Function linear_interpolate 

pub fn linear_interpolate<X, Y>(
    xs: &[Optioned<X>],
    ys: &[Optioned<Y>],
    target_x: X,
) -> Optioned<Y>
where
    X: Quantity + Noned + PartialOrd + Sub<X>,
    <X as Sub<X>>::Output: Quantity + Noned,
    Y: Quantity + Noned + Sub<Y>,
    <Y as Sub<Y>>::Output: Quantity,

Interpolate values given two parallel vectors of data and a target value.

Assumes that xs is monotonic.