/// <summary>
/// Constructs a new Receiver Operating Characteristic point.
/// </summary>
internal Point(ReceiverOperatingCharacteristic curve, double cutoff,
int truePositives, int trueNegatives, int falsePositives, int falseNegatives)
: base(truePositives, trueNegatives, falsePositives, falseNegatives)
{
this.Cutoff = cutoff;
}
/// <summary>
/// Updates the accuracy using the current results.
/// </summary>
protected virtual void UpdateAccuracy()
{
double nlpdThreshold = -Math.Log(0.001);
int labelCount = TrueLabel.First(kvp => kvp.Value != null).Value.Dimension;
var confusionMatrix = Util.ArrayInit(labelCount, labelCount, (i, j) => 0.0);
int correct = 0;
double logProb = 0.0;
int goldX = 0;
// Only for binary labels
if (Mapping.LabelCount == 2)
{
trueBinaryLabel = new List <double>();
probTrueBinaryLabel = new List <double>();
}
foreach (var kvp in GoldLabels)
{
if (kvp.Value == null)
{
continue;
}
// We have a gold label
goldX++;
Discrete trueLabel = null;
if (TrueLabel.ContainsKey(kvp.Key))
{
trueLabel = TrueLabel[kvp.Key];
}
if (trueLabel == null)
{
trueLabel = Discrete.Uniform(Mapping.LabelCount);
//continue; // No inferred label
}
var probs = trueLabel.GetProbs();
double max = probs.Max();
var predictedLabels = probs.Select((p, i) => new
{
prob = p,
idx = i
}).Where(a => a.prob == max).Select(a => a.idx).ToArray();
int predictedLabel = predictedLabels.Length == 1 ? predictedLabels[0] : predictedLabels[Rand.Int(predictedLabels.Length)];
this.PredictedLabel[kvp.Key] = predictedLabel;
int goldLabel = kvp.Value.Value;
confusionMatrix[goldLabel, predictedLabel] = confusionMatrix[goldLabel, predictedLabel] + 1.0;
var nlp = -trueLabel.GetLogProb(goldLabel);
if (nlp > nlpdThreshold)
{
nlp = nlpdThreshold;
}
logProb += nlp;
if (trueBinaryLabel != null)
{
trueBinaryLabel.Add(goldLabel);
probTrueBinaryLabel.Add(probs[goldLabel]);
}
}
Accuracy = correct / (double)goldX;
NegativeLogProb = logProb / goldX;
ModelConfusionMatrix = confusionMatrix;
// Average recall
double sumRec = 0;
for (int i = 0; i < labelCount; i++)
{
double classSum = 0;
for (int j = 0; j < labelCount; j++)
{
classSum += confusionMatrix[i, j];
}
sumRec += confusionMatrix[i, i] / classSum;
}
AvgRecall = sumRec / labelCount;
// WorkerLabelAccuracy: Perc. agreement between worker label and gold label
int sumAcc = 0;
var LabelSet = Mapping.DataWithGold;
int numLabels = LabelSet.Count();
foreach (var datum in LabelSet)
{
sumAcc += datum.WorkerLabel == datum.GoldLabel ? 1 : 0;
}
WorkerLabelAccuracy = sumAcc / (double)numLabels;
if (trueBinaryLabel != null && trueBinaryLabel.Count > 0)
{
RocCurve = new ReceiverOperatingCharacteristic(trueBinaryLabel.ToArray(), probTrueBinaryLabel.ToArray());
RocCurve.Compute(0.001);
BinaryConfusionMatrix = new ReceiverOperatingCharacteristic.ConfusionMatrix((int)confusionMatrix[1, 1], (int)confusionMatrix[0, 0], (int)confusionMatrix[0, 1], (int)confusionMatrix[1, 0]);
}
}
