wlsqm 1.0.0

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,
    and dev environments are managed with PDM.

• Language change on "Taylor series."

  • The storage layout still uses the same slots a Taylor expansion would (e.g.
    in 2D, f, ∂f/∂x, ∂f/∂y, ∂²f/∂x², ∂²f/∂x∂y, ∂²f/∂y², …), but the
    comments and docstrings no longer call the polynomial 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
    the truncation of a Taylor series would predict.
  • The internal C-API function names taylor_1D/2D/3D are kept for backwards
    compatibility of downstream cimports — see
    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.