Welcome to HODDIES’s documentation!

HODDIES is a Python toolkit to generate mock galaxy catalogs based on Halo Occupation Distribution (HOD) models. It also provides tools to fit HOD models on data.

_images/HOD_cartoon.png

A typical generation of a HOD-based mock is as simple as:

from HODDIES import HOD
# Initiate the HOD instance with default parameter file parameters_HODdefaults.yaml
# Using path to catalog

path_to_halo_catalog = '/path/to/halo_catalog' # catalog type can be fits, h5, asdf
HOD_obj= HOD(hcat_file='path_to_halo_catalog')

# Using a preloaded catalog.
# This catalog need to be a dictonary / structured array or mpy Catalog.
# Colunms names should be at least:
# ['x', 'y', 'z', 'vx', 'vy', 'vz','Mh', 'Rh', 'Rs', 'c', 'Vrms', 'halo_id']

HOD_obj= HOD(hcat_file=mycatalog)

# Using root AbacusSummit simulation path, example at NERSC

HOD_obj= HOD(path_to_abacus_sim='/global/cfs/cdirs/desi/cosmosim/Abacus')

# Generate the mock catalog

mock_cat = HOD_obj.make_mock_cat(fix_seed=None)

# Compute clustering statistics

rp, wp = HOD_obj.get_wp(cats, tracers='ELG')
s, xi = HOD_obj.get_2PCF(cats, tracers='ELG')

Example notebooks are provided in nb.

User Documentation

Indices and tables