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

.. :: warning
    Mesher is only supported on Macos and Linux

Installation of mesher is possible via ``pip``, ``conda``, or ``spack``. A ``spack``  build will be the easiest due to
all the potentially complex dependencies of vtk and gal being handled automatically. See below on how to install with
``pip`` which requires system library installs. ``conda`` builds are particularly tested and YMMV.


Wheels are not prebuilt for mesher. Instead, mesher will need to be compiled as part of the install step.
This thus requires a functional build environment.


Install spack
+++++++++++++++
Install `spack <https://spack-tutorial.readthedocs.io/en/latest/tutorial_basics.html>`__

Use the git repository and use the develop branch, as significant bug fixes to packages mesher uses have been made in
this branch.

Configure Spack
+++++++++++++++++++
It is critical to ensure spack is correctly
configured, as described in the `Spack Getting Started <https://spack.readthedocs.io/en/latest/getting_started.html>`__
guide.

If you need to build a compiler via spack to use and the spack libraries, this is the time to do it.
Otherwise, ensure
the `external compiler is found by
spack <https://spack.readthedocs.io/en/latest/getting_started.html#spack-compiler-find>`__ and correctly configured.

If you use a system MPI or intel-oneapi-(mkl|tbb) (i.e., a not-spack built version), this is when it should be configured
`as a spack external <https://spack.readthedocs.io/en/latest/packages_yaml.html#external-packages>`__ package.


::

    spack repo add https://github.com/Chrismarsh/spack-repo.git
    spack install py-mesher


conda
++++++

::

    # ensure conda-forge is added
    conda config --add channels conda-forge
    conda config --set channel_priority strict

    conda install mesher


pip
++++

Using pip, mesher must be built against system libraries.

.. note::
   Depending on your python install, ``pip`` may be ``pip3``


Ensure the following are installed via package manager:

For macos:

::

      brew install gdal
      brew install boost
      brew install cgal
      brew install metis

For Ubuntu:

::

    sudo apt-get install libgdal-dev
    sudo apt-get install libcgal-dev
    sudo apt-get install gdal-bin
    sudo apt-get install libcgal-dev
    sudo apt-get install libboost-filesystem-dev
    sudo apt-get install libboost-program-options-dev
    sudo apt-get install libmetis-dev

    # on Ubuntu 20.04+
    sudo apt-get install python3-gdal
    # prior to Ubuntu 20.04, use this instead of python3-gdal
    # sudo apt-get install python-gdal


.. :: warning
    On linux you may need ``libffi`` if, upon running ``pip``, there is an error about ``_ctypes``

    On Ubuntu
    ``apt-get install libffi-dev``

    On CentOS/Fedora
     ``dnf install libffi-devel``

Then install mesher with

::

    pip install mesher