Enrico Pontelli, Gopal Gupta, and Dongxing Tang. Determinacy driven optimization of And-parallel prolog implementations. In Proceedings of International Conference on Logic Programming 95, pages 615-- 629. MIT Press, June 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....when the subgoals in the clause body do not affect each other (there are no variables in common) dependent And Parallelism arises when nonindependent goals are executed in parallel. Some exploitation of parallelism in prolog has concentrated on extracting only one of the two forms of parallelism [10, 14, 9, 16, 13, 6, 1] and some on combination of the two [15, 8, 5, 11, 3] But in whichever parallel logic system the case is the same: the subtask (subgoal) can fork their own subtasks before join and thus there may exist many subtasks at the same time which come from different layers of the search tree and are ....

Enrico Pontelli, Gopal Gupta, and Dongxing Tang. Determinacy driven optimization of And-parallel prolog implementations. In Proceedings of International Conference on Logic Programming 95, pages 615-- 629. MIT Press, June 1995.

....backtracking points, are not necessary. However, it should be noted that the same optimizations can also be done in general purpose abstract machines supporting and parallelism, such as the RAP WAM, if the particular case is identified, and without losing the general case [Her86a, PGH95, SH94, PGT95, PGT 96] Both dynamic and static detection of such special cases has been studied. A similar argument can be made regarding some other minor optimizations that, for lack of space, will not be addressed explicitly. On the other hand, a number of optimizations, generally related to the Reform ....

E. Pontelli, G. Gupta, and D. Tang. Determinacy Driven Optimizations of AndParallel Prolog Implementations. In Proc. of the Twelfth International Conference on Logic Programming. MIT Press, June 1995.

....The kernel language described above is supported by a comparatively simple abstract machine. The design of the abstract machine is based on the parallelism and concurrency capabilities of the PWAM Prolog abstract machine [Her86, HG91] and recent work on extending its capabilities and efficiency [PGT95a, PGH95, PGT 95b] The abstract machine includes native support for attributed variables [Hol92, Hui90, Neu90] which are used extensively in the implementation of constraint solvers (as in other systems such as Eclipse [Eur93] and SICStus 3 [Swe95] and in supporting communication among ....

E. Pontelli, G. Gupta, and D. Tang. Determinacy Driven Optimizations of And-Parallel Prolog Implementations. In Proc. of the Twelfth International Conference on Logic Programming. MIT Press, June 1995.

....Reform Prolog compiler was written by me, while the execution engine was written by Bevemyr. The compiler optimizations were designed in collaboration with with Johan Bevemyr and implemented by me. 1.3. Related work 15 Reflections and later work Our results inspired a number of subsequent papers [70, 112, 111] which incorporate some of the Reform Prolog techniques into control parallel systems, in particular the fast unfolding of Reform compilation. Examples of such systems are Prolog [68] and ACE [63] Results have generally been encouraging. Recently, Bevemyr [18] and the author [88] have ....

E. Pontelli, G. Gupta, Determinacy Driven Optimization of AndParallel Prolog Implementations, Int. Conf. Logic Programming, MIT Press, 1995. f15g

....using program transformation techniques. These have some similarities to the transformations described by Tarnlund [199] in his thesis. Hermenegildo and Carro also discuss how the Prolog implementation can be extended with low level primitives to support dataparallelism. Pontelli and Gupta [87, 156, 157, 158, 159] present a number of similar techniques for minimising the overheads for creating processes in ACE. They then argue that data parallelism can be efficiently exploited. However, there are still some significant differences compared to Reform Prolog. They can only exploit independent ....

....we argue that parallel implementation overheads can be made minimal. Our scheme can be viewed as merging deterministic parallel subgoals with the topmost parallel computation. This is similar to AKL [108, 107, 140] where deterministic AND boxes are promoted. Gupta, Pontelli [156, 158] and Tang [157] use a similar technique in ACE for reducing the overheads for independent AND parallelism. Carro, Gupta, Hermenegildo, Pontelli, Santos Costa, Tang [95, 94, 99, 100, 159, 157, 87] and others have proposed different schemes for reducing the overheads for nested independent AND parallelism. These ....

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E. Pontelli, G. Gupta, Determinacy Driven Optimization of AndParallel Prolog Implementations, Intl. Conf. Logic Programming, MIT Press, 1995. --17, 81

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