Function isolated_vertex_ratio 

pub fn isolated_vertex_ratio(graph: &Graph) -> IgraphResult<f64>

Compute the isolated vertex ratio.

Fraction of vertices with degree 0. Returns 0.0 for empty graphs (no vertices).

Examples

use rust_igraph::{Graph, isolated_vertex_ratio};

// 5 isolated vertices → 1.0
let g = Graph::with_vertices(5);
assert!((isolated_vertex_ratio(&g).unwrap() - 1.0).abs() < 1e-10);