SMAA-2 — Stochastic extension of SMAA2

SMAA-2 (Lahdelma & Salminen 2001) extends base SMAA by computing the full rank acceptability index matrix b_i^r for all ranks r=1..m (not only rank 1) and aggregating into a holistic acceptability a_i^h = Σ_r α^r b_i^r (Eq.18) via monotone metaweights α^1 ≥ ... ≥ α^m ≥ 0, α^1=1. Monte Carlo samples (x^{(k)}, w^{(k)}) drawn from f_X and uniform W; per-sample additive utility (Eq.11) → rankings → b_i^r → a_i^h. Final ranking by a_i^h descending. No defuzzification — SMAA-2 is probabilistic, not fuzzy.