diff --git a/kwant/builder.py b/kwant/builder.py
index 7d8d3738ba68909379bd1969170b3bd39ea4f90c..abf1cc69541ffc5964771085d6b5d6d3d13b90bf 100644
--- a/kwant/builder.py
+++ b/kwant/builder.py
@@ -3025,3 +3025,16 @@ class InfiniteVectorizedSystem(_VectorizedFinalizedBuilderMixin, system.Infinite
i -= cs
j -= cs
return super().hamiltonian(i, j, *args, params=params)
+
+
+def is_finite_system(syst):
+ return isinstance(syst, (FiniteSystem, FiniteVectorizedSystem))
+
+
+def is_infinite_system(syst):
+ return isinstance(syst, (FiniteSystem, FiniteVectorizedSystem))
+
+
+def is_system(syst):
+ return isinstance(syst, (FiniteSystem, FiniteVectorizedSystem,
+ InfiniteSystem, InfiniteVectorizedSystem))
diff --git a/kwant/operator.pyx b/kwant/operator.pyx
index 5133ebb522994d288ef2c5344cb9d016366f6fa9..8de1cad8aae740a77bdf36b39ee7c0175cb2f02e 100644
--- a/kwant/operator.pyx
+++ b/kwant/operator.pyx
@@ -24,7 +24,7 @@ from .graph.core cimport EdgeIterator
from .graph.core import DisabledFeatureError, NodeDoesNotExistError
from .graph.defs cimport gint
from .graph.defs import gint_dtype
-from .system import InfiniteSystem, Site
+from .system import is_infinite, Site
from ._common import UserCodeError, get_parameters, deprecate_args
@@ -149,7 +149,7 @@ def _get_all_orbs(gint[:, :] where, gint[:, :] site_ranges):
def _get_tot_norbs(syst):
cdef gint _unused, tot_norbs
- is_infinite_system = isinstance(syst, InfiniteSystem)
+ is_infinite_system = is_infinite(syst)
n_sites = syst.cell_size if is_infinite_system else syst.graph.num_nodes
_get_orbs(np.asarray(syst.site_ranges, dtype=gint_dtype),
n_sites, &tot_norbs, &_unused)
@@ -165,7 +165,7 @@ def _normalize_site_where(syst, where):
otherwise it should contain integers.
"""
if where is None:
- if isinstance(syst, InfiniteSystem):
+ if is_infinite(syst):
where = list(range(syst.cell_size))
else:
where = list(range(syst.graph.num_nodes))
@@ -173,7 +173,7 @@ def _normalize_site_where(syst, where):
try:
where = [syst.id_by_site[s] for s in filter(where, syst.sites)]
except AttributeError:
- if isinstance(syst, InfiniteSystem):
+ if is_infinite(syst):
where = [s for s in range(syst.cell_size) if where(s)]
else:
where = [s for s in range(syst.graph.num_nodes) if where(s)]
@@ -187,7 +187,7 @@ def _normalize_site_where(syst, where):
where = np.asarray(where, dtype=gint_dtype).reshape(-1, 1)
- if isinstance(syst, InfiniteSystem) and np.any(where >= syst.cell_size):
+ if is_infinite(syst) and np.any(where >= syst.cell_size):
raise ValueError('Only sites in the fundamental domain may be '
'specified using `where`.')
if np.any(np.logical_or(where < 0, where >= syst.graph.num_nodes)):
@@ -208,7 +208,7 @@ def _normalize_hopping_where(syst, where):
if where is None:
# we cannot extract the hoppings in the same order as they are in the
# graph while simultaneously excluding all inter-cell hoppings
- if isinstance(syst, InfiniteSystem):
+ if is_infinite(syst):
raise ValueError('`where` must be provided when calculating '
'current in an InfiniteSystem.')
where = list(syst.graph)
@@ -241,7 +241,7 @@ def _normalize_hopping_where(syst, where):
where = np.asarray(where, dtype=gint_dtype)
- if isinstance(syst, InfiniteSystem) and np.any(where > syst.cell_size):
+ if is_infinite(syst) and np.any(where > syst.cell_size):
raise ValueError('Only intra-cell hoppings may be specified '
'using `where`.')
