isobenefit 0.2.0

Rust simulation core for Isobenefit Urbanism (arrays-in / arrays-out).

isobenefit

The Rust simulation core for the Isobenefit Urbanism QGIS plugin.

It is a pure compute engine: arrays in, arrays out. It never imports QGIS or performs any GIS IO — the plugin handles reading layers, reprojection, rasterization and writing rasters, then hands plain numpy arrays to this core.

Layout

• src/neighbours.rs — neighbour iteration, contiguity counting, green-span checks
• src/access.rs — heap-based bounded Dijkstra accessibility (parallel map-reduce)
• src/density.rs — deterministic per-work-item RNG + density draws
• src/sim.rs — the Simulation state machine and run_ensemble
• src/lib.rs / src/py_bindings.rs — PyO3 bindings (built only with --features python)

Development

cargo test                 # pure-Rust algorithm tests (no Python needed)
maturin develop --release  # build + install the extension into the active venv
pytest tests_py            # Python-level golden + property tests

Parallelism (rayon) and determinism are first-class: results are independent of thread count. Reproducibility comes from per-work-item seeding (ChaCha8Rng derived from (seed, work_id)) and order-independent integer-sum reductions in the accessibility kernels.

Licensed under AGPL-3.0-or-later.