first example

example1.py

""" Graphene DOS

    Lattice : Graphene lattice;
    Disorder : None;
    Configuration : size of the system 512x512, without domain decomposition (nx=ny=1), periodic boundary conditions,
                    double precision, automatic scaling;
    Calculation : DOS;
    Modification : magnetic field is off;
"""
import numpy as np
import pybinding as pb
import kite


def graphene(onsite=(0, 0)):
    """Make a honeycomb lattice with nearest neighbor hopping

    Parameters
    ----------
    onsite : tuple or list
        Onsite energy at different sublattices.
    """

    theta = np.pi / 3
    t = 2.8  # eV
    a1 = np.array([1 + np.cos(theta), np.sin(theta)])
    a2 = np.array([0, 2 * np.sin(theta)])
    lat = pb.Lattice(
        a1=a1, a2=a2
    )
    lat.add_sublattices(
        # name, position, and onsite potential
        ('A', [0, 0], onsite[0]),
        ('B', [1, 0], onsite[1])
    )
    lat.add_hoppings(
        ([0, 0], 'A', 'B', - t),
        ([-1, 0], 'A', 'B', - t),
        ([-1, 1], 'A', 'B', - t)
    )

    return lat


# make a graphene lattice
lattice = graphene_initial()
# number of decomposition parts in each direction of matrix.
# This divides the lattice into various sections, each of which is calculated in parallel
nx = ny = 1
# number of unit cells in each direction.
lx = ly = 512
# make config object which caries info about
# - the number of decomposition parts [nx, ny],
# - lengths of structure [lx, ly]
# - boundary conditions, setting True as periodic boundary conditions, and False elsewise,
# - info if the exported hopping and onsite data should be complex,
# - info of the precision of the exported hopping and onsite data, 0 - float, 1 - double, and 2 - long double.
# - scaling, if None it's automatic, if present select spectrum_bound=[e_min, e_max]
configuration = kite.Configuration(divisions=[nx, ny], length=[lx, ly], boundaries=[True, True],
                                   is_complex=False, precision=1)
# require the calculation of DOS
calculation = kite.Calculation(configuration)
calculation.dos(num_points=1000, num_moments=512, num_random=5, num_disorder=1)
# configure the *.h5 file
kite.config_system(lattice, configuration, calculation, filename='example1.h5')