EPW Forum

I found a solution: In the scf/nscf calculations nosym must be true but noinv must be false. It looks like EPW always expects inversion symmetry for phonons, which however is not considered if noinv=true before the ph.x call.

Hi all, I'm trying to run EPW for a distorted MoS2 single layer system. Due to the distortion most of the symmetries are gone. For the undistorted lattice I get 7 irreducible q-points for a 6x6x1 phonon grid. For the distorted lattice the number of irreducible q-points increases to 13. This is what ...

I recompiled QE v6.4 with the following compiler/libraries:
openmpi 3.1
gnu compiler 8.2
mkl 2017

So the only thing I have changed is the compiler. EPW runs fine now. If anybody using an intel compiler experiences similar issues, I highly recommend to try the gnu compiler.

Dear Samuel, I compiled QE with the gnu compiler v8.2 and with openmpi v3.1. The problem has not occurred ever since. It looks like several runtime issues appear when QE is compiled with the intel compiler. I will stick with the gnu compiler form now on. Thanks for your suggestions and best regards ...

Hello, I get the following error at random points: =================================================================== irreducible q point # 12 =================================================================== Symmetries of small group of q: 4 Number of q in the star = 2 List of q in the star: 1 0 ...

Hello, I just read in the QE v6.4 change log that EPW now supports USPP. Are there any restrictions when using USPP (e.g. some quantities can't be calculated while others can)? I noticed that EPW v5.0 doesn't complain if USPP are used. Does it mean that v5.0 already supports USPP? Btw.: In ephwann ...

I switched software:
QE v6.3 ---> QE v6.4rc
OpenMPI 3.0 ---> OpenMPI 3.1
MKL 11.3.4 ---> MKL 2017

The error is gone.

PS: The important part was actually to switch from the intel compiler to the gnu compiler!

Hello, when using input_dft=vdw-DF and more than two CPU cores, EPW stalls in the subroutine setup_dgc when allocating memory in these lines: IF(.NOT.ALLOCATED(dvxc_rr)) ALLOCATE (dvxc_rr(dfftp%nnr, nspin_gga , nspin_gga)) IF(.NOT.ALLOCATED(dvxc_sr)) ALLOCATE (dvxc_sr(dfftp%nnr, nspin_gga , nspin ...

Anyway, you can verify this by e.g. comparing the band structure that you obtain with and without vdw corrections, of course using the same relaxed structure that you obtained with vdw corrections. Dear Carla, the band structure looks almost identical. There is a very slight shift of several meV of ...

Hello, the system of interest has a 4x4x4 k-mesh and 27 irreducible k-points. EPW runs fine with mpirun -np 16 epw.x -npool 16 < epw.in and also with 4, 8 and 12 for np/npool. The problem occurs when I specify 27 for np/npool. Then EPW crashes with malloc(): memory corruption right after printing G ...