[rules-users] OptaPlanner - best strategy for variable number of planning entities?

[Geoffrey De Smet]

Without a construction heuristic, local search waste a lot of time doing 
easy work.
No CH is like swimming 25 meter with LS.
CH with LS is like jumping 10 meters into the pool and then swimming the 
remaining 15.
I've seen cases were it takes minutes for LS to make up for the work of CH.

> it seems to
> just end right away with an initial solution of "all sessions off",
Turn on debug and then trace logging to find out what's going on.


On 05-03-14 08:11, Nadim wrote:
> ge0ffrey wrote
>> Sounds weird to me.
>> It's sounds like you're assigning the pigeon holes to the pigeons,
>> instead of assigning the pigeons to the pigeon holes.
>> [...]
>> @PlanningEntity
>> class SessionAttendance {
>>      Session session;
>>      @PlanningVariable boolean attending;
>> }
>>
>> Based on that, your start and end times can be calculated.
>> Either in the score calculation itself (insertLogicals etc like in nurse
>> rostering)
>> Or with shadow variables (like in vehicle routing and project job
>> scheduling)
>> http://blog.athico.com/2013/06/shadow-variables-planningvariablelisten.html
>> Shadow variables is probably more efficient.
> Exactly why I asked...there's a certain art to framing the problem in a way
> that makes it work well with the engine.  I tried restructuring the problem
> the other way around...I hadn't thought of calculating the windows on the
> fly, but it does make a lot of sense.  The engine now seems to be giving
> much better answers faster.  I'm still just determining the windows directly
> in the score calculation, but now that it looks like it's functioning
> better, I'll explore more efficient approaches like shadow variables or
> using rules-based calculation.
>
> I still haven't found the construction phase to be of any use...it seems to
> just end right away with an initial solution of "all sessions off", but
> maybe I just need to play with the configuration file some.
>
> Lots to learn, but looks like a powerful and flexible tool framework.
> Thanks again for the suggestion!
>
>
>
>
> --
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