/// Return how to implement distinct except 0
int distinct_except_0(void) const { return _distinct_except_0.value(); }
/// Return how to implement same or 0
int same_or_0(void) const { return _same_or_0.value(); }
/// Return how to implement distinct except 0
int no_monochrome_rectangle(void) const {
return _no_monochrome_rectangle.value();
}
/// Return how to implement not all equals
int not_all_equal(void) const { return _not_all_equal.value(); }
/// Whether to use permutation constraints. Only active if d=4
bool permutation(void) const {
return d() == 4 && _permutation.value();
}