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ERROR FEXCP: supplied Exchange-correletion table

Posted: Mon Feb 08, 2021 1:23 pm
by gus.hart
The error has occurred with a handful of binary/ternary structures, ideal fcc supercells, with atoms on ideal lattice sites (Ni, Ti, and Hf). The volumes are slightly larger than the fully relaxed case (slightly negative pressures). The first ionic step runs fine, but at the beginning of the second, the error is triggered.

It must be related to symmetry because if I distort the unit cell slightly, the error goes away (but this is an inefficient solution as many more kpoints are then needed...).

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MLIP output to VASP                     
     1.6569974008899999    1.6569974008899999   -1.6569974008899999
    -1.6569974008899999    4.9709922026699997    1.6569974008899999
     1.6569974008899999    1.6569974008899999    4.9709922026699997
   Hf   Ni
     1     3
  0.0000000000000000  0.0000000000000000  0.0000000000000000
  0.5000000000000000  0.5000000000000000  0.0000000000000000
  0.0000000000000000  0.5000000000000000  0.5000000000000000
  0.5000000000000000  0.0000000000000000  0.5000000000000000
And my INCAR:

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And this is the output:

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 running on    2 total cores
 distrk:  each k-point on    2 cores,    1 groups
 distr:  one band on    2 cores,    1 groups
 using from now: INCAR     
 vasp. (build Nov 06 2019 09:29:44) complex          
 POSCAR found type information on POSCAR  Hf Ni
 POSCAR found :  2 types and       4 ions
 scaLAPACK will be used
 LDA part: xc-table for Pade appr. of Perdew
 POSCAR, INCAR and KPOINTS ok, starting setup
 FFT: planning ...
 WAVECAR not read
 entering main loop
       N       E                     dE             d eps       ncg     rms          rms(c)
DAV:   1     0.513267535195E+03    0.51327E+03   -0.33640E+04 53504   0.162E+03
DAV:   2     0.383616667962E+01   -0.50943E+03   -0.50070E+03 41624   0.541E+02
DAV:   3    -0.260244998308E+02   -0.29861E+02   -0.28259E+02 52710   0.123E+02
DAV:   4    -0.277637185265E+02   -0.17392E+01   -0.16493E+01 49250   0.237E+01
DAV:   5    -0.278418422729E+02   -0.78124E-01   -0.71411E-01 50104   0.440E+00    0.529E+01
DAV:   6    -0.397461630533E+02   -0.11904E+02   -0.10367E+02 50790   0.100E+02    0.421E+01
DAV:   7    -0.250291518641E+02    0.14717E+02   -0.76993E+01 50870   0.732E+01    0.212E+01
DAV:   8    -0.246432029168E+02    0.38595E+00   -0.33468E+00 47366   0.122E+01    0.870E+00
DAV:   9    -0.246574552460E+02   -0.14252E-01   -0.18537E-01 55642   0.241E+00    0.865E+00
DAV:  10    -0.246606150554E+02   -0.31598E-02   -0.24144E-01 56844   0.378E+00    0.285E+00
DAV:  11    -0.246514367564E+02    0.91783E-02   -0.11175E-02 43710   0.687E-01    0.215E+00
DAV:  12    -0.246310467136E+02    0.20390E-01   -0.59750E-02 58002   0.111E+00    0.579E-01
DAV:  13    -0.246320279035E+02   -0.98119E-03   -0.46513E-03 53366   0.372E-01    0.490E-01
DAV:  14    -0.246314370311E+02    0.59087E-03   -0.77332E-04 53298   0.191E-01    0.411E-01
DAV:  15    -0.246313580610E+02    0.78970E-04   -0.90609E-05 54460   0.480E-02
   1 F= -.24631358E+02 E0= -.24631360E+02  d E =-.246314E+02
 BRION: g(F)=  0.756E-57 g(S)=  0.115E+02
 bond charge predicted
       N       E                     dE             d eps       ncg     rms          rms(c)
 ERROR FEXCP: supplied Exchange-correletion table
    is too small, maximal index :        3866

Re: ERROR FEXCP: supplied Exchange-correletion table

Posted: Wed Feb 10, 2021 10:27 pm
by henrique_miranda
I am not able to reproduce this issue locally.
Could you attach the OUTCAR as well?
In particular, I want to check which POTCARS you are using as well as the section 'exchange correlation table'.

Re: ERROR FEXCP: supplied Exchange-correletion table

Posted: Thu Feb 11, 2021 10:29 am
by gus.hart
Attached are the requested files

Re: ERROR FEXCP: supplied Exchange-correletion table

Posted: Fri Feb 12, 2021 5:56 pm
by henrique_miranda
Ah, ok now I can reproduce the issue.
I tried with different pseudopotentials: PAW_PBE Hf and PAW_PBE Ni.
You are using: PAW_PBE Hf_pv and PAW_PBE Ni_pv.

Anyway, this issue was already reported in a previous thread:

In this particular case, I also have to point out that when performing ionic relaxations where the cell volume is allowed to change it is recommended to use a larger cutoff than the one specified in the POTCAR:
(see note at the very end)

Setting ENCUT=400 seems to solve the issue.
Note however that this might be just because the stress is computed more accurately in the first step and the volume change is not so large.
If you find a case where increasing the cutoff does not solve the issue please report back to us.

Hope this helps!