<p align="center">
<a href="http://www.galpy.org" target="_blank"><img src="https://galpy.readthedocs.io/en/latest/_static/galpy-logo-small.gif"></a><br/>
<b>Galactic Dynamics in python</b>
</p>
[galpy](http://www.galpy.org) is a Python package for galactic dynamics. It supports orbit integration in a variety of potentials, evaluating and sampling various distribution functions, and the calculation of action-angle coordinates for all static potentials. `galpy` is an [astropy](http://www.astropy.org/) [affiliated package](http://www.astropy.org/affiliated/) and provides full support for astropy’s [Quantity](http://docs.astropy.org/en/stable/api/astropy.units.Quantity.html) framework for variables with units.
[](https://github.com/jobovy/galpy/actions/workflows/build.yml) [](https://github.com/jobovy/galpy/actions/workflows/build_windows.yml) [](https://ci.appveyor.com/project/jobovy/galpy) [](http://codecov.io/github/jobovy/galpy?branch=main) [](http://docs.galpy.org/en/latest/)
[](https://pypi.python.org/pypi/galpy/) [](https://pypi.python.org/pypi/galpy/) [](https://anaconda.org/conda-forge/galpy) [](https://github.com/jobovy/galpy/commits/main)
[](https://github.com/jobovy/galpy/blob/main/LICENSE) [](http://dx.doi.org/10.1088/0067-0049/216/2/29) [](http://www.astropy.org/) [](https://join.slack.com/t/galpy/shared_invite/zt-p6upr4si-mX7u8MRdtm~3bW7o8NA_Ww)
AUTHOR
======
Jo Bovy - bovy at astro dot utoronto dot ca
See
[AUTHORS.txt](https://github.com/jobovy/galpy/blob/main/AUTHORS.txt)
for a full list of contributors.
If you find this code useful in your research, please let me know. **If
you use galpy in a publication, please cite** [Bovy
(2015)](http://adsabs.harvard.edu/abs/2015ApJS..216...29B) **and link to
http://github.com/jobovy/galpy**. See [the acknowledgement documentation
section](http://docs.galpy.org/en/latest/index.html#acknowledging-galpy)
for a more detailed guide to citing parts of the code. Thanks!
LOOKING FOR HELP?
=================
The latest documentation can be found
[here](http://docs.galpy.org/en/latest/). You can also join the
[galpy slack community](https://galpy.slack.com/) for any questions
related to `galpy`; join
[here](https://join.slack.com/t/galpy/shared_invite/zt-p6upr4si-mX7u8MRdtm~3bW7o8NA_Ww).
If you find *any* bug in the code, please report these using the [Issue
Tracker](http://github.com/jobovy/galpy/issues) or by joining the [galpy
slack community](https://galpy.slack.com/).
If you are having issues with the installation of `galpy`, please first
consult the [Installation
FAQ](http://docs.galpy.org/en/latest/installation.html#installation-faq).
PYTHON VERSIONS AND DEPENDENCIES
================================
`galpy` supports Python 3. Specifically, galpy supports Python 3.7,
3.8, 3.9, 3.10. It should also work on earlier Python 3.\* versions,
but this is not extensively tested on an ongoing basis and because
libraries that `galpy` depends on are dropping earlier Python 3.\*
versions, `galpy` itself likely doesn't fully work on them. GitHub
Actions CI builds regularly check support for Python 3.10 (and of 3.7,
3.8, and 3.9 using a more limited, core set of tests) on Linux and
Windows (and 3.10 on Mac OS); Appveyor builds regularly check support
for Python 3.10 on Windows. Python 2.7 is no longer supported.
This package requires [Numpy](https://numpy.org/),
[Scipy](http://www.scipy.org/), and
[Matplotlib](http://matplotlib.sourceforge.net/). Certain advanced
features require the GNU Scientific Library
([GSL](http://www.gnu.org/software/gsl/)), with action calculations
requiring version 1.14 or higher. Other optional dependencies include:
* Support for providing inputs and getting outputs as Quantities with units is provided through
[`astropy`](http://www.astropy.org/).
* Querying SIMBAD for the coordinates of an object in the `Orbit.from_name` initialization method requires [`astroquery`](https://astroquery.readthedocs.io/en/latest/).
* Displaying a progress bar for certain operations (e.g., orbit integration of multiple objects at once) requires [`tqdm`](https://github.com/tqdm/tqdm).
* Plotting arbitrary functions of Orbit attributes requires [`numexpr`](https://github.com/pydata/numexpr).
* Speeding up the evaluation of certain functions in the C code requires [`numba`](https://numba.pydata.org/).
* Constant-anisotropy DFs in `galpy.df.constantbetadf` require [`JAX`](https://github.com/google/jax).
* Use of `SnapshotRZPotential` and `InterpSnapshotRZPotential` requires [`pynbody`](https://github.com/pynbody/pynbody).
Other parts of the code may require additional packages and you will be alerted by the code if they are
not installed.
CONTRIBUTING TO GALPY
=====================
If you are interested in contributing to galpy\'s development, take a
look at [this brief
guide](https://github.com/jobovy/galpy/wiki/Guide-for-new-contributors)
on the wiki. This will hopefully help you get started!
Some further development notes can be found on the
[wiki](http://github.com/jobovy/galpy/wiki/). This includes a list of
small and larger extensions of galpy that would be useful
[here](http://github.com/jobovy/galpy/wiki/Possible-galpy-extensions) as
well as a longer-term roadmap
[here](http://github.com/jobovy/galpy/wiki/Roadmap). Please let the main
developer know if you need any help contributing!
DISK DF CORRECTIONS
===================
The dehnendf and shudf disk distribution functions can be corrected to
follow the desired surface-mass density and radial-velocity-dispersion
profiles more closely (see
[1999AJ\....118.1201D](http://adsabs.harvard.edu/abs/1999AJ....118.1201D)).
Calculating these corrections is expensive, and a large set of
precalculated corrections can be found
[here](http://github.com/downloads/jobovy/galpy/galpy-dfcorrections.tar.gz)
\[tar.gz archive\]. Install these by downloading them and unpacking them
into the galpy/df/data directory before running the setup.py
installation. E.g.:
curl -O https://github.s3.amazonaws.com/downloads/jobovy/galpy/galpy-dfcorrections.tar.gz
tar xvzf galpy-dfcorrections.tar.gz -C ./galpy/df/data/