distributed config && float library

packages/gecode/clp_examples/queens.yap

@@ -0,0 +1,38 @@
+
+:- use_module(library(gecode/clpfd)).
+:- use_module(library(maplist)).
+
+queens(N, Queens) :-
+	length(Queens, N),
+	Queens ins 1..N,
+	all_distinct(Queens),
+	foldl(inc, Queens, Inc, 0, _), % [0, 1, 2, .... ]
+	foldl(dec, Queens, Dec, 0, _), % [0, -1, -2, ... ]
+	all_distinct(Inc,Queens),
+	all_distinct(Dec,Queens),
+	labeling([], Queens).
+
+inc(_, I0, I0, I) :-
+	I is I0+1.
+
+dec(_, I0, I0, I) :-
+	I is I0-1.
+
+lqueens(N, Queens) :-
+	length(Queens, N),
+	Queens ins 1..N,
+	all_distinct(Queens),
+	lconstrain( Queens, 0 ),
+	labeling([], Queens).
+
+lconstrain([], _).
+lconstrain( [Q|Queens], I0) :-
+	I is I0+1,
+	foldl(constrain(Q, I0), Queens, I, _),
+	lconstrain( Queens, I).
+
+constrain(Q, I, R, J, J1) :-
+	J1 is J+1,
+	Q + I #\= R + J,
+	Q - I #\= R - J.
+