Function modified_first_zagreb_connection 

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

Compute the modified first Zagreb connection index.

ZC₁*(G) = Σ_{(u,v)∈E} (τ(u) + τ(v))

Examples

use rust_igraph::{Graph, modified_first_zagreb_connection};

// K_3: τ(v)=0 for all v (all pairs are direct neighbours)
// ZC₁* = 0
let g = Graph::from_edges(&[(0,1),(1,2),(0,2)], false, Some(3)).unwrap();
assert!((modified_first_zagreb_connection(&g).unwrap()).abs() < 1e-10);