[Wannier] slab hamiltonian construction from case_hr.dat ?

[Gang Li]

Dear all

      I am facing a problem of constructing a slab with many atoms in it that, in the end, the total amount of numerical cost is unfortunately not affordable. I then came to the MLWFs, I tried to build the slab with the same number of atoms, but with only a few orbitals on each atom.  The interpolated band structure from MLWFs agrees well with the Bloch band structure.  My question is about the 'case_hr.dat' file.

     (1)  In 'case_hr.dat', the hopping matrix spans over all projected orbitals for given displacement of the Wigner-Seitz Cell. I guess these displacements are defined in terms of the primitive lattice vectors R1, R2, R3 (correct me, if I am wrong). In the construction of the slab, I need to use another set of lattice vectors R1', R2', R3', how can I translate the hopping matrix in 'case_hr.dat' into the coordinates defined by R1', R2', R3'. 

     (2) What does the degency really tell me? Do they modify the hopping integral listed in 'case_hr.dat'? If they do, how should I use them? 

thanks for any kind reply in advances
Gang