# Crystalline aluminum : conventional cell, comparison with the primitive cell results

 ndtset 4
 chkprim 0

#Definition of the k-point grid
 ngkpt  3*2      # This is a 2x2x2 grid, based on the conventional cell vectors
 nshiftk 1  shiftk 0.0 0.0 0.0

#k-point downsampling for Fock operator
 fockdownsampling 3*2    

 nstep 15          # Maximal number of SCF cycles
 toldfe 1.0d-8     # Will stop when, twice in a row, the difference

#DATASET 1  LDA (the pseudopotential for Al is with LDA)

#DATASET 2  HSE06
 ixc2  -428
 getwfk2   1

#DATASET 3  PBE0
 ixc3  41
 getwfk3   2

#DATASET 4  HSE03
 ixc4  -427
 getwfk4   1

#Definition of occupation numbers
occopt 7
tsmear 0.04

#Definition of the unit cell
acell 3*7.60           # This is equivalent to   7.60 7.60 7.60

#Definition of the atom types
ntypat 1          # There is only one type of atom
znucl 13          # 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 Aluminum


#Definition of the atoms
natom 4           # There is only one atom per cell
typat 4*1           # This atom is of type 1, that is, Aluminum
xred              # This keyword indicate that the location of the atoms
                  # will follow, one triplet of number for each atom
   0.0  0.0  0.0     # Triplet giving the REDUCED coordinate of atom 1.
   0.0  0.5  0.5
   0.5  0.0  0.5
   0.5  0.5  0.0

#Definition of the planewave basis set
ecut  6.0         # Maximal kinetic energy cut-off, in Hartree

 pp_dirpath "$ABI_PSPDIR"
 pseudos "PseudosGTH_pwteter/13al.pspgth"

#%%<BEGIN TEST_INFO>
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test =
#%%   t73.out, tolnlines=  0, tolabs=  0.0e-00, tolrel=  0.0e-00
#%% [paral_info]
#%% max_nprocs = 4
#%% [extra_info]
#%% authors = X. Gonze
#%% keywords =
#%% description =
#%%   Crystalline aluminum, conventional cell. Test of downsampling for HSE06, PBE0, HSE03.
#%%   2x2x2 for the k point grid in the FBZ
#%%   1x1x1 for the k point grid for the Fock operator in the FBZ
#%%   The results can be directly compared with those of the test libxc#72, which use
#%%   a primitive cell, instead of the conventional one here.
#%%   The k point sampling (and down sampling) perfectly match. 
#%%   The observed difference is only due to the differing xc correlation real space sampling.
#%%   Of course, the total energy from the present test is to be divided by 4, to find a total energy per atom.
#%%   The results are, in Ha/atom (present test for conventional cell / previous for primitive cell / difference):
#%%   LDA    -2.075 716 / -2.075 718 / 0.000 002
#%%   HSE06  -2.095 513 / -2.095 539 / 0.000 026
#%%   PBE0   -2.081 192 / -2.081 193 / 0.000 001
#%%   HSE03  -2.123 089 / -2.123 117 / 0.000 028
#%%   The real space grid sampling cannot appear at the level of the Fock operator,
#%%   that is completely formulated in reciprocal space. The real space functional 
#%%   from HSE06 and HSE03 is apparently more affected by the real space sampling than
#%%   the one from LDA and PBE0 ...
#%%<END TEST_INFO>