ark_nonnative_field/
nonnative_field_mul_result_var.rs

1use crate::{AllocatedNonNativeFieldMulResultVar, NonNativeFieldVar};
2use ark_ff::PrimeField;
3use ark_relations::r1cs::Result as R1CSResult;
4
5/// An intermediate representation especially for the result of a multiplication, containing more limbs.
6/// It is intended for advanced usage to improve the efficiency.
7///
8/// That is, instead of calling `mul`, one can call `mul_without_reduce` to
9/// obtain this intermediate representation, which can still be added.
10/// Then, one can call `reduce` to reduce it back to `NonNativeFieldVar`.
11/// This may help cut the number of reduce operations.
12#[derive(Debug)]
13#[must_use]
14pub enum NonNativeFieldMulResultVar<TargetField: PrimeField, BaseField: PrimeField> {
15    /// as a constant
16    Constant(TargetField),
17    /// as an allocated gadget
18    Var(AllocatedNonNativeFieldMulResultVar<TargetField, BaseField>),
19}
20
21impl<TargetField: PrimeField, BaseField: PrimeField>
22    NonNativeFieldMulResultVar<TargetField, BaseField>
23{
24    /// Create a zero `NonNativeFieldMulResultVar` (used for additions)
25    pub fn zero() -> Self {
26        Self::Constant(TargetField::zero())
27    }
28
29    /// Create an `NonNativeFieldMulResultVar` from a constant
30    pub fn constant(v: TargetField) -> Self {
31        Self::Constant(v)
32    }
33
34    /// Reduce the `NonNativeFieldMulResultVar` back to NonNativeFieldVar
35    #[tracing::instrument(target = "r1cs")]
36    pub fn reduce(&self) -> R1CSResult<NonNativeFieldVar<TargetField, BaseField>> {
37        match self {
38            Self::Constant(c) => Ok(NonNativeFieldVar::Constant(*c)),
39            Self::Var(v) => Ok(NonNativeFieldVar::Var(v.reduce()?)),
40        }
41    }
42}
43
44impl<TargetField: PrimeField, BaseField: PrimeField>
45    From<&NonNativeFieldVar<TargetField, BaseField>>
46    for NonNativeFieldMulResultVar<TargetField, BaseField>
47{
48    fn from(src: &NonNativeFieldVar<TargetField, BaseField>) -> Self {
49        match src {
50            NonNativeFieldVar::Constant(c) => NonNativeFieldMulResultVar::Constant(*c),
51            NonNativeFieldVar::Var(v) => {
52                NonNativeFieldMulResultVar::Var(AllocatedNonNativeFieldMulResultVar::<
53                    TargetField,
54                    BaseField,
55                >::from(v))
56            }
57        }
58    }
59}
60
61impl_bounded_ops!(
62    NonNativeFieldMulResultVar<TargetField, BaseField>,
63    TargetField,
64    Add,
65    add,
66    AddAssign,
67    add_assign,
68    |this: &'a NonNativeFieldMulResultVar<TargetField, BaseField>, other: &'a NonNativeFieldMulResultVar<TargetField, BaseField>| {
69        use NonNativeFieldMulResultVar::*;
70        match (this, other) {
71            (Constant(c1), Constant(c2)) => Constant(*c1 + c2),
72            (Constant(c), Var(v)) | (Var(v), Constant(c)) => Var(v.add_constant(c).unwrap()),
73            (Var(v1), Var(v2)) => Var(v1.add(v2).unwrap()),
74        }
75    },
76    |this: &'a NonNativeFieldMulResultVar<TargetField, BaseField>, other: TargetField| { this + &NonNativeFieldMulResultVar::Constant(other) },
77    (TargetField: PrimeField, BaseField: PrimeField),
78);
ark_nonnative_field/nonnative_field_mul_result_var.rs

ark_nonnative_field/
nonnative_field_mul_result_var.rs
