# Crystalline silicon
# Calculation of the GW correction to the direct band gap in Gamma
# Dataset 1: ground state calculation 
# Dataset 2: calculation of the WFK file 
# Dataset 3: calculation of the screening (epsilon^-1 matrix for W)
# Dataset 4: calculation of the Self-Energy matrix elements (GW corrections)

ndtset      4

ngkpt    2 2 2         # Density of k points used for the automatic tests of the tutorial
#ngkpt    4 4 4        # Density of k points needed for a converged calculation

nshiftk  4
shiftk   0.0 0.0 0.0  # This grid contains the Gamma point, which is the point at which
         0.0 0.5 0.5  # we will compute the (direct) band gap. There are 19 k points
         0.5 0.0 0.5  # in the irreducible Brillouin zone, if ngkpt 4 4 4 is used.
         0.5 0.5 0.0
istwfk  *1            # For the GW computations, do not take advantage of the 
                      # specificities of k points to reduce the number of components of the
                      # wavefunction.

# Dataset1: usual self-consistent ground-state calculation
# Definition of the k-point grid
nband1  6
tolvrs1 1e-10

# Dataset2: calculation of WFK file
# Definition of k-points
iscf2    -2             # Non self-consistent calculation
getden2  -1             # Read previous density file
nband2   120
nbdbuf2   20
tolwfr2  1.0d-12   

# Dataset3: Calculation of the screening (epsilon^-1 matrix)
optdriver3   3       # Screening calculation
getwfk3     -1       # Obtain WFK file from previous dataset
nband3      50       # Bands to be used in the screening calculation
ecuteps3    6.0      # Dimension of the screening matrix
ppmfrq3    16.7 eV  # Imaginary frequency where to calculate the screening


# Dataset4: Calculation of the Self-Energy matrix elements (GW corrections)
optdriver4  4        # Self-Energy calculation
getwfk4     -2       # Obtain WFK file from dataset 1
getscr4     -1       # Obtain SCR file from previous dataset
nband4      100      # Bands to be used in the Self-Energy calculation
ecutsigx4    8.0     # Dimension of the G sum in Sigma_x
                     
nkptgw4      1               # number of k-point where to calculate the GW correction
kptgw4                       # k-points
  0.000    0.000    0.000    # (Gamma)
bdgw4       4  5             # calculate GW corrections for bands from 4 to 5

# Definition of the unit cell: fcc
acell  3*10.26         # Experimental lattice constants
rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
       0.5  0.0  0.5   
       0.5  0.5  0.0

# Definition of the atom types
ntypat  1         # There is only one type of atom
znucl 14          # 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 2           # There are two atoms
typat  1 1        # They both are of type 1, that is, Silicon.
xred              # Reduced coordinate of atoms
      0.0  0.0  0.0
      0.25 0.25 0.25

# Definition of the planewave basis set (at convergence 16 Rydberg 8 Hartree)
ecut 8.0          # Maximal kinetic energy cut-off, in Hartree

# Definition of the SCF procedure
nstep   10        # Maximal number of SCF cycles
diemac  12.0      # Although this is not mandatory, it is worth to
                  # precondition the SCF cycle. The model dielectric
                  # function used as the standard preconditioner
                  # is described in the "dielng" input variable section.
                  # Here, we follow the prescription for bulk silicon.




 pp_dirpath "$ABI_PSPDIR"
 pseudos "Pseudodojo_nc_sr_04_pbe_standard_psp8/Si.psp8"

##############################################################
# This section is used only for regression testing of ABINIT #
##############################################################
#%%<BEGIN TEST_INFO>
#%% [setup]
#%% executable = abinit
#%% [files]
#%% files_to_test = 
#%%   tgw1_6.abo, tolnlines= 70, tolabs=  7.000e-02, tolrel=  3.000e-02, fld_options= -ridiculous
#%% [paral_info]
#%% max_nprocs = 4
#%% [extra_info]
#%% authors = V. Olevano, F. Bruneval, M. Giantomassi
#%% keywords = GW
#%% description = 
#%%   Crystalline silicon
#%%   Calculation of the GW correction to the direct band gap in Gamma
#%%   Dataset 1: ground state calculation 
#%%   Dataset 2: calculation of the WFK file 
#%%   Dataset 3: calculation of the screening (epsilon^-1 matrix for W)
#%%   Dataset 4: calculation of the Self-Energy matrix elements (GW corrections)
#%%<END TEST_INFO>
