Hello,
I am doing shearing calculations for Aluminum with 12 layers. The shear is implemented by tilting the lattice vector normal to the layers. For most shears, I can use a kpoint mesh such as 16x16x4. However for a couple of shears I get the following error:
VERY BAD NEWS! internal error in subroutine IBZKPT:
Reciprocal lattice and k-lattice belong to different class of lattices.
The number of times this appears is equal to the number of CPUs that I am running. This is odd since the shears that have no errors have the same symmetry as the ones that do have the errors. I have tried this calculation with ISYM=0 and I still receive this error. So can the error be ignored?
I have also tried odd meshes and the error still appears. A kmesh that works is NxNxN mesh, such as 16x16x16. This however is a much larger mesh than needed. Is there any way to get around this?
INCAR:
SYSTEM = C
restart settings
ISTART = 0
ICHARG = 2
output settings
LCHARG = T
LWAVE = .FALSE.
LORBIT=10
settings for parallel version (ignored in serial run)
NPAR = 1 how many bands in parallel
LPLANE = .TRUE. distribute each wave over processors
Electronic Relaxation 1
ENCUT = 350
PREC = High
EDIFF = 1E-06
IALGO = 48
Ionic Relaxation
IBRION = -1
ISIF = 2
NSW = 0
EDIFFG = -1E-02
Symmetry settings
ISYM = 0
SYMPREC = 0.0001
DOS related values:
ISMEAR = 1 -4-tet -1-fermi 1=Methfessel/Paxton 1.order
SIGMA = 0.1 broadening in eV
VERY BAD NEWS! internal error in subroutine IBZKPT
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VERY BAD NEWS! internal error in subroutine IBZKPT
Last edited by sergio on Mon Aug 02, 2010 5:39 pm, edited 1 time in total.
VERY BAD NEWS! internal error in subroutine IBZKPT
I contacted VASP support directly and they said to do the following:
1) Decrease SYMPREC to 1e-8. This will get rid of the errors but not always.
2) Turning off the symmetry, one does not need to be bothered about the message
1) Decrease SYMPREC to 1e-8. This will get rid of the errors but not always.
2) Turning off the symmetry, one does not need to be bothered about the message
Last edited by sergio on Thu Aug 26, 2010 5:55 pm, edited 1 time in total.