PROLOG all different
I have a very weird problem with PROLOG. I have used it before, but it's been a while and I'm rusty. I have a list of variables and I need to ensure that none of them are the same.
I have tried:
use_module(library(bounds)).
all_different(A, B, C, D, 6, 8).
However, when I try this, I get an error saying that all_different/6 is undefined.
How can I go about solving this issue? Is there any library function that I can call directly for this?
I am VERY stuck and would greatly appreciate any help.
Thanks in advance.
solve([
[A, 6, 1],
[B, 5, C, 2, D, E, F, G, 6],
[6, H, I, 5, J, K, 2, L, 3],
[5, M, 6, N, O, 4, P, Q, 5],
[4, R, S, T, U, 6, V, 4, W],
[2, 0, X]
]) :-
all_different([A,6,1,2,D,E]),
all_different([B,5,C,6,H,I]),
all_different([C,2,D,I,5,J]),
all_different([D,E,F,J,K,2]),
all_different([F,G,6,2,L,3]),
all_different([H,I,5,M,6,N]),
all_different([5,J,K,N,O,4]),
all_different([K,2,L,4,P,Q]),
all_different([5,M,6,4,R,S]),
all_different([6,N,O,S,T,U]),
all_different([O,4,P,U,6,V]),
all_different([P,Q,5,V,4,W]),
all_different([T,U,6,2,1,X]),
A<7, A>0, B<7, B>0, C<7, C>开发者_开发技巧;0, D<7, D>0,
E<7, E>0, F<7, F>0, G<7, G>0, H<7, H>0,
I<7, I>0, J<7, J>0, K<7, K>0, L<7, L>0,
M<7, M>0, N<7, N>0, O<7, O>0, P<7, P>0,
Q<7, Q>0, R<7, R>0, S<7, S>0, T<7, T>0,
U<7, U>0, V<7, V>0, W<7, W>0, X<7, X>0.
all_different([A,B,C,D,6,8]).
I believe that only a List can be passed into all_different.
I guess that >/2 and </2 may know nothing about attributes that all_different/1 applied to the vars in list. In SWI-Prolog that predicate is provided by library(clpfd) and among other predicates in that library there is #</2 .
?- all_different([X,Y]), 0 #< X, X #< 3, 1 #< Y, Y #< 4, indomain(X), indomain(Y). X = 1, Y = 2 ; X = 1, Y = 3 ; X = 2, Y = 3.
P.S. indomain/1 from the same library yields all feasible values within applied constraints.
The "ic" constraint library of Eclipse Prolog provides the predicate alldifferent/1, which takes a list of variables as its argument, e.g., alldifferent([X,Y])
and computes what you are looking for.
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