Template matching

For matching an arbitrary query graph (not a small named catalog motif), graphlet provides a thin parallel arm delegating to petgraph's VF2 subgraph_isomorphisms_iter:

use graphlet::template::{induced_matches_unlabelled, count_induced_matches};

let matches = induced_matches_unlabelled(&pattern, &host); // Vec<Vec<usize>>
let n = count_induced_matches(&pattern, &host);

Induced-native

petgraph's subgraph_isomorphisms_iter returns node-induced subgraph isomorphisms natively (its docstring states "'subgraph' always means a 'node-induced subgraph'", its is_feasible rejects extra host edges, and empirically a P3 pattern finds 0 matches in a triangle host). So the induced arm is free — graphlet delegates and does no filtering. Pass node_match / edge_match predicates via induced_matches to match on node/edge attributes.

Why no non-induced template arm

Non-induced (monomorphism) matching of an arbitrary template is deliberately not implemented. It cannot be recovered by filtering petgraph's output (induced ⊂ monomorphism — a post-filter only shrinks the set), the k-bounded s(P,C) trick from the catalog does not apply to an unbounded template, and no consumer needs it today (science domains are induced; small named software patterns are served by the catalog arm). It is reserved as a future additive method, never an erroring runtime toggle.