Re: JESS: On the Performance of Logical Retractions

I don't think there's a particular reason in general. Retracting a  
fact takes only a little longer than asserting one, on average. But if  
we assume liberal use of "logical", retracting a single fact could  
result in a sort of "cascade effect" whereby retracting a single fact  
would result in many other facts, and many activations, being removed  
also due to dependencies.  All of that would take time.  Still, your  
case seems extreme. Maybe there's something pathological about this  
particular case.


On Jun 5, 2011, at 3:18 PM, Md Oliya wrote:

> Hi,
>
> I am doing some experiments with a set of rules which contain the  
> "logical" CE.
> I intend to see the performance of Jess on a set of assertions as  
> well as retractions.
>
> After some experiments, I found that the runtime for assertions is  
> much less than that of retractions.
> In fact, the performance on retractions is so bad that I would  
> rather re (run) jess on a retracted kb.
>
>
> A sample test case:
> The KB size,  number of assertions, number of retractions, and  
> number of rules are 100K, 50K, 1k, and 100, respectively.
> runtimes are >> initial run: 860ms,  assertions:320ms --   
> retractions: 4s.
>
>
> Would you please give some hints on the reason?
>
>
> Thanks in advance.
> --Oli.

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com







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