quantum-espresso/KCW/examples/example04

This example shows how to use the auxiliary tool merge_wann.x to 
merge the results of a block wannierizations into a unique one and 
then run a kcw calculaton for GaAs. This is needed in case we do 
not want the Wannierization to mix KS states too far in energy.

1) run a standard scf and nscf calculation at PBE level on a regular 2x2x2 mesh. 
   The regular mesh is needed by Wannier90. 
   input=GaAs.(n)scf.in, output=GaAs.(n)scf.out

2) perform a separate wannierization for the occupied manifold. 
   Using exclude_bands we perform 3 different wannierzations
   results in ./wann_*block 

3) use the merge_wann.x tool to merge the U matrices (and centers) in 
   unique U (and centres) file 

4) prepare the KCW calculation 
   input=kc.w2ki output=kc.w2ko

5) calculate, interpolate and diagonalize the KI Hamiltonian 
   input=kc.khi, output=kc.kho

The band structure is in GaAs.kcw_bands.dat.

NB: this is a miningless calculation as 
 i)  we use nspin = 1  
 ii) the screening coefficients are set to 1

NB2: run_example_1block perform a standard procedure, i.e. 
     without the block wannierization. This is for reference