Yambo Community Forum

Dear developers,

I calculated monolayer black phosphorus with GoWo method and want to plot a band structure with ypp. But when I begin with "ypp -s b -V qp" command and executed the ypp order, the following problem appeared,

<---> [01] CPU structure, Files & I/O Directories
<---> [02] Y(ambo) P(ost)/(re) P(rocessor)
<---> [03] Core DB
<---> :: Electrons : 20.00000
<---> :: Temperature [ev]: 0.000000
<---> :: Lattice factors [a.u.]: 6.23680 21.10044 8.74011
<---> :: K points : 24
<---> :: Bands : 25
<---> :: Symmetries : 4
<---> :: RL vectors : 25539
<---> [04] K-point grid
<---> :: Q-points (IBZ): 24
<---> :: X K-points (IBZ): 24
<---> [05] CORE Variables Setup
<---> [05.01] Unit cells
<---> [05.02] Symmetries
<---> [05.03] RL shells
<---> [05.04] K-grid lattice
<---> [05.05] Energies [ev] & Occupations
<---> [06] Interpolation tool
<---> [06.01] External QP corrections (G)
<---> [QP@G] E<ndb.QP[ PPA XG:153 Xb:1 25 Scb:1 25]
<---> [QP] Kpts covered exactly [o/o]: 100.0000
<01s> Number of K-points in the circuit : 4
<01s> [INTERPOLATION] Number of shells: 255
<01s> [INTERPOLATION] Errors: Max, Avg, Avg_rel = 1.92224979E-06 2.05602390E-07 2.67753944E-06
<01s> [07] Game Over

The ypp.in file is also attached, I hope you can offer some suggestions to solve it, thank you.

Best regards
Tianshu Li
Jilin University

Dear Tianshu,
Can you please specify what kind of problem you are facing? From the standard output you are reporting it seems that
ypp is running until the end of the interpolation and you should find the interpolated bands in the output file.

Best,
Daniele

Dear Daniele,

As you can see, at the end of interpolation, an error message appeared. The o.band_interpolation and o-bands_build.in are exist, but the eigenvalues in o.band_interpolation are different from the results in o-gw.qp, it can be said that the eigenvalues in o.band_interpolation are wrong. So I don't know the cause of this error, is it possible related to some neglect setting for 2D calculation in ypp? I hope you can offer some suggestions. Thank you.



Best regards
Tianshu Li
Jilin University

Dear Tianshu Li,
what you see at the end it is not an error message, but the error in the interpolation, the smaller the better.
The eigenvalues in o-gw.qp are the one you calculated from a regular grid, the interpolation are on a given path,
I presume you can compare just few of them, contained in o-bands_build.in .
In any case ypp has done the interpolation, in some cases it is not very accurate and the algorithm it is not very robust,
we have recently worked on that and soon it will be released a new way to interpolate bands.
If you are not satisfied with the current implementation, you can have a try to the wanner90/yambo interface, how to use it is explained
in this thread.
Finally if you want to upload the input and output files I can have a look in the next days.

Best,

Daniele

Dear Daniele,

I have already solved this problem with ypp. Thank you for your help



Best regards
Tianshu Li
Jilin University