# -*- coding: utf-8 -*-
#
# (c) 2015-2018, ETH Zurich, Institut fuer Theoretische Physik
# Author: Dominik Gresch <greschd@gmx.ch>
"""
This module contains a helper function to create a list of hoppings from a given matrix (:meth:`matrix_to_hop`).
"""
import typing as ty
import numpy as np
from fsc.export import export
[docs]@export
def matrix_to_hop(
mat: ty.Sequence[ty.Sequence[complex]],
orbitals: ty.Optional[ty.Sequence[int]] = None,
R: ty.Sequence[int] = (0, 0, 0),
multiplier: float = 1.0,
) -> ty.List[ty.List[ty.Union[complex, int, np.ndarray]]]:
r"""
Turns a square matrix into a series of hopping terms.
Parameters
----------
mat :
The matrix to be converted.
orbitals :
Indices of the orbitals that make up the basis w.r.t. which the
matrix is defined. By default (``orbitals=None``), the first
``len(mat)`` orbitals are used.
R :
Lattice vector for all the hopping terms.
multiplier :
Multiplicative constant for the hopping strength.
"""
if orbitals is None:
orbitals = list(range(len(mat)))
hop = []
for i, row in enumerate(mat):
for j, x in enumerate(row):
hop.append(
[multiplier * x, orbitals[i], orbitals[j], np.array(R, dtype=int),]
)
return hop