@hackage / pure-cdt

Changelog for pure-cdt

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 the Haskell Package Versioning Policy.

0.2.0.0 - 2026-09-04

First public release. Version 0.1.0.0 existed only in the repository, under the name triangulation, and was never uploaded.

• triangulate: Delaunay triangulation of a point set by divide and conquer, with halves of at least 256 points evaluated in parallel through Control.Parallel.Strategies.
• constrainedTriangulate: triangulation of a polygon with holes. The boundary and hole edges are forced in, triangles outside the region are dropped, and the boundary may be non-convex. An input point on a polygon edge subdivides it.
• refine: Delaunay refinement (Ruppert's algorithm) to a minimum angle and a maximum triangle area, preserving the boundary and hole edges. refineWithBudget returns the mesh reached when the insertion budget runs out.
• toMesh, boundaryEdges: the triangulation as node coordinates and counter-clockwise index triples, with the boundary edges identified — the form finite element code and mesh file formats expect.
• Exact geometric predicates: orientation and in-circle are decided by a floating-point filter backed by Rational arithmetic, and the algorithm runs on symbolically perturbed points (Simulation of Simplicity), so collinear and cocircular input — grids, regular polygons, concentric shapes — is triangulated correctly.
• No partial functions and no exceptions in the library: a point set that spans no triangle comes back as Nothing.
• Point, Edge, Triangle and Polygon derive Eq, Ord, Hashable and NFData. Edge and Triangle are abstract and normalise their vertices, so equality and hashing do not depend on construction order.
• Tests on tasty: QuickCheck properties for the triangulation (Delaunay condition, planarity, triangle count, convex hull), for the region mesh and for the refinement, next to unit tests for each geometric primitive. Benchmarks on tasty-bench.