70 research outputs found
Constraint Design Rewriting
We propose an algebraic approach to the design and transformation of constraint networks, inspired by Architectural Design Rewriting. The approach can be understood as (i) an extension of ADR with constraints, and (ii) an application of ADR to the design of reconfigurable constraint networks. The main idea is to consider classes of constraint networks as algebras whose operators are used to denote constraint networks with terms. Constraint network transformations such as constraint propagations are specified with rewrite rules exploiting the networkās structure provided by terms
Value withdrawal explanations: a theoretical tool for programming environments
Constraint logic programming combines declarativity and efficiency thanks to
constraint solvers implemented for specific domains. Value withdrawal
explanations have been efficiently used in several constraints programming
environments but there does not exist any formalization of them. This paper is
an attempt to fill this lack. Furthermore, we hope that this theoretical tool
could help to validate some programming environments. A value withdrawal
explanation is a tree describing the withdrawal of a value during a domain
reduction by local consistency notions and labeling. Domain reduction is
formalized by a search tree using two kinds of operators: operators for local
consistency notions and operators for labeling. These operators are defined by
sets of rules. Proof trees are built with respect to these rules. For each
removed value, there exists such a proof tree which is the withdrawal
explanation of this value.Comment: 14 pages; Alexandre Tessier, editor; WLPE 2002,
http://xxx.lanl.gov/abs/cs.SE/020705
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