Function full_graph 

pub fn full_graph(n: u32, directed: bool, loops: bool) -> IgraphResult<Graph>

Build the full (complete) graph on n vertices.

The semantics follow igraph_full(graph, n, directed, loops):

• directed = false, loops = false → K_n with n·(n−1)/2 edges.
• directed = false, loops = true → K_n plus one self-loop per vertex (n·(n+1)/2 edges total).
• directed = true, loops = false → directed K_n with both (i, j) and (j, i) arcs for every i ≠ j (n·(n−1) arcs).
• directed = true, loops = true → above plus a self-loop on every vertex (n² arcs total).

Errors

• IgraphError::InvalidArgument — the upper bound on the edge count (n² in the worst case) overflows usize, so the edge buffer cannot be sized safely. Computed via usize::checked_mul so the failure mode is deterministic.

Examples

use rust_igraph::full_graph;

// K_4 — undirected complete graph on 4 vertices, 6 edges.
let k4 = full_graph(4, false, false).unwrap();
assert_eq!(k4.vcount(), 4);
assert_eq!(k4.ecount(), 6);
assert!(!k4.is_directed());

// Directed K_3 with loops — 9 arcs (3 × 3).
let dk3 = full_graph(3, true, true).unwrap();
assert_eq!(dk3.vcount(), 3);
assert_eq!(dk3.ecount(), 9);
assert!(dk3.is_directed());