#GaAs in hypothetical wurzite (hexagonal) structure

ndtset 2

# Set 1 : initial self-consistency

kptopt1   1

# Set 2 : response-function strain calculation

getwfk2  -1
kptopt2   2
  nqpt2   1
   qpt2   0  0  0
rfstrs2   1
 rfdir2   1  1  0

#comon input data

 acell    7.5526  7.5526  12.3333
 diemac   10.0
   ecut   6.0
  natom   4
  nband   8
  ngkpt   2  2  2
nshiftk   1
  nstep   40
 ntypat   2
 prtvol   10
  rprim   0.866025403784439  0.5  0.0
         -0.866025403784439  0.5  0.0
          0.0                0.0  1.0
 shiftk   0.0 0.0 0.5
 tolvrs   1.0d-16
  typat   1 1 2 2
#coordinates were optimized
   xred   0.3333333333333333  0.6666666666666667  0.000878861213
          0.6666666666666667  0.3333333333333333  0.500878861213
          0.3333333333333333  0.6666666666666667  0.374132194455
          0.6666666666666667  0.3333333333333333  0.874132194455
   znucl  31 33

 pp_dirpath "$ABI_PSPDIR"
 pseudos "PseudosHGH_pwteter/31ga.3.hgh, PseudosHGH_pwteter/33as.5.hgh"

#%%<BEGIN TEST_INFO>
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test = 
#%%   t63.out, tolnlines = 2, tolabs = 2.0e-06, tolrel = 3.0e-04, fld_options =  -medium
#%% [paral_info]
#%% max_nprocs = 2
#%% [extra_info]
#%% authors =  D. R. Hamann
#%% keywords = NC, DFPT
#%% description = 
#%%   Test of the strain perturbation.
#%%   GaAs in a hypothetical wurzite (hexagonal) strucure, using HGH
#%%   potentials.  The main point here is to test the strain derivatives
#%%   in a hexagonal symmetry situation.  The indexing of the strain
#%%   components is pert=natom+3 for 3 uniaxial components, and
#%%   pert=natom+4 for 3 shear components, translating in this
#%%   case to (dir, pert, cartesian strain) triplets
#%%   1 7 xx          1 8 yz
#%%   2 7 yy          2 8 xz
#%%   3 7 zz          3 8 xy
#%%   We see that the cartesian 2nd-order matrix has the expected symmetry
#%%   despite the lack of any x<->y symmetry operations in this space group.
#%%   A curious user might wish to extend this test to all strain
#%%   components (rfstrs2  3; rfdir2 1 1 1) and observe an unexpected
#%%   symmetry among the cartesian internal strain terms.  In particular,
#%%   certain diagonal and shear terms are identical, such as 1 1 1 7 (x, xx)
#%%   and 2 1 3 8 (y, xy) where (.,.) means (force, strain).
#%% topics = DFPT
#%%<END TEST_INFO>