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<p>Hello Mateus,</p>
<p>you can compute these force constants with a much smaller cost
using my code "d3q" that uses perturbation theory in reciprocal
space. The entire calculation for the 4×4×4 grid with a 12×12×12
shifted grid of k-points only takes around 12 hours on 64 CPUs.</p>
<p>(I can provide inputs and outputs on request, as it is all
published results)</p>
<p>cheers</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 22/05/2025 20:03, Mateus Corradini
Lopes wrote:<br>
</div>
<blockquote type="cite"
cite="mid:7bd46713-4102-4ac8-8d4b-5af78ae20f3d@ifi.unicamp.br">Dear
all,
<br>
<br>
I have recently been working on obtaining transport properties for
certain types of materials. One of the parts of the work is to
obtain the lattice thermal conductivity (\kappa_latt), so I'm
trying to use phono3py+Quantum Espresso to calculate the supercell
and obtain the force constants.
<br>
<br>
At the moment I'm trying to calculate the \kappa_latt of GaAs as a
test, I've already managed to generate the supercells (4x4x4 and
3x3x3 based on the conventional GaAs cell, which gives 512 and 216
atoms respectively) and I've used phono3py's --cutoff-pair to
reduce the number of inputs, but even though I've tried various
ways of running the calculation I haven't found a way to make it
feasible in terms of computational time and RAM (the lowest I
could get was “Estimated total dynamical RAM > 115.43 GB”). I
have access to a cluster with 480 processors (10 nodes with 48
processors each) and I would like to know what is the best way to
run this system, in terms of optimizing the 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>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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<div class="moz-signature">-- <br>
<small>Dr. Lorenzo Paulatto<br>
IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN <br>
phone: +33 (0)1 442 79822 / telegram: lpaulatto<br>
<a href="http://www.impmc.upmc.fr/~paulatto/"
class="moz-txt-link-freetext">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/"
class="moz-txt-link-freetext">https://anharmonic.github.io/</a><br>
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