problem with ypp

[Longjun Xiang]

Dear developers:

I am trying to calculate the GW bandstructure when the spin-orbit coupling is ignored. The ndb.QP database has been obtained and the interpolated LDA bandstructure is OK. But when I perform the GW interpolation for a given path with ypp, I got the following error messages:

[xianglj@head FixSymm]$ ypp -F inputs/03_ypp_gw_band.in -C 03_ypp_gw_band.out



_| _| _|_| _| _| _|_|_| _|_|
_| _| _| _| _|_| _|_| _| _| _| _|
_| _|_|_|_| _| _| _| _|_|_| _| _|
_| _| _| _| _| _| _| _| _|
_| _| _| _| _| _|_|_| _|_|



<---> [01] CPU structure, Files & I/O Directories
<---> [02] Y(ambo) P(ost)/(re) P(rocessor)
<---> [03] Core DB
<---> :: Electrons : 18.00000
<---> :: Temperature [ev]: 0.000000
<---> :: Lattice factors [a.u.]: 5.95264 5.15514 30.00000
<---> :: K points : 64
<---> :: Bands : 100
<---> :: Symmetries : 12
<---> :: RL vectors : 44073
<---> [04] K-point grid
<---> :: Q-points (IBZ): 64
<---> :: X K-points (IBZ): 64
<---> [05] CORE Variables Setup
<---> [05.01] Unit cells
<---> [05.02] Symmetries
<---> [WARNING]Spatial Inversion not found among the given symmetry list
<---> [05.03] RL shells
<---> [05.04] K-grid lattice
<---> [05.05] Energies [ev] & Occupations
<---> [06] Electronic DOS
<---> [06.01] External/Internal QP corrections
<---> E<./SAVE/ndb.QP[ E-E PPA: 27.21138 XG: 109 Xb: 1 100 Scb: 1 100]
<---> [QP_ctl (Nearest K-pt)] Kpts covered exactly [o/o]: 57.81250
<---> [QP_ctl (Nearest K-pt)] Nighbours : 1
<---> [QP_ctl (Nearest K-pt)] Kpts covered [o/o]: 42.18750

[ERROR] STOP signal received while in :[06.01] External/Internal QP corrections
[ERROR]The system contains less than 1 electron

What's the reason and how can I fix this?

(1) DATABASE
[xianglj@head FixSymm]$ yambo -D

[RD./SAVE//ns.db1]------------------------------------------
Bands : 100
K-points : 64
G-vectors [RL space]: 44073
Components [wavefunctions]: 5551
Symmetries [spatial]: 12
Spinor components : 1
Spin polarizations : 1
Temperature [ev]: 0.000000
Electrons : 18.00000
WF G-vectors : 7205
Max atoms/species : 2
No. of atom species : 2
Exact exchange fraction in XC : 0.000000
Exact exchange screening in XC : 0.000000
Magnetic symmetries : no
- S/N 002302 -------------------------- v.04.02.03 r.00127 -
[RD./SAVE//ns.wf]-------------------------------------------
Fragmentation :yes
Bands in each block : 100
Blocks : 1
- S/N 002302 -------------------------- v.04.02.03 r.00000 -
[RD./SAVE//ndb.kindx]---------------------------------------
Fragmentation :no
Polarization last K : 64
QP states : 1 64
X grid is uniform :yes
BS scattering :no
COLL scattering :no
- S/N 002302 -------------------------- v.04.02.03 r.00000 -
[RD./SAVE//ndb.QP]------------------------------------------
Lattice constants : 5.95264 5.15514 30.00000
Coulomb cutoff potential :none
Electronic Temperature [K]: 0.000000
Bosonic Temperature [K]: 0.000000
Green`s function energies :Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
wavefunctions :Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
PPA diel. fun. energies :Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
wavefunctions :Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
QP tot states : 555
GW SC iterations :0
GW solver : Newton
PPA imaginary pt [ev]: 27.21138
GW SC iterations :0
dS/dw steps : 2
dS/dw step [ev]: 0.10000
X G`s [used]: 109
X G`s [disk]: 109
X bands : 1 100
X poles [o/o]: 100.0000
X e/h E range [ev]:-1.000000 -1.000000
X xc-Kernel : none
X BZ energy Double Grid: no
X BZ Double Grid points:0
Sc/G bands : 1 100
Sc/G damping [ev]: 0.10000
Sc bands terminator : no
Sx RL components : 44073
QP @ K 001 - 037 : b 001 - 015
- S/N 002302 -------------------------- v.04.02.03 r.00000 -
[RD./SAVE//ns.kb_pp_pwscf]----------------------------------
Fragmentation :yes
- S/N 002302 -------------------------- v.04.02.03 r.00000 -

