Struct IndexedHypergraph 

pub struct IndexedHypergraph { /* private fields */ }

A hypergraph with usize-indexed nodes and rich algorithmic support.

Example

use scirs2_graph::hypergraph::{IndexedHypergraph, clique_expansion};

let mut hg = IndexedHypergraph::new(5);
hg.add_hyperedge(vec![0, 1, 2], 1.0).unwrap();
hg.add_hyperedge(vec![2, 3, 4], 1.0).unwrap();

let g = clique_expansion(&hg);
assert!(g.edge_count() >= 3);

Implementations

impl IndexedHypergraph

pub fn new(n_nodes: usize) -> Self

Create an empty hypergraph with n_nodes nodes indexed 0..n_nodes.

pub fn n_nodes(&self) -> usize

Number of nodes (constant after construction).

pub fn n_hyperedges(&self) -> usize

Number of hyperedges.

pub fn hyperedges(&self) -> &[Hyperedge]

Immutable reference to all hyperedges.

pub fn add_hyperedge(&mut self, nodes: Vec<usize>, weight: f64) -> Result<usize>

Add a new hyperedge. Nodes that exceed n_nodes are rejected.

Returns the newly assigned hyperedge id.

pub fn hyperedges_of_node(&self, node: usize) -> Option<&[usize]>

Return all hyperedge ids that contain node.

pub fn degree(&self, node: usize) -> usize

Degree of a node = number of hyperedges it belongs to (unweighted).

pub fn weighted_degree(&self, node: usize) -> f64

Weighted degree of a node = sum of weights of incident hyperedges.

pub fn incidence_matrix(&self) -> Array2<f64>

Compute the node–hyperedge incidence matrix B of shape (n_nodes × n_hyperedges).

B[i, e] = sqrt(w_e) when node i is in hyperedge e, else 0.

pub fn incidence_matrix_binary(&self) -> Array2<f64>

Compute the raw (unweighted) incidence matrix B where B[i,e] ∈ {0,1}.

pub fn star_expansion(&self) -> Graph<usize, f64>

Build the star expansion of this hypergraph.

Each hyperedge e is replaced by a new auxiliary node (indexed n_nodes + e). The auxiliary node is connected to every member of e with weight w_e. The resulting graph has n_nodes + n_hyperedges nodes.

pub fn bipartite_representation(&self) -> BaseHypergraph<usize, f64>

Build the bipartite representation of this hypergraph.

Returns a hypergraph where the left partition contains original nodes (indices 0..n_nodes) and the right partition contains hyperedge auxiliary nodes (indices n_nodes..n_nodes+n_hyperedges). Each 2-element hyperedge {original_node, aux_hyperedge_node} encodes a membership relation.

Trait Implementations

impl Clone for IndexedHypergraph

fn clone(&self) -> IndexedHypergraph

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for IndexedHypergraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.