Error (wfhelp_occupy): Not implemented for this stype

exciting
1

Hi everyone!
I am getting an error message in the wannierization step to calculate the band spectrum using the HSE06 hybrid functional,

Error (wfhelp_occupy): Not implemented for this type.

I am using stype=‘Fermi Dirac’. Trying some other options for stype gives the same error. I should be grateful if anyone can help me understand the nature of this error and the options to avoid it.

3

Actually, a solution seems to set stype=‘libbzint’. Trying it out…

4

Hi Claudia,

The problem has been forwarded to Sebastian, who implemented the Wannier code. Hopefully he will provide some feedback.

Cheers,
Alex

5

Thanks Alex! Setting stype=‘libbzint’ did not help. This error occurs when the system is in a metallic state. For the same system, by varying the lattice parameter and opening a gap, the Wannier calculation proceeds to the end.

6

Hi Claudio,

I also did some tests and indeed as you said, the problem only occurs when calculating metals with hybrid functionals. The problem is, that for hybrids, irrespective of the input, always the tetrahedron integration (stype=“libbzint”) is used internally to determine the Fermi level and occupation numbers. Hence, changing the stype in the input file does not work and internally it always falls back to “libbzint” which however is not yet implemented in the Wannier part of the code. For systems with gap, this error does not occur since the Fermi level and occupation numbers are determined in a simplified way.
Thanks for pointing out this problem. I will work on fixing it and you’ll get noticed when there is a fixed version available to be cloned from our git repository.

Cheers,
Sebastian

7

Dear Sebastian,
Thank you very much for your reply clarifying this issue!!
Best regards,
Claudio