Yambo Community Forum

Dear Experts

I succeeded with Yambo using YPP when attempting to plot the QP band structure but not with Yambopy. I'm getting the following error when I run Yambopy with the same database which is used for ypp. I attempted using a different compounds, but I ultimately encountered the same issue. However, I tested it with the sample datafiles from the git hub tutorials, and it worked well. I have no idea why every system I test here gives me the same issue. Please assist me in solving this.


valence bands:
slope: 1.0485322565414141
intercept: -0.5751880942862253
r_value: 0.9989934251638968
p_value: 0.0
std_err: 0.0009590458305241883

conduction bands:
slope: 0.941546671218113
intercept: 1.1078789343380597
r_value: 0.9910867631097893
p_value: 0.0
std_err: 0.0025091951541632886
direct dft gap: 0.0
direct qp gap: 0.0
♂scissor list (shift,c,v) [eV,adim,adim]: [0.0, 0.941546671218113, 1.0485322565414141]
404 kpoints expanded to 800
This interpolation is provided by the SKW interpolator implemented in Abipy
[[ 0. 0. 0. ]
[ 0. 0. 0.1 ]
[ 0. 0. 0.2 ]
...
[ 0.5 0.375 -0.19633202]
[ 0.5 0.375 -0.29633203]
[ 0.5 0.375 -0.39633203]]
[[ 0. 0. 0. ]
[ 0. 0. 0.1 ]
[ 0. 0. 0.2 ]
...
[ 0.5 0.375 -0.196332]
[ 0. 0. 0. ]
[ 0.5 0.375 -0.396332]]
Traceback (most recent call last):
File "C:\Users\marri\Desktop\CaTaO2N\ring_8_A2\chain_plot-qp.py", line 53, in <module>
ks_bs, qp_bs = ydb.interpolate(lat,path,what='QP+KS',lpratio=20)
File "C:\Users\pri\anaconda3\lib\site-packages\yambopy-0.2.0-py3.10.egg\yambopy\dbs\qpdb.py", line 246, in interpolate
raise ValueError("The QP database is not consistent with the lattice")
ValueError: The QP database is not consistent with the lattice

Thanks and regards
Priyanka
University of Modena and Reggio Emilia
Italy.

PS: I couldn't attach my files because they are too large.

Dear Priyanka,

What is the bravais lattice type of your system? (ibrav in quantum espresso)
You said you encountered the issue for many systems. Which lattice types have you tried?

In case you used the sample python script provided in the tutorial, keep in mind that the reciprocal-space coordinates for an hexagonal lattice were used in that specific example, and would need to be changed to the lattice type under investigation inside the script.

Finally, in order to reproduce the problem, I would just need the ns.db1 and ndb.QP databases. Is it possible to attach just those two? If they are too heavy to be attached here, you could maybe run a test with a smaller system that still gives the error, and then attach those lighter databases.

Best,
Fulvio

Dear Fulvio

Greetings. Thank you for your response.
Kindly find the attachment of Si system. I'm experiencing the similar error as was previously mentioned. Kindly check and let me know where I'm making mistakes.

Thanks and regards
Priyanka
University of Modena and Reggio Emilia
Italy.

Dear Priyanka,

Indeed, it seems that there is a mismatch between the kpoints obtained at initialization (i.e., the ones stored in ns.db1) and those used for the GW calculation (i.e., the ones stored in ndb.QP). Are you sure that the ndb.QP database was generated on top of the SAVE corresponding to the ns.db1 that you sent? Did you choose custom kpoints in the GW run or used all of them?

By plotting the kpts from the two DBs (see figure) I find the following:
1) different number of kpts in the plane
2) different indexing
3) many repetitions of the gamma point in the ndb.QP file
4) 47 kpoints are present in ns.db1, but only 46 in ndb.QP

This is why the code throws the error you mentioned. Cheers,
Fulvio