def test_tocoo():
syst = kwant.Builder()
lat1 = kwant.lattice.chain(norbs=1)
syst[lat1(0)] = syst[lat1(1)] = 0
syst = syst.finalized()
op = ops.Density(syst)
assert isinstance(op.tocoo(), coo_matrix)
# Constant and non-constant values.
assert np.all(op.tocoo().todense() == np.eye(2))
op = ops.Density(syst, lambda site: 1)
assert np.all(op.tocoo().todense() == np.eye(2))
# Correct treatment of where
op = ops.Density(syst, where=[lat1(0)])
assert np.all(op.tocoo().todense() == [[1, 0], [0, 0]])
# No accidental transpose.
syst = kwant.Builder()
lat2 = kwant.lattice.chain(norbs=2)
syst[lat2(0)] = lambda site, paramerer: np.eye(2)
syst = syst.finalized()
op = ops.Density(syst, [[1, 1], [0, 1]], check_hermiticity=False)
assert np.all(op.tocoo().todense() == [[1, 1], [0, 1]])
op = ops.Density(syst,
lambda site, p: [[1, 1], [0, 1]],
check_hermiticity=False)
op = op.bind(args=(1, ))
raises(ValueError, op.tocoo, [1])
def test_opservables_finite():
lat, syst = _random_square_system(3)
fsyst = syst.finalized()
ev, wfs = la.eigh(fsyst.hamiltonian_submatrix())
Q = ops.Density(fsyst)
Qtot = ops.Density(fsyst, sum=True)
J = ops.Current(fsyst)
K = ops.Source(fsyst)
for i, wf in enumerate(wfs.T): # wfs[:, i] is i'th eigenvector
assert np.allclose(Q.act(wf), wf) # this operation is identity
_test(Q, wf, reduced_val=1) # eigenvectors are normalized
_test(Qtot, wf, per_el_val=1) # eigenvectors are normalized
_test(J, wf, per_el_val=0) # time-reversal symmetry: no current
_test(K, wf, per_el_val=0) # onsite commutes with hamiltonian
# check that we get correct (complex) output
for bra, ket in zip(wfs.T, wfs.T):
_test(Q, bra, ket, per_el_val=(bra * ket))
# check with get_hermiticity=False
Qi = ops.Density(fsyst, 1j, check_hermiticity=False)
for wf in wfs.T: # wfs[:, i] is i'th eigenvector
assert np.allclose(Qi.act(wf), 1j * wf)
# test with different numbers of orbitals
lat2 = kwant.lattice.chain(norbs=2)
extra_sites = [lat2(i) for i in range(len(fsyst.sites))]
syst[extra_sites] = np.eye(2)
syst[zip(fsyst.sites, extra_sites)] = ta.matrix([1, 1])
fsyst = syst.finalized()
ev, wfs = la.eigh(fsyst.hamiltonian_submatrix())
Q = ops.Density(fsyst)
Qtot = ops.Density(fsyst, sum=True)
J = ops.Current(fsyst)
K = ops.Source(fsyst)
for wf in wfs.T: # wfs[:, i] is i'th eigenvector
assert np.allclose(Q.act(wf), wf) # this operation is identity
_test(Q, wf, reduced_val=1) # eigenvectors are normalized
_test(Qtot, wf, per_el_val=1) # eigenvectors are normalized
_test(J, wf, per_el_val=0) # time-reversal symmetry: no current
_test(K, wf, per_el_val=0) # onsite commutes with hamiltonian
def test_operator_construction():
lat, syst = _random_square_system(3)
fsyst = syst.finalized()
N = len(fsyst.sites)
# test construction failure if norbs not given
latnone = kwant.lattice.chain()
syst[latnone(0)] = 1
for A in opservables:
raises(ValueError, A, syst.finalized())
del syst[latnone(0)]
# test construction failure when dimensions of onsite do not match
for A in opservables:
raises(ValueError, A, fsyst, onsite=np.eye(2))
# test that error is raised when input array is the wrong size
for A in opservables:
a = A(fsyst)
kets = list(map(np.ones, [(0, ), (N - 1, ), (N + 1, ), (N, 1)]))
for ket in kets:
raises(ValueError, a, ket)
raises(ValueError, a, ket, ket)
raises(ValueError, a.act, ket)
raises(ValueError, a.act, ket, ket)
# Test failure on non-hermitian
for A in (ops.Density, ops.Current, ops.Source):
raises(ValueError, A, fsyst, 1j)
# Test output dtype
ket = np.ones(len(fsyst.sites))
for A in (ops.Density, ops.Current, ops.Source):
a = A(fsyst)
a_nonherm = A(fsyst, check_hermiticity=False)
assert a(ket, ket).dtype == np.complex128
assert a(ket).dtype == np.float64
assert a_nonherm(ket, ket).dtype == np.complex128
assert a_nonherm(ket).dtype == np.complex128
# test construction with different numbers of orbitals
lat2 = kwant.lattice.chain(norbs=2)
extra_sites = [lat2(i) for i in range(N)]
syst[extra_sites] = np.eye(2)
syst[zip(fsyst.sites, extra_sites)] = ta.matrix([1, 1])
for A in opservables:
raises(ValueError, A, syst.finalized(), onsite=np.eye(2))
A(syst.finalized())
A.onsite == np.eye(2)
del syst[extra_sites]
check = [(ops.Density, np.arange(N).reshape(-1, 1), ta.identity(1)),
(ops.Current, np.array(list(fsyst.graph)), ta.identity(1)),
(ops.Source, np.arange(N).reshape(-1, 1), ta.identity(1))]
# test basic construction
for A, where, onsite in check:
a = A(fsyst)
assert np.all(np.asarray(a.where) == where)
assert all(a.onsite == onsite for i in range(N))
# test construction with dict `onsite`
for A in opservables:
B = A(fsyst, {lat: 1})
assert all(B.onsite(i) == 1 for i in range(N))
# test construction with a functional onsite
for A in opservables:
B = A(fsyst, lambda site: site.pos[0]) # x-position operator
assert all(B.onsite(i) == fsyst.sites[i].pos[0] for i in range(N))
# test construction with `where` given by a sequence
where = [lat(2, 2), lat(1, 1)]
fwhere = tuple(fsyst.id_by_site[s] for s in where)
A = ops.Density(fsyst, where=where)
assert np.all(np.asarray(A.where).reshape(-1) == fwhere)
where = [(lat(2, 2), lat(1, 2)), (lat(0, 0), lat(0, 1))]
fwhere = np.asarray([(fsyst.id_by_site[a], fsyst.id_by_site[b])
for a, b in where])
A = ops.Current(fsyst, where=where)
assert np.all(np.asarray(A.where) == fwhere)
# test construction with `where` given by a function
tag_list = [(1, 0), (1, 1), (1, 2)]
def where(site):
return site.tag in tag_list
A = ops.Density(fsyst, where=where)
assert all(fsyst.sites[A.where[w, 0]].tag in tag_list
for w in range(A.where.shape[0]))
where_list = set(kwant.HoppingKind((1, 0), lat)(syst))
fwhere_list = set(
(fsyst.id_by_site[a], fsyst.id_by_site[b]) for a, b in where_list)
def where(a, b):
return (a, b) in where_list
A = ops.Current(fsyst, where=where)
assert all((a, b) in fwhere_list for a, b in A.where)
# test that `sum` is passed to constructors correctly
for A in opservables:
A(fsyst, sum=True).sum == True