Function ltsolve 

pub fn ltsolve<T: Numeric<T>>(l: &Sprs<T>, x: &mut [T])

Solves L’x=b. Where x and b are dense.

On input, X contains the right hand side, and on output, the solution.

Example:

let l = [
    vec![1.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000],
    vec![0.3376, 1.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000],
    vec![0.8260, 0.2762, 1.0000, 0.0000, 0.0000, 0.0000, 0.0000],
    vec![0.5710, 0.1764, 0.5430, 1.0000, 0.0000, 0.0000, 0.0000],
    vec![0.9194, 0.3583, 0.6850, 0.6594, 1.0000, 0.0000, 0.0000],
    vec![0.2448, 0.5015, -0.2830, 0.2239, 0.4723, 1.0000, 0.0000],
    vec![0.2423, 0.2332, -0.8355, 0.7522, -0.3700, 0.1985, 1.0000]
];
let mut l_sparse = rsparse::data::Sprs::new();
l_sparse.from_vec(&l);

let mut b = [
    0.444841,
    0.528773,
    0.988345,
    0.097749,
    0.996166,
    0.068040,
    0.844511
];

rsparse::ltsolve(&l_sparse, &mut b);