.gmail.com">
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<div dir="ltr">
<div>Hi,</div>
<div><br>
</div>
<div>first of all it would be nice also to have the command you
use to run pw.x (because if you for example use pools, this
replicates the memory requirements).</div>
<div><br>
</div>
<div>Second: which k-point grid do you use to sample the
Brillouin zone? In the case of a 1x1x1 grid, do you use
gamma-only algorithms?</div>
<div><br>
</div>
<div>Third: which ecutwfc and ecutrho do you use?</div>
<div><br>
</div>
<div>Fourth: I understand you need a "perfect" supercell as
derived from replicating a bulk cubic cell. Coordinates
like 0.0013807042891237 or 0.1874999906250000 are harmful
(unless you need to break symmetry or they are exactly what
you want), in that they prevent pw.x from finding symmetries.
The latter might be quite helpful in (sometimes even
significantly) reducing the calculation load (in terms of
k-points but not only!). So, I would round all coordinates so
as to obtain exactly the number you expect.</div>
<div><br>
</div>
<div>Hope this helps.</div>
<div>Giovanni</div>
<div><br>
</div>
<div>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr"><span style="color:rgb(0,0,0)">-- <br>
<br>
Giovanni Cantele, PhD<br>
CNR-SPIN<br>
c/o Dipartimento di Fisica<br>
Universita' di Napoli "Federico II"<br>
Complesso Universitario M. S. Angelo - Ed. 6<br>
Via Cintia, I-80126, Napoli, Italy<br>
<a href="mailto:giovanni.cantele@spin.cnr.it"
style="color:rgb(17,85,204)" target="_blank"
moz-do-not-send="true">e-mail:
giovanni.cantele@spin.cnr.it</a><br>
Phone: +39 081 676910<br>
Skype contact: giocan74<br>
<br>
ResearcherID: <a
href="http://www.researcherid.com/rid/A-1951-2009"
style="color:rgb(17,85,204)" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">http://www.researcherid.com/rid/A-1951-2009</a><br>
Web page: </span><a
href="https://sites.google.com/view/giovanni-cantele/home"
style="color:rgb(17,85,204)" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">https://sites.google.com/view/giovanni-cantele/home</a><br>
</div>
</div>
</div>
<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">Il giorno gio 22 mag 2025 alle
ore 20:03 Mateus Corradini Lopes <<a
href="mailto:mclopes@ifi.unicamp.br" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">mclopes@ifi.unicamp.br</a>>
ha scritto:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear
all,<br>
<br>
I have recently been working on obtaining transport properties
for <br>
certain types of materials. One of the parts of the work is to
obtain <br>
the lattice thermal conductivity (\kappa_latt), so I'm trying
to use <br>
phono3py+Quantum Espresso to calculate the supercell and
obtain the <br>
force constants.<br>
<br>
At the moment I'm trying to calculate the \kappa_latt of GaAs
as a test, <br>
I've already managed to generate the supercells (4x4x4 and
3x3x3 based <br>
on the conventional GaAs cell, which gives 512 and 216 atoms <br>
respectively) and I've used phono3py's --cutoff-pair to reduce
the <br>
number of inputs, but even though I've tried various ways of
running the <br>
calculation I haven't found a way to make it feasible in terms
of <br>
computational time and RAM (the lowest I could get was
“Estimated total <br>
dynamical RAM > 115.43 GB”). I have access to a cluster
with 480 <br>
processors (10 nodes with 48 processors each) and I would like
to know <br>
what is the best way to run this system, in terms of
optimizing the <br>
input and the parallelism used, balancing precision and
computational time.<br>
<br>
Ps. I'm attaching an example of the input I'm currently using.<br>
<br>
Thank you in advance,<br>
<br>
M.Sc. Mateus Corradini Lopes<br>
PhD. student<br>
Gleb Wataghin Institute of Physics - Unicamp<br>
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<pre wrap="" class="moz-quote-pre">_______________________________________________________________________________
The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
--------------------------------------------------------------------------------
Quantum ESPRESSO is supported by MaX (<a class="moz-txt-link-abbreviated" href="http://www.max-centre.eu">www.max-centre.eu</a>)
users mailing list <a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a>
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