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From Marco Neumann <marco.neum...@gmail.com>
Subject Re: [GenericRuleReasoner] inner workings
Date Wed, 13 Mar 2019 11:19:27 GMT
in any event good to have your view on this as a "consensus"

On Wed, Mar 13, 2019 at 11:11 AM Dave Reynolds
<dave.e.reynolds@gmail.com> wrote:
>
> Hi Marco,
>
> Not a "consensus" that I'm part of so not something I could comment on.
>
> Dave
>
> On 13/03/2019 10:49, Marco Neumann wrote:
> > correct if me if I am wrong but from my vantage point I seem to notice
> > a silent consensus in the RDF community to go from SPIN rules to SHACL
> > which now comes with its own SHACL rule engine [1].
> >
> > The new SHACL efforts are mostly guided by TopQuadrant and a change
> > from the initial layered approach to go with SPARQL RDF
> > (SPIN+(SHACL-rules)). So I presume the current game plan is that SHACL
> > will "rule" them all in the end.
> >
> > If so it would be nice to have a feature list for SHACL rules. And
> > does this mean it will be rules without validation and just CONSTRUCT
> > queries or are the rule semantic restrictions build into SHACL? I am
> > sure this will work fine for many use cases we have but since we are
> > starting to blur the lines between rules/reasoner/sparql would be nice
> > to have some general autoritative clarification here.
> >
> > [1] https://github.com/TopQuadrant/shacl/blob/master/src/main/java/org/topbraid/shacl/rules/RuleEngine.java
> >
> >
> > On Wed, Mar 13, 2019 at 10:14 AM Dave Reynolds
> > <dave.e.reynolds@gmail.com> wrote:
> >>
> >> Hi Marco,
> >>
> >> Sorry, I'm not aware of other rule engines having been wired to Jena but
> >> that doesn't mean it hasn't been done. In particular I'm surprised
> >> there's not a drools-for-jena project somewhere. People have certainly
> >> experimented with that, even written papers comparing performance [1],
> >> but I'm not aware of any supported tooling.
> >>
> >> Dave
> >>
> >> [1] https://ieeexplore.ieee.org/document/7516153
> >>
> >> On 12/03/2019 22:18, Marco Neumann wrote:
> >>> so what's your current recommendation for a superior third party rules
> >>> reasoner that works efficiently with the jena tooling? free & commercial
> >>> option welcome
> >>>
> >>> Marco
> >>>
> >>>
> >>>
> >>> On Mon 14. Jan 2019 at 19:16, Dave Reynolds <dave.e.reynolds@gmail.com>
> >>> wrote:
> >>>
> >>>> Hi Barry,
> >>>>
> >>>> [Agreed that dev is probably the better place to discuss this.]
> >>>>
> >>>> The two engines in jena are indeed loosely styled on RETE and on tabled
> >>>> datalog. However, I wouldn't claim they were particularly complete or
> >>>> good implementations of either. So while looking at some of the source
> >>>> literature that inspired them might be helpful don't expect very much
of
> >>>> what's covered in the literature to be present in the code.
> >>>>
> >>>> For RETE then the wikipedia article [1] is a good summary and source
of
> >>>> starting references. I had a copy of the original Forgy paper [1](ref
> >>>> 1), among others,when I was doing the work. There has been a *lot* of
> >>>> work on improvements to RETE since the 80s and while there were times
> >>>> when we might have done a new forward engine using more modern
> >>>> techniques it never happened.
> >>>>
> >>>> For the backward engine the approach is a variant of SLG-WAM as used
for
> >>>> XSB but highly highly simplified since we can't express general tuples
> >>>> or recursive data structures within jena's triples. A few google
> >>>> searches haven't turned up the exact paper that originally inspired
the
> >>>> approach. The closest I've found are [2] and [3], which probably cover
> >>>> the same ground.
> >>>>
> >>>> Let me reinforce that the Jena engines are really simplified. They were
> >>>> enough to get the job done at the time (over a decade ago now) and have
> >>>> proved useful for some people since but I wouldn't want to defend any
of
> >>>> the implementation choices.
> >>>>
> >>>> Dave
> >>>>
> >>>> [1] https://en.wikipedia.org/wiki/Rete_algorithm
> >>>> [2]
> >>>>
> >>>> https://pdfs.semanticscholar.org/2078/96964ee85f983cd861a4f8c5dff0bfc9f03e.pdf
> >>>> [3]
> >>>>
> >>>> https://pdfs.semanticscholar.org/6c6d/26e8fe1b755140ffcb57025b021a046b2a3b.pdf
> >>>>
> >>>> On 14/01/2019 16:33, ajs6f wrote:
> >>>>> I have no useful general information about the reasoning framework,
but
> >>>> I am copying this over to dev@. Discussions of how to extend Jena
> >>>> definitely have a place there.
> >>>>>
> >>>>> ajs6f
> >>>>>
> >>>>>> On Jan 14, 2019, at 6:40 AM, Nouwt, B. (Barry)
> >>>> <barry.nouwt@tno.nl.INVALID> wrote:
> >>>>>>
> >>>>>> Hi all, I want to investigate the inner workings of the
> >>>> GenericRuleReasoner (with the purpose of extending it in the future).
In
> >>>> Jena's documentation I read:
> >>>>>>
> >>>>>> "Jena includes a general purpose rule-based reasoner which is
used to
> >>>> implement both the RDFS and OWL reasoners but is also available for
general
> >>>> use. This reasoner supports rule-based inference over RDF graphs and
> >>>> provides forward chaining, backward chaining and a hybrid execution
model.
> >>>> To be more exact, there are two internal rule engines one forward chaining
> >>>> RETE engine and one tabled datalog engine - they can be run separately
or
> >>>> the forward engine can be used to prime the backward engine which in
turn
> >>>> will be used to answer queries."
> >>>>>> source: https://jena.apache.org/documentation/inference/#rules
> >>>>>>
> >>>>>> Apart from Jena's documentation, Jena's mailing lists and its
source
> >>>> code, are there any resources that can better help me grasp what is
> >>>> happening inside the generic rule reasoner? For example, the text above
> >>>> mentions the forward chaining RETE engine and the tabled datalog engine,
> >>>> are there any scientific papers that I might read to better understand
> >>>> their inner workings?
> >>>>>>
> >>>>>> Maybe this question is better suited for the dev@jena.apache.org
> >>>> <mailto:dev@jena.apache.org>?
> >>>>>>
> >>>>>> Regards, Barry
> >>>>>> This message may contain information that is not intended for
you. If
> >>>> you are not the addressee or if this message was sent to you by mistake,
> >>>> you are requested to inform the sender and delete the message. TNO accepts
> >>>> no liability for the content of this e-mail, for the manner in which
you
> >>>> use it and for damage of any kind resulting from the risks inherent
to the
> >>>> electronic transmission of messages.
> >>>>>
> >>>>
> >
> >
> >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
> >



-- 


---
Marco Neumann
KONA

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