Function dyad_census 

pub fn dyad_census(graph: &Graph) -> IgraphResult<DyadCensus>

Counts the mutual, asymmetric, and null dyads in a directed graph.

A dyad is an unordered pair of vertices. In a directed graph:

• Mutual: both (u,v) and (v,u) edges exist.
• Asymmetric: exactly one of (u,v) or (v,u) exists.
• Null: neither edge exists.

Self-loops and multi-edges are ignored (only simple edges counted). For undirected graphs, all edges are treated as mutual.

Uses f64 to avoid overflow for large graphs where n*(n-1)/2 may exceed u32::MAX.

Examples

use rust_igraph::{Graph, dyad_census};

let mut g = Graph::new(4, true).unwrap();
// Mutual: 0↔1
g.add_edge(0, 1).unwrap();
g.add_edge(1, 0).unwrap();
// Asymmetric: 2→3
g.add_edge(2, 3).unwrap();

let dc = dyad_census(&g).unwrap();
assert!((dc.mutual - 1.0).abs() < 1e-10);
assert!((dc.asymmetric - 1.0).abs() < 1e-10);
assert!((dc.null - 4.0).abs() < 1e-10);