Structural uncertainty

StructuralUncertainty accepts explicitly named, non-negative standard-deviation contributions labeled Structural and combines them by root-sum-of-squares. structural_score converts finite competing scores into an Akaike-style normalized ambiguity 1 - Σw².

Neither calculation discovers alternatives or proves their independence. Root-sum-of-squares assumes the contributions may be combined as independent variances; the score ambiguity is not a posterior probability over causal structures.