Cartesian product validator ignores check conditions

[ujhelyiz]

The cartesian product validator does not connect variables used in check expressions. E.g. in the moreFriendsThan pattern from the school demo it reports that the two students are in different partition.

    pattern moreFriendsThan(S1 : Student, S2 : Student) {
        N == count find inTheCircleOfFriends(S1, _Sx1);
        M == count find inTheCircleOfFriends(S2, _Sx2);
        check(N > M);
    }

As a solution, the variable set of the check expression (a method in CorePatternLanguageHelper returns these variables) might be considered connected.

I'm not sure whether this issue needs to be fixed, but I believe it is - but it is enough to do it for 0.7 (in other words, we should not delay 0.6.9 for this).

[istvanrath]

As per @bergmanngabor 's recommendations detailed on http://viatra.inf.mit.bme.hu/performance#Optimizing_queries_and_transformations , I'm not convinced that connecting variables inside check() expressions should be considered good practice in general. In special cases, such as the example above, the warning (as currently generated by the validator) might be confusing/misleading though.

[okrosa]

It works like this by design. Actually the validator does connect them in a loose way, hence the error message (The pattern body contains constraints which are only loosely connected.).

[istvanrath]

Closing - WONTFIX.