Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-24T03:50:28.774Z Has data issue: false hasContentIssue false

A CHR-based implementation of known arc-consistency

Published online by Cambridge University Press:  01 July 2005

MARCO ALBERTI
Affiliation:
Dipartimento di Ingegneria, Universitá degli Studi di Ferrara, Ferrara, Italy (e-mail: malberti@ing.unife.it)
MARCO GAVANELLI
Affiliation:
Dipartimento di Ingegneria, Universitá degli Studi di Ferrara, Ferrara, Italy (e-mail: malberti@ing.unife.it)
EVELINA LAMMA
Affiliation:
Dipartimento di Ingegneria, Universitá degli Studi di Ferrara, Ferrara, Italy (e-mail: malberti@ing.unife.it)
PAOLA MELLO
Affiliation:
Dipartimento di Elettronica, Informatica e Sistemistica, Universitá degli Studi di Bologna, Bologna, Italy
MICHELA MILANO
Affiliation:
Dipartimento di Elettronica, Informatica e Sistemistica, Universitá degli Studi di Bologna, Bologna, Italy

Abstract

In classical CLP(FD) systems, domains of variables are completely known at the beginning of the constraint propagation process. However, in systems interacting with an external environment, acquiring the whole domains of variables before the beginning of constraint propagation may cause waste of computation time, or even obsolescence of the acquired data at the time of use. For such cases, the Interactive Constraint Satisfaction Problem (ICSP) model has been proposed (Cucchiara et al. 1999a) as an extension of the CSP model, to make it possible to start constraint propagation even when domains are not fully known, performing acquisition of domain elements only when necessary, and without the need for restarting the propagation after every acquisition. In this paper, we show how a solver for the two sorted CLP language, defined in previous work (Gavanelli et al. 2005) to express ICSPs, has been implemented in the Constraint Handling Rules (CHR) language, a declarative language particularly suitable for high level implementation of constraint solvers.

Type
Regular Papers
Copyright
© 2005 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)