/// <summary>
/// Assumes that higher (or equal) to calculated score compared to threshold will give higher trueScore
/// calculatedScore and true Score, both are of the same size
/// </summary>
/// <param name="calculatedScore"></param>
/// <param name="trueScore"></param>
/// <param name="stepSize"></param>
/// <returns></returns>
public static OptimumBinClassRetType CalculateOptimumBinClassificationAndAccuracy(List <double> calculatedScore, List <int> trueScore, double stepSize)
{
OptimumBinClassRetType optimumBinClassRetType = new OptimumBinClassRetType(Double.MinValue, 0.0);
double min = (from c in calculatedScore select c).Min();
double max = (from c in calculatedScore select c).Max();
int hit, maxHit = int.MinValue;
for (double d = min; d <= max; d += stepSize)
{
hit = 0;
for (int i = 0; i < calculatedScore.Count; i++)//traverse all calculatedScore elements. It might not be sorted
{
if (calculatedScore[i] >= d)
{
hit += trueScore[i] == 1 ? 1 : 0;//above partition. If truescore is 1, it a hit.
}
else
{
hit += trueScore[i] == 0 ? 1 : 0;
}
}
//compare and update if applicable
if (hit > maxHit)
{
maxHit = hit;
optimumBinClassRetType.optimumPoint = d;
}
}
optimumBinClassRetType.accuracyPercentage = ((double)maxHit / calculatedScore.Count);
return(optimumBinClassRetType);
}
private void button1_Click(object sender, EventArgs e)
{
double stepSize = 1.0;
txtBxOutput.AppendText("\nBegin binary classification optimisation with step size " + stepSize + "\n");
double [] x = new double[] { 8, 7, 6, 5.5, 5.5, 5, 5, 4, 2, 1 };
int [] y = new int[] { 1, 1, 1, 0, 0, 1, 1, 0, 0, 0 };
txtBxOutput.AppendText("\nThe calculated score is:\n");
txtBxOutput.AppendText(Utility.getArrayMemberAsString(x));
txtBxOutput.AppendText("\nThe trueRisk/binary result is:\n");
txtBxOutput.AppendText(Utility.getArrayMemberAsString(y));
DataMining.OptimumBinClassRetType opbc = DataMining.BasicDBMining.CalculateOptimumBinClassificationAndAccuracy(x.ToList(), y.ToList(), stepSize);
txtBxOutput.AppendText("\n\nThreshold " + opbc.optimumPoint + ". Accuracy: " + opbc.accuracyPercentage);
}
