feanor_math/algorithms/poly_factor/
rational.rs

1
2use crate::algorithms::poly_factor::factor_locally::poly_factor_integer;
3use crate::computation::*;
4use crate::rings::poly::dense_poly::DensePolyRing;
5use crate::ring::*;
6use crate::rings::poly::*;
7use crate::homomorphism::*;
8use crate::divisibility::*;
9use crate::rings::rational::RationalFieldBase;
10use crate::rings::zn::zn_64::*;
11use crate::algorithms::eea::signed_lcm;
12use crate::pid::EuclideanRing;
13
14use super::IntegerRing;
15
16#[stability::unstable(feature = "enable")]
17pub fn poly_factor_rational<'a, P, I, Controller>(poly_ring: P, poly: &El<P>, controller: Controller) -> (Vec<(El<P>, usize)>, El<<P::Type as RingExtension>::BaseRing>)
18    where P: RingStore,
19        P::Type: PolyRing + EuclideanRing,
20        <P::Type as RingExtension>::BaseRing: RingStore<Type = RationalFieldBase<I>>,
21        I: RingStore,
22        I::Type: IntegerRing,
23        ZnBase: CanHomFrom<I::Type>,
24        Controller: ComputationController
25{
26    assert!(!poly_ring.is_zero(poly));
27    let QQX = &poly_ring;
28    let QQ = QQX.base_ring();
29    let ZZ = QQ.base_ring();
30
31    let den_lcm = QQX.terms(poly).map(|(c, _)| QQ.get_ring().den(c)).fold(ZZ.one(), |a, b| signed_lcm(a, ZZ.clone_el(b), ZZ));
32    
33    let ZZX = DensePolyRing::new(ZZ, "X");
34    let f = ZZX.from_terms(QQX.terms(poly).map(|(c, i)| (ZZ.checked_div(&ZZ.mul_ref(&den_lcm, QQ.get_ring().num(c)), QQ.get_ring().den(c)).unwrap(), i)));
35    let mut factorization = poly_factor_integer(&ZZX, f, controller);
36    factorization.sort_unstable_by_key(|(factor, e)| (ZZX.degree(factor).unwrap(), *e));
37
38    let ZZX_to_QQX = QQX.lifted_hom(&ZZX, QQ.inclusion());
39    return (
40        factorization.into_iter().map(|(f, e)| (QQX.normalize(ZZX_to_QQX.map(f)), e)).collect(),
41        QQ.clone_el(QQX.lc(poly).unwrap())
42    );
43}
feanor_math/algorithms/poly_factor/rational.rs

feanor_math/algorithms/poly_factor/
rational.rs
