CHANGELOG: shorten 1.0.0 entry; fix heading levels

Author: Technologicat

CHANGELOG.md

@@ -1,98 +1,88 @@
-## Changelog
-
-### v1.0.0
-
-First release under modern Python and modern packaging. Python 2.7 and 3.4
-are no longer supported.
-
-#### New
-
-- **Python 3.11 – 3.14 supported.** Pre-built wheels on PyPI for Linux,
-  macOS, and Windows, across all four Python versions, with OpenMP
-  parallelism enabled in every wheel.
-- **Finite-difference stencil reproduction.** A WLSQM fit on a classical
-  central-difference stencil (3-point 1D, 5-point plus 2D, 7-point plus 3D)
-  now reproduces the hand-coded stencil result to machine precision on any
-  smooth input, not just polynomials. This is the natural generalization of
-  WLSQM's polynomial-recovery property and is pinned by the test suite.
-
-#### Fixed
-
-- **Data race in `fit_1D_many_parallel`**, pre-existing from 2016. The 1D
-  branch of the basic parallel many-case fitter passed a compile-time
-  constant `TASKID = 0` to `impl.solve()` instead of the per-thread
-  `taskid = openmp.omp_get_thread_num()`. Every OpenMP worker clobbered
-  thread-0's work buffer, producing silently wrong fits whenever the
-  parallel 1D many-case path ran with `ntasks > 1`. The 2D/3D branch, the
-  iterative parallel variant, and the serial variant were always correct.
-  A regression test (64 cases × 4 threads) now pins this.
-- **`rescale_dgeequ` no longer silently accepts singular matrices.** It now
-  checks LAPACK's `info` return and raises `numpy.linalg.LinAlgError` when
-  a row or column is exactly zero, instead of returning nonsense scaling
-  factors that would poison the downstream solve.
-
-#### Changed
-
-- **Installation is now `pip install wlsqm`.** The old `python setup.py
-  install` path is gone; `setup.py` has been removed. The build system is
-  [meson-python](https://meson-python.readthedocs.io/), and dev environments
-  are managed with [PDM](https://pdm-project.org/).
-- **Language change on "Taylor series."** The package's internal storage
-  layout still uses the same slots a Taylor expansion would (function
-  value, first derivatives, second derivatives divided by `2!`, …), but
-  the comments and docstrings no longer call the model a "Taylor series."
-  The coefficients come from a least-squares fit, not from analytic
-  differentiation, and the error behavior is much better than Taylor
-  truncation would predict. The internal C-API function names
-  `taylor_1D/2D/3D` are kept for backwards compatibility of downstream
-  `cimport`s — see [`wlsqm/fitter/polyeval.pyx`](wlsqm/fitter/polyeval.pyx).
-- **Comprehensive pytest suite.** 57 tests covering polynomial recovery
-  across dimensions and orders, `ExpertSolver` prepare/solve round-trips,
-  interpolation accuracy at interior points, parallel ≡ serial equivalence,
-  finite-difference stencil reproduction, first-derivative robustness to
-  Gaussian noise, edge cases, the LAPACK driver layer, and `.pxd`
-  installability for downstream `cimport` users.
-
-#### Internal
-
-- Port from Cython 0.29 to Cython 3.x. `noexcept` audit on every `cdef
-  ... nogil` function, split between pure computational helpers
-  (`noexcept`) and LAPACK wrappers / fit dispatchers (`except -1`). `fma`
-  now imported from `libc.math` instead of a manual `cdef extern` hack
-  that worked around a long-fixed bug in Cython 0.20.1.
-- All `DEF` compile-time constants replaced with module-level `cdef`
-  constants or inlined as literals at call sites (Cython 3 deprecated
-  `DEF`). Function-local protocol constants like `TASKID`, `NTASKS`, and
-  `MODE_BASIC` / `MODE_ITERATIVE` live at module scope in `simple.pyx`
-  where the value is a project-wide convention, and inside each function
