[gecode-users] Fwd: Multi-objective Model with Searchcombinators in Gecode

[Mohamed Rezgui]

Dear Guido,

I would like to know when I have more objectives like 3 objectives to
minimize (all of them), is the following syntax correct ?

annotation three_stage_bnb(var int: obj1, var int: obj2, var int:
obj3, ann: s) =
let { svar int: best1 = 1000000,
      svar int: best2 = 0,
      svar int: best3 = 0 }
in (
  portfolio([and(post(obj1 < lv("best1"), and(s,assign(best1,obj1))),
                 prune),
             post(obj1=lv("best1"),
               post(obj2 < lv("best2"), and(s,assign(best2,obj2)))
             post(obj2=lv("best2"),
               post(obj3 < lv("best3"), and(s,assign(best3,obj3)))
             )]));

and how can I call this annotation in the minizinc instance ?

Best Regards,
Mohammed REZGUI

2014-03-09 14:02 GMT+01:00 Mohamed Rezgui <kyo.alone at gmail.com>:
> Thank you very much for your answer. My problem is a pseudo bin
> packing problem.
> I would like to minimize a number of components of a certain sizes and
> minimize the number of bins.
> So I would like to do a lexicographic order on my multi-objective solutions.
>
> Best Regards,
> Mohammed REZGUI
>
> 2014-03-09 10:54 GMT+01:00 Guido Tack <tack at gecode.org>:
>> Hi,
>>
>> could you clarify in what way you want to reuse the solution?
>>
>> Here's a combinator that first minimizes obj1, then maximizes obj2 keeping obj1 at the optimal value:
>>
>> annotation two_stage_bnb(var int: obj1, var int: obj2, ann: s) =
>> let { svar int: best1 = 1000000,
>>       svar int: best2 = 0 }
>> in (
>>   portfolio([and(post(obj1 < lv("best1"), and(s,assign(best1,obj1))),
>>                  prune),
>>              post(obj1=lv("best1"),
>>                post(obj2 > lv("best2"), and(s,assign(best2,obj2)))
>>              )]));
>>
>> Cheers,
>> Guido
>>
>> On 9 Mar 2014, at 9:43 am, Mohamed Rezgui <kyo.alone at gmail.com> wrote:
>>
>>> Dear Sir,
>>>
>>> I would like to know how can I use searchcombinators in my
>>> multi-objective model in FlatZinc.
>>> I have 2 objectives. I minimize the first and I reuse the solution for
>>> the minimization of the second objective.
>>> Can you give me the good syntax in FlatZinc with searchcombinators to
>>> do that please ?
>>>
>>> Best Regards,
>>> Mohammed REZGUI
>>> PhD Student
>>>
>>> _______________________________________________
>>> Gecode users mailing list
>>> users at gecode.org
>>> https://www.gecode.org/mailman/listinfo/gecode-users
>>
>
>
>
> --
> Cordialement,
> Mohamed REZGUI



--
Cordialement,
Mohamed REZGUI


-- 
Cordialement,
Mohamed REZGUI