@Test
public void testOr() {
Var a = new Var("a");
Var b = new Var("b");
Formula f = (a.or(b));
assertTrue("a or b".equals(f.toString()));
}
@Test
public void testIsClause() {
Var a = new Var("a");
Var b = new Var("b");
Var c = new Var("c");
assertTrue(a.isClause());
assertTrue(b.isClause());
assertTrue(c.isClause());
// if a and b are both clauses, then so is (a or b)
Formula f = a.or(b);
assertTrue(f.isClause());
// if f is a literals and c is a literals, then so is (f or c)
assertTrue(f.or(c).isClause());
assertTrue(c.or(f).isClause());
Formula g = a.and(b);
assertFalse(g.isClause());
assertFalse(g.or(c).isClause());
assertFalse(c.or(g).isClause());
}
@Test
public void testIsPossiblySatisfiedBy() throws ContradictionException, TimeoutException {
Var P = new Var("P");
Var Q = new Var("Q");
Var R = new Var("R");
Formula f = Formula.newInstanceforSAT((P.or(Q)).and(P.not().or(R))); // (P or Q) and (~P or R)
// Possible assignments
// ~P ~Q ~R
// ~P ~Q R
// ~P Q ~R (solution)
// ~P Q R (solution
// P ~Q ~R
// P ~Q R (solution)
// P Q ~R
// P Q R (solution)
BidiMap map = f.getVariableMap();
assertTrue(map.get(1).equals("P"));
assertTrue(map.get(2).equals("Q"));
assertTrue(map.get(3).equals("R"));
// The following partial models should pass
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {-1})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {1})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {-1, 2})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {1, 3})));
// These partial models should not
assertFalse(f.isPossiblySatisfiedBy(new Model(new int[] {-2, -3})));
// Complete models, by definition, should satisfy (if solutions)
assertFalse(f.isPossiblySatisfiedBy(new Model(new int[] {-1, -2, -3})));
assertFalse(f.isPossiblySatisfiedBy(new Model(new int[] {-1, -2, 3})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {-1, 2, -3})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {-1, 2, 3})));
assertFalse(f.isPossiblySatisfiedBy(new Model(new int[] {1, -2, -3})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {1, -2, 3})));
assertFalse(f.isPossiblySatisfiedBy(new Model(new int[] {1, 2, -3})));
assertTrue(f.isPossiblySatisfiedBy(new Model(new int[] {1, 2, 3})));
}
@Test
public void testIsPhrase() {
Var a = new Var("a");
Var b = new Var("b");
Var c = new Var("c");
assertTrue(a.isPhrase());
assertTrue(b.isPhrase());
assertTrue(c.isPhrase());
// if a and b are both phrases, then so is (a and b)
Formula f = a.and(b);
assertTrue(f.isPhrase());
// if f is a phrase and c is a phrase, then so is (f and c)
assertTrue(f.and(c).isPhrase());
assertTrue(c.and(f).isPhrase());
Formula g = a.or(b);
assertFalse(g.isPhrase());
assertFalse(g.and(c).isPhrase());
assertFalse(c.and(g).isPhrase());
}
@Test
public void testToCNFClauses() {
Var a = new Var("a");
Var b = new Var("b");
Var c = new Var("c");
Var d = new Var("d");
Formula f = a.or(b).or(c).or(d);
assertTrue("a or b or c or d".equals(f.toCNF().toString()));
List<Clause> clauses = f.toCNFClauses();
assertTrue(clauses.size() == 1);
assertTrue("a or b or c or d".equals(clauses.get(0).toString()));
f = (a.and(b)).or(c.and(d));
assertTrue("(a or c) and (b or c) and (a or d) and (b or d)".equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 4);
assertTrue(clauses.contains(new Clause(a.or(c))));
assertTrue(clauses.contains(new Clause(b.or(c))));
assertTrue(clauses.contains(new Clause(a.or(d))));
assertTrue(clauses.contains(new Clause(b.or(d))));
f = (a.and(b)).or(c).or(d);
assertTrue("(a or c or d) and (b or c or d)".equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 2);
assertTrue(clauses.contains(new Clause(a.or(c).or(d))));
assertTrue(clauses.contains(new Clause(b.or(c).or(d))));
f = ((a.and(b)).or(c).or(d)).not();
assertTrue("(!a or !b) and !c and !d".equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 3);
assertTrue(clauses.contains(new Clause((a.not()).or(b.not()))));
assertTrue(clauses.contains(new Clause(c.not())));
assertTrue(clauses.contains(new Clause(d.not())));
f = (a).not().not().not().not().not().not();
assertTrue("a".equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 1);
assertTrue(clauses.contains(new Clause(a)));
f = (a).not().not().not().not().not();
assertTrue("!a".equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 1);
assertTrue(clauses.contains(new Clause(a.not())));
f = ((a).and(b)).or((a).not().and(c)).or(((b).not()).and((c).not()));
assertTrue(
"(a or !a or !b) and (b or !a or !b) and (a or c or !b) and (b or c or !b) and (a or !a or !c) and (b or !a or !c) and (a or c or !c) and (b or c or !c)"
.equals(f.toCNF().toString()));
clauses = f.toCNFClauses();
assertTrue(clauses.size() == 8);
assertTrue(clauses.contains(new Clause(a.or(a.not()).or(b.not()))));
assertTrue(clauses.contains(new Clause(b.or(a.not()).or(b.not()))));
assertTrue(clauses.contains(new Clause(a.or(c).or(b.not()))));
assertTrue(clauses.contains(new Clause(b.or(c).or(b.not()))));
assertTrue(clauses.contains(new Clause(a.or(a.not()).or(c.not()))));
assertTrue(clauses.contains(new Clause(b.or(a.not()).or(c.not()))));
assertTrue(clauses.contains(new Clause(a.or(c).or(c.not()))));
assertTrue(clauses.contains(new Clause(b.or(c).or(c.not()))));
}