Accession Number : ADA193648

Title :   Combined And-Or Parallel Execution of Logic Programs,

Corporate Author : NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF COMPUTER SCIENCE

Personal Author(s) : Gupta, Gopal ; Jayaraman, Bharat

PDF Url : ADA193648

Report Date : Mar 1988

Pagination or Media Count : 23

Abstract : A number of approaches have recently been proposed for the parallel execution of logic programming languages, but most of them deal with either or-parallelism or and-parallelism but not both. This paper describes a high-level design for efficiently supporting both and-parallelism and or-parallelism. Our approach is based on the binding arrays method for or-parallelism and the RAP method for and-parallelism. Extensions to the binding-arrays method are proposed in order to achieve constant access-time to variables in the presence of and-parallelism. The RAP (Restricted And-Parallelism) method becomes simplified because backtracking is unnecessary in the presence of or-parallelism. The author's approach has the added effect of eliminating redundant computations when goals exhibit both and-and or-parallelism. The paper first briefly describes the basic issues in pure and-parallelism and or-parallelism, states desirable criteria for their implementation (with respect to variable access, task creation and switching), and then describes the combined and-or implementation.

Descriptors :   *HIGH LEVEL LANGUAGES, *SYSTEMS APPROACH, ACCESS, ACCESS TIME, ARRAYS, COMPUTATIONS, PROGRAMMING LANGUAGES, REDUNDANCY, VARIABLES, COMPUTER LOGIC

Subject Categories : Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE