The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear Sun ShaoRui,

The value of dilatmx that you use (200) is extraordinarily large ...
You should likely use something like dilatmx 1.05 for your cell optimisation,
with a reasonable starting acell and rprim. It is likely that you had in mind
setting ntime to 200 ...

Xavier

Sun ShaoRui wrote:
> Dear all:
>      When I calculate the SnO2 with rutile structure, the abinis program 
> stopped with a bug information occurring in the log files.
>      the input file is shown as follows:
> ------------------------------------------------------------------
> ndtset 1 
> dilatmx 200
> optcell 2
> ionmov 3
> ecutsm  0.5 
> #Definition of the k-point grids
> kptopt 1          # Option for the automatic generation of k points, 
> taking
>                   # into account the symmetry
> nshiftk 1
> shiftk  0.5 0.5 0.5  # These shifts will be the same for all grids
>
> ngkpt  5 5 5      # Definition of the different grids
> #Definition of the unit cell
> acell 8.94937 8.94937 6.01897  
>
>         
> spgroup 136
> brvltt -1
> natrd   2
> #Definition of the atom types
> ntypat 2          # There is only one type of atom
> znucl 50 8        # The keyword "znucl" refers to the atomic number of the 
>                   # possible type(s) of atom. The pseudopotential(s) 
>                   # mentioned in the "files" file must correspond
>                   # to the type(s) of atom. Here, the only type is 
> Silicon.
>                          
>
> #Definition of the atoms
> natom 6           # There are two atoms
> typat 1 2 
> xred             # This keyword indicate that the location of the atoms
>                   # will follow, one triplet of number for each atom
>    0.0000  0.0000  0.0000  # Triplet giving the REDUCED coordinate of atom 
> 1.
>    0.3053  0.3053  0.0000
> #Definition of the planewave basis set
> ecut  10.0         # Maximal kinetic energy cut-off, in Hartree
> nband 16
> diemac 8.0
>
>
> #Definition of the SCF procedure
> nstep 20          # Maximal number of SCF cycles
> toldfe 1.0d-10
> ----------------------------------------------------------------
> and the bug information in the log file is shown as follows:
> ---------------------------------------------------------------
> DATASET    1 : space group P4_2/m n m (#136); Bravais tP (primitive 
> tetrag.)
>  getkgrid : length of smallest supercell vector (bohr)=    3.009485E+01
>        Simple Lattice Grid
>  symkpt : found identity, with number  1
>
>  inkpts : istwfk preprocessed, gives following first values (max. 6): 1 1 
> 1 1 1 
> 1
>  chkneu : initialized the occupation numbers for occopt=    1
>     spin-unpolarized case :
>   2.00  2.00  2.00  2.00  2.00  2.00  2.00  2.00  2.00  2.00  2.00  2.00
>   2.00  2.00  2.00  2.00
>
>  getng : BUG -
>   ngfft is bigger than allowed value =        2048.
>   This indicates that desired ngfft is larger than getng
>   can handle. The code has to be changed and compiled.
>
>  leave_new : decision taken to exit ...
> FORTRAN STOP  1
> ---------------------------------------------------------------
>   I also calculated the SnO with 129 spacegroup, and met the same problem.
>   Who could help me to solve it? Any comments are appreciated.
>   Thanks in advances!
>                                                yours S. R.Sun