-  where the value is per-function.
-- `ScalingAlgo` is now a proper `enum.IntEnum`, replacing the old bare-
-  class Python 2 workaround.
-- GitHub Actions CI: lint (ruff + cython-lint), test matrix (3 OSes × 4
-  Python versions), cibuildwheel for Linux/macOS/Windows wheels,
-  meson-python sdist, and trusted-publisher PyPI publishing on `v*` tag
-  push.
-- Copyright updated to 2016–2026 and affiliation updated to JAMK
-  University of Applied Sciences.
-
-
-## Pre-v1.0 history
-
-### [v0.1.5]
+# Changelog
+
+## v1.0.0 (15 April 2026)
+
+First release under modern Python and modern packaging.
+
+Python 2.7 and 3.4 are no longer supported.
+
+### New
+
+- **Python 3.11 – 3.14 supported.**
+  - Pre-built wheels on PyPI for Linux, macOS, and Windows, with OpenMP
+    parallelism enabled in every wheel.
+
+### Fixed
+
+- **Data race in `fit_1D_many_parallel`**, pre-existing from 2016.
+  - Every OpenMP worker clobbered thread-0's work buffer, producing silently
+  wrong fits whenever the parallel 1D many-case path ran with `ntasks > 1`. The
+  2D/3D branch, the iterative parallel variant, and the serial variant were
+  always correct.
+
+- **`rescale_dgeequ` no longer silently accepts singular matrices.**
+  - It now checks LAPACK's `info` return and raises `numpy.linalg.LinAlgError`
+  when a row or column is exactly zero.
+
+### Changed
+
+- **Installation is now `pip install wlsqm`.**
+  - The old `python setup.py install` path is gone; `setup.py` has been removed.
+  - The build system is [meson-python](https://meson-python.readthedocs.io/),
+  and dev environments are managed with [PDM](https://pdm-project.org/).
+
+- **Language change on "Taylor series."**
+  - The package's internal storage layout still uses the same slots a Taylor
+  expansion would (e.g. in 2D, `f`, `∂f/∂x`, `∂f/∂y`, `(1/2!) ∂²f/∂x²`,
+  `∂²f/∂x∂y`, `(1/2!) ∂²f/∂y²`, …), but the comments and docstrings no longer
+  call the model a "Taylor series."
+  - In the WLSQM method, the coefficients actually come from a least-squares
+  fit, not from analytic differentiation. The error behavior is much better than
+  Taylor truncation would predict.
+  - The internal C-API function names `taylor_1D/2D/3D` are kept for backwards
+  compatibility of downstream `cimport`s — see
+  [`wlsqm/fitter/polyeval.pyx`](wlsqm/fitter/polyeval.pyx).
+
+### Internal
+
+- **Port from Cython 0.29 to Cython 3.x**.
+
+- **Comprehensive pytest suite.** 57 tests, covering:
+  - polynomial recovery across dimensions and orders,
+  - `ExpertSolver` prepare/solve round-trips,
+  - interpolation accuracy at interior points,
+  - parallel ≡ serial implementation equivalence,
+  - finite-difference stencil reproduction,
+  - first-derivative robustness to Gaussian noise,
+  - edge cases,
+  - the LAPACK driver layer, and
+  - `.pxd` installability for downstream `cimport` users.
+
+- `ScalingAlgo` is now a proper `enum.IntEnum`, replacing the old bare-class
+  Python 2 workaround.
+
+- **GitHub Actions CI**: lint (ruff + cython-lint), test matrix
+  (3 OSes × 4 Python versions), cibuildwheel for Linux/macOS/Windows
+  wheels, meson-python sdist, and auto-publishing of releases on PyPI.
+
+
+# Pre-v1.0 history (2016-2017)
+
+## [v0.1.5]
  - support both Python 3.4 and 2.7
 
-### [v0.1.4]
+## [v0.1.4]
  - actually use the shorter short description (oops)
 
-### [v0.1.3]
+## [v0.1.3]
  - setup.py is now Python 3 compatible (but wlsqm itself is not yet!)
  - fixed sdist: package also CHANGELOG.md
 
-### [v0.1.2]
+## [v0.1.2]
  - set zip_safe to False to better work with Cython (important for libs that depend on this one)
 
-### [v0.1.1]
+## [v0.1.1]
  - change distribution system from distutils to setuptools
 
-### [v0.1.0]
+## [v0.1.0]
   - initial version