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Hi,

I get quite often the following error message:

VERY BAD NEWS! internal error in subroutine IBZKPT:
Reciprocal lattice and k-lattice belong to different class of lattices. 168

In the KPOINTS file I require a regular Monkhorst-Pack grid:

0
Monkhorst-Pack
2 4 6
0 0 0

I would understand this error if I would explicitely impose a k-point grid which would be incompatible which the crystal structure. But this is not the case... Additionally, symmetry is switched off using ISYM=0.


What does cause this error/warning and how can it be avoided? Or, does it simply mean that the k-point grid would have a higher symmetry than C_1 which is imposed by ISYM=0?

Thanks

for some hexagonal and low-symmetry lattice types the symmetrisation of the k-points sometimes leads to errors like these if even k-meshes are used.
there are two ways to get rid of that problem
1) use odd k-meshes
2) switch off all symmetrisation
please also have a look at the k-points.pdf file of the vasp-workshop
(http://cms.mpi.univie.ac.at/vasp-workshop) for further details

Returning to this point, I have this problem also. Switching off symmety with ISYM = 0 does not make the warnings go away. I assume though in that case the warnings are meaningless? Why are they still printed?