def test_signatures():
lat = kwant.lattice.square()
syst = kwant.Builder(kwant.TranslationalSymmetry((-3, 0), (0, 1)))
# onsites and hoppings that will be bound as sites
syst[lat(-2, 0)] = 4
syst[(lat(-2, 0), lat(-2, 1))] = -1
#
syst[lat(-1, 0)] = lambda a, E1: E1
syst[(lat(-1, 0), lat(-1, 1))] = lambda a, b, t1: t1
#
syst[lat(0, 0)] = lambda a, E2, **kwargs: E2
syst[(lat(0, 0), lat(0, 1))] = lambda a, b, t2, **kwargs: t2
# hoppings that will be bound as hoppings
syst[(lat(-2, 0), lat(-1, 0))] = -1
syst[(lat(-2, 0), lat(2, 0))] = -1
#
syst[(lat(-2, 0), lat(0, 0))] = -1
syst[(lat(-2, 0), lat(3, 0))] = lambda a, b, t3: t3
syst[(lat(-1, 0), lat(0, 0))] = lambda a, b, t4, **kwargs: t4
syst[(lat(-1, 0), lat(3, 0))] = lambda a, b, t5: t5
wrapped_syst = wraparound(syst)
## testing
momenta = ['k_x', 'k_y']
onsites = [
(lat(-2, 0), momenta, False),
(lat(-1, 0), ['E1', 't1'] + momenta, False),
(lat(0, 0), ['E2', 't2'] + momenta, True),
]
for site, params_should_be, should_take_kwargs in onsites:
params, _, takes_kwargs = get_parameters(wrapped_syst[site])
assert params[1:] == params_should_be
assert takes_kwargs == should_take_kwargs
hoppings = [
((lat(-2, 0), lat(-1, 0)), momenta, False),
((lat(-2, 0), lat(0, 0)), ['t3'] + momenta, False),
((lat(-1, 0), lat(0, 0)), ['t4', 't5'] + momenta, True),
]
for hopping, params_should_be, should_take_kwargs in hoppings:
params, _, takes_kwargs = get_parameters(wrapped_syst[hopping])
assert params[2:] == params_should_be
assert takes_kwargs == should_take_kwargs
def test_signatures():
lat = kwant.lattice.square()
syst = kwant.Builder(kwant.TranslationalSymmetry((-3, 0), (0, 1)))
# onsites and hoppings that will be bound as sites
syst[lat(-2, 0)] = 4
syst[(lat(-2, 0), lat(-2, 1))] = -1
#
syst[lat(-1, 0)] = lambda a, E1: E1
syst[(lat(-1, 0), lat(-1, 1))] = lambda a, b, t1: t1
#
syst[lat(0, 0)] = lambda a, E2: E2
syst[(lat(0, 0), lat(0, 1))] = lambda a, b, t2: t2
# hoppings that will be bound as hoppings
syst[(lat(-2, 0), lat(-1, 0))] = -1
syst[(lat(-2, 0), lat(2, 0))] = -1
#
syst[(lat(-2, 0), lat(0, 0))] = -1
syst[(lat(-2, 0), lat(3, 0))] = lambda a, b, t3: t3
syst[(lat(-1, 0), lat(0, 0))] = lambda a, b, t4: t4
syst[(lat(-1, 0), lat(3, 0))] = lambda a, b, t5: t5
wrapped_syst = wraparound(syst)
## testing
momenta = ('k_x', 'k_y')
onsites = [
(lat(-2, 0), momenta),
(lat(-1, 0), ('E1', 't1') + momenta),
(lat(0, 0), ('E2', 't2') + momenta),
]
for site, params_should_be in onsites:
params = get_parameters(wrapped_syst[site])
assert params[1:] == params_should_be
hoppings = [
((lat(-2, 0), lat(-1, 0)), momenta),
((lat(-2, 0), lat(0, 0)), ('t3', ) + momenta),
((lat(-1, 0), lat(0, 0)), ('t4', 't5') + momenta),
]
for hopping, params_should_be in hoppings:
params = get_parameters(wrapped_syst[hopping])
assert params[2:] == params_should_be
def test_symmetry():
syst = _simple_syst(kwant.lattice.square())
matrices = [np.random.rand(2, 2) for i in range(4)]
laws = (matrices, [(lambda a: m) for m in matrices])
for cl, ch, ph, tr in laws:
syst.conservation_law = cl
syst.chiral = ch
syst.particle_hole = ph
syst.time_reversal = tr
with pytest.warns(RuntimeWarning):
wrapped = wraparound(syst)
assert wrapped.time_reversal is None
assert wrapped.particle_hole is None
for attr in ('conservation_law', 'chiral'):
new = getattr(wrapped, attr)
orig = getattr(syst, attr)
if callable(orig):
params = get_parameters(new)
assert params[1:] == ('k_x', 'k_y')
assert np.all(orig(None) == new(None, None, None))
else:
assert np.all(orig == new)
def function_to_terms(site_or_hop, value, fixed_params):
assert callable(value)
parameters = get_parameters(value)
# remove site or site1, site2 parameters
if isinstance(site_or_hop, builder.Site):
parameters = parameters[1:]
site_or_hop = (site_or_hop,)
else:
parameters = parameters[2:]
free_parameters = (par for par in parameters
if par not in fixed_params.keys())
# first set all free parameters to 0
args = ((fixed_params[par] if par in fixed_params.keys() else 0)
for par in parameters)
h_0 = value(*site_or_hop, *args)
# set one of the free parameters to 1 at a time, the rest 0
terms = []
for p in free_parameters:
args = ((fixed_params[par] if par in fixed_params.keys() else
(1 if par == p else 0)) for par in parameters)
terms.append((p, value(*site_or_hop, *args) - h_0))
return terms + [('1', h_0)]
