On Just in Time Indexing of Dynamic Predicates in Prolog

• Type: Article in International Conference Proceedings Book
• Date: 2009

Authors

Vitor Santos Costa (Author) FCUP

Conference proceedings International

Title: Progress in Artificial Intelligence: Proceedings of the 14th Portuguese Conference on Artificial Intelligence, EPIA2009

Pages: 126-137

14th EPIA - Portuguese Conference on Artificial Intelligence - EPIA 2009

Universidade de Aveiro, Portugal, 12 a 15 de Outubro de 2009

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 4 Citations

Scientific classification

FOS: Natural sciences > Computer and information sciences

Other information

Authenticus ID: P-003-RVF

DOI: 10.1007/978-3-642-04686-5_11

Abstract (EN): Prolog is the most; well-known and widely used logic programming language. A large number of Prolog applications maintains information by asserting and retracting clauses from the database. Such dynamic predicates raise a number of issues for Prolog implementations, such as what are the semantics of a procedure where clauses can be retracted and asserted while the procedure is being executed. One advantage of Logical Update semantics is that it allows indexing. In this paper, we discuss how one call implement just-in-time indexing with Logical Update semantics. Our algorithm is based on two ideas: stable structure and fragmented index trees. By stable structure one means that we define a structure for the indexing tree that not change, even as we assert and as we retract clauses. Second, by fragmented index tree we mean that the indexing tree will be built in such a way that the updates will be local to each fragment. The algorithm was implemented and results indicate significant speedups and reduction of memory usage in test applications.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12