Struct FpChip

pub struct FpChip<'range, F: BigPrimeField, Fp: BigPrimeField> {
    pub range: &'range RangeChip<F>,
    pub limb_bits: usize,
    pub num_limbs: usize,
    pub num_limbs_bits: usize,
    pub num_limbs_log2_ceil: usize,
    pub limb_bases: Vec<F>,
    pub limb_base_big: BigInt,
    pub limb_mask: BigUint,
    pub p: BigInt,
    pub p_limbs: Vec<F>,
    pub p_native: F,
    pub native_modulus: BigUint,
    /* private fields */
}

Fields

range: &'range RangeChip<F>

limb_bits: usize

num_limbs: usize

num_limbs_bits: usize

num_limbs_log2_ceil: usize

limb_bases: Vec<F>

limb_base_big: BigInt

limb_mask: BigUint

p: BigInt

p_limbs: Vec<F>

p_native: F

native_modulus: BigUint

Implementations

impl<'range, F: BigPrimeField, Fp: BigPrimeField> FpChip<'range, F, Fp>

pub fn new( range: &'range RangeChip<F>, limb_bits: usize, num_limbs: usize, ) -> Self

pub fn enforce_less_than_p(&self, ctx: &mut Context<F>, a: ProperCrtUint<F>)

pub fn load_constant_uint( &self, ctx: &mut Context<F>, a: BigUint, ) -> ProperCrtUint<F>

Trait Implementations

impl<'range, F: Clone + BigPrimeField, Fp: Clone + BigPrimeField> Clone for FpChip<'range, F, Fp>

fn clone(&self) -> FpChip<'range, F, Fp>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'range, F: Debug + BigPrimeField, Fp: Debug + BigPrimeField> Debug for FpChip<'range, F, Fp>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'range, F: BigPrimeField, Fp: BigPrimeField> FieldChip<F> for FpChip<'range, F, Fp>

fn range_check( &self, ctx: &mut Context<F>, a: impl Into<ProperCrtUint<F>>, max_bits: usize, )

Assumptions

• max_bits <= n * k where n = self.limb_bits and k = self.num_limbs
• a.truncation.limbs.len() = self.num_limbs

fn is_soft_zero( &self, ctx: &mut Context<F>, a: impl Into<ProperCrtUint<F>>, ) -> AssignedValue<F>

Returns 1 iff a is 0 as a BigUint. This means that even if a is 0 modulo p, this may return 0.

fn is_soft_nonzero( &self, ctx: &mut Context<F>, a: impl Into<ProperCrtUint<F>>, ) -> AssignedValue<F>

Given proper CRT integer a, returns 1 iff a < modulus::<F>() and a != 0 as integers

Assumptions

• a is proper representation of BigUint

const PRIME_FIELD_NUM_BITS: u32 = Fp::NUM_BITS

type UnsafeFieldPoint = CRTInteger<F>

A representation of a field element that is used for intermediate computations. The representation can have “overflows” (e.g., overflow limbs or negative limbs).

type FieldPoint = ProperCrtUint<F>

The “proper” representation of a field element. Allowed to be a non-unique representation of a field element (e.g., can be greater than modulus)

type ReducedFieldPoint = Reduced<ProperCrtUint<F>, Fp>

A proper representation of field elements that guarantees a unique representation of each field element. Typically this means Uints that are less than the modulus.

type FieldType = Fp

A type implementing Field trait to help with witness generation (for example with inverse)

type RangeChip = RangeChip<F>

fn native_modulus(&self) -> &BigUint

fn range(&self) -> &'range Self::RangeChip

fn limb_bits(&self) -> usize

fn get_assigned_value(&self, x: &CRTInteger<F>) -> Fp

fn load_private(&self, ctx: &mut Context<F>, a: Fp) -> ProperCrtUint<F>

Assigns fe as private witness. Note that the witness may not be constrained to be a unique representation of the field element fe.

fn load_constant(&self, ctx: &mut Context<F>, a: Fp) -> ProperCrtUint<F>

Assigns fe as constant.

