How do I obtain ksdata.fmt when using eig_read = .true.?

General discussion around the EPW software

Moderator: stiwari

Post Reply
davidfm2002
Posts: 1
Joined: Mon Jan 05, 2026 3:27 pm
Affiliation: Institut Polytechnique de Paris

How do I obtain ksdata.fmt when using eig_read = .true.?

Post by davidfm2002 »

Hello,

I am running an epw calculation. I need to use eig_read = .true.. For this option to work I need 2 files : prefix.eig and ksdata.fmt. I have the file prefix.eig but I don't know how to obtain the file ksdata.fmt.

I am extracting the eigenvalues from pw.x. I need to use eig_read because I want to use cell parameter to calculate the electron phonon coupling matrix elements and a slightly different cell parameter for the band structure. Is there any option to write ksdata.fmt in Quantum ESPRESSO?

Could someone help me please?
xiaozha
Posts: 24
Joined: Mon Jun 07, 2021 7:59 pm
Affiliation: The University of Michigan

Re: How do I obtain ksdata.fmt when using eig_read = .true.?

Post by xiaozha »

Hi,

I believe for the option to work, prefix.eig itself should be sufficient. ksdata.fmt should be generated by the code itself.

Something you may want to double check is if you did not use eig_read when doing the Wannierzation (so with epwwrite=.true.), but used it later when you calculate functional properties (when epwread=.true.). I think if that is the case, it is not compatible. The two steps need to be consistent.

Thanks,
Xiao
Post Reply