Dynamic Reordering in a Breadth-First Manipulation Based BDD Package: Challenges and Solutions

The breadth-rst manipulation technique has proven eeective in dealing with very large sized BDDs. However , till now the lack of dynamic variable reordering has remained an obstacle in its acceptance. The goal of this work is to provide eecient techniques to address this issue. After identifying the problems with implementing variable swapping (the core operation in dynamic reordering) in breadth-rst based packages, we propose techniques to handle the computational and memory overheads. We feel that combining dynamic reordering with the powerful manipulation algorithms of a breadth-rst based scheme can signiicantly enhance the performance of BDD based algorithms. The ee-ciency of the proposed techniques is demonstrated on a range of examples.