Variable ordering for binary decision diagrams

Abstract

Considers the problem of variable ordering in binary decision diagrams (BDD's). The authors present several heuristics for finding a good variable ordering based on the algebraic structure of the functions. They provide a non-interleaving theorem and an accurate cost formula for the optimal ordering. They treat the output ordering problem when a given circuit has multiple outputs and propose new heuristics for the problem and experimental results which enables a quick comparison of some existing heuristics and the proposed heuristics.<>