From 41a1e91ac95503aff24480745486a058ded406d6 Mon Sep 17 00:00:00 2001 From: sebcrozet Date: Sat, 10 Nov 2018 13:36:08 +0100 Subject: [PATCH] Add an example for the resolution of a linear system. --- examples/linear_system_resolution.rs | 39 ++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 examples/linear_system_resolution.rs diff --git a/examples/linear_system_resolution.rs b/examples/linear_system_resolution.rs new file mode 100644 index 00000000..2d0dc183 --- /dev/null +++ b/examples/linear_system_resolution.rs @@ -0,0 +1,39 @@ +#![cfg_attr(rustfmt, rustfmt_skip)] +#[macro_use] +extern crate approx; // for assert_relative_eq +extern crate nalgebra as na; +use na::{Matrix4, Matrix4x3, Vector4}; + +fn main() { + let a = Matrix4::new( + 1.0, 1.0, 2.0, -5.0, + 2.0, 5.0, -1.0, -9.0, + 2.0, 1.0, -1.0, 3.0, + 1.0, 3.0, 2.0, 7.0, + ); + let mut b = Vector4::new(3.0, -3.0, -11.0, -5.0); + let decomp = a.lu(); + let x = decomp.solve(&b).expect("Linear resolution failed."); + assert_relative_eq!(a * x, b); + + /* + * It is possible to perform the resolution in-place. + * This is particularly useful to avoid allocations when + * `b` is a `DVector` or a `DMatrix`. + */ + assert!(decomp.solve_mut(&mut b), "Linear resolution failed."); + assert_relative_eq!(x, b); + + /* + * It is possible to solve multiple systems + * simultaneously by using a matrix for `b`. + */ + let b = Matrix4x3::new( + 3.0, 2.0, 0.0, + -3.0, 0.0, 0.0, + -11.0, 5.0, -3.0, + -5.0, 10.0, 4.0, + ); + let x = decomp.solve(&b).expect("Linear resolution failed."); + assert_relative_eq!(a * x, b); +}