All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

• New splinepy.helpme.create.swept() function for generating swept surfaces and solids by sweeping a cross-section along a trajectory spline (examples/show_swept.py)
  • Supports curve (1D) and surface (2D) cross-sections to produce surfaces and solids respectively
  • Cross-section orientation uses the projection-normal method (Siltanen & Woodward), following The NURBS Book, Piegl & Tiller, 2nd ed., Chapter 10.4
  • Supports closed trajectories with orientation correction (p. 483 of the NURBS book)
  • anchor parameter controls which reference point of the cross-section is placed on the trajectory ("parametric", "control_box", "geometry_box", or "auto")
  • set_on_trajectory parameter selects between placement at trajectory knot evaluation points or trajectory control points
  • Optional rotation_adaption parameter for additional rotation of the cross-section around the trajectory tangent
  • Added swept surface image to README and documentation

• New Transformation class in splinepy.helpme.integrate encapsulating all quadrature and geometry transformation data needed for IGA discretization:
  • Precomputes quadrature points, supports, Jacobians, Jacobian inverses, and Jacobian determinants per element
  • Configurable quadrature orders
• New FieldIntegrator class in splinepy.helpme.integrate providing a high-level interface for PDE assembly:
  • assemble_matrix(function) — assembles the global stiffness matrix
  • assemble_vector(function) — assembles the global load vector
  • assemble_matrix_and_vector(function) — assembles both simultaneously
  • L2_projection(function) — computes the L2 projection of a function onto the spline space
  • compute_error(function, norm) — computes the L2 or H1 error of the current solution
  • apply_homogeneous_dirichlet_boundary_conditions() — enforces homogeneous Dirichlet BCs
  • apply_dirichlet_boundary_conditions(function) — enforces inhomogeneous Dirichlet BCs from a given function
  • solve_linear_system() — solves the assembled linear system using scipy.sparse.linalg.spsolve
  • Uses sparse matrix assembly via scipy.sparse.dok_matrix

• Extended TileBase with standardised class attributes and properties for parameter validation and introspection:
  • _parameter_bounds / parameter_bounds — bounds for each tile parameter
  • _parameters_shape / parameters_shape — shape of the parameter array
  • _default_parameter_value / default_parameter_value — default values for tile parameters
  • _sensitivities_implemented / sensitivities_implemented — flag indicating whether parameter sensitivities are implemented
  • _closure_directions / closure_directions — list of supported closure directions
  • check_params(parameters) — validates user-supplied parameters against bounds
  • _process_input(parameters, parameter_sensitivities) — shared input-processing logic
  • _check_custom_parameter(value, param_name, bounds) — validates individual parameters
• Derived tile classes now inherit common parameter-processing code from TileBase, reducing code duplication
• Changed evaluation_points, para_dim, and dim from class methods to instance properties for consistency
• Added n_info_per_eval_point property to TileBase
• Derivatives (parameter sensitivities) implemented or fixed for:
  • HollowOctagon (with and without closure)
  • HollowOctagonExtrude (added working closure, with derivatives)
  • Armadillo
  • Chi tile (fixed)
  • InverseCross3D (restructured and fixed)
  • CubeVoid (fixed)
  • EllipsVoid (fixed)
• Fourth-order accurate finite-difference calculation for numerical verification of parameter sensitivities
• Sensitivities calculation now outputs evaluation points when it fails for easier debugging
• Microstructure: integers are now accepted as tile parameters alongside floats

• Added Multipatch.set_interface_orientations(interface_orientations) setter for manually specifying interface orientations, enabling export of scalar-field splines where automatic Jacobian-based orientation computation is not possible

• Added examples/show_swept.py demonstrating swept surface and solid construction
• Added examples/iga/galerkin_laplace_problem_field_integrator.py demonstrating Galerkin IGA for the Laplace problem using FieldIntegrator
• Added examples/iga/collocation_stokes_problem_sparse.py demonstrating IGA collocation for the Stokes problem using sparse matrices

• Dropped Python 3.9 support; added Python 3.14 support (updated workflows and pyproject.toml classifiers)
• Switched macOS CI runner from deprecated macos-13 to macos-15-intel for continued x86_64 testing
• Fixed wheel naming convention issue in CI

• Refactored all tile classes to use common functions from TileBase, reducing code duplication significantly
• TileBase: removed class methods in favour of instance/class properties for dim, para_dim, and evaluation_points
• TileBase: removed unneeded classmethods to simplify the class hierarchy
• Microstructure: replaced bare assert statements with proper raise expressions for parameter validation; improved error messages
• Microstructure: updated zip calls to use strict=True for stricter length checking (Python 3.10+)
• Chi tile is now excluded from macro-sensitivity tests (analytical sensitivities not yet finalized)
• HollowOctagonExtrude removed from the list of skipped test tiles

• Extracted _default_quadrature_orders(spline) helper function (previously inlined in _get_quadrature_information)
• Improved docstrings for _get_integral_measure, _get_quadrature_information, and related functions
• Corrected typos in docstrings (paramtric → parametric, Determinante → Determinant)

• Added helper functions for Gismo export
• Fixed patch range text format for multi-patch exports

• Updated zip calls to use strict=True

• Fixed test data for Cartesian 2D and 3D meshes

• Updated pull request template to use develop as the default base branch

• helpme/create.py: Fixed error in rotation matrix calculation for e2 entries in swept surface generation; improved input validation and error messages throughout
• helpme/integrate.py: Fixed typos and improved docstrings
• microstructure/tiles: Fixed incorrect ordering in finite-difference sensitivity calculation; fixed derivative implementations for Chi, CubeVoid, EllipsVoid, InverseCross3D; fixed typo causing errors in HollowOctagonExtrude
• microstructure/microstructure.py: Fixed typo in class docstring (facilitatae → facilitate)
• multipatch.py: Added check to verify that Jacobians exist before computing interface orientations
• bspline.py: Allow any negative number in the knot vector (previously restricted), fixing issue #476
• utils/data.py: Minor fixes
• Various IO modules: Fixed miscellaneous issues and improved error handling

• Added tests/test_microtiles.py with comprehensive parametrised tests for all microtile classes:
  • All tiles lie within the unit cube for default parameters
  • Tiles with non-default parameters
  • Closure tests
  • Tile derivative (sensitivity) tests, including closure derivatives
  • Macro-sensitivity tests (finite-difference verification)
• Added tests/test_microstructure.py with additional microstructure integration tests
• Added test for Transformation class in tests/helpme/test_integrate.py
• Extended tests/helpme/test_create.py with swept surface tests, including:
  • Comparison of swept vs extruded surfaces
  • Custom cross-section normal vector
  • Anchor modes
  • Derivative checks
• Fixed RNG seed, sensitivity step size, and number of random test points for reproducible results
• Updated various existing tests for compatibility with Python 3.10+ zip(strict=True) changes

• Physical function integration in helpme/integrate.py
• Gismo export helper functions
• Python 3.13 support
• Various bug fixes and CI/CD maintenance

• Proximity / nearest-point query updates

• MFEM 3D single-patch IO
• Padding initializer for splines

• Initial stable release series