How to obtain dielectric function from BSE calculation?

[yunhailiseu]

Dear All,

Does anyone know how to obtain the dielectric function from a BSE calculation using yambo-4.0.x? For yambo prior to 4.0.x the o.eel_xxx and o.eps_xxx files are generated directly after BSE calculation, but it not the case for 4.0.x. Has this feature been removed, or migrated to ypp?

By the way, it seems that the interpolation method is not supported by yambo-4.0.2, as the ypp program cannot recognize the -r flag. By invoking ypp with -H it shows that this flag is absent.

Any suggestions are appreciated.

Best,
Yunhai Li

[Daniele Varsano]

Dear Yunhai Li,
Yambo 4.x as the previous releases, calculate the dielectric function and the output is in o.eps o.eel.
Did you add the BSE solver options in your input file? (yambo -y d, or yambo -y h) depending if you want to diagonalize the BSE matrix or solve it with iterative methods.
If you already did it, it means something went wrong, please post your input/report files.
Best,
Daniele

[yunhailiseu]

Dear Yunhai Li,
Yambo 4.x as the previous releases, calculate the dielectric function and the output is in o.eps o.eel.
Did you add the BSE solver options in your input file? (yambo -y d, or yambo -y h) depending if you want to diagonalize the BSE matrix or solve it with iterative methods.
If you already did it, it means something went wrong, please post your input/report files.
Best,
Daniele

Dear Daniele,

Thank you for the quick reply.

I have checked the input file generated by yambo-4.0.2.r96 and yambo-3.4.2.r93 and find that the one generated by 4.0.2 does not contain the flags specifying the BSE solver even if -V all is appended to the command line. That is, bss and BSSmod are not included in the automatically generated input. Once they are added to the input manually the o.eps and o.eel files are successfully generated.

Possibly a bug?

Best,
Yunhai Li

[Daniele Varsano]

Dear Yunhai Li,

Possibly a bug?

No, it is not a bug. The -V controls the verbosity of the input file. (-V all) include all the option variables. The solver (bss) is a runlevel and BSSmod is a mandatory variable, so they are not controlled by the verbosity. You do not need to add by hand, but you can generate them by using the -y <option> command line when generating the input file.

Typing:
yambo -H

you have the description of the possible options.

Best,

Daniele

[yunhailiseu]

Dear Yunhai Li,

Possibly a bug?

No, it is not a bug. The -V controls the verbosity of the input file. (-V all) include all the option variables. The solver (bss) is a runlevel and BSSmod is a mandatory variable, so they are not controlled by the verbosity. You do not need to add by hand, but you can generate them by using the -y <option> command line when generating the input file.

Typing:
yambo -H

you have the description of the possible options.

Best,

Daniele

Dear Daniele,

Well, I am sure that I have invoked yambo with the "-y d" option. In fact, the same set of command line parameters works well for yambo-3.4.2, but not for 4.0.2.

In the attachment there are the configuration script for compiling yambo and the input files for this run.

Best,
Yunhai Li