ypp: unable to generate bands along high symmetry points

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mirshowkat07
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ypp: unable to generate bands along high symmetry points

Post by mirshowkat07 » Mon Sep 12, 2022 5:53 pm

Dear Yambo Developers/Users

I have done QP calculations in YAMBO. I have followed the Yambo CECAM2021 guidelines.
There was no issue in calculating the QP energies, however when I try to generate the bandstructure with the Yambo using the command.

$ypp -F gw_bands.in -J out.FULL -C BAND_STR
(I have run the QP calculations as
$yambo -F gw_ppa.in -J out.FULL -C HR_out.FULL

)

I am getting the error message as

<---> [01] MPI/OPENMP structure, Files & I/O Directories
<---> [02] Y(ambo) P(ost)/(re) P(rocessor)
<---> [03] Core DB
<---> :: Electrons : 288.0000
<---> :: Temperature : 0.000000 [eV]
<---> :: Lattice factors : 16.17700 16.17700 29.00035 [a.u.]
<---> :: K points : 108
<---> :: Bands : 300
<---> :: Symmetries : 8
<---> :: RL vectors : 1025597
<---> [04] K-point grid
<---> :: Q-points (IBZ): 108
<---> :: X K-points (IBZ): 108
<---> [05] CORE Variables Setup
<---> [05.01] Unit cells
<---> [05.02] Symmetries
<---> [05.03] Reciprocal space
<---> [05.04] K-grid lattice
<---> Grid dimensions : 7 10 10
<---> [05.05] Energies & Occupations
<02s> [06] Interpolation tool
<02s> [06.01] Special Points for the Unknown lattice
<02s> [WARNING]Unknown lattice unit cell
<02s> [06.02] Circuit analyzer/generator
<02s> Number of Q/K-points in the circuit : 133
<02s> [06.03] Interpolation@work: Circuit
<02s> [INTERPOLATION] Number of shells: 1889
<02s> Interpolation@E_K_PATH (star) |########################################| [100%] --(E) --(X)
<02s> Interpolation@E_K_PATH (H fill) |########################################| [100%] --(E) --(X)
<03s> Interpolate@E_K_PATH Fourier |########################################| [100%] --(E) --(X)
<03s> [INTERPOLATION@E_K_PATH] Errors: Max, Avg, Avg_rel = 1.34110451E-06 1.06923054E-07 8.72427656E-04
<03s> Interpolate@E_K_PATH Fourier |########################################| [100%] --(E) --(X)
<03s> [06.04] Fermi Levels
<03s> Fermi Level (BUILT-in bands) : 3.122215 [eV]
<03s> [06.05] Bands output
<03s> Generating output for interpolated bandsforrtl: severe (66): output statement overflows record, unit -5, file Internal Formatted Write
Image PC Routine Line Source
ypp 00000000013690CE Unknown Unknown Unknown
ypp 00000000013A28D1 Unknown Unknown Unknown
ypp 00000000005C1E85 Unknown Unknown Unknown
ypp 000000000066DDD9 Unknown Unknown Unknown
ypp 000000000061B92C Unknown Unknown Unknown
ypp 00000000004985D6 Unknown Unknown Unknown
ypp 000000000042474B Unknown Unknown Unknown
ypp 000000000041DC75 Unknown Unknown Unknown
ypp 0000000000407A6B Unknown Unknown Unknown
ypp 000000000066EC78 Unknown Unknown Unknown
ypp 0000000000405BC5 Unknown Unknown Unknown
libc-2.17.so 00002AEBE3B2CC05 __libc_start_main Unknown Unknown
ypp 00000000004059E9 Unknown Unknown Unknown



I am getting this error only when I try to generate the QP band structure for my own system, which has 32 atoms.
I have run the tutorial for the hBN bulk system where I could generate the QP and LDA band structures successfully.

The report files and input files are attached in a zip folder.

