https://github.com/hersle/symboltz.jl

A symbolic-numeric, approximation-free and differentiable linear Einstein-Boltzmann solver
https://github.com/hersle/symboltz.jl

boltzmann-code cosmology einstein-boltzmann

Last synced: 3 months ago
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A symbolic-numeric, approximation-free and differentiable linear Einstein-Boltzmann solver

• Host: GitHub
• URL: https://github.com/hersle/symboltz.jl
• Owner: hersle
• License: mit
• Created: 2024-01-22T19:06:50.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2025-10-15T19:36:52.000Z (8 months ago)
• Last Synced: 2025-10-16T15:08:08.264Z (8 months ago)
• Topics: boltzmann-code, cosmology, einstein-boltzmann
• Language: Julia
• Homepage: https://hersle.github.io/SymBoltz.jl/
• Size: 32.2 MB
• Stars: 24
• Watchers: 1
• Forks: 0
• Open Issues: 16
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# SymBoltz.jl

[![Documentation](https://img.shields.io/badge/documentation%20-%20stable%20-%20%232e63b8)](https://hersle.github.io/SymBoltz.jl/stable/)

[![Code paper](https://img.shields.io/badge/paper%20-%20arXiv%20-%20%23b31b1b)](https://arxiv.org/abs/2509.24740)

[![Build status](https://img.shields.io/github/actions/workflow/status/hersle/SymBoltz.jl/ContinuousIntegration.yml)](https://github.com/hersle/SymBoltz.jl/actions/workflows/ContinuousIntegration.yml)

[![License](https://img.shields.io/github/license/hersle/SymBoltz.jl)](https://github.com/hersle/SymBoltz.jl/blob/main/LICENSE)

SymBoltz.jl is a Julia package for solving the linear Einstein-Boltzmann equations in cosmology. It is:

- **Symbolic-numeric:** Models are specified with symbolic equations in a simple, convenient and extensible high-level format, then automatically compiled to fast numerical functions that are solved.

- **Approximation-free:** Full equations are solved at all times without tight-coupling, ultrarelativistic fluid and radiation-streaming approximations (TCA, UFA and RSA) using efficient implicit ODE integrators.

- **Differentiable**: Get derivatives of any output (e.g. power spectra) with respect to any input (e.g. cosmological parameters) using automatic differentiation (exact to numerical precision and does not need step size tuning).

## Installation

[Install Julia](https://julialang.org/install/), launch `julia` and run:

```julia

using Pkg; Pkg.add("SymBoltz")

```

## Documentation

Visit [**the documentation pages**](https://hersle.github.io/SymBoltz.jl/) to get started with tutorials and examples.

## Gallery



## Citation

If you use SymBoltz in your work, please cite [this paper](https://arxiv.org/abs/2509.24740):

```

@article{SymBoltz,

  title = {{SymBoltz.jl}: a symbolic-numeric, approximation-free and differentiable linear {Einstein-Boltzmann} solver},

  author = {Herman Sletmoen},

  year = {2025},

  journal = {arXiv},

  eprint = {2509.24740},

  archiveprefix = {arXiv},

  primaryclass = {astro-ph.CO},

  doi = {10.48550/arXiv.2509.24740},

  url = {http://arxiv.org/abs/2509.24740},

}

```