Installing |igraph|
It is recommended to install a binary package that includes both C core and Python interface. You can choose either of PyPI or Conda. Linux users can also use their package manager.
PyPI has installers for Windows, Linux, and macOS. We aim to provide binary packages for the three latest minor versions of Python 3.x.
To install the Python interface of |igraph| globally, use the following command (you might need administrator/root privileges):
$ pip install igraph
If you prefer to install |igraph| in a user folder using a virtual environment, use the following commands instead:
$ python -m venv my_environment $ source my_environment/bin/activate $ pip install igraph
As usual, if you do not want to activate the virtualenv, you can call the pip
executable in it directly:
$ python -m venv my_environment $ my_environment/bin/pip install igraph
Packages are kindly provided by conda-forge:
$ conda install -c conda-forge python-igraph
Like virtualenv, Conda also offers virtual environments. If you prefer that option:
$ conda create -n my_environment $ conda activate my_environment $ conda install -c conda-forge python-igraph
|igraph|'s Python interface and its dependencies are included in several package management systems, including those of the most popular Linux distributions (Arch Linux, Debian and Ubuntu, Fedora, GNU Guix, etc.) as well as some cross-platform systems like NixPkgs or MacPorts.
Note
|igraph| is updated quite often: if you need a more recent version than your
package manager offers, use pip or conda as shown above. For bleeding-edge
versions, compile from source (see below).
Compiling |igraph| from source
You might want to compile |igraph| to test a recently added feature ahead of release or to install |igraph| on architectures not covered by our continuous development pipeline.
Note
In all cases, the Python interface needs to be compiled against a matching version of the |igraph| core C library.
If you want the development version of |igraph|, call:
$ pip install git+https://github.com/igraph/python-igraph
pip is smart enough to download the sources from Github, initialize the
submodule for the |igraph| C core, compile it, and then compile the Python
interface against it and install it. As above, a virtual environment is
a commonly used sandbox to test experimental packages.
If you want the latest release from PyPI but prefer to (or have to) install from source, call:
$ pip install --no-binary ':all:' igraph
Note
If there is no binary for your system anyway, you can just try without the --no-binary option and
obtain the same result.
This section should be rarely used in practice but explains how to compile and
install |igraph| step by step without pip.
First, obtain the bleeding-edge source code from Github:
$ git clone https://github.com/igraph/python-igraph.git
or download a recent release from PyPI or from the Github releases page. Decompress the archive if needed.
Second, go into the folder:
$ cd python-igraph
(it might have a slightly different name depending on the release).
Third, if you cloned the source from Github, initialize the git submodule for the |igraph| C core:
$ git submodule update --init
Note
If you prefer to compile and link |igraph| against an existing |igraph| C core, for instance
the one you installed with your package manager, you can skip the git submodule initialization step. If you
downloaded a tarball, you also need to remove the vendor/source/igraph folder because the setup script
will look for the vendored |igraph| copy first. However, a particular
version of the Python interface is guaranteed to work only with the version
of the C core that is bundled with it (or with the revision that the git
submodule points to).
Fourth, call the standard Python setup.py script, e.g. for compiling:
$ python setup.py build
(press Enter when prompted). That will compile the Python interface in a subfolder called
build/lib.<your system-your Python version>, e.g. build/lib.linux-x86_64-3.8. You can add
that folder to your PYTHONPATH if you want to import directly from it, or you can call the setup.py
script to install it from there:
$ python setup.py install
Note
The setup.py script takes a number of options to customize the install location.
The unit tests are implemented with the standard unittest module so you can
run them like this from your the source folder:
$ python -m unittest discover
Q: I am trying to install |igraph| on Windows but am getting DLL import errors
A: The most common reason for this error is that you do not have the Visual C++ Redistributable library installed on your machine. Python's own installer is supposed to install it, but in case it was not installed on your system, you can download it from Microsoft.
Q: I am trying to use |igraph| but get errors about something called Cairo
A: |igraph| by default uses a third-party called Cairo for plotting. If Cairo is not installed on your computer, you might get an import error. This error is most commonly encountered on Windows machines.
There are two solutions to this problem: installing Cairo or, if you are using a recent versions of |igraph|, switching to the :mod:`matplotlib` plotting backend.
1. Install Cairo: As explained here, you need to install Cairo headers using your package manager (Linux) or homebrew (macOS) and then:
$ pip install pycairo
The Cairo project does not provide pre-compiled binaries for Windows, but Christoph Gohlke maintains a site containing unofficial Windows binaries for several Python extension packages, including Cairo. Therefore, the easiest way to install Cairo on Windows along with its Python bindings is simply to download it from Christoph's site. Make sure you use an installer that is suitable for your Windows platform (32-bit or 64-bit) and the version of Python you are using.
To check if Cairo is installed correctly on your system, run the following example:
>>> import igraph as ig
>>> g = ig.Graph.Famous("petersen")
>>> ig.plot(g)
If PyCairo was successfully installed, this will display a Petersen graph.
2. Switch to matplotlib: You can :doc:`configure <configuration>` |igraph| to use matplotlib instead of Cairo. First, install it:
$ pip install matplotlib
To use matplotlib for a single plot, create a :class:`matplotlib.figure.Figure` and :class:`matplotlib.axes.Axes` beforehand (e.g. using :func:`matplotlib.pyplot.subplots`):
>>> import matplotlib.pyplot as plt
>>> import igraph as ig
>>> fig, ax = plt.subplots()
>>> g = ig.Graph.Famous("petersen")
>>> ig.plot(g, target=ax)
>>> plt.show()
To use matplotlib for a whole session/notebook:
>>> import matplotlib.pyplot as plt
>>> import igraph as ig
>>> ig.config["plotting.backend"] = "matplotlib"
>>> g = ig.Graph.Famous("petersen")
>>> ig.plot(g)
>>> plt.show()
To preserve this preference across sessions/notebooks, you can store it in the default configuration file used by |igraph|:
>>> import igraph as ig >>> ig.config["plotting.backend"] = "matplotlib" >>> ig.config.save()
From now on, |igraph| will default to matplotlib for plotting.