diff --git a/doc/source/pre/whatsnew/1.4.rst b/doc/source/pre/whatsnew/1.4.rst
index c962fb9741f8f6ac8709aa8f8bd62b8ced65f377..a2ea4f32b4a5f99232b61948a5c3dde8c1ba8866 100644
--- a/doc/source/pre/whatsnew/1.4.rst
+++ b/doc/source/pre/whatsnew/1.4.rst
@@ -35,12 +35,12 @@ ensure that the chosen gauge is consistent across the whole system
directions). This release introduces `kwant.physics.magnetic_gauge`,
which calculates the Peierls phases for you::
- import numpy as np
- import kwant
-
def hopping(a, b, t, peierls):
return -t * peierls(a, b)
+ def B_syst(pos):
+ return np.exp(-np.sum(pos * pos))
+
syst = make_system(hopping)
lead = make_lead(hopping).substituted(peierls='peierls_lead')
syst.attach_lead(lead)
@@ -48,11 +48,7 @@ which calculates the Peierls phases for you::
gauge = kwant.physics.magnetic_gauge(syst)
- def B_syst(pos):
- return np.exp(-np.sum(pos * pos))
-
# B_syst in scattering region, 0 in lead.
- # Ensure that the fields match at the system/lead interface!
peierls_syst, peierls_lead = gauge(B_syst, 0)
params = dict(t=1, peierls=peierls_syst, peierls_lead=peierls_lead)
diff --git a/kwant/builder.py b/kwant/builder.py
index ad482a75c838438b709296704ef3ff8ee2419022..79e1f0198c0d2f882bd9cbd736117c2e572e8d08 100644
--- a/kwant/builder.py
+++ b/kwant/builder.py
@@ -1980,7 +1980,9 @@ class FiniteSystem(_FinalizedBuilderMixin, system.FiniteSystem):
to the integer-labeled site ``i`` of the low-level system. The sites
are ordered first by their family and then by their tag.
id_by_site : dict
- The inverse of ``sites``; maps from ``i`` to ``sites[i]``.
+ The inverse of ``sites``; maps high-level `~kwant.builder.Site`
+ instances to their integer label.
+ Satisfies ``id_by_site[sites[i]] == i``.
"""
def __init__(self, builder):
@@ -2097,7 +2099,9 @@ class InfiniteSystem(_FinalizedBuilderMixin, system.InfiniteSystem):
``sites[i]`` is the `~kwant.builder.Site` instance that corresponds
to the integer-labeled site ``i`` of the low-level system.
id_by_site : dict
- The inverse of ``sites``; maps from ``i`` to ``sites[i]``.
+ The inverse of ``sites``; maps high-level `~kwant.builder.Site`
+ instances to their integer label.
+ Satisfies ``id_by_site[sites[i]] == i``.
Notes
-----
diff --git a/kwant/kpm.py b/kwant/kpm.py
index eb161de374b5a1276a7e2030b14a009cd7cd656c..a06d7c6d19af5a3a5266e5fff68103cc9f7b3b04 100644
--- a/kwant/kpm.py
+++ b/kwant/kpm.py
@@ -945,7 +945,7 @@ class LocalVectors:
must be a list of integers with the indices where column vectors
are nonzero.
"""
- def __init__(self, syst, where, *args):
+ def __init__(self, syst, where=None, *args):
self.tot_norbs, self.orbs = _normalize_orbs_where(syst, where)
self._idx = 0
@@ -1006,7 +1006,11 @@ def _normalize_orbs_where(syst, where):
tot_norbs = _get_tot_norbs(syst)
orbs = _from_where_to_orbs(syst, where)
else:
- tot_norbs = csr_matrix(syst).shape[0]
+ try:
+ tot_norbs = csr_matrix(syst).shape[0]
+ except TypeError:
+ raise TypeError("'syst' is neither a matrix "
+ "nor a Kwant system.")
orbs = (range(tot_norbs) if where is None
else np.asarray(where, int))
return tot_norbs, orbs
diff --git a/kwant/physics/tests/test_leads.py b/kwant/physics/tests/test_leads.py
index bc41f671811bd6c2cdae99d48c7b82fa8ebeeb3d..e7994941f9e7375d2b292fe8163ace4df3138553 100644
--- a/kwant/physics/tests/test_leads.py
+++ b/kwant/physics/tests/test_leads.py
@@ -281,7 +281,7 @@ def test_modes_bearded_ribbon():
def check_equivalence(h, t, n, sym='', particle_hole=None, chiral=None,
time_reversal=None):
"""Compare modes stabilization algorithms for a given Hamiltonian."""
- u, s, vh = np.linalg.svd(t)
+ u, s, vh = la.svd(t)
u, v = u * np.sqrt(s), vh.T.conj() * np.sqrt(s)
prop_vecs = []
evan_vecs = []
diff --git a/kwant/qsymm.py b/kwant/qsymm.py
index 93f4bdc3de30600c93f7c69ee6a13d5e26690630..bb752e19314a18cbc7ec53e53eb163df5bf17f80 100644
--- a/kwant/qsymm.py
+++ b/kwant/qsymm.py
@@ -448,7 +448,7 @@ def find_builder_symmetries(builder, momenta=None, params=None,
params = dict()
ham = builder_to_model(builder, momenta=momenta,
- real_space=False, params=params)
+ real_space=spatial_symmetries, params=params)
# Use dense or sparse computation depending on Hamiltonian size
if sparse is None:
diff --git a/kwant/tests/test_qsymm.py b/kwant/tests/test_qsymm.py
index 2a13b5e4983068ecfc53cbd8b387fe666971b799..b21803db7a89743fb7badbbd32bb08a093f65d01 100644
--- a/kwant/tests/test_qsymm.py
+++ b/kwant/tests/test_qsymm.py
@@ -427,6 +427,34 @@ def test_find_builder_discrete_symmetries():
assert sym_dict[class_symmetry] in builder_symmetries_dense
+def test_real_space_basis():
+ lat = kwant.lattice.honeycomb(norbs=[1, 1])
+ sym = kwant.TranslationalSymmetry(lat.vec((1, 0)), lat.vec((0, 1)))
+ bulk = kwant.Builder(sym)
+ bulk[[lat.a(0, 0), lat.b(0, 0)]] = 0
+ bulk[lat.neighbors()] = 1
+
+ # Including real space symmetries
+ symmetries = find_builder_symmetries(bulk)
+ hex_group_2D = hexagonal()
+ hex_group_2D = set(PointGroupElement(np.array(s.R).astype(float),
+ s.conjugate, s.antisymmetry, None)
+ for s in hex_group_2D)
+ assert len(symmetries) == len(hex_group_2D)
+ assert all([s1 in symmetries and s2 in hex_group_2D
+ for s1, s2 in zip(hex_group_2D, symmetries)])
+
+ # Only onsite discrete symmetries
+ symmetries = find_builder_symmetries(bulk, spatial_symmetries=False)
+ onsites = [PointGroupElement(np.eye(2), True, False, None), # T
+ PointGroupElement(np.eye(2), True, True, None), # P
+ PointGroupElement(np.eye(2), False, True, None), # C
+ PointGroupElement(np.eye(2), False, False, None)] # I
+ assert len(symmetries) == len(onsites)
+ assert all([s1 in symmetries and s2 in onsites
+ for s1, s2 in zip(onsites, symmetries)])
+
+
def random_onsite_hop(n, rng=0):
rng = ensure_rng(rng)
onsite = rng.randn(n, n) + 1j * rng.randn(n, n)