Ordered Kronecker functional decision diagrams-a data structure for representation and manipulation of Boolean functions

Ordered Kronecker functional decision diagrams (OKFDD’s) are a data structure for efficient representation and manipulation of Boolean functions. OKFDD’s are a generalization of ordered binary decision diagrams (OBDD’s) and ordered functional decision diagrams and thus combine the advantages of both. In this paper, basic properties of OKFDD’s and their efficient representation and manipulation are given. Starting with elementary manipulation algorithms, we present methods for the construction of small OKFDD’s. Our approach is based on dynamic variable ordering and decomposition-type choice. For changing the decomposition type, we use an efficient reordering-based method. We briefly discuss the implementation of PUMA, an OKFDD package, which was used in all our experiments. These experiments demonstrate the quality of our methods in comparison to sifting and interleaving for OBDD’s.