EPW Forum

Dear eliephys78: As I recall , the velocity matrix elements were not computed in the older version of EPW-3.0.0 As far as lambda (el-ph coupling) calculations are concerned, My calculations are running fine. You are right. vme is used in transport module and adaptive smearing (triggered by degaussw=...

Dear weihua-xiao: Could you try to use vme=.false. in your input (currently, in epw, vme=.true. in default)? You encountered the error related to the velocity matrix element (vme), but vme is used in transport module and adaptive smearing (triggered by degaussw=0). It seems that both of them don't a...

Dear eliephys78: I don't think that your issue is solved; vme=F just skips the part resulting in the error by calculating the dipole matrix elements instead of the velocity matrix elements. Could you provide all contents of *.bvec file (this file was generated when you use vme=T)? Sincerely, H. Lee

Dear eliephys78: Thank you for your reply. Personally, I am very interested in your issue since I realized that there are many issues in EPW related to 2D systems. Unfortunately, I don't have any real example so that I can reproduce errors. 7- The weird thing is that the code outputs decay.H but sto...

Dear eliephys78: Another suggestion and question are: 1. Could you try to include vme=.false. in your epw input? 2. Did you download QE v6.5 at this site (https://gitlab.com/QEF/q-e/-/releases)? I am asking you whether you are using the office EPW v5.2 included in the official QE v6.5. 3. I want to ...

Dear eliephys78: Given information you provided, it is difficult to reproduce your error. Could you confirm that you are using the same number of pools as that of cpus? Also did you try to remove "nosym=.true.' in nscf.in? If you didn't add "nosym=.true.", is the total number of k points in nscf cal...

Dear eliephys78: I assume that you are using the same number of cores as that of k pools. Could you provide nscf and epw inputs which generated this error? Also it helps much to provide the full EPW output. Lastly, I need to know which version of EPW you are using (the official version of EPW or the...

Dear weihua-xiao: The keyword of write_bvec is true in wse2.win Very strage. If write_bvec is true, Wannier90 should generate *.bvec file. In your case, *.bvec file should contain the information (check the page of http://www.wannier.org/ford/proc/plot_bvec.html); if not so, you encounter the error....

Dear weihua-xiao: *.bvec file should not be empty if vme=.true. (I guess it is in default in your case). Could you confirm that there is a line of "write_bvec = .true." in *.win file in your directory? If there is a line of "write_bvec = .true." in your *.win file, please check whether there are som...

Dear weihua-xiao:

Could you provide the EPW output and let me know which version of EPW you are using so that we can reproduce your error?

Sincerely,

H. Lee