measure “imbalanceness” of a sum unit n by the fraction of the maximum and minimum support size
of its children (i.e., maxc1∈in(n) |supp(c1)|
). As demonstrated in Fig. 1(b), more than 20% of the sum
minc2∈in(n) |supp(c2)|
units have imbalanceness ≥ 102, which suggests that the inability of Laplace smoothing to properly
regularize PCs with imbalanced sum units could lead to severe performance degradation in practice.
Tractable Regularization of Probabilistic Circuits