la-stack 0.4.2

Fast, stack-allocated linear algebra for fixed dimensions
Documentation 
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//! Compile-time 4×4 determinant via `det_direct()`.
//!
//! Because `det_direct` is a `const fn` (Rust 1.94+), the determinant is
//! evaluated entirely at compile time — zero runtime cost.

use la_stack::prelude::*;

/// An example 4×4 matrix with small integer entries.
const MAT: Matrix<4> = match Matrix::<4>::try_from_rows([
    [1.0, 2.0, 3.0, 4.0],
    [5.0, 6.0, 7.0, 8.0],
    [2.0, 6.0, 1.0, 5.0],
    [3.0, 8.0, 2.0, 9.0],
]) {
    Ok(matrix) => matrix,
    Err(_) => panic!("matrix entries must be finite"),
};

/// Determinant computed at compile time.
const DET: f64 = match MAT.det_direct() {
    Ok(Some(d)) => d,
    Ok(None) => panic!("det_direct only supports D <= 4"),
    Err(_) => panic!("matrix entries must be finite"),
};

fn main() -> Result<(), LaError> {
    println!("4×4 matrix:");
    for r in 0..4 {
        print!("  [");
        for c in 0..4 {
            if c > 0 {
                print!(", ");
            }
            print!("{:5.1}", MAT.get_checked(r, c)?);
        }
        println!("]");
    }
    println!();
    println!("det (computed at compile time) = {DET}");

    Ok(())
}