Function eigen_adjacency 

pub fn eigen_adjacency(
    graph: &Graph,
    nev: usize,
    which: EigenWhich,
) -> IgraphResult<EigenDecomposition>

Compute selected eigenvalues of a graph’s adjacency matrix.

For undirected graphs, the adjacency matrix is real symmetric and the eigenvalues are real. For directed graphs, the matrix-vector product uses the symmetrized adjacency (A + A^T) / 2 so that the Lanczos solver applies; the eigenvalues correspond to this symmetrized form.

Arguments

• graph — the graph whose adjacency spectrum to compute
• nev — number of eigenvalues to compute (clamped to vcount)
• which — which part of the spectrum to target

Errors

Returns IgraphError::InvalidArgument if the graph has zero vertices.

Examples

use rust_igraph::{Graph, eigen_adjacency, EigenWhich};

let mut g = Graph::with_vertices(4);
g.add_edge(0, 1).unwrap();
g.add_edge(1, 2).unwrap();
g.add_edge(2, 3).unwrap();
g.add_edge(3, 0).unwrap();

let result = eigen_adjacency(&g, 2, EigenWhich::LargestAlgebraic).unwrap();
assert_eq!(result.eigenvalues.len(), 2);