diff --git a/kwant/plotter.py b/kwant/plotter.py
index a9e5ec42793fb37eee4e5908624443cafc1db59d..31a0aba6658b18eb3c79fccc3c0ffcdb2804bedf 100644
--- a/kwant/plotter.py
+++ b/kwant/plotter.py
@@ -427,7 +427,7 @@ def sys_leads_sites(sys, num_lead_cells=2):
lead.builder.sites() for i in
range(num_lead_cells)))
lead_cells.append(slice(start, len(sites)))
- elif isinstance(syst, system.FiniteSystem):
+ elif system.is_finite(syst):
sites = [(i, None, 0) for i in range(syst.graph.num_nodes)]
for leadnr, lead in enumerate(syst.leads):
start = len(sites)
@@ -961,7 +961,7 @@ def plot(sys, num_lead_cells=2, unit='nn',
if site_color is None:
cycle = _color_cycle()
- if isinstance(syst, (builder.FiniteSystem, builder.InfiniteSystem)):
+ if builder.is_system(syst):
# Skipping the leads for brevity.
families = sorted({site.family for site in syst.sites})
color_mapping = dict(zip(families, cycle))
@@ -1291,7 +1291,7 @@ def map(sys, value, colorbar=True, cmap=None, vmin=None, vmax=None, a=None,
if callable(value):
value = [value(site[0]) for site in sites]
else:
- if not isinstance(syst, system.FiniteSystem):
+ if not system.is_finite(syst):
raise ValueError('List of values is only allowed as input '
'for finalized systems.')
value = np.array(value)
@@ -1407,7 +1407,7 @@ def bands(sys, args=(), momenta=65, file=None, show=True, dpi=None,
"for bands()")
syst = sys # for naming consistency inside function bodies
- _common.ensure_isinstance(syst, system.InfiniteSystem)
+ _common.ensure_isinstance(syst, (system.InfiniteSystem, system.InfiniteVectorizedSystem))
momenta = np.array(momenta)
if momenta.ndim != 1:
@@ -1483,7 +1483,7 @@ def spectrum(syst, x, y=None, params=None, mask=None, file=None,
if y is not None and not _p.has3d:
raise RuntimeError("Installed matplotlib does not support 3d plotting")
- if isinstance(syst, system.FiniteSystem):
+ if system.is_finite(syst):
def ham(**kwargs):
return syst.hamiltonian_submatrix(params=kwargs, sparse=False)
elif callable(syst):
@@ -1751,7 +1751,7 @@ def interpolate_current(syst, current, relwidth=None, abswidth=None, n=9):
the extents of `field`: ((x0, x1), (y0, y1), ...)
"""
- if not isinstance(syst, builder.FiniteSystem):
+ if not builder.is_finite_system(syst):
raise TypeError("The system needs to be finalized.")
if len(current) != syst.graph.num_edges:
@@ -1844,7 +1844,7 @@ def interpolate_density(syst, density, relwidth=None, abswidth=None, n=9,
the extents of ``field``: ((x0, x1), (y0, y1), ...)
"""
- if not isinstance(syst, builder.FiniteSystem):
+ if not builder.is_finite_system(syst):
raise TypeError("The system needs to be finalized.")
if len(density) != len(syst.sites):
diff --git a/kwant/system.py b/kwant/system.py
index a65f9259e03f9e048dfa44f43bf74337e6f84815..a1c287bb97a982353d79410b8c2cd4fc2ca4bbad 100644
--- a/kwant/system.py
+++ b/kwant/system.py
@@ -572,6 +572,10 @@ class FiniteVectorizedSystem(VectorizedSystem, FiniteSystemMixin, metaclass=abc.
pass
+def is_finite(syst):
+ return isinstance(syst, (FiniteSystem, FiniteVectorizedSystem))
+
+
class InfiniteSystemMixin(metaclass=abc.ABCMeta):
"""Abstract infinite low-level system.
@@ -731,6 +735,10 @@ class InfiniteVectorizedSystem(VectorizedSystem, InfiniteSystemMixin, metaclass=
inter_cell_hopping = _system.vectorized_inter_cell_hopping
+def is_infinite(syst):
+ return isinstance(syst, (InfiniteSystem, InfiniteVectorizedSystem))
+
+
class PrecalculatedLead:
def __init__(self, modes=None, selfenergy=None):
"""A general lead defined by its self energy.