docker/Dockerfile.conda

@@ -9,7 +9,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         # Additional tools for running CI
         file rsync openssh-client \
         # Documentation building
-        inkscape texlive-full zip \
+        inkscape texlive-full zip librsvg2-bin \
     && apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
@@ -18,3 +18,5 @@ COPY kwant-latest.yml kwant-stable.yml kwant-stable-no-extras.yml /
 RUN conda env create -qf kwant-stable.yml
 RUN conda env create -qf kwant-stable-no-extras.yml
 RUN conda env create -qf kwant-latest.yml
+
+RUN /usr/local/envs/kwant-latest/bin/python -m ipykernel install --user --name kwant-latest

docker/kwant-latest.yml

@@ -23,6 +23,9 @@ dependencies:
     - pytest-flakes
     - pytest-pep8
     # Documentation building
-    - sphinx=1.7.4  # later versions seem to have problems
+    - sphinx
     - numpydoc
     - requests
+    - jupyter_sphinx
+    - pip:
+        - sphinxcontrib-svg2pdfconverter

docker/kwant-stable-no-extras.yml

@@ -19,7 +19,3 @@ dependencies:
     - pytest-cov
     - pytest-flakes
     - pytest-pep8
-    # Documentation building
-    - sphinx=1.7.4  # later versions seem to have problems
-    - numpydoc
-    - requests

docker/kwant-stable.yml

@@ -22,7 +22,3 @@ dependencies:
     - pytest-cov
     - pytest-flakes
     - pytest-pep8
-    # Documentation building
-    - sphinx=1.7.4  # later versions seem to have problems
-    - numpydoc
-    - requests

kwant/__init__.py

@@ -29,22 +29,29 @@ except ImportError:
         raise
 
 from ._common import KwantDeprecationWarning, UserCodeError
-
 __all__.extend(['KwantDeprecationWarning', 'UserCodeError'])
 
-for module in ['system', 'builder', 'lattice', 'solvers', 'digest', 'rmt',
-               'operator', 'kpm', 'wraparound']:
-    exec('from . import {0}'.format(module))
-    __all__.append(module)
+# Pre-import most submodules.  (We make exceptions for submodules that have
+# special dependencies or where that would take too long.)
+from . import system
+from . import builder
+from . import lattice
+from . import solvers
+from . import digest
+from . import rmt
+from . import operator
+from . import kpm
+from . import wraparound
+__all__.extend(['system', 'builder', 'lattice', 'solvers', 'digest', 'rmt',
+                'operator', 'kpm', 'wraparound'])
 
 # Make selected functionality available directly in the root namespace.
-available = [('builder', ['Builder', 'HoppingKind']),
-             ('lattice', ['TranslationalSymmetry']),
-             ('solvers.default',
-              ['smatrix', 'greens_function', 'ldos', 'wave_function'])]
-for module, names in available:
-    exec('from .{0} import {1}'.format(module, ', '.join(names)))
-    __all__.extend(names)
+from .builder import Builder, HoppingKind
+__all__.extend(['Builder', 'HoppingKind'])
+from .lattice import TranslationalSymmetry
+__all__.extend(['TranslationalSymmetry'])
+from .solvers.default import smatrix, greens_function, ldos, wave_function
+__all__.extend(['smatrix', 'greens_function', 'ldos', 'wave_function'])
 
 # Importing plotter might not work, but this does not have to be a problem --
 # only no plotting will be available.

kwant/_common.py

@@ -13,6 +13,7 @@ import inspect
 import warnings
 import importlib
 import functools
+import collections
 from contextlib import contextmanager
 
 __all__ = ['KwantDeprecationWarning', 'UserCodeError']
@@ -191,3 +192,27 @@ class lazy_import:
         package = sys.modules[self.__package]
         setattr(package, self.__module, mod)
         return getattr(mod, name)
+
+
+def _hashable(obj):
+    return isinstance(obj, collections.abc.Hashable)
+
+
+def memoize(f):
+    """Decorator to memoize a function that works even with unhashable args.
+
+    This decorator will even work with functions whose args are not hashable.
+    The cache key is made up by the hashable arguments and the ids of the
+    non-hashable args.  It is up to the user to make sure that non-hashable
+    args do not change during the lifetime of the decorator.
+
+    This decorator will keep reevaluating functions that return None.
+    """
+    def lookup(*args):
+        key = tuple(arg if _hashable(arg) else id(arg) for arg in args)
+        result = cache.get(key)
+        if result is None:
+            cache[key] = result = f(*args)
+        return result
+    cache = {}
+    return lookup

kwant/continuum/__init__.py

@@ -10,11 +10,12 @@ try:
     from .discretizer import discretize, discretize_symbolic, build_discretized
     from ._common import sympify, lambdify
     from ._common import momentum_operators, position_operators
+    from .landau_levels import to_landau_basis, discretize_landau, LandauLattice
 except ImportError as error:
     msg = ("'kwant.continuum' is not available because one or more of its "
            "dependencies is not installed.")
     raise ImportError(msg) from error
 
-
 __all__ = ['discretize', 'discretize_symbolic', 'build_discretized',
+           'to_landau_basis', 'discretize_landau', 'LandauLattice',
            'sympify', 'lambdify', 'momentum_operators', 'position_operators']

kwant/graph/__init__.py

@@ -9,8 +9,7 @@
 """Functionality for graphs"""
 
 # Merge the public interface of all submodules.
-__all__ = []
-for module in ['core', 'defs']:
-    exec('from . import {0}'.format(module))
-    exec('from .{0} import *'.format(module))
-    exec('__all__.extend({0}.__all__)'.format(module))
+from .core import *
+from .defs import *
+
+__all__ = [core.__all__ + defs.__all__]