rlumod

rlumod is a safe, no_std Rust adaptation of LUmod, Michael A. Saunders' software for incrementally updating a dense square matrix and solving systems with the updated matrix. It maintains the LUmod representation L A = U; it does not compute a conventional A = LU decomposition of an arbitrary completed matrix.

The crate provides:

• row-and-column insertion, row replacement, column replacement, and row-and-column removal;
• in-place solution of A x = b and A^T x = b;
• safe, zero-based APIs for both f32 and f64;
• caller-owned factor and workspace storage, with no heap allocation during updates or solves; and
• an optional lumod-c feature exposing a lower-level Rust slice API with the original LUmod names and mode arguments.

rlumod supports dense square matrices only. It does not provide sparse matrix storage or a one-shot factorization API.

Installation

cargo add rlumod

Documentation and examples

The crate documentation is the main user guide. It covers matrix construction, storage lifetime, update and removal semantics, numerical behavior, and migration from the C LUmod API.

Small runnable programs and the larger validation drivers are listed in the examples guide.

Build and open the documentation locally with:

cargo doc --all-features --open

About LUmod and SOL

The original LUmod was written by Michael A. Saunders at Stanford University's Systems Optimization Laboratory (SOL). It maintains the factorization L A = U, where L is a product of stabilized elementary transformations and U is upper triangular.

See the official LUmod page at SOL for the algorithm's provenance, original distributions, and references.

The rlumod project is an independent Rust adaptation and is not affiliated with, endorsed by, or maintained by Michael A. Saunders or SOL.

License

This Rust adaptation is distributed under the MIT License. The original LUmod is used under SOL's MIT license option. Its copyright and license notice are retained in LICENSES/SOL-LUMOD-MIT.txt.