Installation
============

Prerequisites
-------------

Before installing csky, make sure you have the latest pip:

.. code::

    pip install --user --upgrade pip  # or possibly pip3, for python3

**Optional:** install the latest versions of dependencies explicitly (otherwise
pip should still guarantee that valid dependencies are installed):

.. code::

    python -m pip install --user --upgrade pybind11 numpy matplotlib scipy healpy histlite

**On macOS:** install the GNU compiler collection, which will be used instead of the
system compiler.

.. code::

    brew install "gcc@13"


csky installation
-----------------

Once you have the prerequisites, you can install csky.  First obtain the
sources:

.. code::

    cd [someplace where you would like the csky sources to live]
    git clone https://github.com/icecube/csky.git

or for a specific release, e.g.


.. code::

    git clone https://github.com/icecube/csky.git --branch releases/v1.0.0

Then install with pip:

.. code::

    python -m pip install --user --editable csky


Configuration
-------------

Before getting started with using csky, you may want to set the following
environment variables (in ``~/.profile`` or such, check your shell
documentation...).  Note that these settings are not necessary on UW machines
with access to ``/data/ana``, such as the cobalts.

.. code::

    # where you want your mirror of /data/ana/analyses or analogous repository
    export CSKY_DATA_ANALYSES_DIR="/path/to/local/mirror"
    # username for rsync'ing data (leave unset to use wget instead)
    export CSKY_REMOTE_USER="[cobalt username]"


Updating csky
-------------

As long as you've included the ``--editable`` argument as recommended above,
updating should be as simple as ``svn up``.  However, if you see a ``.cpp``
file in an incoming update (or if you modify the C++ code yourself), you'll
need to repeat the pip-install step in order to recompile the C++ extension.


Compatibility
-------------

csky is still compatible with Python 2.7, but it is nevertheless recommended
that you upgrade to Python 3 as soon as possible.  In particular, note that
csky has been tested with

.. code::

    eval `/cvmfs/icecube.opensciencegrid.org/py3-v4.0.1/setup.sh`