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Logic Production Systems: A new mixed logic/imperative programming language

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Re: Logic Production Systems: A new mixed logic/imperative programming language

#21

Post by ch4s3 »

empath75 wrote: post #19
saosebastiao wrote: post #7

Earlier quoted context omitted.

The trendy way to approach the problem these days is to throw massive amounts of data at a deep learning model and let the model try to learn the rules. And my irony detector can't help but squalk out the famous minsky koan: "What are you doing?", asked Minsky. "I am training a randomly wired neural net to play Tic-tac-toe", Sussman replied. "Why is the net wired randomly?", asked Minsky. "I do not want it to have an…

But I think experience has already shown that machine learning models blow away expert systems in a lot of domains.

> in a lot of domains Right, but not some domains where expert systems are not only simpler to build but perform better. The can also be audited and evaluated for correctness.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#22

Post by mosqutopi »

Very long time ago I was trying to program many matroids algorithms, let's say that matroids are a generalization of vector spaces and independence, in prolog. I could program those algorithm in many languages, for example in Lisp, but programming in Prolog was very painful. I think that prolog related programming is a useful tool when the program is similar to those solved by forward chaining but in other cases I can't not see the benefits, the dismissal of Prolog in day to day programming seems to reflect that sentiment.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#23

Post by naasking »

TuringTest wrote: post #17
ansible wrote: post #15

Earlier quoted context omitted.

I'm not hostile to them per-se, but I don't see much usefulness in systems like this one these days. For some kinds of video game agents, traditional logic programming might be fine. But for anything that I would consider using in the real world, I would want to use probabilistic knowledge representation and reasoning. Even for many kinds of video games you'd want that instead. Like in a first person shooter where th…

I work for a living in a company that creates products to calculate timetables and schedules for transport companies. The schedules and timetables need to be exactly, defined according to a large number of requirements (hard constraints and weighted preferences). While these exact schedules could be created through probabilistic means, the systematic approach of logic search provides more consistent results than a st…

http://okmij.org/ftp/kakuritu/logic-programming.html

Re: Logic Production Systems: A new mixed logic/imperative programming language

#24

Post by PaulHoule »

saosebastiao wrote: post #10
trapperkeeper79 wrote: post #8

Earlier quoted context omitted.

Any tips for introductory/intermediate material on the topic? In undergrad, we used Russel and Norvig. Surely there are more advanced books or courses.

On expert systems specifically no. With the AI winter of the early 90's, not only did expert systems research die, but so did publisher interest in the topic. "Expert Systems" is effectively a dead field of study. That being said, the field of Operations Research, at least philosophically speaking, has picked up where AI researchers dropped it off. They've fully embraced the idea that human experts can model many sys…

Today we have production rules systems such as iLog and Drools which are head and shoulders better than OPS5 and other "expert system shells" from the golden age of A.I.

These are in widespread use for a few applications. Probably every bank has at least one iLog instance running for enforcing business rules. Another one is "complex event processing", where a RETE engine makes it easy to aggregate small events into larger events. Also, a few efforts, such as Inform7 and Clara have tried to push the boundaries of programming for non-experts and real-life applications.

It is interesting, however, that the technology is not further applied, and a deep analysis of that could be worthwhile. For instance, RETE networks can eat "callback hell" situations for lunch, much like the complex event processing case. Instead, however, we are seeing one awful Javascript framework after another, and coroutines pushed as a very narrow answer to the problems on the server.

Note that all forms of A.I. have ties to optimization. For instance, usually when you train a neural net you are minimizing some kind of an error function. Drools (and iLog) both have optimization frameworks, etc.

The recent discussion of "superintelligence" has been marked by both a lack of imagination and any awareness of previous work on the subject. For instance, Rules engines are a fairly direct answer to "AI Safety" and "AI Ethics" problems that there is so much handwringing about. Most areas that require computers to be "creative" amount to some kind of multi-objective optimization, and even if rules can't make a system good, they can at least prevent the worst abuses.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#25

Post by PaulHoule »

tannhaeuser wrote: post #18
trapperkeeper79 wrote: post #5

Logic programming and productions are a wonderful idea that I studied in undergrad back in pre-2000. These days, people seem hostile towards them. People just don't like the idea of specifying rules. I couldn't find modern intro textbooks on the topic or classes that cover it on MOOCs. I'm very surprised and confused.

