Trait HornerIter 

pub trait HornerIter: DoubleEndedIterator + Sized {
    // Provided methods
    fn horner_acc<Acc, X>(self, acc: Acc, x: X) -> Acc
       where Acc: Mul<X, Output = Acc> + Add<Self::Item, Output = Acc>,
             X: Clone { ... }
    fn horner<Acc, X>(self, x: X) -> Acc
       where Acc: Default + Mul<X, Output = Acc> + Add<Self::Item, Output = Acc>,
             X: Clone { ... }
}

Horner-style polynomial evaluation over a DoubleEndedIterator.

The iterator yields coefficients in ascending degree order [c_0, c_1, …, c_{n-1}]. Both methods walk the iterator back-to-front via DoubleEndedIterator::rfold, avoiding any allocation.

Convention

Given an evaluation point x and accumulator acc, HornerIter::horner_acc computes

acc · xⁿ + Σ_{i=0..n} c_i · xⁱ
  = c_0 + x · (c_1 + x · (… + x · (c_{n-1} + x · acc)))

HornerIter::horner is the same with acc = Acc::default(), i.e. the polynomial evaluation Σ_i c_i · xⁱ.

For inputs in descending degree order, call .rev() on the iterator first.

Provided Methods

fn horner_acc<Acc, X>(self, acc: Acc, x: X) -> Acc

where Acc: Mul<X, Output = Acc> + Add<Self::Item, Output = Acc>, X: Clone,

Horner fold with an explicit accumulator. See the trait docs for the evaluation convention.

fn horner<Acc, X>(self, x: X) -> Acc

where Acc: Default + Mul<X, Output = Acc> + Add<Self::Item, Output = Acc>, X: Clone,

Horner fold starting from Acc::default(). See the trait docs for the evaluation convention.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<I: DoubleEndedIterator> HornerIter for I