This is a current shortcoming of the minimodel library. For some linear
constraints (such as x==5 in this case) the IntConLevel is ignored. To get the
full propagation, you have to post the constraint directly, like this:
Gecode::rel(*test, test->x_[1], IRT_EQ, 5, test->b_[1], ICL_DOM);
Cheers,
Guido
On 10 Apr 2012, at 19:20, Max Ostrowski wrote:
> I have a small example where i do not understand why no propagation takes
> place.
>
> test is a pointer to the space instance
> x_ is an array of 10 IntVars(0,10)
> b_ is an array of 2 BoolVars(0,1)
>
>
> LinRel rel1(test->x_[0],IRT_EQ,5);
> rel1.post(*test,true,ICL_DEF);
>
> Gecode::distinct(*test,test->x_,ICL_DEF);
>
> LinRel rel2(test->x_[1],IRT_EQ,5);
> Gecode::rel(*test, rel2 == test->b_[1],ICL_DEF);
>
> test->status();
> if (test->failed())
> std::cout << "Failed" << std::endl;
> std::cout << test->x_ << std::endl;
> std::cout << test->b_ << std::endl;
>
>
> So i post das one of my elements x_[0] is 5, and all elements are distinct.
> Now i have a reified constraint that x_[1] == 5.
> The distinct constraint removes 5 from he domain of x_[1],
> but the propagator does not fire.
> The result is:
> {5, {0..4,6..10}, {0..4,6..10}, {0..4,6..10}, {0..4,6..10}, {0..4,6..10},
> {0..4,6..10}, {0..4,6..10}, {0..4,6..10}, {0..4,6..10}}
> {[0..1], [0..1]}
>
> Even with ICL_DOM the boolean variable is not touched if values are removed
> from the domain.
> Also i think this could be easily done with "Advisors" ?
> I have no experience with this, so my question:
> Is this behavior the desired one?
> Can this be changed if i have reifications like mine where i compare to
> constants?
>
> Thanks a lot,
>
> Max
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--
Guido Tack,
http://www.csse.monash.edu/~guidot/
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