EPW Forum

Dear Sir,
I am getting the following error while running epw.in and calculation is stopped,
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine epw_setup (1):
coarse k-mesh needs to be strictly positive in 1st BZ
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Please suggest me how to resolve it.

Regards,
Anindya Bose
JRF.IIITA

Dear anindya@iiita,

You have to specify by hand the homogeneous coarse grid for the nscf calculations before the epw calculation.

The grid must be between 0-1 (and not between -0.5 and 0.5).

Best wishes,
Samuel

Hi Samuel,

When I use open_grid.x with a coarse automatic grid, I also get the same error since the k points are between -0.5 and 0.5. Is there a workaround to run these calculations if I want to avoid an nscf calculation (e.g. in case of hybrids).

Best,
Zeeshan

Hi Zeeshan,

You can generate the homogeneous coarse grid for the nscf calculations using a script 'kmesh.pl' from wannier90 community, please check inside wannier90-3.1.0/utility or https://github.com/wannier-developers/w ... y/kmesh.pl

For example; if you want to use 8x8x8 mesh; use wannier90-3.1.0/utility/kmesh.pl 8 8 8 >>nscf.in

I hope it helps,

Happy EPWing,
Hari