public static FOLKnowledgeBase createLovesAnimalKnowledgeBase(InferenceProcedure infp)
{
FOLKnowledgeBase kb = new FOLKnowledgeBase(DomainFactory.lovesAnimalDomain(), infp);
kb.tell("FORALL x (FORALL y (Animal(y) => Loves(x, y)) => EXISTS y Loves(y, x))");
kb.tell("FORALL x (EXISTS y (Animal(y) AND Kills(x, y)) => FORALL z NOT(Loves(z, x)))");
kb.tell("FORALL x (Animal(x) => Loves(Jack, x))");
kb.tell("(Kills(Jack, Tuna) OR Kills(Curiosity, Tuna))");
kb.tell("Cat(Tuna)");
kb.tell("FORALL x (Cat(x) => Animal(x))");
return(kb);
}
public void testExamplePg296AIMA2e()
{
FOLDomain domain = DomainFactory.lovesAnimalDomain();
FOLParser parser = new FOLParser(domain);
Sentence origSentence = parser
.parse("FORALL x (FORALL y (Animal(y) => Loves(x, y)) => EXISTS y Loves(y, x))");
CNFConverter cnfConv = new CNFConverter(parser);
CNF cnf = cnfConv.convertToCNF(origSentence);
Assert.AreEqual(
"[Animal(SF0(x)), Loves(SF1(x),x)],[~Loves(x,SF0(x)), Loves(SF1(x),x)]",
cnf.ToString());
}
static void fOL_CNFConversion()
{
System.Console.WriteLine("-------------------------------------------------");
System.Console.WriteLine("Conjuctive Normal Form for First Order Logic Demo");
System.Console.WriteLine("-------------------------------------------------");
FOLDomain domain = DomainFactory.lovesAnimalDomain();
FOLParser parser = new FOLParser(domain);
Sentence origSentence = parser.parse("FORALL x (FORALL y (Animal(y) => Loves(x, y)) => EXISTS y Loves(y, x))");
CNFConverter cnfConv = new CNFConverter(parser);
CNF cnf = cnfConv.convertToCNF(origSentence);
System.Console.WriteLine("Convert '" + origSentence + "' to CNF.");
System.Console.WriteLine("CNF=" + cnf.ToString());
System.Console.WriteLine("");
}
public void testExamplesPg299AIMA2e()
{
FOLDomain domain = DomainFactory.lovesAnimalDomain();
FOLParser parser = new FOLParser(domain);
// FOL A.
Sentence origSentence = parser
.parse("FORALL x (FORALL y (Animal(y) => Loves(x, y)) => EXISTS y Loves(y, x))");
CNFConverter cnfConv = new CNFConverter(parser);
CNF cnf = cnfConv.convertToCNF(origSentence);
// CNF A1. and A2.
Assert.AreEqual(
"[Animal(SF0(x)), Loves(SF1(x),x)],[~Loves(x,SF0(x)), Loves(SF1(x),x)]",
cnf.ToString());
// FOL B.
origSentence = parser
.parse("FORALL x (EXISTS y (Animal(y) AND Kills(x, y)) => FORALL z NOT(Loves(z, x)))");
cnf = cnfConv.convertToCNF(origSentence);
// CNF B.
Assert.AreEqual("[~Animal(y), ~Kills(x,y), ~Loves(z,x)]",
cnf.ToString());
// FOL C.
origSentence = parser.parse("FORALL x (Animal(x) => Loves(Jack, x))");
cnf = cnfConv.convertToCNF(origSentence);
// CNF C.
Assert.AreEqual("[~Animal(x), Loves(Jack,x)]", cnf.ToString());
// FOL D.
origSentence = parser
.parse("(Kills(Jack, Tuna) OR Kills(Curiosity, Tuna))");
cnf = cnfConv.convertToCNF(origSentence);
// CNF D.
Assert.AreEqual("[Kills(Curiosity,Tuna), Kills(Jack,Tuna)]",
cnf.ToString());
// FOL E.
origSentence = parser.parse("Cat(Tuna)");
cnf = cnfConv.convertToCNF(origSentence);
// CNF E.
Assert.AreEqual("[Cat(Tuna)]", cnf.ToString());
// FOL F.
origSentence = parser.parse("FORALL x (Cat(x) => Animal(x))");
cnf = cnfConv.convertToCNF(origSentence);
// CNF F.
Assert.AreEqual("[~Cat(x), Animal(x)]", cnf.ToString());
// FOL G.
origSentence = parser.parse("NOT(Kills(Curiosity, Tuna))");
cnf = cnfConv.convertToCNF(origSentence);
// CNF G.
Assert.AreEqual("[~Kills(Curiosity,Tuna)]", cnf.ToString());
}
public void testBinaryResolventsOrderDoesNotMatter()
{
// This is a regression test, to ensure
// the ordering of resolvents does not matter.
// If the order ends up mattering, then likely
// a problem was introduced in the Clause class
// unifier, or related class.
// Set up the initial set of clauses based on the
// loves animal domain as it contains functions
// new clauses will always be created (i.e. is an
// infinite universe of discourse).
FOLKnowledgeBase kb = new FOLKnowledgeBase(DomainFactory.lovesAnimalDomain());
kb.tell("FORALL x (FORALL y (Animal(y) => Loves(x, y)) => EXISTS y Loves(y, x))");
kb.tell("FORALL x (EXISTS y (Animal(y) AND Kills(x, y)) => FORALL z NOT(Loves(z, x)))");
kb.tell("FORALL x (Animal(x) => Loves(Jack, x))");
kb.tell("(Kills(Jack, Tuna) OR Kills(Curiosity, Tuna))");
kb.tell("Cat(Tuna)");
kb.tell("FORALL x (Cat(x) => Animal(x))");
ISet <Clause> clauses = CollectionFactory.CreateSet <Clause>();
clauses.AddAll(kb.getAllClauses());
ISet <Clause> newClauses = CollectionFactory.CreateSet <Clause>();
long maxRunTime = 30 * 1000; // 30 seconds
IDateTime finishTime = CommonFactory.Now().AddMilliseconds(maxRunTime);
do
{
clauses.AddAll(newClauses);
newClauses.Clear();
Clause[] clausesA = clauses.ToArray();
for (int i = 0; i < clausesA.Length; ++i)
{
Clause cI = clausesA[i];
for (int j = 0; j < clausesA.Length; j++)
{
Clause cJ = clausesA[j];
newClauses.AddAll(cI.getFactors());
newClauses.AddAll(cJ.getFactors());
ISet <Clause> cIresolvents = cI.binaryResolvents(cJ);
ISet <Clause> cJresolvents = cJ.binaryResolvents(cI);
if (!cIresolvents.SequenceEqual(cJresolvents))
{
System.Console.WriteLine("cI=" + cI);
System.Console.WriteLine("cJ=" + cJ);
System.Console.WriteLine("cIR=" + cIresolvents);
System.Console.WriteLine("cJR=" + cJresolvents);
Assert.Fail("Ordering of binary resolvents has become important, which should not be the case");
}
foreach (Clause r in cIresolvents)
{
newClauses.AddAll(r.getFactors());
}
if (CommonFactory.Now().BiggerThan(finishTime))
{
break;
}
}
if (CommonFactory.Now().BiggerThan(finishTime))
{
break;
}
}
} while (CommonFactory.Now().SmallerThan(finishTime));
}