Function pairwise_distances 

pub fn pairwise_distances<T, P, A, M>(points: &A, metric: &M) -> Vec<T>
where
    T: SpatialScalar,
    P: SpatialPoint<T>,
    A: SpatialArray<T, P>,
    M: DistanceMetric<T, P>,

Calculate pairwise distances between all points in a collection