[Pellet-users] Slow inference/Restrict inference

[Serge Libotte]

Hola Alejandro,

I'm not suggesting that your modeling approach is wrong.
Just give a try to some of the recommendations I've made to test their
impact on the behaviour of the reasoner. I found that just removing just one
kind of axiom can make things technically better (or at least technically
possible) If it's the case then youre are facing a modeling limitation
because of the technical implementation. This could be frustrating but is
not unusual and you then have to find a work around.

Be kind to keep me informed about any conclusion you have as I'll do on my
side the same kind of work.

Regards,

Serge.


2008/2/1, Alejandro Rodríguez González <jalo.javier at gmail.com>:
>
> Hi Serge,
>
> In first place, thanks for your answer :-)
>
> I was checking my ontology and my code. I have UNA option set tu true,
> and talking about axioms..
>
> This is an example of the axioms that i have in my classes:
>
> (hasSymptom some Nausea_and_vomiting_Class) or (hasSymptom some
> Fever_unspecified_Class) or (hasSymptom some Headache_Class) or (....)
>
> And
>
> hasSymptom only (Nausea_and_vomiting_Class or Fever_unspecified_Class or
> Headache_Class or ...)
>
> This is to specify that the disease can have the mentioned symptoms, and
> only the mentioned symptoms.. Cardinality axioms are only set in the
> "test instances".
>
> This is made because RDF/OWL make an open world assumption, so, if i say
> that the "test instance" has symptoms A,B and C that doesn't mean it
> doesn't also have other symptoms not yet mentioned in the description.
> So, adding a cardinality restriction of 3 on the individual and forcing
> all the symptom instances to be distinct i'm clossing the world and
> making it possible to test compliance with the allValuesFrom restriction.
>
> So.. i'm not sure what to do, because if i change this axioms probably
> the inferences will be wrong.. :-/
>
> Serge Libotte escribió:
> > Hi Alejandro,
> >
> > Strangly this is the kind of question the list tend to forget it seems
> ;-)
> >
> > Try those kind of things:
> > - Set UNA option of Pellet to 'true'
> > - Remove ALL 'one of' axioms
> > - Remove ALL cardinality Axioms
> >
> > Those recommendations were inspired by reading carefully the attached
> > document.
> >
> > If it helps, wonder if you can live without those axioms.
> > On our side we are testing other reasoners.
> >
> > Good luck.
> >
> > Serge.
> >
> >
> >
> > 2008/1/31, Alejandro Rodríguez González <jalo.javier at gmail.com
> > <mailto:jalo.javier at gmail.com>>:
> >
> >     Hello,
> >
> >     I ask a few days ago about how to restrict the inference domain in
> >     pellet but no one answered me so.. i will try to make again the
> >     question
> >     (maybe no one understand me, i don't know).
> >
> >     I have an ontology ( http://www.jalojavier.es/humandisease.owl ) and
> >     Jena+pellet code ( http://rafb.net/p/k1yHie11.html ) to make the
> >     inferences.
> >
> >     The problem is that the inference that i try to make with the code
> >     mentioned take a lot of time (near to 180 seconds)..
> >
> >     I make some test splitting the ontology into small parts, and i
> think
> >     that the problem is the number of instances of the ontology (now i
> >     have
> >     near to 600 individuals and 1500 classes)..
> >
> >     I think that may be it's possible to optimize the inference speed
> >     making
> >     a restriction over the inference domain. I have "Diaseses",
> >     "Symptoms",
> >     and "Lab Test" superclasses that are involucrated in the inferences,
> >     but, the results of the inferences are only subclasses of "Diseases"
> >     (that only has near to 30 instances).
> >
> >     It's possible say to pellet that only must search the results in
> this
> >     superclass and ignore the rest?
> >
> >     Or any other solution that optimize the inference speed..
> >
> >     Thanks.
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>
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