Concurrent loglisp

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5749012

Nayak, H R

The subject of this dissertation is the implementation of OR parallelism in the execution of Loglisp programs and the various issues arising in the exploitation of OR parallelism. The design of this parallel Loglisp uses concurrent searches, the existing sequential Loglisp developed at Syracuse University by Robinson and Sibert, and the Scheme based concurrent Lisp called Multilisp developed at MIT by Halstead. The implementation exploits lexical scope rules and closures. The hardware computing context is a fixed number of processors with shard memory architecture. The basic mode of execution is an invocation of a concurrent Logic call, and recursive invocations of Logic, but a capability for invoking concurrent calls of Logic with user's concurrent Lisp programs has also been provided. The concurrent implementation is somewhat transparent to Loglisp users, that is, no special syntax or commands are needed to use this new system. However, when all the results of a query are requested, the order of results in the list returned is not predictable. Also there is no defined rule for selecting a subset of all instances when less than all are requested. The present implementation does not yield very useful performance. Nonetheless, it provides a reasonable framework for investigating concurrent logic implementations, and offers a useful degree of concurrency. The author presents empirical evidence that the present implementation, if run on a high-performance, concurrent Lisp system, can yield desired performance improvements. Indeed the system sometimes shows super linear speedup when a parallel search finds a solution early on.

• Research Organization: Syracuse Univ., NY (USA)
• OSTI ID: 5749012
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
990200* -- Mathematics & Computers
ARRAY PROCESSORS
COMPUTER ARCHITECTURE
DESIGN
IMPLEMENTATION
INFORMATION RETRIEVAL
LISP
MATHEMATICAL LOGIC
MEMORY DEVICES
PARALLEL PROCESSING
PERFORMANCE
PROGRAMMING
PROGRAMMING LANGUAGES