The ABINIT Users Mailing List ( CLOSED )

[Hua Bao <hbao@purdue.edu>]

Dear abinit-user,

I was trying to do geometry optimization of corundum. And it has such 
error message,

symanal : COMMENT -
The Bravais lattice determined only from the primitive
vectors, bravais(1)= 6, is more symmetric
than the real one, iholohedry= 1, obtained by taking into
account the atomic positions.
symspgr : the symmetry operation no. 1 is the identity
symspgr : spgroup= 1 P1 (=C1^1)
getkgrid : length of smallest supercell vector (bohr)= 3.598190E+01
Simple Lattice Grid
getkgrid : BUG -
The argument nkpt= 36, does not match
the number of k points generated by kptopt, kptrlatt, shiftk,
and the eventual symmetries, that is, nkpt= 32.
However, note that it might due to the user,
if nkpt is explicitely defined in the input file.
In this case, please check your input file.
Action : contact ABINIT group.


Is that a bug? What is the best way to sample the k-point of such 
material? And corundum should have a space group 167, why the program 
think it is simply P1?

My input file is as follow,
ionmov 3 # Use the modified Broyden algorithm
ntime 200 # Maximum number of Broyden "timesteps"
tolmxf 5.0d-4 # Stopping criterion for the geometry optimization : when

chkprim 0
xangst
……

toldff 5.0d-5

nband 72
#Definition of the unit cell
acell 4.7602 4.7602 12.9933 angstrom # The keyword "acell" refers to the
angdeg 90 90 120

ntypat 2 #
znucl 13 8 # The keyword "znucl" refers to the atomic number of the


#Definition of the atoms
natom 30
typat 1 1 1 1 1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

#Definition of the planewave basis set
ecut 30.0 # Maximal kinetic energy cut-off, in Hartree

#Definition of the k-point grid
ngkpt 4 4 4
kptopt 1

#Definition of the SCF procedure
nstep 100 # Maximal number of SCF cycles