% File 'hamiltonian': Computing Hamiltonian cycles using smodels.
% Copy lparse and smodels from directory /projects/tag/smodels/current/sun/ .
% Command line: 'lparse -n 0 < hamiltonian | smodels'.

% DOMAINS

node(0..5).

edge(0,1).
edge(1,2).
edge(2,0).
edge(3,4).
edge(4,5).
edge(5,3).
edge(4,0).
edge(2,5).

% GENERATE

1 {in(X,Y) : edge(X,Y)} 1 :- node(X).
1 {in(X,Y) : edge(X,Y)} 1 :- node(Y).

% DEFINE

reachable(X) :- node(X), in(0,X).
reachable(Y) :- node(X), node(Y), reachable(X), in(X,Y).

% TEST

:- not reachable(X), node(X).

% HIDE

hide node(X).
hide edge(X,Y).
hide reachable(X).