1use winter_math::{FieldElement, batch_inversion};
 2
 3
 4pub fn barycentric_weights<E: FieldElement>(points: &[(E, E)]) -> Vec<E> {
 5    let n = points.len();
 6    let tmp = (0..n)
 7        .map(|i| (0..n).filter(|&j| j != i).fold(E::ONE, |acc, j| acc * (points[i].0 - points[j].0)))
 8        .collect::<Vec<_>>();
 9    batch_inversion(&tmp)
10}
11
12pub fn evaluate_barycentric<E: FieldElement>(
13    points: &[(E, E)],
14    x: E,
15    barycentric_weights: &[E],
16) -> E {
17    for &(x_i, y_i) in points {
18        if x_i == x {
19            return y_i;
20        }
21    }
22
23    let l_x: E = points.iter().fold(E::ONE, |acc, &(x_i, _y_i)| acc * (x - x_i));
24
25    let sum = (0..points.len()).fold(E::ZERO, |acc, i| {
26        let x_i = points[i].0;
27        let y_i = points[i].1;
28        let w_i = barycentric_weights[i];
29        acc + (w_i / (x - x_i) * y_i)
30    });
31
32    l_x * sum
33}