pub fn associate_to_reference_points(
population: &[Individual],
ref_points: &[Vec<f64>],
ideal: &[f64],
nadir: &[f64],
) -> Vec<(usize, f64)>Expand description
For each individual, find the nearest reference point and compute the distance to its reference line.
Returns a vector of (ref_idx, distance) tuples, one per individual.