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[Stephane BECU <stephane.becu@st.com>]

Dear all,

I would like to make convergence study on Ecut for a calculation that needs 3 
datasets. For example with two Ecut values I would have to define 2x3 = 6 
datasets, but I don't know how to declare them. What is the best way to make 
such double loops? Here is my .in file for only one Ecut... What would be the 
numerotation for two Ecut for example?

Thanks for your help,
Stéphane 


FILE.IN
ndtset  3

ecut    3.0

#Ground state calculation
  kptopt1   1             # Automatic generation of k points, taking
                          # into account the symmetry
  tolvrs1   1.0d-18       # SCF stopping criterion
    iscf1   5             # Self-consistent calculation, using algorithm 5

#Response Function calculation : d/dk
  rfelfd2   2             # Activate the calculation of the d/dk perturbation
   rfdir2   1 0 0         # Need to consider the perturbation in the 
x-direction only due to the high symmetry of the Si crystal. In general, just 
use rfdir 1 1 1.In the present version of ABINIT (v4.6), symmetry cannot be 
used to reduce the number of ddk perturbations.

    nqpt2   1
     qpt2   0.0 0.0 0.0   # This is a calculation at the Gamma point

  getwfk2   -1            # Uses as input the output wf of the previous 
dataset

  kptopt2   2             # Automatic generation of k points,
                          # using only the time-reversal symmetry to decrease
                          # the size of the k point set.

    iscf2  -3             # The d/dk perturbation must be treated 
                          # in a non-self-consistent way
  tolwfr2   1.0d-22       # Must use tolwfr for non-self-consistent 
calculations
                          # Here, the value of tolwfr is very low.

#Response Function calculation : electric field perturbation and phonons
  rfphon3   1             # Activate the calculation of the atomic 
dispacement perturbations
 rfatpol3   1 1           # All the atoms will be displaced
  rfelfd3   3             # Activate the calculation of the electric field 
perturbation
   rfdir3   1 1 1         # All directions are selected. However, symmetries 
will be used to decrease
                          # the number of perturbations, so only the x 
electric field is needed
                          # (and this explains why in the second dataset, 
rfdir was set to 1 0 0).

    nqpt3   1
     qpt3   0.0 0.0 0.0   # This is a calculation at the Gamma point

  getwfk3   -2            # Uses as input wfs the output wfs of the dataset 1
  getddk3   -1            # Uses as input ddk wfs the output of the dataset 2

  kptopt3   2             # Automatic generation of k points,
                          # using only the time-reversal symmetry to decrease
                          # the size of the k point set.
  tolvrs3   1.0d-8
    iscf3   5             # Self-consistent calculation, using algorithm 5


#######################################################################
#Common input variables

#Definition of the unit cell
acell 3*10.217         
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               
znucl 14              

#Definition of the atoms
natom 2                # There are two atoms
typat 1 1         # They both are of type 1, that is, Silicon.
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.
   1/4  1/4  1/4  # Triplet giving the REDUCED coordinate of atom 2.

#Gives the number of band, explicitely (do not take the default)
nband  4                

#Exchange-correlation functional
ixc 1             # LDA Teter Pade parametrization


#Definition of the k-point grid
nshiftk  4
shiftk   0.5 0.5 0.5  # These shifts will be the same for all grids
         0.5 0.0 0.0
         0.0 0.5 0.0
         0.0 0.0 0.5
ngkpt   8 8 8


#Definition of the SCF procedure
nstep 20               # Maximal number of SCF cycles
diemac 12.0