New methods to color the vertices of a graph
Communications of the ACM
Radio Link Frequency Assignment
Constraints
Contradicting Conventional Wisdom in Constraint Satisfaction
PPCP '94 Proceedings of the Second International Workshop on Principles and Practice of Constraint Programming
Global Cut Framework for Removing Symmetries
CP '01 Proceedings of the 7th International Conference on Principles and Practice of Constraint Programming
Constraint Processing
Automated Planning: Theory & Practice
Automated Planning: Theory & Practice
Backjump-Based Techniques versus Conflict-Directed Heuristics
ICTAI '04 Proceedings of the 16th IEEE International Conference on Tools with Artificial Intelligence
Random constraint satisfaction: Easy generation of hard (satisfiable) instances
Artificial Intelligence
Proceedings of the 2006 conference on ECAI 2006: 17th European Conference on Artificial Intelligence August 29 -- September 1, 2006, Riva del Garda, Italy
QUICKXPLAIN: preferred explanations and relaxations for over-constrained problems
AAAI'04 Proceedings of the 19th national conference on Artifical intelligence
Journal of Artificial Intelligence Research
AAAI'05 Proceedings of the 20th national conference on Artificial intelligence - Volume 1
AAAI'05 Proceedings of the 20th national conference on Artificial intelligence - Volume 1
Exact phase transitions in random constraint satisfaction problems
Journal of Artificial Intelligence Research
Conflict-directed backjumping revisited
Journal of Artificial Intelligence Research
Domain filtering consistencies
Journal of Artificial Intelligence Research
PDDL2.1: an extension to PDDL for expressing temporal planning domains
Journal of Artificial Intelligence Research
An optimal coarse-grained arc consistency algorithm
Artificial Intelligence
Branching and pruning: An optimal temporal POCL planner based on constraint programming
Artificial Intelligence
Constraint Networks: Techniques and Algorithms
Constraint Networks: Techniques and Algorithms
Using CSP look-back techniques to solve real-world SAT instances
AAAI'97/IAAI'97 Proceedings of the fourteenth national conference on artificial intelligence and ninth conference on Innovative applications of artificial intelligence
Soft arc consistency revisited
Artificial Intelligence
Towards parallel non serial dynamic programming for solving hard weighted CSP
CP'10 Proceedings of the 16th international conference on Principles and practice of constraint programming
DR.FILL: crosswords and an implemented solver for singly weighted CSPs
Journal of Artificial Intelligence Research
Pairwise decomposition for combinatorial optimization in graphical models
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Three
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Constraint programming is a popular paradigm to deal with combinatorial problems in artificial intelligence. Backtracking algorithms, applied to constraint networks, are commonly used but suffer from thrashing, i.e. the fact of repeatedly exploring similar subtrees during search. An extensive literature has been devoted to prevent thrashing, often classified into look-ahead (constraint propagation and search heuristics) and look-back (intelligent backtracking and learning) approaches. In this paper, we present an original look-ahead approach that allows to guide backtrack search toward sources of conflicts and, as a side effect, to obtain a behavior similar to a backjumping technique. The principle is the following: after each conflict, the last assigned variable is selected in priority, so long as the constraint network cannot be made consistent. This allows us to find, following the current partial instantiation from the leaf to the root of the search tree, the culprit decision that prevents the last variable from being assigned. This way of reasoning can easily be grafted to many variations of backtracking algorithms and represents an original mechanism to reduce thrashing. Moreover, we show that this approach can be generalized so as to collect a (small) set of incompatible variables that are together responsible for the last conflict. Experiments over a wide range of benchmarks demonstrate the effectiveness of this approach in both constraint satisfaction and automated artificial intelligence planning.