Dear siesta developers, I am trying to read HSX file and calculate corresponding band structure myself (because I need wave function information). The HSX file is generated with a gamma-point-only scf calculation, and thus it is necessary to do some modification to the `xij` variable.
For example, suppose I have a ten-atom chain: 1-2-3-4-5-6-7-8-9-10 A gamma point calculation will introduce hopping between atom 1 and atom 10 (<1|H|10>) due to periodic boundary condition. To calculate band structure, it is necessary to realize the hopping is across the cell boundaries. Currently, `xij` is the vector pointing from 1 to 10 in the home unit cell: 1-------->10. Some modification is needed such that it points to the left side of the unit cell: 10<-1-2-3-4-5-6-7-8-9-10. I can do this modification myself, but I guess there is already a subroutine in siesta that does this trick. Where is it? Best Chong Wang
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
