Documentation

Developer documentation for ras-commander-fast-hdf: the native HEC-RAS HDF engine and its Python extension, which together are ras-commander's default HDF engine. ras-commander 0.107.1 and later install it automatically on Windows x64, Linux x64 and macOS arm64; pip install ras-commander is enough.

If you only want to use the engine from ras-commander (installation, the auto | h5py | native modes, which methods run natively, performance and limitations), read the user guide on the ras-commander site: Native Rust HDF engine.

Guides

Page	Read it to
Architecture	Understand the three layers (engine, extension, ras-commander adapter), how a read flows, and why refusals are safe.
Python extension	See what ras_commander_fast_hdf exposes: versions, sessions, read functions, kernels, errors.
Rust engine	Use ras-commander-rust from Rust: Cargo features, modules, status vocabulary, budgets.
Performance	See how much faster each ras-commander method is with the native engine, and how that was measured.
Building	Build the wheel or the crates from source on Windows, Linux or macOS.
Testing and qualification	Run the Rust tests, and qualify a wheel against h5py with ras-commander's equivalence suites.
Releasing	Version, build, qualify and publish a release.
Roadmap	See planned and in-progress work: reading HDF files directly from AWS S3 next, then read coverage, performance, upstream and packaging items.

Reference

Detailed contracts, kept as they were written while each surface was built. They are exact but terse; start with the guides above.

Page	Covers
Engine API contract	Every engine surface, its statuses, limits and the history of API generations.
Read families	Stored table families (structures, reference lines/points, terrain modifications, land cover, ...) and their qualification.
Mesh results	2D mesh summary, time-series and boundary-condition reads.
1D geometry and results	Cross sections, 1D summary output, 1D structures and pumps.
Conformance	How the engine was checked against real HEC-RAS files.
Extension contract	The full ras_commander_fast_hdf binding contract, by API generation.
Sessions	HdfSession lifetime, caching and ras-commander's session policy.
Session performance design	Why sessions are reused and how their caches are bounded.
Validation	Measured results of the original qualification of the extension.
Provenance	Where the source came from.