la-stack 0.4.3

Fast, stack-allocated linear algebra for fixed dimensions
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

//! 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: Result<Matrix<4>, LaError> = 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],
]);

/// Determinant computed at compile time.
const DET: Result<Option<f64>, LaError> = match MAT {
    Ok(matrix) => matrix.det_direct(),
    Err(err) => Err(err),
};

fn main() -> Result<(), LaError> {
    let mat = MAT?;

    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!();
    match DET? {
        Some(det) => println!("det (computed at compile time) = {det}"),
        None => println!("det_direct is only available for D <= 4"),
    }

    Ok(())
}