Relations between MDDs and Tuples and Dynamic Modifications of MDDs based constraints
This work addresses incremental improvements in constraint programming for researchers and practitioners, focusing on dynamic modifications of MDD-based constraints.
The paper tackles the problem of efficiently representing and modifying Multi-valued Decision Diagrams (MDDs) for constraint satisfaction, improving transformation methods and introducing in-place algorithms for dynamic tuple modifications, with experiments showing MDD constraints are competitive with Table constraints.
We study the relations between Multi-valued Decision Diagrams (MDD) and tuples (i.e. elements of the Cartesian Product of variables). First, we improve the existing methods for transforming a set of tuples, Global Cut Seeds, sequences of tuples into MDDs. Then, we present some in-place algorithms for adding and deleting tuples from an MDD. Next, we consider an MDD constraint which is modified during the search by deleting some tuples. We give an algorithm which adapts MDD-4R to these dynamic and persistent modifications. Some experiments show that MDD constraints are competitive with Table constraints.