Hi Guido, Thanks for your help. I've first used :
linear(*this, fpr.row(i), IRT_EQ, _NFPR[i]) which works as expected. Now, I use : rel(*this, sum(fpr.row(i)) == _NFPR[i]); which is more readable thanks to minimodel. I was confused, because p44 i've read : "A Boolean variable is not an integer variable with a domain that is included in {0, 1}." So i thought that it was not possible to sum boolean variables. However, p46 we can read : "The only difference between integer and Boolean variables is that Boolean variables can only take the values 0 or 1" Thanks again, Cheers, Philippe _______________________________________________ Gecode users mailing list users@gecode.org https://www.gecode.org/mailman/listinfo/gecode-users