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

[Guido Tack]

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
> 
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