[rules-users] Re: Drools-solver performance optimizations?
Wim Vancroonenburg
ikbenvanmars at gmail.com
Sat Feb 14 06:41:27 EST 2009
I'll be sure to do those tests. However I don't know if I can publish these
results, since it is part of my thesis, but I imagine that Mr. Demeester
won't have any problem with sharing these results with you.
Sincerely,
Wim Vancroonenburg.
----- Original Message -----
From: "Geoffrey De Smet" <ge0ffrey.spam at gmail.com>
Newsgroups: gmane.comp.java.drools.user
To: <rules-users at lists.jboss.org>
Sent: Saturday, February 14, 2009 10:12 AM
Subject: Re: Drools-solver performance optimizations?
> I've worked at Kaho and I know Peter De Meester, his custom algorithms do
> pretty well :)
>
> I am really interested in how the different components measure up in
> speed:
> - calculating a single score (no doubt drools-solver will lose this one
> due to the warmup time of drools)
> - calculating 10.000 scores after calculating 10.000 scores to give
> hotspot compiling some time to warm up. Each scores changes into the next
> by a move (to allow score delta calculation).
> - number of calculated scores per second and only start measuring after
> 100 seconds
> - average number of moves per minute
> - average number of moves per step
> - average number of steps per minute
> You'd do me a grand favor by publishing any results on this mailing list,
> so we can find out where and how drools-solver needs improving.
> Patches on drools-solver are always welcome of course too.
>
> One thing that drools-solver currently lacks is build-in support for
> rotating (phasing) through different local search solvers (first simulated
> annealing, then tabu search, then great deluge, then start over). It
> shouldn't be hard to implement that on top of drools-solver for now.
> Also drools-solver currently only utilizes one CPU (it's single threaded).
> Multi-thread support is coming. So you might want to take a look at how
> the number of CPU's affect the other algorithms.
>
> Anyway, first clean up your rules, tweak relativeSelection, use a starting
> solution initializer, tweak other configuration, ...: that will make a big
> difference. It's a game of perseverance - may the best algorithm win :)
>
> With kind regards,
> Geoffrey De Smet
>
>
> Wim Vancroonenburg schreef:
>> Thanks to everybody for the tips. I will see what I can do with them to
>> squeeze out that last bit of performance.
>>
>> To Geoffrey:
>>
>> I just wanted to let you know that I'm the thesis student from KAHOSL
>> that is using Drools Solver for the Patient Admission Scheduling-problem.
>> The performance of Drools Solver isn't bad, but I'm trying to match my
>> promotor's code. His code is substantialy faster at the moment (a
>> hyperheuristic implementation). So I'm trying to squeeze out every bit of
>> performance. Thanks for the tips and the quick response by the way.
>>
>> Sincerely,
>>
>> Wim Vancroonenburg.
>>
>>
>> ----- Original Message ----- From: "Geoffrey De Smet"
>> <ge0ffrey.spam at gmail.com>
>> Newsgroups: gmane.comp.java.drools.user
>> To: <rules-users at lists.jboss.org>
>> Sent: Friday, February 13, 2009 3:32 PM
>> Subject: Re: Drools-solver performance optimizations?
>>
>>
>>> Take a look at some of the tricks in the ITC2007 examination example:
>>>
>>> - <relativeSelection>0.002</relativeSelection> Real-world problems are
>>> so big that you can't evaluate all moves for every step. You need to
>>> take a random percentage (for example 0.2%) of all moves to evaluate.
>>> If you aren't using this, use it and you should see a big difference.
>>> Once you're a 100% confident in your score function, use the benchmarker
>>> to determine the perfect relativeSelection.
>>>
>>> - I calculate a TopicConflict list before starting the solver and use it
>>> in my score drl, because none of the move change the result of that
>>> calculation - and it's used a lot.
>>>
>>> - avoid backwards chaining functions when possible, like accumulate,
>>> exists, collect, ... Forward chaining = free score delta calculation.
>>>
>>> - Use the most limiting facts first, so
>>> $room : Room(sexRestriction == Sex.Dependent && capacity > 1);
>>> before
>>> $n : Night();
>>>
>>>
>>> Most of your rules look good. I do recommend turning them off one by one
>>> to see if none outclasses all others in CPU consumption, so you know
>>> which one to put your time into.
>>>
>>> I would rewrite the patientsToBeAssignedToRoomsOfAppropriateSex as such
>>>
>>> rule "patientsToBeAssignedToRoomsOfAppropriateSex"
>>> when
>>> $room : Room(sexRestriction == Sex.Dependent && capacity
>>> > 1);
>>> ps1 : PatientStay(bed.room == $room, n : night, $leftId
>>> : id, g : patient.admission.sex)
>>> ps2 : PatientStay(bed.room == $room, night == $n,
>>> patient.admission.sex != $g, id > $leftId)
>>> then
>>> insertLogical(new
>>> IntConstraintOccurrence("patientsToBeAssignedToRoomsOfAppropriateSex",ConstraintType.NEGATIVE_HARD,
>>> 50, $ps1, $ps2));
>>> end
>>>
>>> I do the id thing because otherwise it would match twice, once for A and
>>> B and once for B and A
>>>
>>> PS: be carefull with "PatientStay(bed.room == ...), IIRC it gets MVEL'ed
>>> (= a bit performance loss) or flattening is a problem because the move
>>> only does an update(PatientStay) (=> score gets corrupted on second
>>> calculation)
>>> PatientStay(room == ...) with PatiantStay.getRoom(){return
>>> getBed().getRoom()) isn't dangerous
>>> Mark or Edson could probably answer this question.
