A Go library package providing utility functions including sorting algorithms with custom comparators.
## Features
- 🔢 **Sorting Utilities**: Sort integers, strings, and floats in ascending or descending order
- 🎯 **Custom Sorting**: Sort any type with custom comparison functions or key extractors
- 🔍 **Binary Search**: Fast search on sorted data
- 🧭 **KDTree (NN Search)**: Build a KDTree over points with generic payloads; nearest, k-NN, and radius queries with Euclidean, Manhattan, Chebyshev, and Cosine metrics
- 📦 **Generic Functions**: Type-safe operations using Go generics
- ✅ **Well-Tested**: Comprehensive test coverage
- 📖 **Documentation**: Full documentation available at GitHub Pages
- Dual backend support: Linear (always available) and an optimized KD backend enabled when building with `-tags=gonum`. Linear is the default; with the `gonum` tag, the optimized backend becomes the default.
- Complexity: Linear backend is O(n) per query. Optimized KD backend is typically sub-linear on prunable datasets and dims ≤ ~8, especially as N grows (≥10k–100k).
- Insert is O(1) amortized; delete by ID is O(1) via swap-delete; order is not preserved.
- Concurrency: the KDTree type is not safe for concurrent mutation. Protect with a mutex or share immutable snapshots for read-mostly workloads.
- See multi-dimensional examples (ping/hops/geo/score) in docs and `examples/`.
- Performance guide: see docs/Performance for benchmark guidance and tips: [docs/perf.md](docs/perf.md) • Hosted: https://snider.github.io/Poindexter/perf/
- Euclidean (L2): smooth trade-offs across axes; solid default for blended preferences.
- Manhattan (L1): emphasizes per-axis absolute differences; good when each unit of ping/hop matters equally.
- Chebyshev (L∞): dominated by the worst axis; useful for strict thresholds (e.g., reject high hop count regardless of ping).
- Cosine: angle-based for vector similarity; pair it with normalized/weighted features when direction matters more than magnitude.
See the multi-dimensional KDTree docs for end-to-end examples and weighting/normalization helpers: [Multi-Dimensional KDTree (DHT)](docs/kdtree-multidimensional.md).
## Maintainer Makefile
The repository includes a maintainer-friendly `Makefile` that mirrors CI tasks and speeds up local workflows.
- help — list available targets
- tidy / tidy-check — run `go mod tidy`, optionally verify no diffs
- fmt — format code (`go fmt ./...`)
- vet — `go vet ./...`
- build — `go build ./...`
- examples — build all programs under `examples/` (if present)
- test — run unit tests
- race — run tests with the race detector
- cover — run tests with race + coverage (writes `coverage.out` and prints summary)
- coverhtml — render HTML coverage report to `coverage.html`
