The new fill() sets each hoppings only once.

The filling starts now at (one or multiple) sites, not at a domain.
This is more consistent, since the flood fill works on the graph of
sites.

Other changes:

* max_sites is now the maximal number of sites that is still OK
* fill() no longer raises an exception when no sites were added, it
  warns now.

Rafal Skolasinski authored 7 years ago and Joseph Weston committed 7 years ago

Previously, only onsite matrix elements were tested, whereas the
test should have also tested the hopping elements.

Additionally, make sure to test the LLL code accordingly.

Rafal Skolasinski authored 7 years ago and Bas Nijholt committed 7 years ago

Calling "kwant.continuum.discretize('A * k_x', substitutions={'A': 'A + B'})"
ends with performing substitutions twice. Fixed by removing redundant second
substitution. Fixes issue #121.

Previously 'Builder.fill' did not respect the symmetry of the target
Builder. This change also adds a test to check that target system
symmetry is respected.

Fixes #119

Rafal Skolasinski authored 7 years ago and Joseph Weston committed 7 years ago

Current implementation uses ``kwant.physics.Bands``. This example fails
when one substitute ``k_x**2`` with for example ``k_x**4`` due to farther
then nearest neighbours hoppings. Using wraparound provides also easier way
to extend it to multidimensional band structures (except of plotting).

Closes #109.

The Mathjax CDN is shutting down:
https://www.mathjax.org/cdn-shutting-down/

Closes #116.

When the fundamental domains of the constituent symmetries
of a wrapped around system do not coincide, it was previously
possible for wrapping around to fail when 'keep' was provided,
even if wrapping around succeeded with 'keep=None'.

Rafal Skolasinski authored 8 years ago and Joseph Weston committed 7 years ago

Arguments of "discretize", "discretize_symbolic", and "build_discretized"
that does not represent Hamiltonian or discrete coordinates are now keyword-only.
Also "lattice_constant" argument is renamed to "grid_spacing" in order to
distinguish it from real lattice constant of a crystal. Closes 110.

Closes #113.

This allows to provide a helpful error message when someone tries to
import Kwant with Python 2.

Note that I moved the version code into a module of its own:
kwant.version.  The rationale is to separate this code from unrelated
stuff in kwant._common that requires various external libs.  The
kwant.version module should work on its own without any third-party
libraries.

This makes it possible to use colormaps that are white at zero and still
distinguish areas with and without sites.

This function is adapted to plotting band structure in the case
where the translation symmetry vectors are not orthogonal
(e.g. graphene). It can only handle a very limited subset of
systems (2D lattices in 2D realspace), and most of the time
use of 'plotter.spectrum' should be preferred.

This adds some extra attributed on finalization, which allow the
momentum parameter names and symmetry of the original Builder to
be accessed from the finalized wrapped-around builder.

'plotter.spectrum' can be used to plot the spectrum of
a Hamiltonian as a function of arbitrary parameters. This is
generically useful functionality, so we factor it out.

We build conda packages on 'master' (on all forks) by default.
Builds for branches may be triggered manually.

Conda forge removes support for Python 3.4. If anyone is using
conda then they can easily upgrade to newer Python in any case.

Previously we used 'ssh-keyscan' on every upload, so derived
no security from host key checking. 'ssh-keyscan' caused the CI
server's IP to be blacklisted, so now we just ignore the host key
entirely. We never send private information, so this is fine.

We previously restricted conda package uploading to master branch on the
main Kwant repository, as otherwise this step would fail for forked
repositories without a valid anaconda key. Now we build the conda
packages and upload to anaconda in two separate jobs, and the upload job
is only run on the main Kwant repository.