public Tuple <string, double> findBestSplitNumerical()
{
sortTable();
ClassCounter allTable = new ClassCounter(this);
string splitValue = attributes[0].getValueAsString();
double bestGini = 999;
double currentGini;
int j = 0;
for (int i = 0; i < attributes.Count - 1; i++)
{
if (!attributes[i].getValueAsString().Equals(attributes[i + 1].getValueAsString()))
{
var tuple = splitTableNumerical(i + 1);
currentGini = rateSplit(tuple.Item1, tuple.Item2, allTable);
if (currentGini < bestGini)
{
bestGini = currentGini;
splitValue = attributes[i].getValueAsString();
j = i;
}
}
}
bestGini = (attributes[j].getValueAsDouble() + attributes[j + 1].getValueAsDouble()) / 2;
Tuple <string, double> toReturn = new Tuple <string, double>(splitValue, bestGini);
return(toReturn);
}
private double rateSplit(AttributeTable first, AttributeTable second, ClassCounter allTable)
{
ClassCounter firstCounter = new ClassCounter(first);
ClassCounter secondCounter = new ClassCounter(second);
return(firstCounter.calculateGiniSplit(allTable) + secondCounter.calculateGiniSplit(allTable));
}
public double calculateGiniSplit(ClassCounter globalTable)
{
double nominator = (double)counters.Sum();
double denominator = (double)globalTable.counters.Sum();
return(calculateGini() * nominator / denominator);
}