Hermit Debugging

Posted by Mehmed on
URL: http://owlready.306.s1.nabble.com/Hermit-Debugging-tp2517.html

Dear JiBa,

I have a question regarding the reasoner Hermit. I have different ontologies, some are simple constructed (less number of axios/classes/individuals), some are complex and they are including other ontologies.  I use owlready to read these ontologies and reason them with the Hermit. Similar to Protege the reasoning with Hermit over owlready takes for some ontologies a very long time (> minute(s)) due to complexities of ontology or may existing mistakes in the ontology.

To debug it I use the Debugger on Protege and  by hermit created the temp file or export file or log file.
The Debugger finds no problem (e.g. ontology is coherent and consistent),  by Hermit created log data is not comprehensive information to understand the problem, if the reasoner gets stuck.  You can recognize that it is a problem, but you don't know what is exact the problem or why it is occurring and how you can deal with it. Do you have any suggestions, how I have to debug the reasoner?

Another phenomenal point is the time consuming of the hermit on owlready. I tested the same ontology many times and I got different time consumption under the same conditions.  Do you have an explanation why it was so different?

Owlready2 * HermiT took 133.1376292705536 seconds
Owlready2 * HermiT took 62.45776987075806 seconds
Owlready2 * HermiT took 90.68753051757812 seconds
Owlready2 * HermiT took 46.87136745452881 seconds
Owlready2 * HermiT took 40.390302658081055 seconds
Owlready2 * HermiT took 63.536184787750244 seconds

Last point, if I use "only" by the restriction for equivalent_to the reasoning gets much worse. Maybe the missing closer axioms cause a huge solution space.  But if I only use the "some" expression the  time consumption drops drastically.

Regards, 
Mehmed