Function spring_layout 

pub fn spring_layout<N, E, Ix>(
    graph: &Graph<N, E, Ix>,
    iterations: usize,
    area_width: f64,
    area_height: f64,
) -> HashMap<N, Position>
where
    N: Node + Clone + Debug,
    E: EdgeWeight + Into<f64>,
    Ix: IndexType,

Compute a spring layout using force-directed placement

This is a simplified version of the Fruchterman-Reingold algorithm.