.. Copyright 2023 Lawrence Livermore National Security, LLC and other
   Benchpark Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: Apache-2.0

===================
Compare Build Specs
===================
``lib/scripts/diffBuildSpecs.py``

Compare two experiment build specs (dependence graphs with versions of dependencies), 
generated by Spack for specified packages+options.
This script enables the user to compare packages and versions of two spack builds.
Given two yaml package specs (use ``spack spec --yaml``), 
the script outputs which components of the packages are different.

.. note::
   If you are trying to compare benchpark benchmarks, try using ``diffExperimentBuilds.py``.

Example: dray with/without MPI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In this example, we see the difference of ``dray`` built with and without ``mpi``.
The difference between the specs ``dray+mpi`` and ``dray~mpi`` is indicated in the output 
by ``-> [openmpi]`` and the console output highlights the package differences in red.

.. code-block:: console

   $ spack spec --yaml dray+mpi > dray-mpi.yaml
   $ spack spec --yaml dray~mpi > dray-nompi.yaml
   $ spack-python lib/scripts/diffBuildSpecs.py ./dray-mpi.yaml ./dray-nompi.yaml

.. figure:: /_static/images/dray-diffspecs.png
   :align: center

   (Image output is truncated)


.. Note::

  ``spack-python`` is required to import the spack libraries needed for this script. It will automatically be added to your ``$PATH`` when you run ``benchpark setup ...``.

Example: Installed packages
~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you want to compare already installed packages, provide the hashes

.. code-block:: console

   $ spack find -L quicksilver

   -- linux-rhel8-sapphirerapids / gcc@12.1.1 ----------------------
   fubnce7wzgjxhkim2cylijt4cbpfhxi6 quicksilver@master

   -- linux-rhel8-sapphirerapids / intel@2021.6.0-classic ----------
   qwev4yodp2joikf2oxvlo224ksjcqve3 quicksilver@master
   ==> 2 installed packages

   $ spack-python lib/scripts/diffBuildSpecs.py quicksilver/fubnce7wzgjxhkim2cylijt4cbpfhxi6 quicksilver/qwev4yodp2joikf2oxvlo224ksjcqve3

.. figure:: /_static/images/quicksilver-diffspecs.png
   :align: center