Function degree_structural_info 

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

Structural information content based on degree sequence.

I = log2(|V|!) - Σ_k log2(n_k!)

where n_k is the number of vertices with degree k. This approximates the logarithm of the automorphism group size from the degree partition alone.

Examples

use rust_igraph::{Graph, degree_structural_info};

// Regular graph: all vertices equivalent → I = 0
let g = Graph::from_edges(&[(0,1),(1,2),(2,3),(3,0)], false, Some(4)).unwrap();
let info = degree_structural_info(&g).unwrap();
assert!(info.abs() < 1e-10);