use autofloat::{AutoFloat, AutoFloat2};
use num_traits::One;

fn main() {
    // Define some target function for which we want to compute the derivative.
    // This variant is defined as closure.
    let func = |x, y| (x - AutoFloat::one()) * (AutoFloat::constant(2.0) * y - AutoFloat::one());

    // Use AutoFloat2 because we use a 2-dimensional function and
    // we want a 2-dimensional gradient.
    // The first parameter determines the value of the variable.
    // The second prameter determines the index of the derivative
    // for this variable within the gradient vector.
    let x = AutoFloat2::variable(2.25, 0);
    let y = AutoFloat2::variable(-1.75, 1);

    let result = func(x, y);

    println!(
        "result={} gradient_x={} gradient_y={}",
        result.x, result.dx[0], result.dx[1]
    );
}