PlasmaPy v0.3.0 (2020-01-25)
============================

Backwards Incompatible Changes
------------------------------

- Created simulation subpackage; move ``Species`` particle tracker there; rename to ``particletracker`` (`#665 <https://github.com/plasmapy/plasmapy/pull/665>`__)
- Changed ``plasmapy.classes.Species`` to ``plasmapy.simulation.ParticleTracker`` (`#668 <https://github.com/plasmapy/plasmapy/pull/668>`__)
- Moved pytest helper functionality from `plasmapy.utils` to
  ``plasmapy.utils.pytest_helpers`` (`#674 <https://github.com/plasmapy/plasmapy/pull/674>`__)
- Moved ``plasmapy.physics``, ``plasmapy.mathematics`` and ``plasmapy.transport`` into the common `plasmapy.formulary` subpackage (`#692 <https://github.com/plasmapy/plasmapy/pull/692>`__)
- Changed ``ClassicalTransport`` methods into attributes (`#705 <https://github.com/plasmapy/plasmapy/pull/705>`__)

Deprecations and Removals
-------------------------

- Removed :file:`parameters_cython.pyx`, switching to Numba for the future of computationally intensive code in PlasmaPy (`#650 <https://github.com/plasmapy/plasmapy/pull/650>`__)
- Removed ``plasmapy.constants``, which was a thin wrapper around `astropy.constants`
  with no added value (`#651 <https://github.com/plasmapy/plasmapy/pull/651>`__)

Features
--------

- Generalized ``ion_sound_speed`` function to work for all values of :math:`k^2 \lambda_{D}^2` (i.e. not just in the non-dispersive limit). (`#700 <https://github.com/plasmapy/plasmapy/pull/700>`__)
- Optimized ``add__magnetostatics`` for a 16x speedup in tests! (`#703 <https://github.com/plasmapy/plasmapy/pull/703>`__)

Bug Fixes
---------

- Defined ``preserve_signature`` decorator to help IDEs parse signatures of decorated functions. (`#640 <https://github.com/plasmapy/plasmapy/pull/640>`__)
- Fixed Pytest deprecations of ``message`` argument to ``raise`` and ``warn`` functions. (`#666 <https://github.com/plasmapy/plasmapy/pull/666>`__)
- Fixed ``h5py`` warning in OpenPMD module, opening files in read mode by default (`#717 <https://github.com/plasmapy/plasmapy/pull/717>`__)


Improved Documentation
----------------------

- Added real-world examples to examples/plot_physics.py and adjusted the plots to be more human-friendly. (`#721 <https://github.com/plasmapy/plasmapy/pull/721>`__)
- Added examples images to the top of the main doc page in :file:`docs\index.rst` (`#655 <https://github.com/plasmapy/plasmapy/pull/655>`__)
- Added examples to the documentation to ``mass_density``
   and ``Hall_parameter`` functions (`#709 <https://github.com/plasmapy/plasmapy/pull/709>`__)
- Added docstrings to decorator :func:`plasmapy.utils.decorators.converter.angular_freq_to_hz`. (`#729 <https://github.com/plasmapy/plasmapy/pull/729>`__)


Trivial/Internal Changes
------------------------

- Replaced decorator ``plasmapy.utils.decorators.checks.check_quantity`` with decorator
  :func:`plasmapy.utils.decorators.validators.validate_quantities`.  Permanently delete decorator
  ``plasmapy.utils.decorators.checks.check_quantity`` and its supporting code.  For functions
  :func:`plasmapy.formulary.quantum.chemical_potential` and
  ``plasmapy.formulary.quantum._chemical_potential_interp``, add a ``raise NotImplementedError`` due
  to bug outlined in issue `<https://github.com/PlasmaPy/PlasmaPy/issues/726>`_.  Associated pytests
  are marked with ``pytest.mark.xfail`` and doctests are marked with ``doctests: +SKIP``. (`#722 <https://github.com/plasmapy/plasmapy/pull/722>`__)
- Added |towncrier| automated changelog creation support (`#643 <https://github.com/plasmapy/plasmapy/pull/643>`__)
- Moved existing "check" decorators to new ``plasmapy.utils.decorators`` module (`#647 <https://github.com/plasmapy/plasmapy/pull/647>`__)
- Allowed running our sphinx-gallery examples as Jupyter notebooks via Binder (`#656 <https://github.com/plasmapy/plasmapy/pull/656>`__)
- Overhauled CI setup, following the example of SunPy (`#657 <https://github.com/plasmapy/plasmapy/pull/657>`__)
- Patched ``sphinx_gallery.binder`` to output custom links to Binder instance (`#658 <https://github.com/plasmapy/plasmapy/pull/658>`__)
- Removed the now unnecessary ``astropy_helpers`` submodule (`#663 <https://github.com/plasmapy/plasmapy/pull/663>`__)
- Follow-up PR to CI overhaul (`#664 <https://github.com/plasmapy/plasmapy/pull/664>`__)
- Added a Codemeta file (:file:`codemeta.json`) (`#676 <https://github.com/plasmapy/plasmapy/pull/676>`__)
- Overhauled and simplified CI, added Python 3.8 to tests, bumped minimal required package versions, and fixed docs. (`#712 <https://github.com/plasmapy/plasmapy/pull/712>`__)
- Updated communication channels in docs (`#715 <https://github.com/plasmapy/plasmapy/pull/715>`__)
- Code style fixes to the ``atomic`` subpackage (`#716 <https://github.com/plasmapy/plasmapy/pull/716>`__)
- Cleaned up main package namespace, removing ``plasmapy.test`` (`#718 <https://github.com/plasmapy/plasmapy/pull/718>`__)
- Reduced precision of tests and doctests to allow for refinements of
  fundamental constants. (`#731 <https://github.com/plasmapy/plasmapy/pull/731>`__)
- Created decorators for checking/validating values and units of function/method input
  and return arguments.  Defined decorators include
  :func:`~plasmapy.utils.decorators.checks.check_values`,
  :func:`~plasmapy.utils.decorators.checks.check_units`, and
  :func:`~plasmapy.utils.decorators.validators.validate_quantities`.  These decorators are
  fully defined by "decorator classes" :class:`~plasmapy.utils.decorators.checks.CheckBase`,
  :class:`~plasmapy.utils.decorators.checks.CheckValues`,
  :class:`~plasmapy.utils.decorators.checks.CheckUnits`, and
  :class:`~plasmapy.utils.decorators.validators.ValidateQuantities`. (`#648 <https://github.com/plasmapy/plasmapy/pull/648>`__)
- Created a decorator to change output of physics functions from "radians/s" to "hz" (`#667 <https://github.com/plasmapy/plasmapy/pull/667>`__)
- Added ``pytest.mark.slow`` to pytest markers.
  Updated documentation to notify developers of functionality. (`#677 <https://github.com/plasmapy/plasmapy/pull/677>`__)