ForestFlow

Lyman-alpha Cosmology Emulator. This code is a normalising flow emulator for the 3D flux power spectrum of the Lyman-alpha forest.

Emulator parameters:

These are the parameters that describe each individual P3D(k, mu) power spectrum. We have detached these from redshift and traditional cosmology parameters.

Cosmological parameters:

Delta2_p is the amplitude of the (dimensionless) linear spectrum at k_p = 0.7 1/Mpc

n_p is the slope of the linear power spectrum at k_p

IGM parameters:

mF is the mean transmitted flux fraction in the box (mean flux)

sigT_Mpc is the thermal broadening scale in comoving units, computed from T_0 in the temperature-density relation

gamma is the slope of the temperature-density relation

kF_Mpc is the filtering length (or pressure smoothing scale) in inverse comoving units

Tutorials:

In the Notebooks folder, there are several tutorials one can run to learn how to use the emulators and archives.

• Archive tutorial: notebooks/Tutorial_archive.ipynb
• Emulator tutorial: notebooks/Tutorial_emulator.ipynb

Installation

(Last update Jan 19 2024)

• Create a new conda environment. It is usually better to follow python version one or two behind. In January 2024, the latest is 3.12, so we recommend 3.11.

conda create -n forestflow -c conda-forge python=3.11 camb fdasrsf pip=24.0
conda activate forestflow

• Install LaCE:

Follow the instructions from https://github.com/igmhub/LaCE

• Clone the ForestFlow repo and perform an editable installation:

git clone https://github.com/igmhub/ForestFlow.git
cd ForestFlow
pip install -e . [jupyter] # try with or without space between the . and jupyter if you need it

• Generate notebooks:

pip install jupytext
jupytext --to ipynb notebooks/*/*.py

• If you want to use notebooks via JupyterHub, you'll also need to download ipykernel:

pip install ipykernel
python -m ipykernel install --user --name forestflow --display-name forestflow

• If you want to use Px routines, you need to install hankl:

pip install -e .[px]