Description

Python package of utility functions that are useful in analyzing various datasets, in particular, catalogs of particles or galaxies/halos from cosmological simulations. (The GizmoAnalysis and HaloAnalysis packages depend on this package.)

Requirements

python 3, numpy, scipy, h5py, matplotlib

Content

lower-level utilities

array.py

• create, manipulate, analyze arrays

binning.py

• binning of array data

constant.py

• physical constants and unit conversions

coordinate.py

• manipulate positions and velocities

io.py

• read, write, print during run time

math.py

• math, statistics, and fitting

plot.py

• supplementary functions for plotting with matplotlib

higher-level utilities

catalog.py

• analyze catalogs of halos/galaxies

cosmology.py

• calculate cosmological values, including cosmic density, distance, age, volume

halo_property.py

• calculate halo properties at different radii, convert between virial definitions

orbit.py

• compute orbital quantities such as peri/apo-centric distance, orbital time, in a given gravitational potential

particle.py

• high-level analysis of N-body particle data

simulation.py

• tools to help set up and run a simulation

Units

Unless otherwise noted, this package stores all quantities in (combinations of) these base units

• mass [M_sun]
• position [kpc comoving]
• distance, radius [kpc physical]
• time [Gyr]
• temperature [K]
• magnetic field [Gauss]
• elemental abundance [linear mass fraction]

These are the common exceptions to those standards

• velocity [km/s]
• acceleration [km/s / Gyr]
• gravitational potential [km^2 / s^2]
• rates (star formation, cooling, accretion) [M_sun / yr]
• metallicity (if converted from stored massfraction) [log10(mass_fraction / mass_fraction_solar)], using Asplund et al 2009 for Solar

Installing

The easiest way to install this packages is by using pip:

python -m pip install utilities_awetzel

Alternately, to install the latest stable version from source, clone from bitbucket:

git clone git://bitbucket.org/awetzel/utilities.git

then either point your PYTHONPATH to this repository or you build and install this project via pip by going inside the top-level utilities directory and:

python -m pip install .

Using

Once installed, you can use individual modules like this:

import utilities as ut
ut.particle