Handling Side-effects with Selective Recomputation in AND/OR Parallel Execution Models

The side-eeect problem in AND/OR parallel execution of logic programs is complex and need to be further investigated. This paper presents a Selective Recomputation(SR) approach for handling side-eeects in the OR-forest model which can exploit both AND-and OR-parallelism. In contrast to merely AND-and merely OR-parallel execution models/systems, handling side-eeects in AND/OR parallel execution models/systems is much more diicult because of the complex orderings among side-eeect built-ins. Firstly, we give a brief description of the OR-forest model. Secondly, we analyze the side-eeect problem in merely AND-parallel, merely OR-parallel and AND/OR parallel models/systems. Thirdly, we describe the Selective Recomputation(SR) approach in detail in the OR-forest model. This approach can solve the side-eeect problem with minimum recomputation and maximum parallelism, and it is applicable to other AND/OR parallel execution models/systems as well.

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