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[<ilukacevic@fizika.unios.hr>]

Dear all!

I'm having a problem while trying to calculate the elastic constants of
silicons beta-Sn phase at the pressure of 12GPa. I have converged all the
parameters for both relaxation and response function calculation. Ecut, ngkpt,
tsmear and ecutsm are kept the same during these two calcs. 
However, the rf calc keeps to abort ecause of an error at the beginning of
dataset 3:

 getcut: wavevector=  0.0000  0.0000  0.0000  ngfft=  45  45  45
         ecut(hartree)=     50.000   => boxcut(ratio)=   2.08080
-P-0000  leave_test : synchronization done...
 mkrho: loop on k-points and spins done in parallel
 Total charge density [el/Bohr^3]
,     Maximum=    7.4874E-02  at reduced coord.    0.8889    0.7111    0.8222
,     Minimum=    1.1366E-02  at reduced coord.    0.0000    0.0000    0.0000
-P-0000  leave_test : synchronization done...
 symkchk : found identity, with number  1
 symkchk : ERROR -
   k-point set must have full space-group symmetry
   there is no match for kpt   1 transformed by symmetry   3
   Action : change kptopt to 2 or 3 and/or change or use shiftk
            shiftk = 0 0 0 is always a safe choice.
-P-0000
-P-0000  leave_new : decision taken to exit ...


It is strange to me, because I've already calculated a number of these (at
different pressures, with these kptopt and shiftk = 0.5 0.5 0.5) and never has
this error occured.
Has anyone encountered this error before? Could someone give me a hint why 
this
occurs?

Input file is given below.

I'm using abinit 5.8.4 on a linux set cluster.

Thank you all in advance!

Igor Lukacevic


#Si beta-Sn (tetragonal) structure
#Response function calculation for:
#    * rigid-atom elastic tensor
#    * rigid-atom piezoelectric tensor
#    * interatomic force constants at gamma


   ndtset   3

# Set 1 : Initial self-consistent run
#dilatmx   1.2
    iscf1   5
  kptopt1   1
  tolvrs1   1.0d-20  #need excellent convergence of GS quantities for RF runs


# Set 2 : Calculate the ddk wf's - needed for piezoelectric tensor and

  getwfk2  -1
    iscf2  -3        #this option is needed for ddk
  kptopt2   2        #use time-reversal symmetry only for k points
    nqpt2   1        #one wave vector will be specified
     qpt2   0 0 0    #need to specify gamma point
  rfelfd2   2        #set for GS ddk wf's only
   rfdir2   1 1 1    #full set of directions needed
  tolwfr2   1.0d-16  #only wf convergence can be monitored here

# Set 3 : response-function calculations for all needed perturbations

  getddk3  -1
  getwfk3  -2
    iscf3   5
  kptopt3   2        #use time-reversal symmetry only for k points
    nqpt3   1
     qpt3   0 0 0
  rfphon3   1        #do atomic displacement perturbation
 rfatpol3   1 2      #do for all atoms
  rfstrs3   3        #do strain perturbation
   rfdir3   1 1 1    #use symmetry ???
#  rfelfd3   3        #set for ddk wf's only
  tolvrs3   1.0d-14  #need reasonable convergence of 1st-order quantities

# Common input data
# acell...taken from the struct. relax. calc.
# pressure 12 GPa

    acell   2*8.778490928768713131  4.746093721018639149

# Space group info
  spgroup   141
   angdeg   90 90 90
   brvltt  -1
# chkprim   0

# Definition of the atom types and atoms
 ntypat   1
  znucl   14
  natom   2
  typat   1 1

# xred  COPY RELAXED RESULT FROM PREVIOUS CALCULATION
# Si - fixed xred for symmetry reasons
   xred  0   0    0
         0   0.5  0.25

#Gives the number of bands, explicitely (do not take the default)
  nband  8               # For an insulator (if described correctly as an
                         # insulator by DFT), conduction bands should not
                         # be included in response-function calculations
 occopt  4
 tsmear  0.05

#Definition of the plane wave basis set
   ecut  50              # Maximum kinetic energy cutoff (Hartree)
 ecutsm  0.5             # Smoothing energy needed for lattice paramete
                         # optimization.  This will be retained for
                         # consistency throughout.

#Definition of the k-point grid
 kptopt   1              # Use symmetry and treat only inequivalent points
  ngkpt   10 10 20
nshiftk   1              # Use one copy of grid only (default)
 shiftk   0.5 0.5 0.5

#Definition of the self-consistency procedure
   iscf   5              # Use conjugate-gradient SCF cycle
  nstep   30             # Maxiumum number of SCF iterations

    ixc   1

timopt   2