Struct Poly

pub struct Poly<C>(/* private fields */);

A polynomial that is using a scalar for the variable x and a generic element for the coefficients.

The coefficients must be able to multiply the type of the variable, which is always a scalar.

Implementations

impl<C> Poly<C>

pub fn from(c: Vec<C>) -> Self

Creates a new polynomial from the given coefficients.

pub fn constant(&self) -> &C

Returns the constant term of the polynomial.

pub fn degree(&self) -> u32

Returns the degree of the polynomial

pub fn required(&self) -> u32

Returns the number of required shares to reconstruct the polynomial.

This will be the threshold

impl<C: Element> Poly<C>

pub fn commit(commits: Poly<Scalar>) -> Self

Commits the scalar polynomial to the group and returns a polynomial over the group.

This is done by multiplying each coefficient of the polynomial with the group’s generator.

pub fn zero() -> Self

Returns a zero polynomial.

pub fn get(&self, i: u32) -> C

Returns the given coefficient at the requested index.

It panics if the index is out of range.

pub fn set(&mut self, index: u32, value: C)

Set the given element at the specified index.

It panics if the index is out of range.

pub fn add(&mut self, other: &Self)

Performs polynomial addition in place

pub fn evaluate(&self, i: u32) -> Eval<C>

Evaluates the polynomial at the specified value.

pub fn recover<'a, I>(t: u32, evals: I) -> Result<C, Error>

where C: 'a, I: IntoIterator<Item = &'a Eval<C>>,

Recovers the constant term of a polynomial of degree less than t using at least t evaluations of the polynomial.

This function uses Lagrange interpolation to compute the constant term (i.e., the value of the polynomial at x=0) given at least t distinct evaluations of the polynomial. Each evaluation is assumed to have a unique index, which is mapped to a unique x-value as x = index + 1.

Warning

This function assumes that each evaluation has a unique index. If there are duplicate indices, the function may fail with an error when attempting to compute the inverse of zero.

Trait Implementations

impl<C: Clone> Clone for Poly<C>

fn clone(&self) -> Poly<C>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<C: Debug> Debug for Poly<C>

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

Formats the value using the given formatter.

impl<C: Element> EncodeSize for Poly<C>

fn encode_size(&self) -> usize

Returns the encoded size of this value (in bytes).

impl<C: PartialEq> PartialEq for Poly<C>

fn eq(&self, other: &Poly<C>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<C: Element> Read<usize> for Poly<C>

fn read_cfg(buf: &mut impl Buf, expected: &usize) -> Result<Self, CodecError>

Reads a value from the buffer using the provided configuration cfg.

impl<C: Element> Write for Poly<C>

fn write(&self, buf: &mut impl BufMut)

Writes the binary representation of self to the provided buffer buf.

impl<C: Eq> Eq for Poly<C>

impl<C> StructuralPartialEq for Poly<C>