Antimonotony-based Delay Avoidance for CHR
نویسندگان
چکیده
We present an optimisation for Constraint Handling Rules (CHR) that reduces the amount of variables a constraint delays on. This optimisation reduces the overhead of delaying on variables as well as the needless reawakening of delayed constraint. A correctness proof of the optimisation based on the refined operational semantics establishes the validity of the optimisation and sheds light on possible extensions as well as related optimisations. The delay avoidance optimisation shows good speedups for some programs and no noticable slowdown for others. Antimonotony-based Delay Avoidance for CHR Tom Schrijvers Bart Demoen {toms,bmd}@cs.kuleuven.ac.be Abstract We present an optimisation for Constraint Handling Rules (CHR) that reduces the amount of variables a constraint delays on. This optimisation reduces the overhead of delaying on variables as well as the needless reawakening of delayed constraint. A correctness proof of the optimisation based on the refined operational semantics establishes the validity of the optimisation and sheds light on possible extensions as well as related optimisations. The delay avoidance optimisation shows good speedups for some programs and no noticable slowdown for others.We present an optimisation for Constraint Handling Rules (CHR) that reduces the amount of variables a constraint delays on. This optimisation reduces the overhead of delaying on variables as well as the needless reawakening of delayed constraint. A correctness proof of the optimisation based on the refined operational semantics establishes the validity of the optimisation and sheds light on possible extensions as well as related optimisations. The delay avoidance optimisation shows good speedups for some programs and no noticable slowdown for others.
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This is a summary of the Ph.D. thesis of Tom Schrijvers [4]. Constraint Handling Rules (CHR) [3] is a rule-based language commonly embedded in a host language. It combines elements of Constraint Logic Programming and term rewriting. Several implementations of CHR exist: in Prolog, Haskell, Java and HAL. Typical applications of CHR are in the area of constraint solving, but currently CHR is also...
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