fn add_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, b: impl Into<CRTInteger<F>>, ) -> CRTInteger<F>

fn add_constant_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, c: Fp, ) -> CRTInteger<F>

output: a + c

fn sub_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, b: impl Into<CRTInteger<F>>, ) -> CRTInteger<F>

fn negate(&self, ctx: &mut Context<F>, a: ProperCrtUint<F>) -> ProperCrtUint<F>

fn scalar_mul_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, c: i64, ) -> CRTInteger<F>

a * c

fn scalar_mul_and_add_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, b: impl Into<CRTInteger<F>>, c: i64, ) -> CRTInteger<F>

a * c + b

fn mul_no_carry( &self, ctx: &mut Context<F>, a: impl Into<CRTInteger<F>>, b: impl Into<CRTInteger<F>>, ) -> CRTInteger<F>

fn check_carry_mod_to_zero(&self, ctx: &mut Context<F>, a: CRTInteger<F>)

fn carry_mod(&self, ctx: &mut Context<F>, a: CRTInteger<F>) -> ProperCrtUint<F>

fn enforce_less_than( &self, ctx: &mut Context<F>, a: ProperCrtUint<F>, ) -> Reduced<ProperCrtUint<F>, Fp>

Constrains that a is a reduced representation and returns the wrapped a.

fn is_zero( &self, ctx: &mut Context<F>, a: impl Into<ProperCrtUint<F>>, ) -> AssignedValue<F>

fn is_equal_unenforced( &self, ctx: &mut Context<F>, a: Reduced<ProperCrtUint<F>, Fp>, b: Reduced<ProperCrtUint<F>, Fp>, ) -> AssignedValue<F>

fn assert_equal( &self, ctx: &mut Context<F>, a: impl Into<ProperCrtUint<F>>, b: impl Into<ProperCrtUint<F>>, )

fn gate(&self) -> &<Self::RangeChip as RangeInstructions<F>>::Gate

fn load_private_reduced( &self, ctx: &mut Context<F>, fe: Self::FieldType, ) -> Self::ReducedFieldPoint

Assigns fe as private witness and contrains the witness to be in reduced form.

fn is_equal( &self, ctx: &mut Context<F>, a: impl Into<Self::FieldPoint>, b: impl Into<Self::FieldPoint>, ) -> AssignedValue<F>

fn mul( &self, ctx: &mut Context<F>, a: impl Into<Self::UnsafeFieldPoint>, b: impl Into<Self::UnsafeFieldPoint>, ) -> Self::FieldPoint

If using UnsafeFieldPoint, make sure multiplication does not cause overflow.

fn divide( &self, ctx: &mut Context<F>, a: impl Into<Self::FieldPoint>, b: impl Into<Self::FieldPoint>, ) -> Self::FieldPoint

Constrains that b is nonzero as a field element and then returns a / b.

fn divide_unsafe( &self, ctx: &mut Context<F>, a: impl Into<Self::UnsafeFieldPoint>, b: impl Into<Self::UnsafeFieldPoint>, ) -> Self::FieldPoint

Returns a / b without constraining b to be nonzero.

fn neg_divide( &self, ctx: &mut Context<F>, a: impl Into<Self::FieldPoint>, b: impl Into<Self::FieldPoint>, ) -> Self::FieldPoint

Constrains that b is nonzero as a field element and then returns -a / b.

fn neg_divide_unsafe( &self, ctx: &mut Context<F>, a: impl Into<Self::UnsafeFieldPoint>, b: impl Into<Self::UnsafeFieldPoint>, ) -> Self::FieldPoint

impl<'range, F: BigPrimeField, Fp: BigPrimeField> PrimeFieldChip<F> for FpChip<'range, F, Fp>

fn num_limbs(&self) -> usize

fn limb_mask(&self) -> &BigUint

fn limb_bases(&self) -> &[F]

impl<'range, F: BigPrimeField, Fp: BigPrimeField> Selectable<F, CRTInteger<F>> for FpChip<'range, F, Fp>

fn select( &self, ctx: &mut Context<F>, a: CRTInteger<F>, b: CRTInteger<F>, sel: AssignedValue<F>, ) -> CRTInteger<F>

fn select_by_indicator( &self, ctx: &mut Context<F>, a: &impl AsRef<[CRTInteger<F>]>, coeffs: &[AssignedValue<F>], ) -> CRTInteger<F>

impl<'range, F: BigPrimeField, Fp: BigPrimeField> Selectable<F, ProperCrtUint<F>> for FpChip<'range, F, Fp>

fn select( &self, ctx: &mut Context<F>, a: ProperCrtUint<F>, b: ProperCrtUint<F>, sel: AssignedValue<F>, ) -> ProperCrtUint<F>

fn select_by_indicator( &self, ctx: &mut Context<F>, a: &impl AsRef<[ProperCrtUint<F>]>, coeffs: &[AssignedValue<F>], ) -> ProperCrtUint<F>