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Propagating differences: An efficient new fixpoint algorithm for distributive constraint systems [chapter]

Christian Fecht, Helmut Seidl
1998 Lecture Notes in Computer Science  
constraint systems.  ...  Integrating semi-naive xpoint iteration from deductive data bases 3, 2, 4] as well as continuations into worklist-based solvers, we derive a new application independent local xpoint algorithm for distributive  ...  For distributive S with gct's as right-hand sides, algorithm WR computes an X-stable partial least solution.  ... 
doi:10.1007/bfb0053565 fatcat:3erobddvzrcvpgml3yzxcaiexm

Global difference constraint propagation for finite domain solvers

Thibaut Feydy, Andreas Schutt, Peter J. Stuckey
2008 Proceedings of the 10th international ACM SIGPLAN symposium on Principles and practice of declarative programming - PPDP '08  
Difference constraints of the form x − y ≤ d are well studied, with efficient algorithms for satisfaction and implication, because of their connection to shortest paths.  ...  Finite domain propagation algorithms however do not make use of these algorithms, and typically treat each difference constraint as a separate propagator.  ...  et al. 1999 ), while they also give an algorithm for checking implication of difference constraints on addition.  ... 
doi:10.1145/1389449.1389478 dblp:conf/ppdp/FeydySS08 fatcat:wduj6opazfdg7gbh4mmv73j2re

Efficient constraint propagation engines

Christian Schulte, Peter J. Stuckey
2008 ACM Transactions on Programming Languages and Systems  
Efficient Constraint Propagation Engines · 3 event-based optimizations used in current propagation systems. -We extend event-based propagation systems to use dynamically changing event sets.  ...  for greater efficiency.  ...  ACKNOWLEDGMENTS We thank Mikael Lagerkvist, Guido Tack and the anonymous reviewers for many helpful suggestions that improved the paper.  ... 
doi:10.1145/1452044.1452046 fatcat:nf5uxn7nbbgyvc2nrsckfjh4bm

Schedulers and Redundancy for a Class of Constraint Propagation Rules [article]

Sebastian Brand, Krzysztof R. Apt
2004 arXiv   pre-print
We study here schedulers for a class of rules that naturally arise in the context of rule-based constraint programming.  ...  This leads to an implementation that yields a considerably better performance for these rules than their execution as standard CHR rules.  ...  Acknowledgments We thank Christian Holzbaur and Eric Monfroy for helpful discussions on the implementation and on an early version of this paper.  ... 
arXiv:cs/0403037v3 fatcat:k77jvxrtlbdlvbremwimezhufa

Maintaining State in Propagation Solvers [chapter]

Raphael M. Reischuk, Christian Schulte, Peter J. Stuckey, Guido Tack
2009 Lecture Notes in Computer Science  
Constraint propagation solvers interleave propagation, removing impossible values from variable domains, with search. The solver state is modified during propagation.  ...  This paper sets out the possible ways in which a propagation solver can choose to maintain state, and the restrictions that such choices place on the resulting system.  ...  We thank Thibaut Feydy and Sebastian Brand for many interesting discussions related to this work.  ... 
doi:10.1007/978-3-642-04244-7_54 fatcat:3t72mnyzafhefikijtlma56boe

From Support Propagation to Belief Propagation in Constraint Programming

Gilles Pesant
2019 The Journal of Artificial Intelligence Research  
From that exposed structure in the form of so-called global constraints, powerful inference algorithms have shared information between constraints by propagating it through shared variables' domains, traditionally  ...  Its advantage over standard belief propagation is that the higher-level models featuring large-arity (global) constraints do not tend to create as many cycles, which are known to be problematic for convergence  ...  Acknowledgements The author wishes to thank Arthur Godet for an initial implementation of this work, Alessandro Zanarini for early discussions, and the anonymous referees for their constructive criticism  ... 
doi:10.1613/jair.1.11487 fatcat:7m55dd4bnbfg5dfwaww73owqnq

Schedulers and redundancy for a class of constraint propagation rules

SEBASTIAN BRAND, KRZYSZTOF R. APT
2005 Theory and Practice of Logic Programming  
1 We study here schedulers for a class of rules that naturally arise in the context of rule-based constraint programming.  ...  This leads to an implementation that yields a considerably better performance for these rules than their execution as standard CHR rules.  ...  Acknowledgments We thank Christian Holzbaur and Eric Monfroy for helpful discussions on the implementation and on an early version of this paper.  ... 
doi:10.1017/s1471068405002401 fatcat:742telhxqzcwvf52mcwm6lgqcy

