Some heuristics for generating tree-like FBDD types

Reduced ordered binary decision diagrams (OBDD´s) are nowadays the state-of-the-art representation scheme for Boolean functions in Boolean manipulation. Recent results have shown that it is possible to use the more general concept of free binary decision diagrams (FBDD´s) without giving up most of the useful computational properties of OBDD´s, but possibly reducing the space requirements considerably. The amount of space reduction depends essentially on the shape of so-called FBDD-types the Boolean manipulation in terms of FBDD´s is based on. Here, we propose some heuristics for deriving tree-like FBDD-types from given circuit descriptions. The experimental results we obtained clearly demonstrate that the FBDD-approach is not only of theoretical interest, but also of practical usefulness even in the ease of using merely such simple-structured tree-based FBDD-types as produced by the investigated heuristics