Pablo Piskunow authored 7 years ago and Joseph Weston committed 6 years ago

  When passing `energy_resolution`, the number of moments is set using
  the yet undefined parameter `self._a`. Now the number of moments is
  set after defining `self._a`.

If 'mplot3d' is not available then plotting 2D systems fails because
'plot' calls 'set_colors', which references 'mplot3d'.

The check is meant to make sure we don't use a hopping length that
is smaller than a certain threshold (10E-5 previously). Here we
correct the check and increase the threshold so as not to have
too fine-grained gridding.

Thanks to Jörg Behrmann for reporting this problem!

Add RELEASE.rst that documents the process of making
a Kwant release.

See merge request kwant/kwant!184

Also include grammatical/stylistic changes, and a re-ordering
of some sections.

Closes #188.

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

Running "kwant.continuum.discretize('k_x**2 + 1')" was resulting
in an "AssertionError". This happend because "1 * expr = expr"
in SymPy and therefore a wrong argument has been passed to
"_read_offset" function.

While we *may* choose only to specify that finalize() returns
a system.Finitesystem (or system.InfiniteSystem), this is probably
a bad idea, as the docstring of finalize() is the only place that
people can find out about builder.FiniteSystem (which contains
the documentation for the 'sites' attribute, for example).

Matplotlib backends like PDF cannot display arbitrarily thin lines.
That's why kwant.plotter.streamplot simulates thinner lines by blending
them into the background.

Previously if no lines were blended, i.e. all had the same color value
1, the background color would be used for drawing them instead of the
line color.

Bas Nijholt authored 7 years ago and Anton Akhmerov committed 7 years ago

Closes #182

This commit fixes the bug in phs_symmetrization when it fails to produce ph eigenstates
with PH^2 = +1 when one of the wave functions is mapped exactly onto another one by PH,
as in this case the PH symmetrized wf's from the two are identical. This is the case
with wfs = np.eye(2) and  particle_hole = sigma[1], the second vector returned is an
eigenstate with eigenvalue -1 not +1. In general this can be even worse, if there are
multiple such vector pairs some vectors may not be ph eigenstates at all.

The new code uses an improved version of the matrix square root method from
Applied Mathematics and Computation 234 (2014) 380-384.

Tests are modified to clear up the random unitary generation process (using kwant.rmt).
Tests are now guaranteed to feed orthonormal set of vectors to phs_symmetrization().
Add extra tests for the fully off-diagonal case where the old method fails.

Previously, in order to not to fix the matplotlib backend, we required
users to import matplotlib.pyplot before calling any Kwant plotting
functions.  This did not have the desired effect, since we did import
`matplotlib.backends` and that also fixes the backend.

Now, both backends and pyplot are imported at the last possible moment
and a warning is emitted if this fixes the backend.

The problem was introduced in commit 7c802539.

Closes #47.

Previously it was never made explicit that the current
returned from an operator is ordered like the system graph, or
that the density is ordered as the sites of the system.

Closes #172.

Backport deprecation warning fixes from 'master' to 'stable'
(these changes should have been applied to 'stable' directly).

The lead does not have connected unit cells and serves no purpose.
We also remove the check for the number of 'collections' in the
resulting plots, as now both 'syst_2d' and 'syst_3d' produce
systems with 2 leads.

Improve mode documentation.

See !190 for details.