[Pellet-users] How to use taxonomy computeLCA(...)?

[Evren Sirin]

On 4/18/08 10:01 AM, Ian Dickinson wrote:
> Hi Evren,
>   
>> This function is not meant to be part of the public functions. It is
>> used internally for a specific purposes and known to cause problems in
>> more general cases. So use it at your own risk ;) Below I give some
>> information on how to use it but you might consider alternatives like
>> the one provided in Jena [1]. Though I have not personally used the Jena
>> function and I'm not sure if it does the same thing (Pellet returns a
>> list of classes as LCA since there might not always be a unique LCA but
>> I see that Jena function returns a single class. You might get help
>> about the Jena function on the Jena mailing list).
>>     
> I had some difficulty tracking down an algorithm I could use for the 
> Jena utility (marked 'experimental' for good reasons :-). I used 
> Tarjan's algorithm, but it's really intended for trees not graphs. Do 
> you have a reference for the approach Pellet uses, or other suggestions?
>   

No, unfortunately not :( I'm not aware of any easily-implementable LCA 
algorithm for DAGs even though there are some for trees. I think all of 
the LCA-DAG algorithms I came across were designed for all-pairs LCA 
problem and required a preprocessing step that was too much for my use 
case (As I mentioned before, LCA in Pellet was intended only to support 
an internal optimization technique). For this reason, the implementation 
in Pellet is rather ad-hoc and I don't encourage anyone to use it :)

Cheers,
Evren
> Thanks,
> Ian
>
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