I will be highly grateful for any help.
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Best regards
Showkat Mir
Postdoctoral fellow
Department of Physics
HRI, Allahabad, India-211019

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Daniele Varsano
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Re: ypp: unable to generate bands along high symmetry points

Post by Daniele Varsano » Thu Sep 15, 2022 7:36 am

Dear Showkat,

this is a format error, probably you have too many bands, so the produced files produce too many columns and this is not allowed by the internal format.
Do you need such many bands?
You can reduce the number of bands, considering few bands around the gap in:

Code: Select all

% BANDS_bands
 136 | 154 |                         # Number of bands
% 
If you need all these bands, you can split your calculation in different runs.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

mirshowkat07
Posts: 9
Joined: Wed Sep 19, 2018 11:05 am
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Re: ypp: unable to generate bands along high symmetry points

Post by mirshowkat07 » Sat Sep 17, 2022 5:10 am

Dear Daniele

Thank you for your reply.
I followed your suggestion and was able to generate the quasi-particle band structure with a lesser number of bands,

Code: Select all

%BANDS_bands 
138 | 152
%
 
.

I want to know whether using fewer bands will affect the excitonic spectra, especially when a large number of bands are present near the conduction and valence band edges. I have attached the band structure of the system I am working on for your perusal. Kindly have a look at it.
Also, if one uses the scissor to correct the quasi-particle energies for solving BSE to calculate the excitonic spectra. Will such a procedure affect the final conclusion of the excitonic properties?
You do not have the required permissions to view the files attached to this post.
Best regards
Showkat Mir
Postdoctoral fellow
Department of Physics
HRI, Allahabad, India-211019

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Daniele Varsano
Posts: 3773
Joined: Tue Mar 17, 2009 2:23 pm
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Re: ypp: unable to generate bands along high symmetry points

Post by Daniele Varsano » Sat Sep 17, 2022 7:58 am

Dear Showkat,
I want to know whether using fewer bands will affect the excitonic spectra,
The number of bands to be included in the BSE matrix is one of the parameter that needs to be checked and converged.
This is explained e.g. in this tutorial (https://www.yambo-code.eu/wiki/index.ph ... parameters).

Please note, that this is governed by the %BSEBands namelist and it is not related to the BANDS_bands you use in ypp to interpolate the band structure.
Also, if one uses the scissor to correct the quasi-particle energies for solving BSE to calculate the excitonic spectra. Will such a procedure affect the final conclusion of the excitonic properties?
The scissor operator procedure is an approximation and it is needed to check if it is valid or not, this is really system dependent. You can calculate the QP correction for few bands (k points) and inspect if the scissor+stretching approximation is valid in the energy range you are interested in.
See e.g. the tutorial:
https://www.yambo-code.eu/wiki/index.ph ... rial:_h-BN
in Step 3: Interpolating Band Structures:
by plotting E_qp vs E_ks it is easy to see if a scissor+stretching operator is a good approximation and the scissor/stretching parameter can be extracted.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

mirshowkat07
Posts: 9
Joined: Wed Sep 19, 2018 11:05 am
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Re: ypp: unable to generate bands along high symmetry points

Post by mirshowkat07 » Mon Sep 19, 2022 10:59 am

Dr. Daniele Varsano
Thank you for your quick response.
I have one more question about the discrepancy in the K_PATH length of band structure calculated by QE and YAMBO.
In the attached band structure file, one can see that length of K_Path is from 0 to 4.01 for the one calculated in Yambo with GW- corrections
while the other one has K_Path length ranging from 0 to 3.01 (calculated in QE).

The GW band structure in Yambo is calculated using the CECAM2021 tutorial

Code: Select all

 https://www.yambo-code.eu/wiki/index.php/GW_hBN_Yambo_Virtual_2021_version
The same K-PATH was used for QE calculations by specifying the K_points as

Code: Select all

K_POINTS crystal_b
7
 0.33300 -.66667 0.00000  15
 0.00000 0.00000 0.00000  15
 0.50000 -.50000 0.00000  15
 0.33300 -.66667 0.00000  15
 0.33300 -.66667 0.50000  15
 0.00000 0.00000 0.50000  15
 0.50000 -.50000 0.50000  15
Kindly help me how to solve this problem.
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Best regards
Showkat Mir
Postdoctoral fellow
Department of Physics
HRI, Allahabad, India-211019

User avatar
Daniele Varsano
Posts: 3773
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: ypp: unable to generate bands along high symmetry points

Post by Daniele Varsano » Tue Sep 20, 2022 7:30 am

Dear Showkat,


the best way to spot the problem is to individuate and label high symmetry points in the two calculations.
Actually, it is needed to look at the report/ouput file of the two calculations, as it is not clear what you are actually plotting in abscissa.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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