public void RegressionImpurityCalculator_ImpurityImprovement()
{
var values = new double[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, };
var parentInterval = Interval1D.Create(0, values.Length);
var sut = new RegressionImpurityCalculator();
sut.Init(new double[0], values, new double[0], parentInterval);
var impurity = sut.NodeImpurity();
sut.UpdateIndex(50);
var improvement1 = sut.ImpurityImprovement(impurity);
Assert.AreEqual(75.0, improvement1, 0.000001);
sut.UpdateIndex(96);
var improvement2 = sut.ImpurityImprovement(impurity);
Assert.AreEqual(69.473379629629648, improvement2, 0.000001);
}
public void RegressionImpurityCalculator_ImpurityImprovement_Weighted()
{
var values = new double[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, };
var weights = values.Select(t => Weight(t)).ToArray();
var parentInterval = Interval1D.Create(0, values.Length);
var sut = new RegressionImpurityCalculator();
sut.Init(new double[0], values, weights, parentInterval);
var impurity = sut.NodeImpurity();
sut.UpdateIndex(50);
var improvement1 = sut.ImpurityImprovement(impurity);
Assert.AreEqual(167.04545454545456, improvement1, 0.000001);
sut.UpdateIndex(96);
var improvement2 = sut.ImpurityImprovement(impurity);
Assert.AreEqual(162.78860028860029, improvement2, 0.000001);
}