Yambo Community Forum

Dear developer,
I would like to reproduce the result of Linear response in real time for hBN. I followed the following step (as given in Lumen tutorials) to get the result,

step1: pw.x
step2: p2y
step3: yambo_rt (set up run for real time)
step4: ypp_rt -y (To reduce the symmetry), then I run ypp_rt, thereby the folder Fixsymm is created
step5: yambo_rt is executed inside the Fixsymm.
step6: yambo_nl -u to calculate linear response in real time. this run produces a input file as follows,

nloptics # [R NL] Non-linear optics
% NLBands
3 | 6 | # [NL] Bands
%
NLverbosity= "low" # [NL] Verbosity level (low | high)
NLtime=-1.000000 fs # [NL] Simulation Time
NLCorrelation= "IPA" # [NL] Correlation ("IPA/HARTREE/TDDFT/LRC/LRW/JGM/SEX")
NLLrcAlpha= 0.000000 # [NL] Long Range Correction
% NLEnRange
0.200000 | 8.000000 | eV # [NL] Energy range
%
NLEnSteps= 80 # [NL] Energy steps
NLDamping= 0.200000 eV # [NL] Damping
NLGvecs= 6021 RL # [NL] Number of G vectors in NL dynamics for Hartree/TDDFT
% ExtF_Dir
1.000000 | 0.000000 | 0.000000 | # [NL ExtF] Versor
%

When I run the calculation with the command yambo_nl,
I got the error message,

ERROR] STOP signal received while in :[03.01] Initialization
[ERROR] Non-linear optics works only in double precision, configure with --enable-dp flag
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0.

I have installed yambo 4.4.0. Could you tell me the steps to be followed for rela time calculation.

Dear Bramhachari Khamari

this problem is easy to solve.
Normally Yambo is compiled in single precision, but non-linear response requires double precision to work.
In order to compile yambo in double precision
go in the yambo folder, do

make distclean

reconfigure yambo and add the flag --enable-dp to the configure

./configure --enable-dp

recompile all executables.
And now you can run the non-linear optics simulations

best
Claudio

Dear Sir,
Thank you for the reply.

Regards,
Bramha