Theory propagation and reification

Ed Robbins, Jacob M. Howe, Andy King
2015 Science of Computer Programming  
The approach is also illustrated with SMT solvers for linear constraints and integer difference constraints.  ...  The solution to this problem requires an SMT solver where the theory is that of rational-tree constraints, a theory not supported in off-the-shelf SMT solvers, but realised as unification in Prolog systems  ...  We also thank Wei-Ming Khoo for explaining his approach to type recovery and Mats Carlsson for his help with SICStus Prolog.  ... 
doi:10.1016/j.scico.2014.05.013 fatcat:xncs4me3s5f47dzogf3guqse2m

Towards Solver-Independent Propagators [chapter]

Jean-Noël Monette, Pierre Flener, Justin Pearson
2012 Lecture Notes in Computer Science  
We present an extension to indexicals to describe propagators for global constraints. The resulting language is compiled into actual propagators for different solvers, and is solver-independent.  ...  Therefore, our language can be used for the rapid prototyping of new global constraints.  ...  This allows one to prototype rapidly a propagator for a new constraint, for which one has no built-in propagator or no (good enough) decomposition; the generated propagator may even serve as a baseline  ... 
doi:10.1007/978-3-642-33558-7_40 fatcat:bfdk3e6f6rgyhd4p3bgrniffri

Other things besides number: Abstraction, constraint propagation, and string variable types

Joseph Scott
2016 Constraints  
Constraints are more than a modeling convenience: every constraint is partially implemented by an inference algorithm, called a propagator, that rules out some but not necessarily all infeasible candidate  ...  We define, via a Galois connection, an over-approximation for bounded-length strings, and demonstrate two different methods for implementing this overapproximation in a CP solver.  ...  of event systems is important because propagation events are used in the fixpoint algorithm to schedule propagator algorithms for execution; use of a non-monotonic event system makes propagator scheduling  ... 
doi:10.1007/s10601-016-9263-9 fatcat:uvugx6dln5fl3kbrhltpdfashm

A high-level derivation of global search algorithms (with constraint propagation)

Peter Pepper, Douglas R. Smith
1997 Science of Computer Programming  
The algorithm is based on the concepts of global search and constraint propagation and was originally derived using KIDS (Kestrel Interactive Development System).  ...  In this paper we describe the formal derivation of a transportation scheduling algorithm.  ...  Acknowledgements We thank our colleagues from Kestrel Institute, notably Richard Jtillig Yellamraju Srinivas, for many stimulating discussions during the derivation of paper.  ... 
doi:10.1016/s0167-6423(96)00023-8 fatcat:lzq2e2ng2vhuhiynfvexg7l2ua

Safety verification of hybrid systems by constraint propagation-based abstraction refinement

Stefan Ratschan, Zhikun She
2007 ACM Transactions on Embedded Computing Systems  
We put this method into an abstraction refinement framework and improve it by developing an additional refinement step that employs interval constraint propagation to add information to the abstraction  ...  without introducing new grid elements.  ...  The authors thank Martin Fränzle for carefully removing some of our initial ignorance about the intricacies of hybrid systems.  ... 
doi:10.1145/1210268.1210276 fatcat:4gkpnx6hznh4bknm6jby22skpy

Safety Verification of Hybrid Systems by Constraint Propagation Based Abstraction Refinement [chapter]

Stefan Ratschan, Zhikun She
2005 Lecture Notes in Computer Science  
We put this method into an abstraction refinement framework and improve it by developing an additional refinement step that employs interval constraint propagation to add information to the abstraction  ...  without introducing new grid elements.  ...  The authors thank Martin Fränzle for carefully removing some of our initial ignorance about the intricacies of hybrid systems.  ... 
doi:10.1007/978-3-540-31954-2_37 fatcat:o2njvppiobfb7gsxy4z34syohq

Compact Difference Bound Matrices [chapter]

Aziem Chawdhary, Andy King
2017 Lecture Notes in Computer Science  
Octagon constraints are classically represented using a Difference Bound Matrix (DBM), where the entries in the DBM store bounds c for inequalities of the form xi´xj ď c, xi'xj ď c or´xi´xj ď c.  ...  The size of such a DBM is quadratic in the number of variables, giving a representation which can be excessively large for number systems such as rationals.  ...  Acknowledgements We thank Colin King at Canonical Limited for his tireless patience and help with the performance analysis which underpinned this work.  ... 
doi:10.1007/978-3-319-71237-6_23 fatcat:xi3muphymzgotbby4bdhk5ye5u

Complete Propagation Rules for Lexicographic Order Constraints over Arbitrary Domains [chapter]

Thom Frühwirth
2006 Lecture Notes in Computer Science  
We give an efficiently executable specification of the global constraint of lexicographic order in the Constraint Handling Rules (CHR) language.  ...  We also show completeness of constraint propagation, i.e. that all possible logical consequences of the constraint are generated by the implementation.  ...  The author would like to thank Marc Meister and Tom Schrijvers for discussions and help with implementation and testing, and the reviewers for their helpful comments.  ... 
doi:10.1007/11754602_2 fatcat:flyvd4qytzcupbdbehmdq5hwfi
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