Package: event-horyzen
Table of ContentsInstallationpipManuallyUsageExampleEvent hoRyzenis a Python library designed to simulate and visualize geodesic motion around Schwarzschild, Reisner-Nordstrom, Kerr, and Kerr-Newman black holes.
It uses a slightly modified version of Pierre Christian and Chi-kwan Chan’s FANTASY geodesic integration code (seehttps://github.com/pierrechristian/FANTASY+ Pierre Christian and Chi-kwan Chan 2021ApJ90967).Installationpippip install event-horyzenorpip install event-horzyen[pyqt](If you usezshas your shell you will need to quote the package name for optional dependencies, i.e., “event-horyzen[pyqt]”)Depending on whether or not you’d like to use thepyqtgraphandopenglplotting modules (They are not small dependencies. The option to plot with matplotlib is included in the base package).Manuallygit clone https://github.com/UCF-SPS-Research-21/event-horyzenIf you use Poetry for package and venv management, you can usepoetry installorpoetry install -E pyqtIf you don’t, you canpip install -r requirements.txtorconda install --file requirements.txt.
There are multiple versions of requirements.txt provided, it should be evident what each is for.UsageThe code is configured with a YAML configuration file.
Please see the example at <event_horyzen/config.yml>ExampleI use Unix paths in the examples. Windows paths will work too — just make sure you escape backslashes or make use ofpathlib’s functionality.If you’d like to use the default configuration, you can just leave the argument toevent_horyzen.run()empty.
To copy the default config and edit it, do the following.from pathlib import Path
from event_horyzen import event_horyzen

dest = Path("./foo/")
event_horyzen.copy_default_config(dest)If you don’t specify a destination, it will copy the file to your current working directory.
Now, assuming you’ve edited the config to your liking and its namedconfig.yml:from pathlib import Path
from event_horyzen import event_horyzen

conf_path = Path('./config.yml')
event_horyzen.run(conf_path)or for multiple geodesics simulated in parallelfrom pathlib import Path
from event_horyzen import event_horyzen

conf_path1 = Path('./config1.yml')
conf_path2 = Path('./config2.yml')
conf_path3 = Path('./config3.yml')

confs = [conf_path1, conf_path2, conf_path3]

event_horyzen.run(confs)A unique directory under the output directory specified in the configuration file will be created in the format<output-dir>/<date+time>_<name-of-config-file>.
So, it makes sense to give your configuration files meaningful names.
The geodesic in both spherical and cartesian coordinates will be saved to this directory asresults.h5.
The configuration file used to generate the simulation will be copied to this directory as well to ensure reproducibility.
A basic plot of the geodesic is also created and saved in the directory as both a .PNG and apicklefile so that the figure can be reloaded and interacted with.Example Kerr-Newman PlotIf you want to load the pickled Matplotlib plot, you can do the following.import pickle as pl
from pathlib import Path

plot_path = Path("<path-to-plot>/basic-plot.pickle")

with open(plot_path, "rb") as plot:
    fig = pl.load(plot)

# Now do whatever you want with the figure!

fig.show()For the 3D plotting,from pathlib import Path
from event_horyzen import animated_plot as ap

results = Path("./results.h5")
viz = ap.Visualizer(results)
viz.animation()or for multiple geodesics on the same plotfrom pathlib import Path
from event_horyzen import animated_plot as ap

results1 = Path("./results1.h5")
results2 = Path("./results2.h5")
results3 = Path("./results3.h5")

results = [results1, results2, results3]

viz = ap.Visualizer(results)
viz.animation()By default, it puts a photon sphere for a M=1 (geometrized units) schwarzschild black hole on the plot for reference.
This can be turned off or modified in the call toVisualizer().Both the simulation and the plotting can be ran directly from the command lineFirst, the simulation tools.event-horyzen -h

usage: event-horyzen [-h] [datapath ...]

positional arguments:
  datapath    The path(s) to the configuration file(s). Defaults to the
              included `config.yml` if not provided.

options:
  -h, --help  show this help message and exitNow, the plotting tools.event-horyzen-plot -h

usage: event-horyzen-plot [-h] datapath [datapath ...]

positional arguments:
  datapath    The path(s) to the data file(s).

options:
  -h, --help  show this help message and exit