PROLOG-REQUEST@SU-SCORE.ARPA (Chuck Restivo, The Moderator) (09/14/86)
PROLOG Digest Monday, 15 Sep 1986 Volume 4 : Issue 50 Today's Topics: Announcement - Parallel Inference System ---------------------------------------------------------------------- Date: Thu, 11 Sep 86 17:08:33 EDT From: Jack Minker <minker@mimsy.umd.edu> Subject: Parallel Inference System at Maryland AI and Database Research Laboratory at the University of Maryland Jack Minker - Director The AI and Database Research Laboratory at the Univer- sity of Maryland is pleased to announce that a parallel logic programming system (PRISM) is now operational on the McMOB multiprocessosor. The system uses up to sixteen pro- cessors to exploit medium grained parallelism in logic pro- grams. The underlying ideas behind PRISM appeared in [Eis- inger et. al., 1982] and [Kasif et. al., 1983]. The McMOB multiprocessor is a direct offspring of ZMOB [Reiger et. al.,1980]. It consists of sixteen Motorola MC68010 processors interconnected via a high speed belt. PRISM consists of several parts: a user host interface that exists on the host machine; a set of machines (moblets) designated as problem solvers (PSMs); a set of machines designated as Extensional Database Machines (EDB) that store ground atomic formulae (relational database tables); and, a set of machines designated as Intensional Database Machines (IDB) that store procedures (the general rules in the sys- tem). The system can also optionally include Constraint Machines (CM) that use user-supplied constraints to prune unsatisfiable paths in the proof tree. The system supports both AND and OR parallelism. The user can specify control in terms of the sequence of atoms to be executed in a set of problems to be solved. Atoms can be executed in parallel, sequentially, or as specified by a partial ordering. Similarly procedures can be specified as being executed sequentially, in parallel, or as specified by a partial order. The PSM has been written in a modular fashion to permit alternative control structure programs to be incorporated in the system. Alternative node and literal selection algorithms may be incorporated as part of the con- trol structure. The user may specify the configuration (i.e., the number of moblets required as a minimum) in which a problem is to be run. If additional moblets are avail- able, the PRISM will automatically take advantage of them. A large number of problems are currently being pro- grammed in PRISM and experiments will be run with these to determine the effectiveness of PRISM as a problem solving system. The major research directions in the laboratory over the coming year will be devoted to the following areas: (1) Experimentation Using PRISM (2) Control Structure Investigations (3) Expert systems and PRISM (4) Parallel problem solving and Architecture Issues If you would like further information on PRISM, please contact MINKER@MARYLAND or MADHUR@MARYLAND. We would also be very interested in hearing from people who may have prob- lems we could run on PRISM. References: 1. Eisinger, N., Kasif, S., and Minker, J., "Logic Pro- gramming: A Parallel Approach", in Proceedings of the First International Logic Programming Conference, Mar- seilles, France, 1982. 2. Kasif, S., Kohli, M., and Minker, J., "PRISM - A Paral- lel Inference System for Problem Solving", in IJCAI-83, Karlsruhe, Germany, 1983. 3. Rieger, C., Bane, j., and Trigg, R., "ZMOB: A Highly Parallel Multiprocessor", University of Maryland, TR- 911, May 1980 ------------------------------ End of PROLOG Digest ********************