# Aluminum molecule, treated with varying occupation numbers
# Compare finite differences to analytical derivatives
# Do not use a very high precision for the finite differences

 ndtset 5

#GS at k
  prtden1  1
#GS at k+q
  getden2  1
  getwfk2  1
    iscf2  -2
    nqpt2  1
     qpt2  0.0 0.0 0.5
  tolwfr2  1.0d-26

#Specific to the RF dataset
  rfphon3  1
 rfatpol3  2 2
   rfdir3  1 0 0
    nqpt3  1
     qpt3  0.0 0.0 0.5
  getwfk3  1
  getwfq3  2
  diemix3  0.35
  diemac3  1.0
  toldfe3  1.0d-10
   nstep3  10

#Computation in a doubled cell, with exactly same atomic positions
#This should give exactly twice the total energy of dataset #1
   acell4 11 11 32
    xred4 0.0 0.0 -0.090     0.0 0.0 0.090
          0.0 0.0  0.410     0.0 0.0 0.590
   natom4 4
   nband4 10
    nkpt4 1
    typat4 1 1 1 1
     kpt4 0.0 0.0 0.0
     wtk4 1.0

#Computation in a doubled cell, with slightly disturbed positions
   acell5 11 11 32
  getwfk5 4
    xred5 0.0 0.0 -0.090     0.0001  0.0 0.090
          0.0 0.0  0.410    -0.0001  0.0 0.590
   natom5 4
   nband5 10
    nkpt5 1
    typat5 1 1 1 1
     kpt5 0.0 0.0 0.0
     wtk5 1.0

#Common data
 acell 11 11 16
 amu 1.0d0
 diemac 1.0d0
 diemix 0.333333333333d0
 ecut 2.5
 ixc   1
 kpt   3*0.0  0.0 0.0 0.5
 natom  2
 nband 5
 nbdbuf 0
 kptopt 0
 nkpt 2
 nstep 40
 nsym 1
 ntypat  1
 occopt 4
 rprim 1 0 0  0 1 0  0 0 1
 tolvrs 1.d-20
 tsmear 0.08
 typat  1 1
 wtk  2*0.5
 xred   0.0 0.0 -0.180   0.0 0.0  0.180
 znucl 13.0

 pp_dirpath "$ABI_PSPDIR"
 pseudos "13al.981214.fhi"

#%%<BEGIN TEST_INFO>
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test = 
#%%   t36.out, tolnlines = 0, tolabs = 3.450e-08, tolrel = 1.001e+00, fld_options = -easy
#%% [paral_info]
#%% max_nprocs = 1
#%% [extra_info]
#%% keywords = NC, DFPT
#%% authors = Unknown
#%% description = 
#%%   Al2 molecule in a big box. Treat 8 bands, occupied using occopt=4.
#%%   For a metallic occopt, the frozen-phonon (finite-difference) approach
#%%   is strictly equivalent to the RF approach only at q/=Gamma.
#%%   Here, computes the result at q=(0 0 1/2).
#%%   With delta(xred)=0.0001 (DATASET 5), one gets 
#%%   delta(etot)/delta(xred)=0.42807994 .
#%%   The direct computation of 2DTE at the target geometry
#%%   gives 0.428080350 .
#%%<END TEST_INFO>