howzat-kit

howzat-kit is a small Rust library providing:

• parsing backend specifications from their string encoding, and
• running the chosen backend synchronously on f64 or exact i64 vertex data.

This is a convenience frontend for howzat, shared by kompute-hirsch (hirsch sandbox bench) and the FFI crates.

Backend Specs

Backend specs are strings like:

• howzat-dd[purify[snap]]:f64[eps[1e-12]] (default)
• howzat-dd:f64
• cddlib:gmprational
• lrslib+hlbl

Syntax:

KIND[OPTIONS][:SPEC]

Backend options ([OPTIONS]) are comma-separated and may include:

• adj[dense] / adj[sparse]: force dense bitset graphs vs adjacency lists (if supported natively)
• purify[...]: configure howzat-dd purifiers, e.g. purify[snap] or purify[upsnap[gmprat]]

Supported KIND[:SPEC] forms:

• cddlib[:f64|gmpfloat|gmprational]
• cddlib+hlbl[:f64|gmpfloat|gmprational]
• howzat-dd[:PIPELINE]
• howzat-lrs[:rug|dashu]
• lrslib+hlbl[:gmpint]
• ppl+hlbl[:gmpint]

howzat-dd PIPELINE is a --separated list of steps like:

• NUM (compute), e.g. f64, gmprat, dashurat
• repair[NUM] or resolve[NUM] (check)

Example: howzat-dd[purify[snap],adj[dense]]:f64.

When adj[...] is omitted and the backend supports both adjacency representations, howzat-kit chooses dense unless the dense bitset representation would exceed 128MiB (for either the vertex graph, or the facet graph upper bound), in which case it chooses sparse.

For CLI-style parsing (supporting ^ / % prefixes), use BackendArg:

use howzat_kit::BackendArg;

let arg: BackendArg = "^howzat-dd[purify[snap]]:f64[eps[1e-12]]".parse().unwrap();
assert!(arg.authoritative);

For parsing only the backend itself, use Backend:

use howzat_kit::Backend;

let backend = Backend::parse("howzat-dd[purify[snap]]:f64[eps[1e-12]]").unwrap();

Running

The core entrypoint is Backend::solve_row_major, which accepts a contiguous row-major buffer of f64 coefficients (plus a Representation) and returns either dense or sparse adjacency graphs (BackendRunAny).

use howzat_kit::{Backend, BackendRunAny, BackendRunConfig, Representation};

let backend = Backend::parse("howzat-dd[purify[snap]]:f64[eps[1e-12]]").unwrap();
let config = BackendRunConfig::default();

let coords = [
    0.0, 0.0,
    1.0, 0.0,
    0.0, 1.0,
];
let run = backend
    .solve_row_major(Representation::EuclideanVertices, &coords, 3, 2, &config)
    .unwrap();
match run {
    BackendRunAny::Dense(run) => println!("{:?}", run.stats),
    BackendRunAny::Sparse(run) => println!("{:?}", run.stats),
}

For exact integer inputs, use Backend::solve_row_major_exact or Backend::solve_exact.