  We give some quantum circuits for calculating the probability $P(G|D)$ of a
graph $G$ given data $D$. $G$ together with a transition probability matrix for
each node of the graph, constitutes a Classical Bayesian Network, or CB net for
short. Bayesian methods for calculating $P(G|D)$ have been given before (the so
called structural modular and ordered modular models), but these earlier
methods were designed to work on a classical computer. The goal of this paper
is to "quantum computerize" those earlier methods.
