Function is_primitive_via_orbitals 

pub fn is_primitive_via_orbitals(degree: usize, gens: &[Perm]) -> bool

Primitivity via Higman’s theorem: a transitive group is primitive iff every non-diagonal orbital graph is connected. An independent route to is_primitive; when a non-diagonal orbital graph is disconnected, its connected components are a block system. (Returns false for an intransitive group.)