public void GiniImpurityMetric_Impurity()
{
var set1 = new double[] { 0, 1, 2, 3, 4, 3, 2, 1, 0 };
var set2 = new double[] { 1, 1, 1, 1, 2, 2, 2, 2 };
var set3 = new double[] { 1, 1, 1, 1, 1, 1, 1, 1 };
var sut = new GiniImpurityMetric();
var val1 = sut.Impurity(set1);
Assert.AreEqual(0.79012345679012341, val1);
var val2 = sut.Impurity(set2);
Assert.AreEqual(0.5, val2);
var val3 = sut.Impurity(set3);
Assert.AreEqual(0.0, val3);
}
public void GiniImpurityMetric_Impurity_Weights()
{
var set1 = new double[] { 0, 1, 2, 3, 4, 3, 2, 1, 0 };
var set2 = new double[] { 1, 1, 1, 1, 2, 2, 2, 2 };
var set3 = new double[] { 1, 1, 1, 1, 1, 1, 1, 1 };
var weights = new double[] { 3, 1, 4, 1, 0.5, 1, 2, 1, 10 };
var sut = new GiniImpurityMetric();
var val1 = sut.Impurity(set1, weights, Interval1D.Create(0, set1.Length));
Assert.AreEqual(0.96921684019918519, val1);
var val2 = sut.Impurity(set2, weights, Interval1D.Create(0, set2.Length));
Assert.AreEqual(0.82441700960219477, val2);
var val3 = sut.Impurity(set3, weights, Interval1D.Create(0, set3.Length));
Assert.AreEqual(0.64883401920438954, val3);
}
public void GiniImpurityMetric_Impurity_Weights_None()
{
var set1 = new double[] { 0, 1, 2, 3, 4, 3, 2, 1, 0 };
var set2 = new double[] { 1, 1, 1, 1, 2, 2, 2, 2 };
var set3 = new double[] { 1, 1, 1, 1, 1, 1, 1, 1 };
var weights = new double[] { 1, 1, 1, 1, 1, 1, 1, 1, 1 };
var sut = new GiniImpurityMetric();
var val1 = sut.Impurity(set1, weights, Interval1D.Create(0, set1.Length));
Assert.AreEqual(0.79012345679012341, val1);
var val2 = sut.Impurity(set2, weights, Interval1D.Create(0, set2.Length));
Assert.AreEqual(0.5, val2);
var val3 = sut.Impurity(set3, weights, Interval1D.Create(0, set3.Length));
Assert.AreEqual(0.0, val3);
}
public void GiniImpurityMetric_Impurity_Interval()
{
var set1 = new double[] { 0, 1, 2, 3, 4, 3, 2, 1, 0 };
var set2 = new double[] { 1, 1, 1, 1, 2, 2, 2, 2 };
var set3 = new double[] { 1, 1, 1, 1, 1, 1, 1, 1 };
var sut = new GiniImpurityMetric();
var interval = Interval1D.Create(2, 7);
var val1 = sut.Impurity(set1, interval);
Assert.AreEqual(0.64, val1);
var val2 = sut.Impurity(set2, interval);
Assert.AreEqual(0.48, val2);
var val3 = sut.Impurity(set3, interval);
Assert.AreEqual(0.0, val3);
}