(2) INPUT file
#
# /$$ /$$ /$$$$$$ /$$ /$$ /$$$$$$$ /$$$$$$
# | $$ /$$//$$__ $$| $$$ /$$$| $$__ $$ /$$__ $$
# \ $$ /$$/| $$ \ $$| $$$$ /$$$$| $$ \ $$| $$ \ $$
# \ $$$$/ | $$$$$$$$| $$ $$/$$ $$| $$$$$$$ | $$ | $$
# \ $$/ | $$__ $$| $$ $$$| $$| $$__ $$| $$ | $$
# | $$ | $$ | $$| $$\ $ | $$| $$ \ $$| $$ | $$
# | $$ | $$ | $$| $$ \/ | $$| $$$$$$$/| $$$$$$/
# |__/ |__/ |__/|__/ |__/|_______/ \______/
#
# GPL Version 4.2.3 Revision 127. (Based on r.14793 h.bfefd4
# MPI+SLK Build
# http://www.yambo-code.org
#
electrons # [R] Electrons (and holes)
bnds # [R] Bands
cooIn= "rlu" # Points coordinates (in) cc/rlu/iku/alat
BANDS_steps=1 # Number of divisions
% INTERPGrid
-1 |-1 |-1 | # Interpolation BZ Grid
%
ShellFac= 20.00000 # The bigger it is a higher number of shells is used
dos # [R] DOS
%QPkrange # generalized Kpoint/Band indices
1| 64| 4| 14|
%
%BKpts # K points of the bands circuit
0.0000000 | 0.0000000 | 0.0000000 |
0.0166667 | 0.0000000 | 0.0000000 |
0.0333333 | 0.0000000 | 0.0000000 |
0.0500000 | 0.0000000 | 0.0000000 |
0.0666667 | 0.0000000 | 0.0000000 |
0.0833333 | 0.0000000 | 0.0000000 |
0.1000000 | 0.0000000 | 0.0000000 |
0.1166667 | 0.0000000 | 0.0000000 |
0.1333333 | 0.0000000 | 0.0000000 |
0.1500000 | 0.0000000 | 0.0000000 |
0.1666667 | 0.0000000 | 0.0000000 |
0.1833333 | 0.0000000 | 0.0000000 |
0.2000000 | 0.0000000 | 0.0000000 |
0.2166667 | 0.0000000 | 0.0000000 |
0.2333333 | 0.0000000 | 0.0000000 |
0.2500000 | 0.0000000 | 0.0000000 |
0.2666667 | 0.0000000 | 0.0000000 |
0.2833333 | 0.0000000 | 0.0000000 |
0.3000000 | 0.0000000 | 0.0000000 |
0.3166667 | 0.0000000 | 0.0000000 |
0.3333333 | 0.0000000 | 0.0000000 |
0.3500000 | 0.0000000 | 0.0000000 |
0.3666667 | 0.0000000 | 0.0000000 |
0.3833333 | 0.0000000 | 0.0000000 |
0.4000000 | 0.0000000 | 0.0000000 |
0.4166667 | 0.0000000 | 0.0000000 |
0.4333333 | 0.0000000 | 0.0000000 |
0.4500000 | 0.0000000 | 0.0000000 |
0.4666667 | 0.0000000 | 0.0000000 |
0.4833333 | 0.0000000 | 0.0000000 |
0.5000000 | 0.0000000 | 0.0000000 |
0.4944444 | 0.0111111 | 0.0111111 |
0.4888889 | 0.0222222 | 0.0222222 |
0.4833333 | 0.0333333 | 0.0333333 |
0.4777778 | 0.0444444 | 0.0444444 |
0.4722222 | 0.0555556 | 0.0555556 |
0.4666667 | 0.0666667 | 0.0666667 |
0.4611111 | 0.0777778 | 0.0777778 |
0.4555556 | 0.0888889 | 0.0888889 |
0.4500000 | 0.1000000 | 0.1000000 |
0.4444444 | 0.1111111 | 0.1111111 |
0.4388889 | 0.1222222 | 0.1222222 |
0.4333333 | 0.1333333 | 0.1333333 |
0.4277778 | 0.1444444 | 0.1444444 |
0.4222222 | 0.1555556 | 0.1555556 |
0.4166667 | 0.1666667 | 0.1666667 |
0.4111111 | 0.1777778 | 0.1777778 |
0.4055556 | 0.1888889 | 0.1888889 |
0.4000000 | 0.2000000 | 0.2000000 |
0.3944444 | 0.2111111 | 0.2111111 |
0.3888889 | 0.2222222 | 0.2222222 |
0.3833333 | 0.2333333 | 0.2333333 |
0.3777778 | 0.2444444 | 0.2444444 |
0.3722222 | 0.2555556 | 0.2555556 |
0.3666667 | 0.2666667 | 0.2666667 |
0.3611111 | 0.2777778 | 0.2777778 |
0.3555556 | 0.2888889 | 0.2888889 |
0.3500000 | 0.3000000 | 0.3000000 |
0.3444444 | 0.3111111 | 0.3111111 |
0.3388889 | 0.3222222 | 0.3222222 |
0.3333333 | 0.3333333 | 0.3333333 |
0.3222222 | 0.3222222 | 0.3222222 |
0.3111111 | 0.3111111 | 0.3111111 |
0.3000000 | 0.3000000 | 0.3000000 |
0.2888889 | 0.2888889 | 0.2888889 |
0.2777778 | 0.2777778 | 0.2777778 |
0.2666667 | 0.2666667 | 0.2666667 |
0.2555556 | 0.2555556 | 0.2555556 |
0.2444444 | 0.2444444 | 0.2444444 |
0.2333333 | 0.2333333 | 0.2333333 |
0.2222222 | 0.2222222 | 0.2222222 |
0.2111111 | 0.2111111 | 0.2111111 |
0.2000000 | 0.2000000 | 0.2000000 |
0.1888889 | 0.1888889 | 0.1888889 |
0.1777778 | 0.1777778 | 0.1777778 |
0.1666667 | 0.1666667 | 0.1666667 |
0.1555556 | 0.1555556 | 0.1555556 |
0.1444444 | 0.1444444 | 0.1444444 |
0.1333333 | 0.1333333 | 0.1333333 |
0.1222222 | 0.1222222 | 0.1222222 |
0.1111111 | 0.1111111 | 0.1111111 |
0.1000000 | 0.1000000 | 0.1000000 |
0.0888889 | 0.0888889 | 0.0888889 |
0.0777778 | 0.0777778 | 0.0777778 |
0.0666667 | 0.0666667 | 0.0666667 |
0.0555556 | 0.0555556 | 0.0555556 |
0.0444444 | 0.0444444 | 0.0444444 |
0.0333333 | 0.0333333 | 0.0333333 |
0.0222222 | 0.0222222 | 0.0222222 |
0.0111111 | 0.0111111 | 0.0111111 |
0.0000000 | 0.0000000 | 0.0000000 |
%

