[gecode-users] rtest_eq_dom doesnt lead to RT_TRUE !?!?!

[Martin Mann]

Hi,

first of all: I am using the trunc version... but I checked and the 
corresponding source for the stable version is the same!

I found a strange behavior of the Gecode::rel function using IRT_NQ as 
an reified constraint.

I used 2 variables with the following domains:

d1 = (1)
d2 = (0,2)

also I ve got a reified constraint like that

rel(home, d1, IRT_NQ, d2, isNQ, ICL_DOM)

so isNQ should be true if d1 an d2 are unequal!

BUT: isNQ is NOT assigned!

i dived into the source and followed the my instance of the rel function:

rel
-> Rel::ReEqDom<IntView,NegBoolView>
-> ReEqDom<View,CtrlView>::propagate()
-> rtest_eq_dom()
->
and found this...
===================================
   template <class View>
   forceinline RelTest
   rtest_eq_dom(View x, View y) {
     RelTest rt = rtest_eq_bnd(x,y);
     if (rt != RT_MAYBE) return rt;
     return (x.range() || y.range()) ? RT_MAYBE :
        test_eq_dom_check(x,y);
   }
==================================
   template <class View>
   RelTest
   rtest_eq_dom_check(View x, View y) {
     ViewRanges<View> rx(x), ry(y);
     while (rx() && ry()) {
       if (rx.max() < ry.min()) {
	++rx;
       } else if (ry.max() < rx.min()) {
	++ry;
       } else return RT_MAYBE;
     }
     return RT_FALSE;
   }
==================================
   template <class View>
   forceinline RelTest
   rtest_eq_bnd(View x, View y) {
     if ((x.min() > y.max()) || (x.max() < y.min())) return RT_FALSE;
     return (x.assigned() && y.assigned()) ? RT_TRUE : RT_MAYBE;
   }
==================================


if I m right... rtest_eq_dom will never return RT_TRUE if this cant be 
determinated via bound constraint.... ???
this is because the called rtest_eq_dom_check() function will never 
return RT_TRUE ...

but this isnt what i expect if i am using ICL_DOM or?

in my case non of the 2 called functions lead to RT_TRUE but at least 
one should do ...

is it a bug or a feature? ;)

thanks for a closer look

Martin