swiftsimio 0.1.1

SWIFTsim (swift.dur.ac.uk) i/o routines for python.

SWIFTsimIO

The SWIFT astrophysical simulation code (http://swift.dur.ac.uk) is used widely. There exists many ways of reading the data from SWIFT, which outputs HDF5 files. These range from reading directly using h5py to using a complex system such as yt; however these either are unsatisfactory (e.g. a lack of unit information in reading HDF5), or too complex for most use-cases. This (thin) wrapper provides an object-oriented API to read (dynamically) data from SWIFT.

Requirements

This requires python3.6.0 or higher. No effort will be made to support python versions below this. Please update your systems.

Python packages

• h5py
• unyt

Usage

Example usage is shown below, which plots a density-temperature phase diagram, with density and temperature given in CGS units:

import swiftsimio as sw

# This loads all metadata but explicitly does _not_ read any particle data yet
data = sw.load("/path/to/swift/output")

import matplotlib.pyplot as plt

data.gas.density.convert_to_cgs()
data.gas.temperature.convert_to_cgs()

plt.loglog()

plt.scatter(
    data.gas.density,
    data.gas.temperature,
    s=1
)

plt.xlabel(fr"Gas density $\left[{data.gas.density.units.latex_repr}\right]$")
plt.ylabel(fr"Gas temperature $\left[{data.gas.temperature.units.latex_repr}\right]$")

plt.tight_layout()

plt.savefig("test_plot.png", dpi=300)

In the above it's important to note the following:

• All metadata is read in when the load function is called.
• Only the density and temperature (corresponding to the PartType0/Density and PartType0/Temperature) datasets are read in.
• That data is only read in once the convert_to_cgs method is called.
• convert_to_cgs converts data in-place; i.e. it returns None.
• The data is cached and not re-read in when plt.scatter is called.