Some results on the complexity of exploiting data dependency in parallel logic programs

Arthur Delcher, Simon Kasif

Research output: Contribution to journalArticle


We consider several problems related to maintaining and analyzing dataflow dependencies in and-parallel execution of logic programs. Several problems related to optimal selection of literals for parallel execution are established to be intractable (NP-complete). Most importantly, we establish intractability even when the arity of the predicates in the logic program is restricted to a small constant. This situation represents PROLOG programs used in practice. We subsequently address the complexity of maintaining data- dependency changes that occur during program execution as variables in the literals become instantiated. For this problem we propose a simple and efficient data structure to maintain the dataflow dependencies among literals during the execution of the program. These dependencies may then be used by an intelligent control to minimize backtracking.

Original languageEnglish (US)
Pages (from-to)229-241
Number of pages13
JournalThe Journal of Logic Programming
Issue number3
Publication statusPublished - 1989
Externally publishedYes


ASJC Scopus subject areas

  • Logic

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