Propagation algorithms for lexicographic ordering constraints
نویسندگان
چکیده
منابع مشابه
Propagation algorithms for lexicographic ordering constraints
Finite-domain constraint programming has been used with great success to tackle a wide variety of combinatorial problems in industry and academia. To apply finite-domain constraint programming to a problem, it is modelled by a set of constraints on a set of decision variables. A common modelling pattern is the use of matrices of decision variables. The rows and/or columns of these matrices are ...
متن کاملConfluence of Reduction Rules for Lexicographic Ordering Constraints
The lex leader method for breaking symmetry in CSPs typically produces a large set of lexicographic ordering constraints. Several rules have been proposed to reduce such sets whilst preserving logical equivalence. These reduction rules are not generally confluent: they may reach more than one fixpoint, depending on the order of application. These fixpoints vary in size. Smaller sets of lex cons...
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We present an arc-consistency algorithm for a chain of lexicographic ordering constraints on m vectors of n variables each. The algorithm maintains arc-consistency and runs in O(nmd) time per invocation, where d is the cost of certain domain operations.
متن کاملComplete Propagation Rules for Lexicographic Order Constraints over Arbitrary Domains
We give an efficiently executable specification of the global constraint of lexicographic order in the Constraint Handling Rules (CHR) language. In contrast to previous approaches, the implementation is short and concise without giving up on the best known worst case time complexity. It is incremental and concurrent by nature of CHR. It is provably correct and confluent. It is independent of th...
متن کاملCombining Symmetry Breaking with Other Constraints: Lexicographic Ordering with Sums
We introduce a new global constraint which combines together the lexicographic ordering constraint with some sum constraints. Lexicographic ordering constraints are frequently used to break symmetry, whilst sum constraints occur in many problems involving capacity or partitioning. Our results show that this global constraint is useful when there is a very large space to explore, such as when th...
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ژورنال
عنوان ژورنال: Artificial Intelligence
سال: 2006
ISSN: 0004-3702
DOI: 10.1016/j.artint.2006.03.002