Function poly_from_roots 

pub fn poly_from_roots<E: FieldElement>(xs: &[E]) -> Vec<E>

Returns the coefficients of polynomial given its roots.

Examples

let xs = vec![1u128, 2].into_iter().map(BaseElement::new).collect::<Vec<_>>();

let mut expected_poly = vec![2u128, 3, 1].into_iter().map(BaseElement::new).collect::<Vec<_>>();
expected_poly[1] *= -BaseElement::ONE;

let poly = poly_from_roots(&xs);
assert_eq!(expected_poly, poly);