Dark Emulator

A repository for a cosmology tool dark_emulator to emulate halo clustering statistics. The code is developed based on Dark Quest simulation suite (https://darkquestcosmology.github.io/). The current version supports the halo mass function and two point correlation function (both halo-halo and halo-matter cross).

Install

In order to install dark emulator package, use pip:

   pip install dark_emulator

or use conda:

   conda install -c nishimichi dark_emulator

(Nov. 2026) v1.2.1 is available on both pip and conda. It fixes NaN outputs of wp and xi_gg for some combinations of cosmological and HOD parameters (#27), and warns when the HOD parameters give a galaxy number density below the range covered by the emulator. v1.2.0 supports recent SciPy versions (removed simps/trapz/scipy.misc.derivative) and fixes two bugs that slightly change numerical outputs: the FFTLog wrapper argument forwarding (#31) and the k-grid of the halo-matter propagator (#32).

If the above does not work for you, you may download the source files from this repository and install via

python -m pip install -e .

after moving to the top directory of the source tree. In that case, you need to install george (a software package for the Gaussian process) and colossus

conda install -c conda-forge george
pip install colossus

From version 1.1.0, dark_emulator uses FFTLog implementation by Fang et al (2019); arXiv:1911.11947.

Usage

You can then check how Dark Emulator works by running a tutorial notebook at

docs/tutorial.ipynb
docs/tutorial-hod.ipynb

See also the documentation on readthedocs.

Code Paper

The main reference for our halo emulation strategy is: "Dark Quest. I. Fast and Accurate Emulation of Halo Clustering Statistics and Its Application to Galaxy Clustering", by T. Nishimichi et al., ApJ 884, 29 (2019), arXiv:1811.09504. Please also refer to the paper "Cosmological inference from emulator based halo model I: Validation tests with HSC and SDSS mock catalogs", by H. Miyatake et al., arXiv:2101.00113 for the implementation and performance of the halo-galaxy connection routines.