Function preference_game 

pub fn preference_game(
    nodes: u32,
    types: u32,
    type_dist: Option<&[f64]>,
    fixed_sizes: bool,
    pref_matrix: &[Vec<f64>],
    directed: bool,
    loops: bool,
    seed: u64,
) -> IgraphResult<(Graph, Vec<u32>)>

Generate a random graph from a type-aware preference (block) model.

Each vertex is assigned to one of types types (uniformly, by type_dist, or pinned by fixed_sizes); each ordered/unordered vertex pair (u, v) is then connected with probability pref_matrix[type(u)][type(v)].

• nodes — number of vertices in the graph.
• types — number of vertex types (≥ 1).
• type_dist — categorical weights over types; None ⇒ uniform.
• fixed_sizes — when true, types are assigned by deterministic block-by-position rather than sampled. With type_dist = Some(td) the block sizes are td[i] (must be integer and sum to nodes). With type_dist = None the function tries to make groups of equal size.
• pref_matrix — types × types connection probabilities in [0, 1]. Must be symmetric when directed = false.
• directed — generate a directed graph.
• loops — allow self-loop edges.
• seed — initialises an internal SplitMix64 PRNG.

Returns

(graph, node_types) where node_types[i] is the type of vertex i in 0..types.

Errors

Returns IgraphError::InvalidArgument when:

• types < 1,
• type_dist length disagrees with types, contains NaN or a negative value,
• pref_matrix is non-square or has the wrong dimensions,
• any pref entry is NaN or outside [0, 1],
• pref_matrix is not symmetric when !directed,
• fixed_sizes and type_dist are both supplied but the entries are not integer or do not sum to nodes,
• nodes exceeds the 2^53 f64-exact ceiling.

Examples

use rust_igraph::preference_game;

// Three types, equal mixture; dense within types, sparse between.
let pref = vec![
    vec![0.20, 0.02, 0.02],
    vec![0.02, 0.20, 0.02],
    vec![0.02, 0.02, 0.20],
];
let (g, types) = preference_game(60, 3, None, false, &pref, false, false, 42).unwrap();
assert_eq!(g.vcount(), 60);
assert_eq!(types.len(), 60);
assert!(types.iter().all(|&t| t < 3));