Function compute_linear_combination

pub fn compute_linear_combination<E, B, C>(
    elements: &[E],
    challenges: &[C],
) -> B
where
    E: Borrow<B>,
    for<'a, 'a> &'a B: Mul<&'a C, Output = B> + Add<&'a B, Output = B>,

Computes the linear combination of two equally-sized slices, returning the sum of pair-wise products.

Conceptually, given two slices
elements = [A1, A2, … , An] and challenges = [c1, c2, … , cn],
the function evaluates

Σ (Ai · ci)  for i = 1 .. n

where · is multiplication for the underlying types and + is the corresponding addition. The result’s type (B) is the same as the borrowed type of each element in elements.

Arguments

• elements – Slice of items whose borrowed values will be multiplied by the corresponding entries in challenges.
• challenges – Slice of multipliers—must be the same length as elements.

Returns

The accumulated sum Σ (elements[i] * challenges[i]) as a value of type B.

Examples

Basic usage with primitive integers:

use std::borrow::Borrow;
use rand::rng;
use labrador::ring::rq::Rq;
use labrador::core::inner_product::compute_linear_combination;

// The function is generic; we can call it directly.
let elems = [Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng())];
let challenges = [Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng()), Rq::random(&mut rng())];
let sum = compute_linear_combination(&elems, &challenges);