public void testDecisionListHandlesEmptyDataSet()
{
// tests first base case of recursion
DecisionList dlist = new DecisionList("Yes", "No");
DLTest test1 = new DLTest();
test1.add("type", "Thai"); // doesn't match first example
dlist.add(test1, "test1success");
}
public void testDecisionListWithSingleTestReturnsTestValueIfTestSuccessful()
{
DecisionList dlist = new DecisionList("Yes", "No");
DataSet ds = DataSetFactory.getRestaurantDataSet();
DLTest test = new DLTest();
test.add("type", "French");
dlist.add(test, "test1success");
Assert.AreEqual("test1success", dlist.predict(ds.getExample(0)));
}
public DecisionList mergeWith(DecisionList dlist2)
{
DecisionList merged = new DecisionList(positive, negative);
foreach (DLTest test in tests)
{
merged.add(test, testOutcomes[test]);
}
foreach (DLTest test in dlist2.tests)
{
merged.add(test, dlist2.testOutcomes[test]);
}
return merged;
}
public DecisionList mergeWith(DecisionList dlist2)
{
DecisionList merged = new DecisionList(positive, negative);
foreach (DLTest test in tests)
{
merged.add(test, testOutcomes[test]);
}
foreach (DLTest test in dlist2.tests)
{
merged.add(test, dlist2.testOutcomes[test]);
}
return(merged);
}
public void testDecisionListFallsThruToDefaultIfNoTestMatches()
{
DecisionList dlist = new DecisionList("Yes", "No");
DataSet ds = DataSetFactory.getRestaurantDataSet();
DLTest test1 = new DLTest();
test1.add("type", "Thai"); // doesn't match first example
dlist.add(test1, "test1success");
DLTest test2 = new DLTest();
test2.add("type", "Burger");
dlist.add(test2, "test2success");// doesn't match first example
Assert.AreEqual("No", dlist.predict(ds.getExample(0)));
}
public void testDecisionListMerge()
{
DecisionList dlist1 = new DecisionList("Yes", "No");
DecisionList dlist2 = new DecisionList("Yes", "No");
DataSet ds = DataSetFactory.getRestaurantDataSet();
DLTest test1 = new DLTest();
test1.add("type", "Thai"); // doesn't match first example
dlist1.add(test1, "test1success");
DLTest test2 = new DLTest();
test2.add("type", "French");
dlist2.add(test2, "test2success");// matches first example
DecisionList dlist3 = dlist1.mergeWith(dlist2);
Assert.AreEqual("test2success", dlist3.predict(ds.getExample(0)));
}
//
// PRIVATE METHODS
//
private DecisionList decisionListLearning(DataSet ds)
{
if (ds.size() == 0)
{
return new DecisionList(positive, negative);
}
List<DLTest> possibleTests = testFactory
.createDLTestsWithAttributeCount(ds, 1);
DLTest test = getValidTest(possibleTests, ds);
if (test == null)
{
return new DecisionList(null, FAILURE);
}
// at this point there is a test that classifies some subset of examples
// with the same target value
DataSet matched = test.matchedExamples(ds);
DecisionList list = new DecisionList(positive, negative);
list.add(test, matched.getExample(0).targetValue());
return list.mergeWith(decisionListLearning(test.unmatchedExamples(ds)));
}
public void testDecisonListWithNoTestsReturnsDefaultValue()
{
DecisionList dlist = new DecisionList("Yes", "No");
DataSet ds = DataSetFactory.getRestaurantDataSet();
Assert.AreEqual("No", dlist.predict(ds.getExample(0)));
}
public void train(DataSet ds)
{
this.decisionList = decisionListLearning(ds);
}
