rustebra 0.5.0

A hybrid no_std/alloc linear algebra crate for Rust, scaling from embedded targets to dynamic Krylov subspace solvers.
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

use rustebra::krylov::lanczos;
use rustebra::storage::{Basis, StaticStorage};

pub(crate) fn run() {
    println!("\n== Lanczos iteration ==");
    // [[4, 1, 2], [1, 3, 1], [2, 1, 5]], symmetric but not already tridiagonal.
    let a = StaticStorage::new([4.0, 1.0, 2.0, 1.0, 3.0, 1.0, 2.0, 1.0, 5.0]);
    let v0 = StaticStorage::new([1.0, 1.0, 1.0]);
    let mut buffer = [0.0; 9];
    let mut basis = Basis::<f64, 3>::new(&mut buffer, 3).unwrap();
    let mut scratch = [0.0; 3];

    let t = lanczos(&a, 3, &v0, 1e-12, &mut basis, &mut scratch).unwrap();
    println!("diagonal = {:?}", t.diagonal());
    println!("off_diagonal = {:?}", t.off_diagonal());

    // Requesting fewer basis vectors than the matrix dimension (K < n) still produces the
    // leading block of the same tridiagonal form, at a fraction of the memory: only `K`
    // vectors of the basis are ever stored.
    let mut partial_buffer = [0.0; 6];
    let mut partial_basis = Basis::<f64, 2>::new(&mut partial_buffer, 3).unwrap();
    let mut partial_scratch = [0.0; 3];
    let partial_t = lanczos(&a, 3, &v0, 1e-12, &mut partial_basis, &mut partial_scratch).unwrap();
    println!("partial diagonal (K = 2) = {:?}", partial_t.diagonal());
}