3.1. kwant – Top level package

For convenience, short names are provided for a few widely used objects from the sub-packages. Otherwise, this package has only very limited functionality of its own.

Generic functionality

The version of Kwant is available under the name __version__. This string respects PEP 440 and has the following format

• Released version: ‘1.3.0’, ‘1.3.1’, etc.

• Alpha version: ‘1.2.0a0’, ‘1.2.0a1’, etc.

• Beta version: ‘1.1.0b0’, ‘1.1.0b1’, etc.

• Development version (derived from git describe --first-parent --dirty): ‘1.3.2.dev27+gdecf6893’, ‘1.1.1.dev10+gabcd012.dirty’, etc.

• Development version with incomplete information: ‘unknown’, ‘unknown+g0123abc’, etc.

KwantDeprecationWarning	Class of warnings about a deprecated feature of Kwant.
UserCodeError	Class for errors that occur in user-provided code.

From kwant.builder

Builder([symmetry, conservation_law, …])	A tight binding system defined on a graph.
HoppingKind(delta, family_a[, family_b])	A pattern for matching hoppings.

From kwant.lattice

TranslationalSymmetry(*periods)

A translational symmetry defined in real space.

From kwant.plotter

plot(sys[, num_lead_cells, unit, …])

Plot a system in 2 or 3 dimensions.

From kwant.solvers.default

greens_function(sys[, energy, args, …])	Compute the retarded Green’s function of the system between its leads.
ldos(sys[, energy, args, check_hermiticity, …])	Calculate the local density of states of a system at a given energy.
smatrix(sys[, energy, args, out_leads, …])	Compute the scattering matrix of a system.
wave_function(sys[, energy, args, …])	Return a callable object for the computation of the wave function inside the scattering region.