allow computations even if a discrete symmetry is broken

Closes #236 and #242

See merge request kwant/kwant!257

Previously if there were more site families than colours in the
matplotlib cycle, then plotting would raise an exception. Now
we cycle through the colours indefinitely.

Closes #257

This was fixed on stable, but due to interim changes and a badly
solved merge conflict, the fix was not applied to master.

This has a lower chance to give an impression that the substitution
happens in-place.

Closes gitlab issue #237

The 'mpl_available' flag was relegated to '_plotter' in
the development version, but the check in the test was still
referring to 'plotter'. The change 'plotter → _plotter' was
made on the development version, so this fix does not need to
be backported to the stable branch.

Currently we test against 5 environments: Ubuntu LTS, Debian stable,
minimum required dependency versions from conda forge, minimum
required dependencies without extras (sympy and matplotlib), and latest
dependency versions from conda forge.

Dániel Varjas authored 7 years ago and Joseph Weston committed 6 years ago

Improve the logic of 'cvp', now it provably works in all cases.
Add 'reduced' option to 'linalg.lll.voronoi', this eliminates
superfluous Voronoi vectors that do not have a corresponding face
of the Voronoi cell, or this face would be smaller than 'rtol'.

Simplify 'lattice.Polyatomic.neighbors' by providing the option
to group equidistant vectors 'group_by_length' in 'linalg.lll.cvp'.

See !165 for details.

Closes #163.

builder.fill: Make starting sites that are not in the template a warning, and improve the warning message in this case.

See merge request kwant/kwant!244

We raise a warning and remove the sites from 'start', so as to avoid
cryptic 'KeyError's later.

Also take an early exit if there are no starting sites in the template,
to avoid a spurious warning about all starting sites already being
present in the target.

Closes #224.

This is the standard way to re-raise errors and makes the messages
easier to follow.

Simplifications and optimizations of how parameters are handled

Closes #228

See merge request kwant/kwant!243

Christoph Groth authored 6 years ago and Joseph Weston committed 6 years ago

Co-authored-by: Joseph Weston <joseph@weston.cloud>

Christoph Groth authored 6 years ago and Joseph Weston committed 6 years ago

With this, wrapping parameter-substituted value functions is no longer
necessary and any overhead of using builder parameter substitutions
disappears.

Co-authored-by: Joseph Weston <joseph@weston.cloud>

Christoph Groth authored 6 years ago and Joseph Weston committed 6 years ago

Co-authored-by: Joseph Weston <joseph@weston.cloud>

Christoph Groth authored 6 years ago and Joseph Weston committed 6 years ago

and without default values.

Co-authored-by: Joseph Weston <joseph@weston.cloud>

Christoph Groth authored 6 years ago and Joseph Weston committed 6 years ago

This requires changes to other modules, but these were kept to a
minimum.  The most important one is that
builder._FinalizedBuilderMixin.hamiltonian() now always calls value
functions using *args.