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PIANISTpy
Particle Initial conditions with ANISoTropy · ver. 1.0.0
  • Get started
    • What PIANISTpy does
    • Install
    • Quick start
    • Representative computing time
  • User guide
    • Models
    • Particles (Sampler)
    • Observables
    • Superposition and inference
    • Units
    • Accuracy
    • Input and output (write, read)
    • Runtime options
  • Examples
    • Tutorials
    • Chiang+(2026d) figures
    • N-body tests with GAMER
  • API reference
    • Functions by subpackage
    • Numerical settings
    • Code and paper notations
    • Accuracy tables
    • Technical notes
  • Development
    • Release notes
    • Accuracy by release
    • Upcoming features
    • Contributing
  • Citation
    • How to cite
    • License and authors
PIANISTpy

User guide

  • Models
    • Density profiles (DoublePowerLaw)
    • Velocity anisotropy (Anisotropy, Component)
    • Distribution functions (compute_df)
    • Truncation in phase space (truncate, solve)
  • Particles (Sampler)
  • Observables
    • Radial velocity dispersion (sigma_r)
    • Tangential velocity dispersion (sigma_t)
    • Line-of-sight velocity distribution (losvd)
    • Line-of-sight velocity distribution in an aperture (aperture_losvd)
    • Local velocity distribution (pdf_v)
    • Line-of-sight table (LosTable)
    • End-to-end differentiability
    • Differentiable observables (Differentiable)
  • Superposition and inference
  • Units
  • Accuracy
    • Flags and refusals
  • Input and output (write, read)
  • Runtime options
  • User guide
  • Models

Models#

A model (Model) is an equilibrium of one or more components, untruncated or truncated in phase space. Each component is a density profile with a velocity anisotropy, and the model holds the distribution function of each component. A model is built in the four main steps below.

  • Density profiles (DoublePowerLaw)
  • Velocity anisotropy (Anisotropy, Component)
  • Distribution functions (compute_df)
  • Truncation in phase space (truncate, solve)

© Copyright 2026, Barry T. Chiang.

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