I want 10 variables with constraints, but Prolog only labels 9. Here's my code:
:- use_module(library(clpfd)).
colour(Regions) :-
Regions = [A,B,C,D,E,F,G,H,I,J],
Regions ins 1..10,
all_distinct(Regions),
labeling([], Regions).
%%% Output:
?-colour(X).
A = [1, 2, 3, 4, 5, 7, 6, 10, 8|...] ; % only 9 variables labelled.
Note:
It works perfectly fine for ins 1..9
with 9 variables.