Struct EvalTrait

pub struct EvalTrait<T: ?Sized, U>(/* private fields */);

A trait struct used for multi-point evaluation of polynomials.

Typically, T will be a type which implements PolyTraits and U will be the type of evaluation point. If the combination of T and U is meaningful, then EvalTrait<T,U> should implement EvalTypes; this indicates that polynomials under trait T can be evaluated at points of type U.

The purpose of this is to allow a polynomial with coefficients of one type (say, integers) to be evaluated at a point with another type (say, complex numbers, or integers modulo a prime).

type Eval = EvalTrait<ClassicalTraits<i32>, f32>;
let coeffs = [1, 0, -2];
let pts = [0.5, -1.5];
let info = Eval::prep(pts.iter().copied());
let mut result = Vec::new();
Eval::post(&mut result, &coeffs, &info);
assert_eq!(result, vec![0.5, -3.5]);

This is essentially a work-around for a problem better solved by GATs. (At the time of this writing, GAT is merged in nightly rust but not stable.)

Trait Implementations

impl<T: Debug + ?Sized, U: Debug> Debug for EvalTrait<T, U>

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

Formats the value using the given formatter.

impl<C, U> EvalTypes for EvalTrait<ClassicalTraits<C>, U>

where C: Clone, U: Clone + Zero + MulAssign + AddAssign, DefConv<C, U>: OneWay<Source = C, Dest = U>,

type Coeff = C

Coefficient type of the polynomial being evaluated.

type Eval = U

Type of the evaluation point(s) and the output(s) of the polynomial evaluation.

type EvalInfo = Vec<U>

Opaque type to hold pre-processing results.

fn prep(pts: impl Iterator<Item = Self::Eval>) -> Self::EvalInfo

Pre-processing for multi-point evaluation.

fn post( out: &mut impl Extend<Self::Eval>, coeffs: &[Self::Coeff], info: &Self::EvalInfo, ) -> Result<()>

Multi-point evaluation after pre-processing.