binius_field/arch/portable/
hybrid_recursive_arithmetics.rs

1// Copyright 2024-2025 Irreducible Inc.
2
3use super::packed_arithmetic::PackedTowerField;
4use crate::{
5	arch::HybridRecursiveStrategy,
6	arithmetic_traits::{MulAlpha, TaggedMul, TaggedMulAlpha, TaggedSquare},
7	packed::PackedField,
8	TowerExtensionField,
9};
10
11impl<P> TaggedMul<HybridRecursiveStrategy> for P
12where
13	P: PackedTowerField,
14	P::Scalar: TowerExtensionField<DirectSubfield = P::DirectSubfield>,
15	P::PackedDirectSubfield: MulAlpha,
16	P::DirectSubfield: MulAlpha,
17{
18	#[inline]
19	fn mul(self, rhs: Self) -> Self {
20		let a0_a1 = self.as_packed_subfield();
21		let b0_b1 = rhs.as_packed_subfield();
22		let z0_z2 = P::from_packed_subfield(a0_a1 * b0_b1);
23
24		P::from_fn(|i| {
25			let (a0, a1) = self.get(i).into();
26			let (b0, b1) = rhs.get(i).into();
27			let (z0, z2) = z0_z2.get(i).into();
28			let z0z2 = z0 + z2;
29			let z1 = (a0 + a1) * (b0 + b1) - z0z2;
30			let z2a = MulAlpha::mul_alpha(z2);
31
32			(z0z2, z1 + z2a).into()
33		})
34	}
35}
36
37impl<P> TaggedSquare<HybridRecursiveStrategy> for P
38where
39	P: PackedTowerField,
40	P::Scalar: TowerExtensionField<DirectSubfield = P::DirectSubfield>,
41	P::DirectSubfield: MulAlpha,
42{
43	#[inline]
44	fn square(self) -> Self {
45		let a0_a1 = self.as_packed_subfield();
46		let z0_z1 = P::from_packed_subfield(PackedField::square(a0_a1));
47
48		P::from_fn(|i| {
49			let (z0, z2) = z0_z1.get(i).into();
50			let z2a = MulAlpha::mul_alpha(z2);
51			(z0 + z2, z2a).into()
52		})
53	}
54}
55
56impl<P> TaggedMulAlpha<HybridRecursiveStrategy> for P
57where
58	P: PackedTowerField,
59	P::Scalar: TowerExtensionField<DirectSubfield = P::DirectSubfield>,
60	P::PackedDirectSubfield: MulAlpha,
61{
62	#[inline]
63	fn mul_alpha(self) -> Self {
64		let a0_a1 = self.as_packed_subfield();
65		let z1 = MulAlpha::mul_alpha(a0_a1);
66
67		P::from_fn(|i| {
68			let (a0, a1) = self.get(i).into();
69			let z1 = z1.get(2 * i + 1);
70
71			(a1, a0 + z1).into()
72		})
73	}
74}
75
76#[cfg(test)]
77mod tests {
78	use super::*;
79	use crate::{
80		arithmetic_traits::TaggedInvertOrZero,
81		test_utils::{
82			define_invert_tests, define_mul_alpha_tests, define_multiply_tests, define_square_tests,
83		},
84	};
85
86	define_multiply_tests!(
87		TaggedMul<HybridRecursiveStrategy>::mul,
88		TaggedMul<HybridRecursiveStrategy>
89	);
90
91	define_square_tests!(
92		TaggedSquare<HybridRecursiveStrategy>::square,
93		TaggedSquare<HybridRecursiveStrategy>
94	);
95
96	define_invert_tests!(
97		TaggedInvertOrZero<HybridRecursiveStrategy>::invert_or_zero,
98		TaggedInvertOrZero<HybridRecursiveStrategy>
99	);
100
101	define_mul_alpha_tests!(
102		TaggedMulAlpha<HybridRecursiveStrategy>::mul_alpha,
103		TaggedMulAlpha<HybridRecursiveStrategy>
104	);
105}
binius_field/arch/portable/hybrid_recursive_arithmetics.rs

binius_field/arch/portable/
hybrid_recursive_arithmetics.rs