(3) INPUT file for ndb.QP
[xianglj@head inputs]$ cat 02_gw_ppa.in
#
# ** ** ** **** **** ****** *******
# //** ** **** /**/** **/** /*////** **/////**
# //**** **//** /**//** ** /** /* /** ** //**
# //** ** //** /** //*** /** /****** /** /**
# /** **********/** //* /** /*//// **/** /**
# /** /**//////**/** / /** /* /**//** **
# /** /** /**/** /** /******* //*******
# // // // // // /////// ///////
#
# GPL Version 4.2.3 Revision 127. (Based on r.14793 h.bfefd4
# MPI+SLK Build
# http://www.yambo-code.org
#
ppa # [R Xp] Plasmon Pole Approximation
gw0 # [R GW] GoWo Quasiparticle energy levels
HF_and_locXC # [R XX] Hartree-Fock Self-energy and Vxc
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
NLogCPUs=0 # [PARALLEL] Live-timing CPU`s (0 for all)
PAR_def_mode= "balanced" # [PARALLEL] Default distribution mode ("balanced"/"memory"/"workload")
X_all_q_CPU= "3 2 2 2" # [PARALLEL] CPUs for each role
X_all_q_ROLEs= "k q v c" # [PARALLEL] CPUs roles (q,k,c,v)
X_all_q_nCPU_LinAlg_INV=4 # [PARALLEL] CPUs for Linear Algebra
SE_CPU= "2 4 3" # [PARALLEL] CPUs for each role
SE_ROLEs= "q qb b" # [PARALLEL] CPUs roles (q,qp,b)
EXXRLvcs= 44073 RL # [XX] Exchange RL components
Chimod= "" # [X] IP/Hartree/ALDA/LRC/BSfxc
% BndsRnXp
1 | 100 | # [Xp] Polarization function bands
%
NGsBlkXp= 100 RL # [Xp] Response block size
% LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
% GbndRnge
1 | 100 | # [GW] G[W] bands range
%
GDamping= 0.10000 eV # [GW] G[W] damping
dScStep= 0.10000 eV # [GW] Energy step to evaluate Z factors
DysSolver= "n" # [GW] Dyson Equation solver ("n","s","g")
%QPkrange # [GW] QP generalized Kpoint/Band indices
1| 37| 1|15|
%

