Function transitivity_degree 

pub fn transitivity_degree(degree: usize, gens: &[Perm], max_t: usize) -> usize

The transitivity degree: the largest t ≤ max_t for which the group is transitive on ordered t-tuples of distinct points (1 = transitive, 2 = 2-transitive, …). 0 if intransitive. Capped at max_t because the t-tuple space grows as degree^t. Sₙ is n-transitive; a regular group is only 1-transitive.