Installation¶
With conda¶
The easiest way to install the latest released version of galpy is using conda:
conda install galpy -c conda-forge
or:
conda config --add channels conda-forge
conda install galpy
With pip¶
galpy can also be installed using pip. Some advanced features require the GNU Scientific Library (GSL; see below). If you want to use these, install the GSL first (or install it later and re-install using the upgrade command above). Then do:
pip install galpy
or to upgrade without upgrading the dependencies:
pip install -U --no-deps galpy
Latest version¶
The latest updates in galpy can be installed using:
pip install -U --no-deps git+git://github.com/jobovy/galpy.git#egg=galpy
or:
pip install -U --no-deps --install-option="--prefix=~/local" git+git://github.com/jobovy/galpy.git#egg=galpy
for a local installation. The latest updates can also be installed from the source code downloaded from github using the standard python setup.py
installation:
python setup.py install
or:
python setup.py install --prefix=~/local
for a local installation.
Installing from a branch¶
If you want to use a feature that is currently only available in a branch, do:
pip install -U --no-deps git+git://github.com/jobovy/galpy.git@dev#egg=galpy
to, for example, install the dev
branch.
Installing the TorusMapper code¶
Since v1.2, galpy
contains a basic interface to the TorusMapper
code of Binney & McMillan (2016). This interface
uses a stripped-down version of the TorusMapper code, that is not
bundled with the galpy code, but kept in a fork of the original
TorusMapper code. Installation of the TorusMapper interface is
therefore only possible when installing from source after downloading
or cloning the galpy code and using the python setup.py install
method above.
To install the TorusMapper code, before running the installation of
galpy, navigate to the top-level galpy directory (which contains the
setup.py
file) and do:
git clone https://github.com/jobovy/Torus.git galpy/actionAngle_src/actionAngleTorus_c_ext/torus
cd galpy/actionAngle_src/actionAngleTorus_c_ext/torus
git checkout galpy
cd -
Then proceed to install galpy using the python setup.py install
technique or its variants as usual.
Installation FAQ¶
What is the required numpy
version?¶
galpy
should mostly work for any relatively recent version of
numpy
, but some advanced features, including calculating the
normalization of certain distribution functions using Gauss-Legendre
integration require numpy
version 1.7.0 or higher.
I get warnings like “galpyWarning: integrateFullOrbit_c extension module not loaded, because galpy_integrate_c.so image was not found”¶
This typically means that the GNU Scientific Library (GSL) was unavailable during galpy’s installation, causing the C extensions not to be compiled. Most of the galpy code will still run, but slower because it will run in pure Python. The code requires GSL versions >= 1.14. If you believe that the correct GSL version is installed for galpy, check that the library can be found during installation (see below).
I get the warning “galpyWarning: actionAngleTorus_c extension module not loaded, because galpy_actionAngleTorus_c.so image was not found”¶
This is typically because the TorusMapper code was not compiled,
because it was unavailable during installation. This code is only
necessary if you want to use
galpy.actionAngle.actionAngleTorus
. See above
for instructions on how to install the TorusMapper code.
How do I install the GSL?¶
Certain advanced features require the GNU Scientific Library (GSL), with action calculations requiring version 1.14 or higher. On a Mac, the easiest way to install the GSL is using Homebrew as:
brew install gsl --universal
You should be able to check your version using:
gsl-config --version
On Linux distributions with apt-get
, the GSL can be installed using:
apt-get install libgsl0-dev
The galpy
installation fails because of C compilation errors¶
galpy
’s installation can fail due to compilation errors, which look like:
error: command 'gcc' failed with exit status 1
or:
error: command 'clang' failed with exit status 1
or:
error: command 'cc' failed with exit status 1
This is typically because the compiler cannot locate the GSL header
files or the GSL library. You can tell the installation about where
you’ve installed the GSL library by defining (for example, when the
GSL was installed under /usr
):
export CFLAGS=-I/usr/include
export LDFLAGS=-L/usr/lib
or:
setenv CFLAGS -I/usr/include
setenv LDFLAGS -L/usr/lib
depending on your shell type (change the actual path to the include
and lib directories that have the gsl directory). If you already have
CFLAGS
and LDFLAGS
defined you just have to add the
'-I/usr/include'
and '-L/usr/lib'
to them.
I’m having issues with OpenMP¶
galpy uses OpenMP to parallelize various
of the computations done in C. galpy can be installed without OpenMP
by specifying the option --no-openmp
when running the python
setup.py
commands above:
python setup.py install --no-openmp
or when using pip as follows:
pip install -U --no-deps --install-option="--no-openmp" git+git://github.com/jobovy/galpy.git#egg=galpy
or:
pip install -U --no-deps --install-option="--prefix=~/local" --install-option="--no-openmp" git+git://github.com/jobovy/galpy.git#egg=galpy
for a local installation. This might be useful if one is using the
clang
compiler, which is the new default on macs with OS X (>=
10.8), but does not support OpenMP. clang
might lead to errors in the
installation of galpy such as:
ld: library not found for -lgomp
clang: error: linker command failed with exit code 1 (use -v to see invocation)
If you get these errors, you can use the commands given above to
install without OpenMP, or specify to use gcc
by specifying the
CC
and LDSHARED
environment variables to use gcc
. Note
that clang
does not seem to have this issue anymore in more recent
versions, but it still does not support OpenMP
.
Configuration file¶
Since v1.2, galpy
uses a configuration file to set a small number
of configuration variables. This configuration file is parsed using
ConfigParser/configparser. It is
currently used to set a default set of distance and velocity scales
(ro
and vo
throughout galpy) for conversion between physical
and internal galpy units, to decide whether to use seaborn plotting with galpy’s defaults (which affects all plotting after importing galpy.util.bovy_plot
), to specify whether output from functions or
methods should be given as an astropy Quantity
with units as much as possible or not, and whether or not to use
astropy’s coordinate transformations (these
are typically somewhat slower than galpy’s own coordinate
transformations, but they are more accurate and more general). The
current configuration file therefore looks like this:
[normalization]
ro = 8.
vo = 220.
[plot]
seaborn-bovy-defaults = False
[astropy]
astropy-units = False
astropy-coords = True
where ro
is the distance scale specified in kpc, vo
the
velocity scale in km/s, and the setting is to not return output as a
Quantity. These are the current default settings.
A user-wide configuration file should be located at
$HOME/.galpyrc
. This user-wide file can be overridden by a
$PWD/.galpyrc
file in the current directory. If no configuration
file is found, the code will automatically write the default
configuration to $HOME/.galpyrc
. Thus, after installing galpy, you
can simply use some of its simplest functionality (e.g., integrate an
orbit), and after this the default configuration file will be present
at $HOME/.galpyrc
. If you want to change any of the settings (for
example, you want Quantity output), you can edit this file. The
default configuration file can also be found here
.