[rules-users] Re: Drools solver performance question

[Geoffrey De Smet]

Hi Greg,

Yes, I expected that too, but my experiments proved me wrong (for now).
The current implementation of accumulate backwards chains I believe.
Backward chaining doesn't do score delta calculation, so it's very bad 
for scalability.

Try it yourself with the nqueens example.
Uncomment the code in nqueensScoreRules.drl and see what happens if you 
go from n=8 to n=16 and more.

With kind regards,
Geoffrey De Smet



Greg Barton schreef:
> I answered a performance question a user had about
> drools-solver, but I'm afraid I answered with a touch of
> ignorance about the way drools-solver is set up.  His rules
> had a new object being inserted into the working memory each
> time a constraint rule was matched.  The constraint objects
> were then accumulated by a low priority rule at the end. 
> After looking at the drools-solver examples it looks like
> they're all that way.  It strikes me that having a
> single accumulator object, and not creating and inserting a
> new object in each constraint rule, would be more efficient.
>  Is it possible to set this up in a solver ruleset? 
>
> Thanks,
> GreG
>
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