Version 0.3.9
=============

**Release Date:** May 30, 2026

**Status:** Stable release

Bruker loader refactor
----------------------

``epyr/sub/loadBES3T.py`` and ``epyr/sub/loadESP.py`` were heavy monolithic
functions (cyclomatic complexity 60 and 89, respectively). They are now
split into small private helpers covering file resolution, header parsing,
abscissa construction, and the scaling pipeline:

- ``loadBES3T``: helpers for IKKF complexity, dimensions, byte order,
  number format, companion-axis files, linear/non-linear abscissa, and
  per-channel scaling (``'n'``, ``'P'``, ``'G'``, ``'T'``, ``'c'``).
- ``loadESP``: helpers for the JSS flag, dimension resolution from the
  conflicting ``ANZ`` / ``SSX`` / ``SSY`` / ``RES`` / ``REY`` / ``XPLS``
  keys, abscissa source selection (GST/GSI vs HCF/HSW vs XXLB/XXWI),
  and the power-sweep ``'P'`` scaling on the Y-axis.

Every public behavior of the loaders is preserved. The 10 example files in
``examples/data/`` load identically before and after the refactor.

API surface
-----------

- ``eprload()`` is now fully type-annotated.
- ``epyr/__init__.py`` no longer uses ``from .X import *``: imports are
  explicit, with the public surface defined by ``__all__`` in each
  submodule. The names exported are unchanged from a user perspective.

Tooling
-------

- ``make format`` now uses Black >= 24, != 25.1.0 (pinned to avoid a
  grammar-table crash on initialization).
- ``mypy`` target Python version bumped from 3.8 to 3.9.
- ``.flake8`` ignores ``I201`` (isort vs flake8-import-order disagree on
  ``tkinter``); max cyclomatic complexity raised to 35 with a comment
  noting which functions still need to be split.
- ``flake8``, ``mypy``, ``isort`` and ``black`` all pass cleanly on the
  ``epyr/`` tree (``make quality-fix`` returns 0).

Documentation
-------------

- Public-API docstring example coverage rose from 18% to 53%. Functions
  enriched include ``eprload``, the ``plot_*`` family, the baseline
  ``models``, the ``baseline_*`` correction functions, the FAIR exporters
  (``save_to_csv``, ``save_to_json``, ``save_to_hdf5``, ``save_to_jpg``,
  ``convert_bruker_to_fair``, ``batch_convert_directory``), and the
  ``physics`` conversion helpers.
- Remaining Google-style ``Args:`` / ``Returns:`` blocks converted to
  NumPy format.
- ``epyr/sub/__init__.py``, ``epyr/sub/utils.py`` and ``epyr/eprload.py``
  gained module docstrings.
- The ReST page ``docs/api/epyr.constants.rst`` was replaced by
  ``docs/api/epyr.physics.rst`` to reflect the actual module layout.
  ``epyr.constants`` remains importable as an alias for
  ``epyr.physics.constants``.
- ``examples/clean/`` exposes five standalone end-to-end scripts covering
  load + plot, baseline + fitting, FFT windowing, the 2D slicer, and Rabi
  frequency analysis.

Repository hygiene
------------------

- Stale root-level ``test_*.png`` and ``test_epr.txt`` artifacts removed.
- ``epyr/.ipynb_checkpoints/`` (containing an old ``eprplot``
  checkpoint) deleted.
- ``.gitignore`` extended for root-level ``test_*.png`` / ``test_*.txt``.

No backwards-incompatible changes.