The code does not work for plaquette model

[jiangmi]

Because the code always treats site pair (0,1) and (1,0) to be the same, namely assumed to belong to the same distance class. However, this is not true in plaquette model, where 0,1 hopping differs from 1,0 hopping.

[jiangmi]

This issue can be circumvented by setting the whole lattice as a single unit cell although in a non-smart way.