sisl is a Python package providing access to a large variety of things.
- creation and manipulation of geometries
- using orbitals for basis-set visualization purposes
- creating tight-binding matrices (:class:`~sisl.physics.Hamiltonian` and :class:`~sisl.physics.DynamicalMatrix` etc.) and manipulations (e.g. atomic or orbital sub-spaces)
- managing 3D real-space quantities such as density and potential grids
- unified interface for interacting with a broad range of electronic structure codes (see :mod:`sisl.io` for complete details)
- command line interfaces for parsing files on the fly for fast exploration of calculations
sisl assumes the user is careful in using consistent units.
The internal units in sisl are:
- Ang (Angstrom)
- eV (electron volt)
If you wish to introduce a specific unit, and its default, please open an `issue`_.
sisl provides a broad set of datastructures, each providing a unique set of capabilities.
The primary data structures includes:
| Class | Description |
|---|---|
| :class:`~sisl.Orbital` | Specifications of orbitals (sub-classed for various functionality) |
| :class:`~sisl.Atom` | Specifications of single atoms, species and orbitals |
| :class:`~sisl.Atoms` | A collection of :class:`~sisl.Atom` objects with smart storage (no coordinates) |
| :class:`~sisl.Lattice` | Handling lattice-vectors, manipulations of lattices |
| :class:`~sisl.Geometry` | Lattice vectors + atoms and coordinates |
| :class:`~sisl.Grid` | Real space quantities for manipulation of 3D grid-data |
| :class:`~sisl.io.Sile` | IO-interactions, reading/writing electronic structure output/input |
These primary classes, which covers the basic usage of sisl, has a dependency graph as shown below:
The vast majority of other data structures in sisl relies on these. For instance :class:`~sisl.physics.Hamiltonian` relies on a :class:`~sisl.Geometry` object.