Yambo Community Forum

Dear all
I am newer to yambo..I install it at fedora 18 and interfaced wit QE 5.0.2. and YAMBO 4.0.0 and YAMBO 4.0.2. It works for the examples given at "http://www.attaccalite.com/quantum-espr ... put-files/ . The code gives result for the above examples. But when I use it for my input file it p2y gives following error.

<---> DBs path set to .
<---> Index file set to data-file.xml
<---> Header/K-points/Energies... done
<---> Cell data... done
<---> Atomic data... done
<---> Symmetries...[SI no]......[-I no]...[TR yes]
<---> XC functional...Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
<---> EXX fraction... 0.000000
<---> EXX screening... 0.000000
<---> K-points mesh... done
<---> RL vectors...

[ERROR]Error in qexml_read_planewaves IOTK error ierr: 2

I dont know where is the error. I am using norm conserving PP.
The inputs are

&CONTROL
calculation='scf',
prefix ='ZnS'
tstress=.f.,tprnfor=.t.,
outdir='./',
pseudo_dir='./'
wf_collect= .true.
/
&SYSTEM
ibrav= 2 ,
celldm(1)= 10.3197,
nat= 2,
ntyp= 2,
ecutwfc=25.0,
ecutrho = 300.0
force_symmorphic=.true.
nosym=.true.,
/
&ELECTRONS
mixing_mode = 'plain'
mixing_beta = 0.6
conv_thr = 1.0d-8
/
ATOMIC_SPECIES
Zn 65.409 Zn.pbe-mt_fhi.UPF
S 32.065 S.pbe-mt_fhi.UPF
ATOMIC_POSITIONS
Zn 0.000 0.000 0.000
S 0.250 0.250 0.250
K_POINTS {automatic}
5 5 5 1 1 1


NSCF

&control
calculation ='nscf'
prefix ='ZnS'
tstress=.f.,tprnfor=.t.,
outdir='./',
pseudo_dir='./'
verbosity='high'
/
&SYSTEM
ibrav= 2 ,
celldm(1)= 10.3197,
nat=2, ntyp= 2,
ecutwfc=25.0,
ecutrho = 300.0
nosym=.true.
nbnd=25
/
&ELECTRONS
diago_thr_init=5.0e-6,
diago_full_acc=.true.
electron_maxstep = 200,
diagonalization='cg'
mixing_mode = 'plain'
mixing_beta = 0.6
conv_thr = 1.0d-8,
/
ATOMIC_SPECIES
Zn 65.409 Zn.pbe-mt_fhi.UPF
S 32.065 S.pbe-mt_fhi.UPF
ATOMIC_POSITIONS
Zn 0.000 0.000 0.000
S 0.250 0.250 0.250
K_POINTS {automatic}
5 5 5 1 1 1

Dear Zafar,

I'll try to reproduce the problem and let you know.
take care
Andrea

BTW: don't forget to add your signature to emails to the forum

Dear Zafar,

the problem turned out to be that you were missing the flag
wf_collect = .TRUE. in the nscf input file.
When this is set everything works fine in my case.

In general note that most of the flags relevant to yambo must be set in the last DFT calculation done
before running yambo (the nscf run, here).

Moreover, a number of QE flags used in scf.in and nscf.in are inconsistent/wrong, such that, at first, I was not even able to converge the scf part.
In particular:
* using a norm-conserving pseudopod ecutrho = 4 * ecutwfc (analytically!)
* ecutwfc = 25 Ry seems very unrealistic for a norm conserving pseudopot (actually 25/300 Ry are standard values for USPP, but not NCPP)
* in my tests using ecutwfc=50Ry made the calculations converging, but I am pretty sure this is not enough to get proper results.
please run detailed convergence tests !!!!!
* force_symmorphic is meaningful only in the nscf part (it is required by yambo, so you don't need it in the scf run)
* not sure it makes sense to specify force_symmorphic=.true. and nosym=.true. together (I would drop nosym)
* mixing_beta = 0.6 is reasonable, but can lead to convergence issues (e.g. 0.3 is safer)

hope it helps
Andrea