[Daniele Varsano]

Dear Longjun Xiang,
in your ypp input file, you should provide the high symmetry points of your path and the number of step you want in the segment connecting two high symmetry point e.g.

BANDS_steps=20
%BKpts
0.0000000 | 0.0000000 | 0.0000000 |
0.5000000 | 0.0000000 | 0.0000000 |
0.5000000 | 0.5000000 | 0.0000000 |
0.0000000 | 0.0000000 | 0.0000000 |
%

Next, it seems ypp get confused with the position of the Fermi level, in order to understand the reason it would desirable to have a look at the report file of your GW calculation. Next, in %QPkrange I would include just few bands across the Fermi level.

Best,
Daniele

[Longjun Xiang]

Thanks for your reply. According to your advice, I have attached the report file of GW calculation and the input file of ypp run.

[Daniele Varsano]

Dear Longjun Xiang,
as I wrote in the previous post the input file for ypp should be changed indicating the high symmetry points and then umber of steps included in each segment. Moreover, now you have BANDS_steps=0 which probably prevent to have the interpolation done. Looking at your report it seems to me that there is some problem in the GW calculation, you have a very large HF correction and most importantly a Z factor differing substantially from 1. I do not know it this is due to lack of convergence or other. For reference, input parameters etc, you can have a look at this paper: PHYSICAL REVIEW B 88, 045412 (2013)

I suggest you check your convergence repeating the calculation for a few bands in high symmetry points (e.g. gamma and K).
%QPkrange # [GW] QP generalized Kpoint/Band indices
1| 1| 8| 11|
37 | 37 | 8 |11
%

This will make you save a lot of computer time, moreover, usually, the bands of interests are the bands around Fermi.
Other suggestion is to parallelize over bands and not over q points, e.g. something like:
X_all_q_CPU= "1 1 2 12" # [PARALLEL] CPUs for each role
X_all_q_ROLEs= "k q v c" # [PARALLEL] CPUs roles (q,k,c,v)
SE_CPU= "1 4 6" # [PARALLEL] CPUs for each role
SE_ROLEs= "q qb b" # [PARALLEL] CPUs roles (q,qp,b)


Best,
Daniele