pub fn coherent_configuration_constants(
num_vars: usize,
clauses: &[Vec<Lit>],
) -> Option<(usize, Vec<Vec<Vec<u128>>>)>Expand description
The coherent configuration (association scheme) that 2-WL stabilizes into: its d basis relations
(the stable pair-color classes R_0,…,R_{d-1}) and their intersection numbers
p[i][j][k] = |{z : (x,z) ∈ R_i and (z,y) ∈ R_j}| for any (x,y) ∈ R_k. Returns (d, p).
The intersection numbers are well-defined because the coloring is coherent (independent of which
(x,y) ∈ R_k is chosen) — and that well-definedness is checked over EVERY pair, FAIL-CLOSED: None if
the 2-WL coloring is somehow not coherent (it always is once stabilized, so this certifies it). These are
the structure constants of the coherent algebra — the combinatorial dual of the class-algebra structure
constants (crate::permgroup::class_multiplication_coefficients); for a group’s orbital configuration
they are the orbital intersection numbers.