>>>
>>>
>>> With kind regards,
>>> Geoffrey De Smet
>>>
>>>
>>> Wim Vancroonenburg schreef:
>>>> Hi,
>>>>
>>>> I'm a student currently evaluating Drools Solver for my dissertation. I
>>>> am currently trying to solve an optimization problem with two different
>>>> solvers (one of which is Drools Solver) and I am comparing the results
>>>> with earlier obtained results from literature. However I am having some
>>>> troubles with the performance of Drools Solver, and I was hoping if
>>>> someone could look at my rules to see if they could be tuned:
>>>>
>>>> rule "patientsToBeAssignedToRoomsOfAppropriateSex"
>>>> when
>>>> $n : Night();
>>>> $room : Room(sexRestriction == Sex.Dependent &&
>>>> capacity > 1);
>>>> $genders : ArrayList(size>1) from collect(
>>>> PatientStay(bed.room == $room, night == $n) );
>>>
>>>> exists PatientStay(bed.room == $room, night == $n, $a :
>>>> admission,
>>>> eval(((PatientStay)$genders.get(0)).getAdmission().getPatient().getSex()
>>>> != $a.getPatient().getSex()));
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("patientsToBeAssignedToRoomsOfAppropriateSex",ConstraintType.NEGATIVE_HARD,50,$room,$n));
>>>> end
>>>>
>>>> rule "hasRequiredRoomProperties"
>>>> when
>>>> $pr : RequiredRoomPropertiesConstraint($a : admission,
>>>> $r : room, $w : weight );
>>>> $ps : PatientStay(admission == $a, bed.room == $r);
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("hasPreferredRoomProperties",ConstraintType.NEGATIVE_SOFT,50*$w,$ps));
>>>> end
>>>>
>>>> rule "unplannedTransfers"
>>>> when
>>>> $ps : PatientStay($a : admission, $b : bed, $n :
>>>> night);
>>>> $ps2 : PatientStay(admission == $a, bed != $b, $n2 :
>>>> night,eval($n.getIndex()+1 == $n2.getIndex()));
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("unplannedTransfers",ConstraintType.NEGATIVE_SOFT,110,$ps,$ps2));
>>>> end
>>>>
>>>> rule "hasPreferredRoomProperties"
>>>> when
>>>> $pr : PreferredRoomPropertiesConstraint($a : admission,
>>>> $r : room, $w : weight );
>>>> $ps : PatientStay(admission == $a, bed.room == $r);
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("hasPreferredRoomProperties",ConstraintType.NEGATIVE_SOFT,20*$w,$ps));
>>>> end
>>>>
>>>> rule "meetsRoomPreference"
>>>> when
>>>> $mr : MeetsRoomPreferenceConstraint($a : admission, $r
>>>> : room);
>>>> $ps : PatientStay(admission == $a, bed.room == $r);
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("meetsRoomPreference",ConstraintType.NEGATIVE_SOFT,8,$ps));
>>>> end
>>>>
>>>> rule "inGoodDepartment"
>>>> when
>>>> $gd : GoodDepartmentConstraint($a : admission, $d :
>>>> department);
>>>> $ps : PatientStay(admission == $a, $b : bed,
>>>> eval($b.getRoom().getDepartment().equals($d)));
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("inGoodDepartment",ConstraintType.NEGATIVE_SOFT,10,$ps));
>>>> end
>>>>
>>>> rule "inGoodRoom"
>>>> when
>>>> $gr : GoodRoomConstraint($a : admission, $r : room, $w
>>>> : weight);
>>>> $ps : PatientStay(admission == $a, bed.room == $r);
>>>> then
>>>> insertLogical(new
>>>> IntConstraintOccurrence("inGoodRoom",ConstraintType.NEGATIVE_SOFT,10*$w,$ps));
>>>> end
>>>>
>>>> rule "calcScore"
>>>> salience -10
>>>> when
>>>> $count : Number() from accumulate(
>>>> IntConstraintOccurrence($w : weight) ,
>>>>
>>>> sum($w) );
>>>> then
>>>> scoreCalculator.setScore(-$count.doubleValue());
>>>> end
>>>>
>>>> The classes with **Constraint in it are possible combinations that
>>>> cause a constraint to be violated, and are calculated and inserted at
>>>> initialization time (and are never changed). I know that the rule
>>>> "patientsToBeAssignedToRoomsOfAppropriateSex" is fairly complex, but
>>>> even when I remove it, the performance is not fantastic. Is there
>>>> anything else I can do to get better performance? I'm already using JDK
>>>> 1.6 and -server mode. Furthermore, all classes used here have their
>>>> default equals and hashCode methods, so they don't have an impact on
>>>> performance.
>>>>
>>>> Sincerely,
>>>>
>>>> Wim Vancroonenburg
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>>
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>>>
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