[Pellet-users] Pellet performance on a Jena project

[Rinke Hoekstra]

Hi Matteo,

You can trigger Pellet by running:

         model.prepare();

and then either one of the following:

         ((PelletInfGraph) model.getGraph()).getKB().classify();
         ((PelletInfGraph) model.getGraph()).getKB().realize();

If you want to simply print the inferred class tree:

	((PelletInfGraph) model.getGraph()).getKB().printClassTree();

But actually listStatements is really slow as well, just like  
writeAll... but I haven't tried it yet.

Btw, for timing, I usually use the Timers from  
org.mindswap.pellet.utils.Timers, for instance:

	Timers timers = new Timers();

         // read the file
         timers.startTimer("Read");
         model.read( ont );
         timers.stopTimer("Read");

	timers.print(true,null);

Cheers,

-Rinke

On 21 mei 2008, at 17:35, Matteo Montalto wrote:

> Hello Rinke, and thanks for your help,
> performances are good if I don't call the writeAll() method. To give  
> an idea, about 2 seconds with a 50+ k ontology written in rdf/xml.  
> But that's trivially expected, because if I don't make a call of a  
> method that causes pellet "triggering", what actually I obtain is  
> nothing but having my owl file stored in an OntModel object. :)
> There's no inference at all in such an OntModel; and nothing can be  
> realized if pellet doesn't trigger....
> (that opens to my second question in my reply: what's the minimum  
> code to make Pellet trigger? :-P I could try to do my task in two  
> distinct moments: 1) pellet triggers (so that i can estimate  
> temporal performances of the engine w.r.t my solution) 2) i could  
> write down the model using listStatements() methods and iterate over  
> the results (this should be a solution that waste less memory than  
> repeated queries ( that's what writeAll() does).
>
>
>
> Rinke Hoekstra ha detto: in data 21/05/2008 17.05:
>> Hi Matteo,
>> What is the performance like if you do not call the model.writeAll  
>> method?
>> -Rinke
>> On 19 mei 2008, at 17:30, Matteo Montalto wrote:
>>> Hello list, please forgive me for this looong post :-P
>>>
>>> I'm doing a work with Jena in order to realize an SWRL rule  
>>> interpreter;
>>> in order to check results and performance, I did two simple programs
>>> that configure a system as follows:
>>>
>>> 1) first solution (mine one): I load an ontology from an .owl file  
>>> into
>>> a base model (with no inference at all); then I build a pellet model
>>> over it (using Pellet as OWL reasoner, disabling the SWRL safe rule
>>> support). Finally, a rule model is built over pellet model.  
>>> "Visually",
>>> the schema is as follows:
>>> -----------------------------
>>> |  upperModel (ruleReasoner)  |
>>> |   ----------------------    |
>>> |  | innerModel (pellet  |    |
>>> |  |           no_SWRL)  |    |
>>> |  |  ----------------   |    |
>>> |  |  | base (OWL_MEM)|  |    |
>>> |  |  ----------------   |    |
>>> |  |                     |    |
>>> |   ---------------------     |
>>> -----------------------------
>>>
>>> 2) second solution (simpler one): I create a pellet model and load  
>>> in it
>>> my ontology (configuring Pellet to support SWRL safe rules): this  
>>> is the
>>> schema:
>>> -----------------------------
>>> !    pelletModel (pellet and  !
>>> !                SWRL support)|
>>> -----------------------------
>>>
>>> An equivalent schema would be:
>>>
>>> -----------------------------
>>> !    pelletModel (pellet and  !
>>> !                SWRL support)|
>>> |     -------------------     |
>>> |    | base (OWL_MEM)    |    |
>>> |     -------------------     |
>>> -----------------------------
>>> meaning, in this last case, that pelletModel is a model built over a
>>> base model that doesn't make inference and is used only to load the
>>> ontology from the file. (I tell "equivalent" since the creation of  
>>> the
>>> "nested" model affects by nothing the performance of the overall  
>>> system
>>> in such a case).
>>>
>>> The problem:
>>> while solution 1) goes smooth and with good performance, solution 2)
>>> seems REALLY slow (my test ontology for this case is this one:
>>> http://www.megafileupload.com/en/file/65341/daycare-swrl-owl.html,  
>>> 35 k,
>>> expressivity ALCOIF(D), with 4 SWRL rules).
>>>
>>> To give an idea  while solution 1) gives an output in few seconds  
>>> (the
>>> output is a call of the writeAll() method from Jena API), the second
>>> solution gives the expected output ("expected" to say that, to me,  
>>> is
>>> correct) in minutes.
>>> I did some tests, using the following java code (that uses Jena):
>>>
>>> //solution 2 - snip of the main()
>>> OntModel pelletModel =
>>> ModelFactory.createOntologyModel(PelletReasonerFactory.THE_SPEC);
>>> pelletModel.read("file:myOntFile.owl");
>>>
>>> then, in order to get an output file, I used:
>>> File f=new File("PelletOutput.owl");
>>> FileOutputStream fos;
>>> fos = new FileOutputStream(f);
>>> PrintStream ps=new PrintStream(fos);
>>> pelletModel.writeAll(ps, "N3", null);
>>> //ps is a PrintStream variable that I use to write directly on a  
>>> file,
>>> N3 is the language used.
>>>
>>> The writeAll() call makes Pellet trigger, so that I know that in  
>>> output
>>> I'll find the entire model (base one + inferred sentences).
>>> Such a implementation takes more than half an hour to terminate
>>> successfully, giving a correct output (e.g., also reporting  
>>> assertions
>>> inferred by the application of SWRL rules).
>>> A similar implementation of solution 1) gives an output in few  
>>> seconds.
>>>
>>> I did also some other tests and asked on the Jena ML, but all  
>>> makes me
>>> thinking that it's a pellet-related question. Also because, in  
>>> solution
>>> 1), where Pellet is used as owl reasoner without SWRL support,
>>> performance are definitely much better.
>>>
>>> Do you have any hint/suggestion to give me?
>>> Thanks! :-)
>>> _______________________________________________
>>> Pellet-users mailing list
>>> Pellet-users at lists.owldl.com
>>> http://lists.owldl.com/mailman/listinfo/pellet-users
>>> _______________________________________________
>>>
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>

-----------------------------------------------
Drs. Rinke Hoekstra

Email: hoekstra at uva.nl    Skype:  rinkehoekstra
Phone: +31-20-5253499     Fax:   +31-20-5253495
Web:   http://www.leibnizcenter.org/users/rinke

Leibniz Center for Law,          Faculty of Law
University of Amsterdam,            PO Box 1030
1000 BA  Amsterdam,             The Netherlands
-----------------------------------------------