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Installation

This page describes a manual developer installation of JANUS and SOCRATES.

Note

The standard way of installing JANUS is within the PROTEUS Framework, as described in the PROTEUS installation guide. Only use the guide below for a standalone installation of JANUS.

Prerequisites

  • git
  • Python 3.10+ (recommended: 3.11)
  • a Fortran/C build toolchain (gfortran, gcc, make)
  • NetCDF tools and NetCDF-Fortran development headers/libraries
  • optional but recommended: Conda

Typical installation commands:

sudo apt install libnetcdff-dev gfortran

sudo dnf install gcc gcc-gfortran gcc-c++ netcdf netcdf-fortran netcdf-fortran-devel \
    lapack lapack-devel lapack-static

brew install git gcc netcdf netcdf-fortran

sudo port install netcdf-fortran +gcc8 wget gcc13

0. Create a Conda environment [optional]

Using a dedicated Conda environment helps avoid dependency conflicts.

conda create -n janus python=3.11 -y
conda activate janus

1. Install SOCRATES

JANUS uses the SOCRATES radiative transfer code as an external dependency. A helper script is provided to clone and build it:

bash tools/get_socrates.sh /path/to/socrates

This clones the repository, runs ./configure, and compiles the code. Once done, add the following to your ~/.bashrc (or ~/.zshrc):

export RAD_DIR=/path/to/socrates

Custom install path

The script accepts an optional path argument. If omitted, SOCRATES is cloned into a socrates/ subdirectory of the current working directory.

Running tests with a custom SOCRATES path

You can override RAD_DIR for a single command without modifying your shell profile:

RAD_DIR=/path/to/socrates pytest

2. Install JANUS

git clone git@github.com:FormingWorlds/JANUS.git
cd JANUS
pip install -e .

3. Download JANUS data

Data is downloaded from the OSF repository.

Set FWL_DATA to define where spectral and stellar data are stored:

export FWL_DATA=/path/to/fwl_data

Download the default datasets:

janus download spectral
janus download stellar

To download a specific spectral dataset with a given number of bands:

janus download spectral -n Frostflow -b 4096

4. Verify installation

Inspect active environment paths with:

janus env

This prints the resolved locations of RAD_DIR and FWL_DATA.

Environment variables

RAD_DIR

Points to the compiled SOCRATES directory. JANUS will not function without this. Set it in your shell profile as shown in step 1, or export it inline:

export RAD_DIR=/path/to/socrates

FWL_DATA

Controls where JANUS stores downloaded spectral and stellar data. By default the location follows the XDG base directory specification. Override it with:

export FWL_DATA=/path/to/fwl_data