Reducing the number of variable movements in exact BDD minimization

Ordered Binary Decision Diagrams (BDDs) are frequently used in logic synthesis. In this paper a new exact BDD minimization algorithm is presented, which is based on state space search. In contrast to all previous approaches, in which variables are moved through the BDD when exploring the state space, the new method makes use of a new technique to expand states to its successor states without expensive variable movements. Experimental results are given to show the efficiency of the approach.