About "ERROR FEXCP: supplied Exchange-correletion table is too small"

Message

ichthyornis · #1 Post by **ichthyornis** » Thu Oct 13, 2005 5:23 am

When I doing a calculation for bcc sodium, getting POTCAR file from pot_GGA/Na_pv/ . I was informed of the error message :

ERROR FEXCP: supplied Exchange-correletion table is too small, maximal index : 3875

What should I do to solve this problem? Could anyone give some advice ? Thanks

#2 Post by **admin** » Fri Nov 25, 2005 2:07 pm

please make sure
1) you use the latest VASP release
2) the input geometry (and hence charge density) is reasonable
(interatomic distances should not be too small)

arijit · #3 Post by **arijit** » Wed Jan 18, 2006 5:33 am

I have also encountered a similar problem while carrying out simulated annealing for geometry optimization of clusters. I am using vasp.4.6 and my input geomtery is also reasonable as obtained from MOLDEN (since Gaussian03 gives me an optimized geomtry out of the same initial configuration). While heating upto 300 K in 100 steps each of size 10 fs ( POTIM = 10.0; SMASS = -1), I did not get any error but for heating upto 600 K from 300 K in the following run, I got the following:
------------------------------
RMM: 59 0.469463372110E+03 0.27194E+00 -0.31151E-02 52 0.652E-01 0.620E+00
RMM: 60 0.469333112513E+03 -0.13026E+00 -0.74460E-01 50 0.283E+00
19 T= 357. E= 0.46965614E+03 F= 0.46933311E+03 E0= 0.46930931E+03 EK= 0.32302E+00 SP= 0.00E+00 SK= 0.00E+00
Information: wave function orthogonal band 1 0.2821
Information: wave function orthogonal band 5 0.7532
Information: wave function orthogonal band 7 0.7653
Information: wave function orthogonal band 8 0.8009
Information: wave function orthogonal band 20 0.1647
Information: wave function orthogonal band 21 0.3141
bond charge predicted
prediction of wavefunctions
N E dE d eps ncg rms rms(c)
ERROR FEXCP: supplied Exchange-correletion table
is too small, maximal index : 8229
-----------------------
Could you please help me out in resolving it?
Thanks a lot.

#4 Post by **admin** » Thu Jan 19, 2006 11:17 am

try to see if that error persists if you use the Davidson algorithm for
electronic convergence (IBRION=1) instead

arijit · #5 Post by **arijit** » Fri Jan 20, 2006 11:43 am

Actually, I wanted to carry out simulated annealing for geometry optimization of a cluster of atoms for which I needed to set IBRION=0, TEBEG=300, TEEND=600. My INCAR file was therefore set as follows:
-----
SYSTEM = cluster

Startparameter for this Run:
NWRITE = 2 write-flag & timer
ISTART = 1 job : 0-new 1-cont 2-samecut
LCHARG = .FALSE.

Electronic Relaxation
ENCUT = 250 eV
IALGO = 48
NELMIN = 4
BMIX = 2.0
MAXMIX = 50

ionic relaxation
NSW = 300
NBLOCK = 1
SMASS = -1
POTIM = 10.0
TEBEG = 300
TEEND = 600
--------
The run gets abruptly stopped at T= 357.
Perhaps, I am missing something somewhere while running vasp for simulated annealing. Could you please help me out in finding it? I doubt whether it is possible to accomplish simulated annealing with IBRION=1
Thanks again.

sridevi · #6 Post by **sridevi** » Fri Sep 01, 2006 9:54 pm

I got the same error "ERROR FEXCP: supplied Exchange-correletion table is too small, maximal index : 2147483647".
But when I use IBRION = 1. I do not have any error.
I want to know if it is possible to do MD with IBRION = 1.
thanks in advance.

#7 Post by **admin** » Wed Sep 06, 2006 8:27 am

no, IBRION=0 has to be set to run a MD. POTIM=10.0 is probably too large to ensure that the system keeps on a MD path with reasonable interatomic distances.

USSTVASP · #8 Post by **USSTVASP** » Tue Jul 27, 2010 6:35 am

maybe the source of this error comes from the mix-parameters' improper seting

freshwind · #9 Post by **freshwind** » Fri Feb 14, 2014 4:31 pm

I have encountered a similar error message but during full structure relaxation of a supercell defect structure of an intercalation compound.
I tried also different IBRION with no effect:

ERROR FEXCP: supplied Exchange-correletion table
is too small, maximal index : 362990237

Someone from VASP support wrote to me it is an MPI related problem, so I am supposed to contact my system administrators. However they refer to the discussions in this forum, saying that it therefore cannot be related to MPI, but that it is most probably VASP internal error.
However I get the impression that this problem was not resolved. Can someone enlighten me? Otherwise I am stuck with this calculation.

My INCAR:
PREC = Accurate
GGA = PE
ISTART = 0
ICHARG = 2
ENCUT = 520 eV
ISMEAR = 0
SIGMA = 0.05
ISPIND = 1
ISPIN = 1
EDIFF = 1E-4
EDIFFG = 10E-4
Geom opt
NSW = 100
NELM = 100
IBRION = 2
ISIF = 5
POTIM = 0.4
ADDGRID = .TRUE.
ALGO = Fast
LASPH = .TRUE.
LREAL = Auto
NPAR = 20
NSIM = 4