[rules-users] Inferencing

[Tim de Jager]

Thanks a lot everybody for their awnsers, this clarifies it to some extend :)! 

What I was talking about was indeed the difference between an: interpreted rete engine vs. code generated rete engine vs. the use of no inference engine at all (e.g. Visual Rules). One of the questions that pop up: Is it possible to maintain the same 'statefull' features with a code generated inference engine? Like you said Take generates a backward chaining algorith, but would it be able to react to a changed fact like drools can with the modify statement? Is code-generated Rete maybe comparable with the drools sequential mode?

It could be that I'm mixing alot of things up, I can't find a whole lot on this subject.

So do you have any insight on the differences between a interpreted rete engine an a code generated one. Would they differ in functionality in any way?

Thanks!

-----Oorspronkelijk bericht-----
Van: rules-users-bounces at lists.jboss.org namens Edson Tirelli
Verzonden: ma 8-3-2010 17:55
Aan: Rules Users List
Onderwerp: Re: [rules-users] Inferencing
 

   Hi Tim,

   That is a nice topic for studies, but be prepared for a tsunami of information and quite a few controversies. :)

   Regarding your question, I am not sure I completely understand what you mean, but it is important to be clear that "generation of code" is an orthogonal concern to the chosen algorithm. I.e., take the Rete algorithm for example: you can have it fully "interpreted" (I am using the term loosely here), you can generate code for it completely, or you can be anywhere in the middle. In all cases, the properties of the algorithm itself will be preserved (assuming the implementations are correct). Incurring the risk of making a mistake here, I will mention that AFAIK Jess falls in the first cathegory, OPSJ falls in the second and Drools falls in the 3rd, and they are all Rete based algorithms.

   Its been a long time since I last looked at TAKE, but at that time it was generating code for a backward-chaining-like algorithm. Not sure what it has now.

   So, my suggestion is that you either focus on the properties of the algorithms itself (for instance, are you comparing classic Rete with known algorithm like LEAPS, TREAT, etc) or focus on the advantages and disadvantages of code generation (for instance "interpreted Rete" versus "code generated Rete", again using terms loosely here). Mixing everything in a single comparison might be misleading.

   Edson


2010/3/8 Tim de Jager <tim.dejager at student.hu.nl>



	Hi everybody,
	
	I'm currently doing my bachelor thesis on Rule engines. This includes
	comapring different Rule engine products. I have set up a small Java program
	(Conway's game of life) and I'm writing the 'engine' in different Rule
	engines, while keeping the same GUI,CellGrid etc. I have already made a
	Drools based engine.
	
	I have been studying the Rule engine subject for somewhat more then a month
	now. And I'm currently seeing two different developments namely the use of
	an inference engine and the generation of embedded code instead (Take,
	Visual Rules etc.)  I can see some of the pro's and cons with both
	paradigms. But I'm wondering what opinion some of you guys have on the
	subject.
	
	I can see that without inferencing  it is very hard (or even impossible) to
	keep a statefull session inside the rule engine, haven't seen a
	non-inferencing rule engine which does offer this possibility. And also lose
	features like TMS. But what would be a concrete example where a statefull
	session is absolutely necessary? Instead of letting the engine reason over
	all the facts in stateless way. And managing conflicts with a ruleflow (see
	Visual Rules for a nice example).
	
	I'm looking forward to hearing your thoughts.
	
	Thanks,
	
	Tim
	
	P.S I already read two of Mark Proctors blogs on inferencing, but while
	enlightening, they didn't supply me with a definitive awnser
	--
	View this message in context: http://n3.nabble.com/Inferencing-tp435411p435411.html
	Sent from the Drools - User mailing list archive at Nabble.com.
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-- 
 Edson Tirelli
 JBoss Drools Core Development
 JBoss by Red Hat @ www.jboss.com


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