Function radius 

pub fn radius(graph: &Graph) -> IgraphResult<Option<u32>>

Radius of graph — the minimum vertex eccentricity. None for a graph with no vertices (matches upstream’s IGRAPH_NAN for the null graph).

Counterpart of igraph_radius(_, NULL_weights, _, IGRAPH_OUT).

Examples

use rust_igraph::{Graph, radius};

let mut g = Graph::with_vertices(4);
g.add_edge(0, 1).unwrap();
g.add_edge(1, 2).unwrap();
g.add_edge(2, 3).unwrap();
assert_eq!(radius(&g).unwrap(), Some(2));