Yambo Community Forum

Dear Sir,

I am getting this error while doing bse calculation:

CpuTiming [Min/Max/Average]: 18h-15m-13s/18h-15m-13s/18h-15m-13s

[06] Response Functions in Transition space
===========================================


[06.01] Transition Groups build-up
==================================

[BSK] Transition groups (total) 116

[06.02] CPU-dependent Block structure
=====================================

my input file is as follows:
#
# ** ** ** **** **** ****** *******
# //** ** **** /**/** **/** /*////** **/////**
# //**** **//** /**//** ** /** /* /** ** //**
# //** ** //** /** //*** /** /****** /** /**
# /** **********/** //* /** /*//// **/** /**
# /** /**//////**/** / /** /* /**//** **
# /** /** /**/** /** /******* //*******
# // // // // // /////// ///////
#
# GPL Version 4.1.2 Revision 120
# Serial Build
# http://www.yambo-code.org
#
BS_CPU= "1 30 2" # [PARALLEL] CPUs for each role
BS_ROLEs= "k eh t" # [PARALLEL] CPUs roles (k,eh,t)
BS_nCPU_invert= 4 # [PARALLEL] CPUs for matrix inversion
BS_nCPU_diago= 4 # [PARALLEL] CPUs for matrix diagonalization
optics # [R OPT] Optics
bss # [R BSS] Bethe Salpeter Equation solver
ppa # [R Xp] Plasmon Pole Approximation
bse # [R BSE] Bethe Salpeter Equation.
bsk # [R BSK] Bethe Salpeter Equation kernel
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
Chimod= "Hartree" # [X] IP/Hartree/ALDA/LRC/BSfxc
BSEmod= "retarded" # [BSE] resonant/retarded/coupling
BSKmod= "SEX" # [BSE] IP/Hartree/HF/ALDA/SEX
BSSmod= "d" # [BSS] (h)aydock/(d)iagonalization/(i)nversion/(t)ddft`
BSENGexx= 57 Ry # [BSK] Exchange components
BSENGBlk= 1 RL # [BSK] Screened interaction block size
#WehCpl # [BSK] eh interaction included also in coupling
KfnQPdb= "E < gw0_output2/ndb.QP" # [EXTQP BSK BSS] Database
KfnQP_N= 1 # [EXTQP BSK BSS] Interpolation neighbours
% KfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP BSK BSS] E parameters (c/v) eV|adim|adim
%
KfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP BSK BSS] Z factor (c/v)
KfnQP_Wv_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (valence)
% KfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (valence) eV| eV|eV^-1
%
KfnQP_Wc_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (conduction)
% KfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (conduction) eV| eV|eV^-1
%
% BEnRange
0.00000 | 10.00000 | eV # [BSS] Energy range
%
% BDmRange
0.10000 | 0.10000 | eV # [BSS] Damping range
%
BEnSteps= 100 # [BSS] Energy steps
% BLongDir
1.000000 | 0.000000 | 0.000000 | # [BSS] [cc] Electric Field
%
% BSEBands
10 | 60 | # [BSK] Bands range
%
XfnQPdb= "none" # [EXTQP Xd] Database
XfnQP_N= 1 # [EXTQP Xd] Interpolation neighbours
% XfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP Xd] E parameters (c/v) eV|adim|adim
%
XfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
XfnQP_Wv_E= 0.000000 eV # [EXTQP Xd] W Energy reference (valence)
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV| eV|eV^-1
%
XfnQP_Wc_E= 0.000000 eV # [EXTQP Xd] W Energy reference (conduction)
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV| eV|eV^-1
%
% BndsRnXp
1 | 100 | # [Xp] Polarization function bands
%
NGsBlkXp= 1 RL # [Xp] Response block size
% LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy

Please help me rectify this error.

Dear Himanim,

I am not sure of what can be the error but you are using a lot of BSEBands... Probably you have a memory problem.

The convergence of this parameter must be done carefully, starting with smaller values and increasing BSEBands gradually.

Cheers,

Alejandro.

Dear Himanim,
please first let me ask you to add your full name and affiliation in your signature, this is a rule of the forum. You can do once for all adding it in your user profile.

As Alejandro wrote you it could be a memory error, but also other source o error can be present. In order to spot the problem can you upload your input file, report file and one of the log files present in the LOG directory? In this way we can check dimensions, compatibility with the parallel structures etc..
Please upload them instead of copy/paste as in this way it is easier for us to navigate into the file. When uploading them in some case you need to rename the file for instance as .txt, or simply you can zip the files and upload just one file.
Finally please note that setting BSENGBlk/NGsBlkXp = 1 RL you are essentially discarding electron-hole attraction and you are doing a sort of
RPA calculation instead of a BSE.

Best,

Daniele

Dear sir,

I have done the BSE calculation again but it is producing errors. I have attached my input and output file.
Can you please help me with this?

Regards,
Himani Mishra
Research Scholar
IIIT Allahabad

Dear Himani,

as you can see at the end of your report: This is because you included only occupied states into the BSE, so no transitions.
The dimension of the BSE is Nk x Nc x Nv (number of kpoints times number of valence bands times number of conduction bands)
As you can see from the report you have 52 occupied states and you need to include at least 1 empty states.
you have: which are both occupied.
Consider few states across the gap: and enlarge the windows until convergence.

Best,
Daniele

Dear sir,

i have done the necessary correction as directed by you but still getting error. Can you tell me what is still wrong???

I am attaching the input and output file.

Dear Himani,

please fill the signature in your profile: in this way you do need to remeber to write it in each post.
About your problem, as you can see at the end of the report there is an incompatibility in your input file for the screening matrix.
you calculated in a previous run.
Screening read (RD) from a previous stage of the run.
Here you asked for just 1 G vector in the dielectric matrix: see also in your input: but then in your input you are asking for 111 components. The BSENGBlk should be less or equal to NGsBlkXp.
Of course if you ask just 1 components mot probably this will be out of convergence.
As a tip: screening calculated by ppa is usually used if you have ppa screening already calculated from a GW calculations, otherwise if you need to calculate it from scratch you can calculate a static screening (em1s) (yambo -b), this is faster as you need to calculated for 1 frequency only (zero frequency) while in PPA it is also calculated at the plasma frequency.

Best,

Daniele

Dear Sir,

Thank you so much with your support i got results.
Now i want to plot the absorption spectra of the material but i have got three files. One is having the density of states. For the other two i am not understanding what they stand for? o-bse_out.eel_q1_diago_bse
o-bse_out.eps_q1_diago_bse

What this eel and eps stand for?

Dear Himanim,

eps is macroscopic dielectric function. the absorption is proportional to the imaginay part (2nd column).
eel is the electron energy loss function.
All this is explained in the tutorials present in the webpage, I strongly invite you to take a tour.

Best,

Daniele