full name: tenpy.models.lattice.get_order_grouped
get_order(), grouping some sites of the unit cell.
In this function, the word ‘direction’ referst to a physical direction of the lattice or the index u of the unit cell as an “artificial direction”. This function is usefull for lattices with a unit cell of more than 2 sites (e.g. Kagome). The argument group is a To explain the order, assume we have a 3-site unit cell in a 2D lattice with shape (Lx, Ly, Lu). Calling this function with groups=((1,), (2, 0)) returns an order of the following form:
# columns: [x, y, u] [0, 0, 1] # first for u = 1 along y [0, 1, 1] : [0, Ly-1, 1] [0, 0, 2] # then for u = 2 and 0 [0, 0, 0] [0, 1, 2] [0, 1, 0] : [0, Ly-1, 2] [0, Ly-1, 0] # and then repeat the above for increasing `x`.
shape (tuple of int) – The shape of the lattice, i.e., the length in each direction.
groups (tuple of tuple of int) – A partition and reordering of range(shape[-1]) into smaller groups. The ordering goes first within a group, then along the last spatial dimensions, then changing between different groups and finally in Cstyle order along the remaining spatial dimensions.
order – An order of the sites for
Lattice.orderin the specified ordering.
- Return type
ndarray (np.prod(shape), len(shape))