001 package aima.test.logictest.foltest;
002
003 import java.util.HashSet;
004 import java.util.Set;
005
006 import aima.logic.fol.CNFConverter;
007 import aima.logic.fol.SubsumptionElimination;
008 import aima.logic.fol.domain.FOLDomain;
009 import aima.logic.fol.kb.data.CNF;
010 import aima.logic.fol.kb.data.Clause;
011 import aima.logic.fol.parsing.FOLParser;
012 import aima.logic.fol.parsing.ast.Sentence;
013 import junit.framework.TestCase;
014
015 /**
016 * @author Ciaran O'Reilly
017 *
018 */
019 public class SubsumptionEliminationTest extends TestCase {
020 public void testFindSubsumedClauses() {
021 // Taken from AIMA pg 679
022 FOLDomain domain = new FOLDomain();
023 domain.addPredicate("patrons");
024 domain.addPredicate("hungry");
025 domain.addPredicate("type");
026 domain.addPredicate("fri_sat");
027 domain.addPredicate("will_wait");
028 domain.addConstant("Some");
029 domain.addConstant("Full");
030 domain.addConstant("French");
031 domain.addConstant("Thai");
032 domain.addConstant("Burger");
033 FOLParser parser = new FOLParser(domain);
034
035 String c1 = "patrons(v,Some)";
036 String c2 = "patrons(v,Full) AND (hungry(v) AND type(v,French))";
037 String c3 = "patrons(v,Full) AND (hungry(v) AND (type(v,Thai) AND fri_sat(v)))";
038 String c4 = "patrons(v,Full) AND (hungry(v) AND type(v,Burger))";
039 String sh = "FORALL v (will_wait(v) <=> (" + c1 + " OR (" + c2
040 + " OR (" + c3 + " OR (" + c4 + ")))))";
041
042 Sentence s = parser.parse(sh);
043
044 CNFConverter cnfConv = new CNFConverter(parser);
045
046 CNF cnf = cnfConv.convertToCNF(s);
047
048 // Contains 9 duplicates
049 assertEquals(40, cnf.getNumberOfClauses());
050
051 Set<Clause> clauses = new HashSet<Clause>(cnf.getConjunctionOfClauses());
052
053 // duplicates removed
054 assertEquals(31, clauses.size());
055
056 clauses.removeAll(SubsumptionElimination.findSubsumedClauses(clauses));
057
058 // subsumed clauses removed
059 assertEquals(8, clauses.size());
060
061 // Ensure only the 8 correct/expected clauses remain
062 Clause cl1 = cnfConv
063 .convertToCNF(
064 parser
065 .parse("(NOT(will_wait(v)) OR (patrons(v,Full) OR patrons(v,Some)))"))
066 .getConjunctionOfClauses().get(0);
067 Clause cl2 = cnfConv
068 .convertToCNF(
069 parser
070 .parse("(NOT(will_wait(v)) OR (hungry(v) OR patrons(v,Some)))"))
071 .getConjunctionOfClauses().get(0);
072 Clause cl3 = cnfConv
073 .convertToCNF(
074 parser
075 .parse("(NOT(will_wait(v)) OR (patrons(v,Some) OR (type(v,Burger) OR (type(v,French) OR type(v,Thai)))))"))
076 .getConjunctionOfClauses().get(0);
077 Clause cl4 = cnfConv
078 .convertToCNF(
079 parser
080 .parse("(NOT(will_wait(v)) OR (fri_sat(v) OR (patrons(v,Some) OR (type(v,Burger) OR type(v,French)))))"))
081 .getConjunctionOfClauses().get(0);
082 Clause cl5 = cnfConv.convertToCNF(
083 parser.parse("(NOT(patrons(v,Some)) OR will_wait(v))"))
084 .getConjunctionOfClauses().get(0);
085 Clause cl6 = cnfConv
086 .convertToCNF(
087 parser
088 .parse("(NOT(hungry(v)) OR (NOT(patrons(v,Full)) OR (NOT(type(v,French)) OR will_wait(v))))"))
089 .getConjunctionOfClauses().get(0);
090 Clause cl7 = cnfConv
091 .convertToCNF(
092 parser
093 .parse("(NOT(fri_sat(v)) OR (NOT(hungry(v)) OR (NOT(patrons(v,Full)) OR (NOT(type(v,Thai)) OR will_wait(v)))))"))
094 .getConjunctionOfClauses().get(0);
095 Clause cl8 = cnfConv
096 .convertToCNF(
097 parser
098 .parse("(NOT(hungry(v)) OR (NOT(patrons(v,Full)) OR (NOT(type(v,Burger)) OR will_wait(v))))"))
099 .getConjunctionOfClauses().get(0);
100
101 assertTrue(clauses.contains(cl1));
102 assertTrue(clauses.contains(cl2));
103 assertTrue(clauses.contains(cl3));
104 assertTrue(clauses.contains(cl4));
105 assertTrue(clauses.contains(cl5));
106 assertTrue(clauses.contains(cl6));
107 assertTrue(clauses.contains(cl7));
108 assertTrue(clauses.contains(cl8));
109 }
110 }