Efficient Calculations

Abstract

The previous chapters have laid a foundation for building probability models and embedding them in a graphical structure. Once we have expressed all of the interrelationships in terms of a joint probability distribution, it is possible to calculate the effect of new information about any subset of the variables on our beliefs about the remaining variables (i.e., to propagate the evidence). This chapter addresses efficient calculation in networks of discrete variables. The objective is to ground intuition with a simplified version of a basic junction-tree algorithm, illustrated in detail with a numerical example.