Reading electron-phonon matrix elements file by EPW

[animeshd]

Hi,

I am trying to read the ephmat files generated by EPW in binary format using Python. I was reading the source code write_ephmat routine within the io_eliashberg.f90 file. I am doing for GaN with 1 band and there are 12 phonon modes. The dense k and q grid is 40^3. I am using 4 nodes and 16 cores so there are 64 processes. Thus I got 64 ephmat files with 1000 kpts in each of them. I wanted to verify the format of the ephmat file generated by EPW. I am using EPW 5.7 and QE7.2. I am also using a large fsthick to ensure all the k and q points are taken into the calculation

So the first line contains the pool id and the number of k points within the pool right? And after that the matrix elements are written. As far as I understood, the first matrix element is the one corresponding to the 1st kpoint 1st qpoint , 1st band and the 1st mode[/b] right? Then the next elements is 1st kpoint, 1st qpoint,1st band and 2nd mode right? In this way it goes upto 12 modes and then is it is for 1st kpt, 2nd qpt, 1st band and 1st modes right?

It would be really great if someone could verify whether I am understanding it correctly.

[Shashi]

Hi Animesh,

I would suggest you use the EPW v5.9 as in older versions you might face problems restarting the calculations and other issues.

The superconductivity module, first checks if k and q-points are within the fsthick window or not. Then it maps those k-points within the window. You can verify this in your epw output file.

Yes, the first line contains the pool id and the number of k points within the fsthick window in the pool.
The elements are written for each q-point.
The first element is iq=1, ikfs=1, 1st band, and 1st mode...all the modes. iq=1, ikfs=2, 1st band, 1st mode .. so on (the modes > eps_acoustic).

You can take a look at the read_ephmat subroutine.

Regards,
Shashi

[animeshd]

Hi,

Thanks for the information. In EPW5.9, can you tell me which .f90 file has the write_ephmat and read_ephmat subroutines. It does not have the io_eliashberg.f90 file which used to have the ephmat subroutines?

Thanks
Animesh

[Shashi]

Hi Animesh,

In EPWv5.9, you can look at EPW/src/io/io_supercond.f90, it contains write_ephmat and read_ephmat subroutines.

Regards,
Shashi