diff --git a/doc/source/reference/kwant.lattice.rst b/doc/source/reference/kwant.lattice.rst
index 6da3fc23b49581e86af672a51a13d359b4c3dea0..e3e975fcdcd4c4880f9ba63ca43aa0f25aea3416 100644
--- a/doc/source/reference/kwant.lattice.rst
+++ b/doc/source/reference/kwant.lattice.rst
@@ -12,6 +12,7 @@ General
general
Monatomic
Polyatomic
+ Shape
Library of lattices
-------------------
diff --git a/doc/source/reference/kwant.linalg.rst b/doc/source/reference/kwant.linalg.rst
index d535789b664b2c889d69cd50dfe5f8740c084a4a..8ce1346bf073a957d840dbb3afc2d0139a984f0d 100644
--- a/doc/source/reference/kwant.linalg.rst
+++ b/doc/source/reference/kwant.linalg.rst
@@ -4,8 +4,9 @@
.. module:: kwant.linalg
This package wraps some selected LAPACK functionality not available via NumPy
-and also contains a Python-wrapper for MUMPS. It is meant for internal use by
-kwant itself, but of course nothing prevents you from using it directly.
+and also contains a Python-wrapper for MUMPS. It also has several algorithms
+for finding approximately orthonormal lattice bases. It is meant for internal
+use by kwant itself, but of course nothing prevents you from using it directly.
The documentation of this package is not included here on purpose in order not
to add too many things to this reference. Please consult the source code
diff --git a/doc/source/tutorial/ab_ring.py b/doc/source/tutorial/ab_ring.py
index 1877973c76a1d7c6516cac9e1d273b103cc64d0c..9ca3130a403e1b6bebaa888bcee1bcfa54f60493 100644
--- a/doc/source/tutorial/ab_ring.py
+++ b/doc/source/tutorial/ab_ring.py
@@ -73,7 +73,7 @@ def make_system(a=1, t=1.0, W=10, r1=10, r2=20):
def lead_shape(pos):
(x, y) = pos
- return (-1 < x < 1) and (-W / 2 < y < W / 2)
+ return (-W / 2 < y < W / 2)
lead[lat.shape(lead_shape, (0, 0))] = 4 * t
lead[lat.nearest] = -t
diff --git a/doc/source/tutorial/graphene.py b/doc/source/tutorial/graphene.py
index 5da941140ce0da0afb75985f980b5e25e07e4985..32a57dc4e6300215b1eb90e88aaf756b8a09a661 100644
--- a/doc/source/tutorial/graphene.py
+++ b/doc/source/tutorial/graphene.py
@@ -70,7 +70,7 @@ def make_system(r=10, w=2.0, pot=0.1):
def lead0_shape(pos):
x, y = pos
- return (-1 < x < 1) and (-0.4 * r < y < 0.4 * r)
+ return (-0.4 * r < y < 0.4 * r)
lead0 = kwant.Builder(sym0)
lead0[graphene.shape(lead0_shape, (0, 0))] = -pot
@@ -80,10 +80,8 @@ def make_system(r=10, w=2.0, pot=0.1):
sym1 = kwant.TranslationalSymmetry(graphene.vec((0, 1)))
def lead1_shape(pos):
- x, y = pos
- u = x * sin_30 + y * cos_30
- v = y * sin_30 - x * cos_30
- return (-1 < u < 1) and (-0.4 * r < v < 0.4 * r)
+ v = pos[1] * sin_30 - pos[0] * cos_30
+ return (-0.4 * r < v < 0.4 * r)
lead1 = kwant.Builder(sym1)
lead1[graphene.shape(lead1_shape, (0, 0))] = pot
diff --git a/doc/source/whatsnew/0.3.rst b/doc/source/whatsnew/0.3.rst
index a99b3fca6073e206f952226c4e1abc2fc4356505..ab56c5998b09ce0055cb220217f0a88b2c12513e 100644
--- a/doc/source/whatsnew/0.3.rst
+++ b/doc/source/whatsnew/0.3.rst
@@ -120,3 +120,14 @@ containing all the parameters as attributes::
Arguments can be passed in an equivalent way in calls to
`~kwant.solvers.default.wave_function` and `~kwant.solvers.default.ldos`.
+
+Lattice and shape improvements
+------------------------------
+`~kwant.lattice.Monoatomic.closest` now returns an exact, and not approximately
+closest point. A new method `~kwant.lattice.Monoatomic.n_closest` was added,
+which returns n closest lattice points. Likewise
+`~kwant.lattice.Polyatomic.shape` has acquired an improved flood-fill
+algorithm, making it work better on narrow ribbon (which were sometimes buggy
+before with non-square lattices). Additionally, it was made symmetry-aware, so
+if a shape is used for a lead, no conditions with regard to coordnate parallel
+to the lead period are required.
diff --git a/kwant/lattice.py b/kwant/lattice.py
index d117e04aa443c224f7843aab2d33f70224fb31cd..ca085e9451cebbccdfd2f54001c43f49e2326ede 100644
--- a/kwant/lattice.py
+++ b/kwant/lattice.py
@@ -74,10 +74,6 @@ class Polyatomic(object):
------
ValueError
If dimensionalities do not match.
-
- Notes
- -----
-
"""
def __init__(self, prim_vecs, basis, name=''):
prim_vecs = ta.array(prim_vecs, float)
@@ -408,6 +404,17 @@ class Shape(object):
and False otherwise.
start : float vector
The origin for the flood-fill algorithm.
+
+ Notes
+ -----
+ A ``Shape`` is a callable object: When called with a
+ `~kwant.builder.Builder` as sole argument, an instance of this class will
+ return an iterator over all the sites from the shape that are in the fundamental domain of the builder's symmetry.
+
+ Because a `~kwant.builder.Builder` can be indexed with functions or
+ iterables of functions, ``Shape`` instances (or any non-tuple
+ iterables of them, e.g. a list) can be used directly as "wildcards" when
+ setting or deleting sites.
"""
self.lat, self.func, self.start = lattice, function, start