Some of what logic programming represented became absorbed into "semantic web" technologies (RDF, SPARQL, OWL/OWL2), and went down with it, though I think actually OWL2 (description logic) isn't half bad and has lots of vertical use in eg. bibliography systems, taxonomic meta knowledge bases for medical and other research support systems, and backends for graph databases like OpenGraph. I remember RDF being used for…

The "semantic web" stuff has not really disappeared, but it hasn't thrived either.

OWL2 points to a world where a production rules or logic language is fronted by a macro language that lets you say something like

"x is a transitive property"

rather than write

"x(a,b) and x(b,c) implies x(a,c)"

In fact, many RDFS and OWL implementations work exactly that way. RDFS/OWL is designed to support data integration in the sense of "this predicate is an alias of that predicate" but aren't revolutionary because it lacks the ability to do things like

"CentigradeTemperature(x,T) implies KelvinTemperature(x,T+273.15)"

which ordinary production rules engines do easily. Many semantic web tools have such a production rules engine hidden inside (Jena/GraphDB/...) but production rules have resisted standardization.

Note that "Datalog", a subset of Prolog that is purely logical and doesn't have cuts and all of that awful stuff, has caught on, but there has never been a "Turbo Datalog" or "Common Datalog" because frequently Datalog-equivalent functionality gets build into semantic web tools, Datomic, or systems that don't claim any formal compatibility with anything else.

RDF suffered a lot because of RDF/XML where it was really unclear where RDF ended and XML started. Today there is Turtle and JSON-LD, both of which are pretty ergonomic.

One issue I see is that many companies have their own "semantic web"-like technologies which are their own secret sauce and competitive advantage (thus not shared) whereas there seems to be a huge amount of fear and loathing of the W3C standards process, especially amoung people who are veterans of it.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#26

Post by saosebastiao »

PaulHoule wrote: post #24
saosebastiao wrote: post #10

Earlier quoted context omitted.

On expert systems specifically no. With the AI winter of the early 90's, not only did expert systems research die, but so did publisher interest in the topic. "Expert Systems" is effectively a dead field of study. That being said, the field of Operations Research, at least philosophically speaking, has picked up where AI researchers dropped it off. They've fully embraced the idea that human experts can model many sys…

Today we have production rules systems such as iLog and Drools which are head and shoulders better than OPS5 and other "expert system shells" from the golden age of A.I. These are in widespread use for a few applications. Probably every bank has at least one iLog instance running for enforcing business rules. Another one is "complex event processing", where a RETE engine makes it easy to aggregate small events into l…

I'm in complete agreement. I didn't mean to give off the idea that you couldn't use Expert Systems anymore, merely that the research and publishing interest died. Implementations have definitely improved. Supposedly, Charles Forgy has continued researching and implementing improvements to his original RETE algorithm, but both the research and implementations are entirely proprietary and mostly inaccessible.

I likewise find it sad that the idea has died so much that we continue to build square wheels that were made obsolete by rule engines. I remember a futile attempt at Amazon to get a team to scrap their system in favor of a RETE based rule engine. Theirs was a poorly performing and fragile homemade "rule engine" that compiled xml rules into if/else statements, which after tens of thousands of rules had slowed to a snails pace. Somehow the magic of O(1) escaped them, and they practically required me to reimplement their system from scratch in order to convince them. So I let it go.

I had never considered the possibility of killing callback hell with a rules engine but I can definitely see it now. I personally have toyed with building a compiler that eschews the pipeline architecture with a rules engine where both analyses and optimizations are implemented as rules. I definitely think there is a world of possibilities out there, but maybe we'll need another AI winter before people consider them again.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#27

Post by PaulHoule »

saosebastiao wrote: post #26
PaulHoule wrote: post #24

Earlier quoted context omitted.

Today we have production rules systems such as iLog and Drools which are head and shoulders better than OPS5 and other "expert system shells" from the golden age of A.I. These are in widespread use for a few applications. Probably every bank has at least one iLog instance running for enforcing business rules. Another one is "complex event processing", where a RETE engine makes it easy to aggregate small events into l…

I'm in complete agreement. I didn't mean to give off the idea that you couldn't use Expert Systems anymore, merely that the research and publishing interest died. Implementations have definitely improved. Supposedly, Charles Forgy has continued researching and implementing improvements to his original RETE algorithm, but both the research and implementations are entirely proprietary and mostly inaccessible. I likewis…

+1 for the rules-driven compiler, it's one of those things that could put programming language innovation into many more hands.

