Hello Mateus,
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.
(I can provide inputs and outputs on request, as it is all published
results)
cheers
On 22/05/2025 20:03, Mateus Corradini Lopes wrote:
Dear all,
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.
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.
Ps. I'm attaching an example of the input I'm currently using.
Thank you in advance,
M.Sc. Mateus Corradini Lopes
PhD. student
Gleb Wataghin Institute of Physics - Unicamp
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_______________________________________________________________________________
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worldwide who are victims of terrorism, military aggression, and indiscriminate
warfare.
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