# Functions by subpackage

Source: https://pianistpy.com/docs/reference/api/

Docstrings cite two documents by number. An equation, section or figure of [Chiang+(2026d)](https://arxiv.org/abs/2610.28758) is cited as
“Chiang+(2026d), Eq. (B9)”, “Chiang+(2026d), Section 2.1” or “Chiang+(2026d), Fig. 14”. An equation,
section or table of the [Technical notes](https://pianistpy.com/docs/reference/notes) is cited by its number, which carries the
prefix “T:”, for example “Eq. (T:2.4)”, “Section T:2.3.1” or “Table T:2.1”.

- [The package](https://pianistpy.com/docs/reference/api/pianistpy)

- [Density profiles](https://pianistpy.com/docs/reference/api/profiles)

- [Velocity anisotropy](https://pianistpy.com/docs/reference/api/anisotropy)

- [Distribution functions and models](https://pianistpy.com/docs/reference/api/df)

- [Particles](https://pianistpy.com/docs/reference/api/particles)

- [Observables](https://pianistpy.com/docs/reference/api/observables)

- [Superposition](https://pianistpy.com/docs/reference/api/superposition)

- [Inference](https://pianistpy.com/docs/reference/api/inference)

- [Units](https://pianistpy.com/docs/reference/api/units)

- [Results and files](https://pianistpy.com/docs/reference/api/io)

- [Settings](https://pianistpy.com/docs/reference/api/settings)

- [Validation](https://pianistpy.com/docs/reference/api/validation)

- [Exceptions](https://pianistpy.com/docs/reference/api/exceptions)

- [Runtime options](https://pianistpy.com/docs/reference/api/runtime)

- [Numerics](https://pianistpy.com/docs/reference/api/numerics)