$set a_num floor(card(a) / %num_folds%)
$set b_num floor(card(b) / %num_folds%)

a_test(%1) = 0;
b_test(%2) = 0;

a_test(%1)$((ord(a) > %a_num%*(ord(p)-1)) and 
	    (ord(a) <= %a_num%*ord(p))) = 1;
! put leftovers in last set
a_test(%1)$((ord(p) eq %num_folds%) and 
	    (ord(a) > %a_num%*%num_folds%)) = 1;

b_test(%2)$((ord(b) > %b_num%*(ord(p)-1)) and 
	    (ord(b) <= %b_num%*ord(p))) = 1;
! put leftovers in last set
b_test(%2)$((ord(p) eq %num_folds%) and 
	    (ord(b) > %b_num%*%num_folds%)) = 1;