Function symmetry_structure 

pub fn symmetry_structure(
    num_vars: usize,
    clauses: &[Vec<Lit>],
) -> SymmetryProfile

Compute the SymmetryProfile of clauses — detect the variable-symmetry generators and read off the whole structural ladder (order via Schreier–Sims, orbits, orbitals/rank, transitivity, primitivity, blocks). The rank and transitivity rungs are gated to moderate sizes (their tuple spaces grow with the degree); 0 signals “not computed” there.