public void PlayGolfExample()
{
//http://www.saedsayad.com/decision_tree.htm
var outlook = new int[] { 0, 0, 1, 2, 2, 2, 1, 0, 0, 2, 0, 1, 1, 2 };
var temp = new int[] { 0, 0, 0, 1, 2, 2, 2, 1, 2, 1, 1, 1, 0, 1 };
var humidity = new int[] { 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0 };
var wind = new int[] { 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1 };
var output = new int[] { 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0 };
DecisionTreeLearning <int> dtl = DecisionTreeLearning <int> .Create <int>(x => output[x], new DecisionTreeOptions()
{
MaxDepth = 3,
});
var outlookStrs = new string[] { "Rainy", "Overcast", "Sunny" };
dtl.AddDiscreteFeature <string>("outlook", a => outlookStrs[outlook[a]]);
var tempStrs = new string[] { "Hot", "Mild", "Cool" };
dtl.AddDiscreteFeature <string>("temp", a => tempStrs[temp[a]]);
dtl.AddDiscreteFeature <int>("humidity", a => humidity[a]);
dtl.AddDiscreteFeature <int>("wind", a => wind[a]);
var dt = dtl.Learn(Enumerable.Range(0, output.Length));
Assert.AreEqual(dt.Feature.Name, "outlook");
Assert.AreEqual(dt.ChildNodes.First(x => (x.Key as DiscreteFeatureValue).Value.ToString() == "Rainy").Value.Feature.Name, "humidity");
Assert.AreEqual(dt.ChildNodes.First(x => (x.Key as DiscreteFeatureValue).Value.ToString() == "Sunny").Value.Feature.Name, "wind");
Assert.IsNull(dt.ChildNodes.First(x => (x.Key as DiscreteFeatureValue).Value.ToString() == "Overcast").Value.Feature, "Overcast node should be leaf");
Assert.AreEqual(dt.GetOutput(0), 0);
Assert.AreEqual(dt.GetOutput(2), 1);
}
public void ContiniousFeatureTest()
{
var data = Enumerable.Range(0, 1000).Select(x => new PatientRecord()).ToArray();
var dt = DecisionTreeLearning <PatientRecord> .Create <int>(x => x.Cancer? 1 : 0, new DecisionTreeOptions());
dt.AddContiniousFeature("Age", x => x.Age);
dt.AddContiniousFeature("Height", x => x.Height);
dt.AddContiniousFeature("Weight", x => x.Weight);
dt.AddDiscreteFeature("Smoke", x => x.Smoke ? 1 : 0);
var node = dt.Learn(data);
Assert.AreEqual(node.Feature.Name, "Smoke");
}