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Installation

This guide covers the installation and setup of VULCAN, a photochemical kinetics code for exoplanetary atmospheres.

Prerequisites

Before installing VULCAN, ensure you have the following:

  • Python 3.11 or higher (Python 3.12 and 3.13 are also supported)
  • C++ compiler (for compiling FastChem)
  • Git (for cloning the repository)
  • Basic build tools (make, cmake, etc.)

Installation steps

0. Install julia

For the coupling to the julia-based 1D radiative-convective model AGNI, julia needs to be installed. Do not install julia via your computer's package manager. Instead:

curl -fsSL https://install.julialang.org | sh

1. Clone the repository

git clone https://github.com/FormingWorlds/VULCAN.git
cd VULCAN

2. Install python dependencies

VULCAN requires the following Python packages (specified in pyproject.toml):

  • numpy (≥2.0.0)
  • scipy
  • matplotlib
  • pandas
  • sympy
  • astropy
  • juliacall
pip install -e .

This installs VULCAN in development mode along with all dependencies.

Option B: Install dependencies manually

pip install numpy scipy matplotlib pandas sympy astropy juliacall

3. Compile FastChem

FastChem is an equilibrium chemistry code used to initialize compositions. It must be compiled before running VULCAN.

cd fastchem_vulcan
make
cd ..

The compilation process: - Compiles the FastChem source code in fastchem_src/ - Builds the model main executable - Links everything together - Creates the necessary executables in the obj/ folder

If compilation succeeds, you'll see: 

compiling done.
linking done.
everything is done and fine. enjoy your day!

4. Verify installation

Test that everything is working by running the demo:

python vulcan.py

This will: - Generate chem_funs.py based on the default chemical network - Run the default model (Earth-like atmosphere) - Display real-time plotting (if use_live_plot = True in config.py) - Take approximately 10-15 minutes to complete

If successful, you'll see output files in the /output folder.