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Collaborating Authors

 CRIL-CNRS and Université d'Artois


Compiling Constraint Networks into Multivalued Decomposable Decision Graphs

AAAI Conferences

Specifically, we present a top-down algorithm cn2mddg for compiling finite-domain CNs into multivalued decomposable We present and evaluate a top-down algorithm for decision graphs. The input of cn2mddg is a CN compiling finite-domain constraint networks (CNs) represented in the XCSP 2.1 format [Roussel and Lecoutre, into the language MDDG of multivalued decomposable 2009]. The output of our compilation algorithm is a representation decision graphs. Though it includes Decision-of the solutions of the CN in the language MDDG DNNF as a proper subset, MDDG offers the same key of multivalued decomposable decision graphs. MDDG is precisely tractable queries and transformations as Decision-the extension to non-Boolean domains of the language DNNF, which makes it useful for many applications. DDG [Fargier and Marquis, 2006] also known as Decision-Intensive experiments showed that our compiler DNNF [Oztok and Darwiche, 2014]: it is based on decomposable cn2mddg succeeds in compiling CNs which -nodes and (multivalued) decision nodes. Similarly are out of the reach of standard approaches based to Decision-DNNF, the MDDG language offers a number of on a translation of the input network to CNF, followed tractable queries, including (possibly weighted) solution finding by a compilation to Decision-DNNF. Furthermore, and counting, solution enumeration (solutions can be enumerated the sizes of the resulting compiled representations with polynomial delay), and optimization w.r.t. a linear turn out to be much smaller (sometimes by objective function. It also offers tractable transformations, several orders of magnitude).


Compile!

AAAI Conferences

This paper is concerned with knowledge compilation (KC), a family of approaches developed in AI for more than twenty years. Knowledge compilation consists in pre-processing some pieces of the available information in order to improve the computational efficiency (especially, the time complexity) of some tasks. In this paper, the focus is laid on three KC topics which gave rise to many works: the development of knowledge compilation techniques for the clausal entailment problem in propositional logic, the concept of compilability and the notion of knowledge compilation map. The three topics, as well as an overview of the main results from the literature, are presented. Some recent research lines are also discussed.


Preprocessing for Propositional Model Counting

AAAI Conferences

Chavira and Darwiche 2008; Apsel and Brafman 2012)) and forms of planning (see e.g., (Palacios et al. 2005; It and more importantly the variable elimination rule (replacing proves useful when the problem under consideration (e.g., in the input CNF formula all the clauses containing a the satisfiability issue) can be solved more efficiently when given variable x by the set of all their resolvents over x) or the input formula has been first preprocessed (of course, the blocked clause elimination rule (removing every clause the preprocessing time is taken into account in the global containing a literal such that every resolvent obtained by resolving solving time). Some preprocessing techniques are nowadays on it is a valid clause).


Knowledge Compilation for Model Counting: Affine Decision Trees

AAAI Conferences

Counting the models of a propositional formula is a key issue for a number of AI problems, but few propositional languages offer the possibility to count models efficiently. In order to fill the gap, we introduce the language EADT of (extended) affine decision trees. An extended affine decision tree simply is a tree with affine decision nodes and some specific decomposable conjunction or disjunction nodes. Unlike standard decision trees, the decision nodes of an EADT formula are not labeled by variables but by affine clauses. We study EADT, and several subsets of it along the lines of the knowledge compilation map. We also describe a CNF-to-EADT compiler and present some experimental results. Those results show that the EADT compilation-based approach is competitive with (and in some cases is able to outperform) the model counter Cachet and the d-DNNF compilation-based approach to model counting.