EPW Forum

Hi, I am trying to calculate the shortrange electron-phonon matrix elements using EPW. Once the run is completed the ephmat files are generated. I understand that the files are in binary format. Is there any way to convert the files into text format so that I can open them to see the contents of the file?

It would be great if someone could provide some information on this.

Thanks

Hi,

The ephmat file is written in binary because if it is written as a text file then it's size will be quite large.
A good idea would be to read the ephmat files directly as binary instead of trying to convert it into a text file.

You can use subroutine "read_ephmat()" in EPW/src/io_eliashberg.f90 for inspiration on reading the binary file.

Best,
Sabya.

Hi,

Thank you for the clarification. But is there a way to change the output format? I will calculate on a coarse grid to check the format of the file and then while using a dense grid, I will use the binary format of the file so that memory is not a problem.

Thanks
Animesh

Hi Animesh,

We do not provide an option to change the file format, so you have to modify "write_ephmat()" in EPW/src/io_eliashberg.f90 to change the format yourself.

Best,
Hitoshi

Hi,

Should I change the "FORM = 'unformatted'" to "FORM = 'formatted'" in OPEN()?
I notice that there are !OPEN(FORM = 'formatted') before or after the OPEN(FORM = 'unformatted').
Since I have no experience in Fortran, Could you give me some advices?

Best,
John

Hi John,

Yes, you can change the format to human-readable one by changing "FORM = 'unformatted'" to "FORM = 'formatted'".
Note that the file size may become larger than that of the binary format.

Best,
Hitoshi

Hi,

After using the ephwrite tag in EPW, it generates the ephmat files, egnv and the freq file. It would be great if someone could tell me what is the unit of phonon frequency used in the freq file?

Hi Animesh,

The unit of phonon frequency used in the freq file in Ry. But while reading_ephmat we convert freq to eV unit.

regards,
Shashi