Function edge_degree_entropy 

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

Shannon entropy of the edge degree-pair distribution.

Each edge (u, v) is classified by the ordered pair (min(deg(u), deg(v)), max(deg(u), deg(v))). This function computes the Shannon entropy (in nats) of the resulting distribution over all distinct degree-pair classes.

Returns 0.0 for graphs with no edges.

Examples

use rust_igraph::{Graph, edge_degree_entropy};

// K3: all edges have degree pair (2,2) → single class → entropy = 0
let g = Graph::from_edges(&[(0, 1), (1, 2), (0, 2)], false, Some(3)).unwrap();
assert!(edge_degree_entropy(&g).unwrap().abs() < 1e-10);