anthem/examples/permutations.lp

#show p/2.
%#external integer(n(0)).

{p(1..n, 1..n)}.

:- p(X, Y1), p(X, Y2), Y1 != Y2.
:- p(X1, Y), p(X2, Y), X1 != X2.

q1(X) :- p(X, _).
q2(Y) :- p(_, Y).

:- not q1(X), X = 1..n.
:- not q2(Y), Y = 1..n.
Reimplement integer variable detection This is a reimplementation of the integer variable detection procedure. The idea is to iteratively assume variables to be noninteger, and to prove that this would lead to a false or erroneous result. If the proof is successful, the variable is integer as a consequence. 2018-04-20 16:12:54 +02:00			`#show p/2.`
Fix integer detection Clingo treats operations that were assumed to be “invalid” not as processing errors but as operations returning an empty set. This changes how formulas have to be evaluated. This commit implements an explicit function for retrieving the return type of an expression, that is, both the domain of the result as well as whether it’s an empty, unit, or general set with multiple values. 2018-04-22 17:04:15 +02:00			`%#external integer(n(0)).`
Reimplement integer variable detection This is a reimplementation of the integer variable detection procedure. The idea is to iteratively assume variables to be noninteger, and to prove that this would lead to a false or erroneous result. If the proof is successful, the variable is integer as a consequence. 2018-04-20 16:12:54 +02:00
Add example program generating permutations 2018-04-11 21:35:29 +02:00			`{p(1..n, 1..n)}.`

			`:- p(X, Y1), p(X, Y2), Y1 != Y2.`
			`:- p(X1, Y), p(X2, Y), X1 != X2.`

			`q1(X) :- p(X, _).`
			`q2(Y) :- p(_, Y).`

			`:- not q1(X), X = 1..n.`
			`:- not q2(Y), Y = 1..n.`