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Genuinely asking: what are the advantages of this approach with other approaches like Prolog? How is the interplay between current state-of-the-art, and finite-
by wslh 2y ago
Genuinely asking: what are the advantages of this approach with other approaches like Prolog? How is the interplay between current state-of-the-art, and finite-choice logic programming over what was previously known about logic programming?
- spencerflem 2y agoThe linked paper tries to justify this
- robsimmons 2y agoUnfortunately, starting from a perspective that logic programming is mostly Prolog is a pretty bad way of getting to understand what Dusa is about. There's nothing wrong with that starting point, it's just... kind of like trying to understand Kotlin because you learned Smalltalk and know that both are object-oriented. The linked page suggests one intro if you have experience with Datalog, another intro if you have experience with Answer Set Programming (ASP), and a third for everyone else. That's because Datalog and ASP are the two logic programming things that are most like finite-choice logic programming. Finite-choice logic programming gives a completely new way of understanding what answer set programs mean. The Dusa implementation is able to solve some problems vastly more efficiently than state-of-the-art ASP solvers, and is able to easily solve other problems that mainstream ASP solvers are simply unable to handle because of something called the "grounding bottleneck." Right now it's not a strict win by any means: there are many problems that Dusa chokes on that state-of-the-art ASP solvers can easily handle, but we know how to solve at least some of those problems for implementations of finite-choice logic programming.
- Epa095 2y agoSo it is not Turing complete? It's more a programming language in the 'answer set programing' sense than 'general purpose programming language' sense?
- maweki 2y agoThere are many useful things that are not turing complete and still considered programming. Regular Excel formulas are always terminating and therefore not computationally complete. SQL without recursive CTEs is always terminating and therefore not computationally complete. Simply typed lambda calculus is always terminating and therefore not computationally complete. It's not the same, but restriction to terminating subsets gives very nice guarantees for a lot of program properties that would otherwise be undecidable.
- Epa095 2y agoI don't have any problems with calling it programming even if it's not Turing complete. But I think it's nice to clarify, so I can understand where it is in the expressivity-landscape. Maybe it's obvious for the intended audience, given the mention of Datalog? But I suspect a lot of compsci people know of Prolog, and know about SAT(and similar) solvers, but don't really know how e.g Datalog places.
- robsimmons 2y agoAll implementations of Answer Set Programming I am aware of are actually Turing complete, as are many practical implementations of the Datalog idea, and so is Dusa — this is a common misconception! From the paper: "often people take “Datalog” to specifically refer to “function- free” logic programs where term constants have no arguments, a condition sufficient to ensure that every program has a finite model. We follow many theoretical developments and practical implementations of datalog in ignoring the function-free requirement." If every program has a finite model, the language cannot be Turing complete: the reverse is not necessarily true but in practice the reverse is usually true.
- Epa095 2y agoCool, I did not know!
- YeGoblynQueenne 2y ago>> If every program has a finite model, the language cannot be Turing complete: the reverse is not necessarily true but in practice the reverse is usually true. What is the reverse here? Sorry it's late and I can't calculate it. Btw, what I know about ASP is that it is incomplete (in the sense of soundness and completeness). Turing completeness is a separate question.