nrfind

nrfind provides a Newton-Raphson root finder for arbitrary differentiable functions, as well as convenient wrappers for common use cases like square roots.

Documentation is available on docs.rs

A simple example of usage to find the roots of x^3 + x^2 + 1 in 18 iterations:

``` extern crate nrfind;

// The function for whose roots find_root will solve fn f(x: f64) -> f64 { x.powi(3) + x.powi(2) + 1.0 }

// That function's derivative fn fd(x: f64) -> f64 { (3.0 * x.powi(2)) + (2.0 * x) }

fn main() { let initial_guess = 100; let precision = 0.1; let iterations = 18;

let result = nrfind::find_root(&f, &fd, 
                               &initial_guess, 
                               &precision, 
                               iterations).unwrap();

// This is known to be the actual answer
let actual: f64 = -1.4656;

// The difference between the actual answer and the found result
// is less than the provided precision.
let difference = (actual - result).abs();
assert!(difference <= precision);

} ```