Re: Logic Production Systems: A new mixed logic/imperative programming language

#28

Post by tannhaeuser »

PaulHoule wrote: post #25
tannhaeuser wrote: post #18

Earlier quoted context omitted.

Some of what logic programming represented became absorbed into "semantic web" technologies (RDF, SPARQL, OWL/OWL2), and went down with it, though I think actually OWL2 (description logic) isn't half bad and has lots of vertical use in eg. bibliography systems, taxonomic meta knowledge bases for medical and other research support systems, and backends for graph databases like OpenGraph. I remember RDF being used for…

The "semantic web" stuff has not really disappeared, but it hasn't thrived either. OWL2 points to a world where a production rules or logic language is fronted by a macro language that lets you say something like "x is a transitive property" rather than write "x(a,b) and x(b,c) implies x(a,c)" In fact, many RDFS and OWL implementations work exactly that way. RDFS/OWL is designed to support data integration in the sen…

Yes, and I'd like to add that W3C's semantic web efforts (in the form of EU-sponsored papers of top researchers in the field) have brought pretty well-understood description logic subsets formalized as OWL2 profiles. But IMHO, in W3C's semantic stack, these pearls get somewhat lost under layers of syntax - not just RDF/XML but also the (IMHO) mediocre SPARQL language syntax/protocol and needless variant syntaxes for description logic axioms such as functional syntax, etc. As you probably know, this all started as a variable-free syntax for logic axioms (such as your example for transitivity) as early as 1991, but I'm arguing not much was won (and in fact, things were made less clear intuitively) by using variable-free ad-hoc syntax for logic.

While many people like JSON-LD, if you see actual uses of it such as Google's corporate contacts ([1]), I can't help but think it merely adds to the already heavy "syntacticity" of the semantic stack. For me, JSON-LD feels like an appeasement to the JSON and pragmatic web developers crowd, but then its JSON gets very complicated/counter-intuitive and squeezes @type, @context and other meta-meta attributes into JSON which won't make pragmatist happy.

Personally, my go-to stack for logic has become Datalog and Prolog once again (unmatched in terms of minimalism, elegance, and power IMHO).

[1]: https://developers.google.com/search/docs/data-types/corpora...

Re: Logic Production Systems: A new mixed logic/imperative programming language

#29

Post by giardini »

empath75 wrote: post #19
saosebastiao wrote: post #7

Earlier quoted context omitted.

The trendy way to approach the problem these days is to throw massive amounts of data at a deep learning model and let the model try to learn the rules. And my irony detector can't help but squalk out the famous minsky koan: "What are you doing?", asked Minsky. "I am training a randomly wired neural net to play Tic-tac-toe", Sussman replied. "Why is the net wired randomly?", asked Minsky. "I do not want it to have an…

But I think experience has already shown that machine learning models blow away expert systems in a lot of domains.

empath75 says:> "But I think experience has already shown that machine learning models blow away expert systems in a lot of domains."

I don't think there have been many head-to-head comparisons. Academic researchers simply ceased using "expert system" in their research grant applications and began to use "neural network".

For real-world applications your choice of model would likely depends on the data available (e.g., human expert vs historical data on electronic media).

I think this Quora posting characterizes well the status of expert systems vis-a-vis neural networks today:

"Artificial Intelligence: Are Expert Systems outdated?"

https://www.quora.com/Artificial-Intelligence-Are-Expert-Sys...

Re: Logic Production Systems: A new mixed logic/imperative programming language

#30

Post by jefurii »

notthemessiah wrote: post #4

I recall trying a few mods that made Kerbal Space Program programmable so you can automate your rocket (Some have used it to make SpaceX-style reusable boosters: https://www.youtube.com/watch?v=sqqQy8cIVFY ), and mods that provided a domain-specific language were more convenient than mods that used an existing conventional programming language. However the kOS language was still ultimately an imperative script, and t…

> I also recall a Minecraft mod called ComputerCraft

There's also OpenComputers https://github.com/MightyPirates/OpenComputers

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