1. Consider that a non-scf calculation has a computational cost of the
same order as for a comparable scf one. If your k-points grid for the
non-scf calculation contains N times more points than the scf
calculation, expect that the former takes N times more than the latter.
2. Just use "mpirun -nk XX", with XX a divisor of the total number of
processors (preferrably also a divisor of the total number of k-points),
such that 360/XX is smaller than the maximum FFT dimension along axis
3. Don't use "-nb N" except for special cases
Paolo
On 4/27/23 15:19, Francesco Delodovici wrote:
Dear users,
I need to use wannier90 on top of quantum espresso to deal with a
multilayer BiFeO3-LaFeO3 with 60 atoms overall.
I run the scf calculation to compute the Kohn-Sham orbitals on a 6x6x4
k-mesh,
and then I need to refine the k-mesh to 18x18x10 with a nscf
calculation, asking for 220 bands.
The calculation is spin-polarized to deal with antiferromagnetism in BFO
with
the Hubbard corrections to the Fe d states included.
I employ the following parallelization parameters over 360 processors:
-nk 36 -nb 10
without OMP parallelization.
The problem here is that the nscf calculation does not complete within
24 hours,
so I wonder: can I change the parallelization options in order to obtain
a better scaling?
What would be a better setting?
I appreciate any suggestion, even though I know that parallelization
does not perform miracles.
Thank you,
Francesco Delodovici, CentraleSupelec Paris-Saclay Université
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
