Consistency issue between BerkeleyGW and QE k-point grid

[박기명(일반대학원 물리학과)]

Dear users,

I’ve found that the k-point grid produced by the BerkeleyGW kgrid.x and the symmetry-reduced k-point grid from Quantum ESPRESSO do not match, even though they should ideally be identical.
I carefully checked the kgrid.x input and the FFT.
My working hypothesis is that, for trigonal structures, the two codes identify reduced k-points differently.
In my GW calculations, I therefore generated WFN and WFNq on a full N×N×N k-point mesh (for WFNq, I applied a 0.001 shift along k_z).
For the epsilon and sigma calculations, however, I used Quantum ESPRESSO’s symmetry-reduced k-point grid.

Could this workflow cause incorrect or inconsistent results?

Best,

GiMyung Park

[Zhenglu Li]

Dear GiMyung,

You can generate k points using other approaches than kgrid.x.  In BerkeleyGW and QE, different symmetries are applied (e.g. QE can include time-reversal, whereas BGW doesn't).  Also they may pick up different parts of the Brillouin zone.

If the kpoints are insufficien, BGW will complain.  Otherwise if the calculations finish, then the provided kpoints were enough.

Best,

Zhenglu

---

From: 박기명(일반대학원 물리학과) <dus...@yonsei.ac.kr>
Sent: Sunday, August 24, 2025 2:13 AM
To: BerkeleyGW Help <he...@berkeleygw.org>
Subject: Consistency issue between BerkeleyGW and QE k-point grid

 

Dear users, I’ve found that the k-point grid produced by the BerkeleyGW kgrid. x and the symmetry-reduced k-point grid from Quantum ESPRESSO do not match, even though they should ideally be identical. I carefully checked the kgrid. x input and

--
You received this message because you are subscribed to the Google Groups "BerkeleyGW Help" group.
To unsubscribe from this group and stop receiving emails from it, send an email to help+uns...@berkeleygw.org.
To view this discussion visit https://groups.google.com/a/berkeleygw.org/d/msgid/help/69427b0c-1a7f-4ffe-bd7c-23d9e5bd25fen%40berkeleygw.org.