/// <summary>
/// Self-evident.
/// </summary>
/// <param name="vals"></param>
/// <param name="labels"></param>
/// <returns></returns>
public static AnnotatedScore[] Populate(double[] vals, float[] labels)
{
AnnotatedScore[] annScores = new AnnotatedScore[vals.Length];
for (int i=0; i<vals.Length; ++i)
{
annScores[i] = new AnnotatedScore(vals[i], labels[i], i);
}
return annScores;
}
public static void DeepCopy(AnnotatedScore[] asIn, AnnotatedScore[] asOut)
{
if(asIn.Length != asOut.Length) throw new Exception("AnnotatedScore: DeepCopy: size mismatch");
for(int i=0; i<asIn.Length; ++i)
{
asOut[i].score = asIn[i].score;
asOut[i].label = asIn[i].label;
asOut[i].srcIdx = asIn[i].srcIdx;
}
}
/// <summary>
/// WARNING: For speed, it is assumed that we can sort the scores and labels in place. Creating scratch space for this in the static
/// constructor won't work with threading, and creating scratch space in the other constructor is very expensive, since may be called
/// often. It is left to the user to make copies beforehand if necessary.
/// </Summary>
/// <param name="scores"></param>
/// <param name="labels"></param>
/// <param name="truncNDCG"></param>
/// <param name="nonTruncNDCG"></param>
public void ComputeDCGs(bool pessimistic, double[] scores, float[] labels, out double truncDCG, out double nonTruncDCG)
{
Debug.Assert(scores.Length == labels.Length, "scores, labels length mismatch");
AnnotatedScore[] annScores = new AnnotatedScore[scores.Length];
for(int i = 0; i < annScores.Length; ++i)
{
annScores[i] = new AnnotatedScore(scores[i], labels[i]);
}
ComputeDCGs(pessimistic, annScores, out truncDCG, out nonTruncDCG);
}
/// <summary>
/// If a bunch of urls have the same score, the mean NDCG for that bunch is the mean gain, times the total markup.
/// Best to call this after ComputeOptimisticDCGs, since then the sorted order will be the same. Note that handling
/// the truncated NDCG is tricky: if a block of urls with equal score, overlaps the truncation level, then you still
/// have to compute the mean gain over the full block, and split the result to get the contribution to the truncated NDCG.
/// </summary>
/// <param name="annScores"></param>
/// <param name="meanTruncDCG"></param>
/// <param name="meanNonTruncDCG"></param>
public void ComputeMeanDCGs(AnnotatedScore[] annScores, out double meanTruncDCG, out double meanNonTruncDCG)
{
Array.Sort(annScores, new OptimisticAnnotatedScoreComparer());
meanTruncDCG = 0.0;
meanNonTruncDCG = 0.0;
double score;
double lastScore = annScores[0].score;
double samePatchCtr = 0.0;
double gain = 0.0;
double markupTrunc = 0.0;
double markupNonTrunc = 0.0;
double deltaDCG;
int truncLevel = DCGScorer.truncLevel < annScores.Length ? DCGScorer.truncLevel : annScores.Length;
for (int rank = 0; rank < truncLevel; ++rank)
{
score = annScores[rank].score;
if (score != lastScore)
{
deltaDCG = ( gain / samePatchCtr ) * markupTrunc;
meanTruncDCG += deltaDCG;
meanNonTruncDCG += deltaDCG;
samePatchCtr = 1.0;
gain = 0.0;
markupTrunc = 0.0;
lastScore = score;
}
else
{
++samePatchCtr;
}
markupTrunc += DCGScorer.discounts[rank];
gain += DCGScorer.scoresMap[(int)annScores[rank].label];
}
bool doneTruncComp = false;
markupNonTrunc = markupTrunc;
for (int rank = truncLevel; rank < annScores.Length; ++rank)
{
score = annScores[rank].score;
if (score != lastScore)
{
if(!doneTruncComp)
{
meanTruncDCG += ( gain / samePatchCtr ) * markupTrunc;
doneTruncComp = true;
}
meanNonTruncDCG += ( gain / samePatchCtr ) * markupNonTrunc;
samePatchCtr = 1.0;
gain = 0.0;
markupNonTrunc = 0.0;
lastScore = score;
}
else
{
++samePatchCtr;
}
markupNonTrunc += DCGScorer.discounts[rank];
gain += DCGScorer.scoresMap[(int)annScores[rank].label];
}
if(!doneTruncComp)
{
meanTruncDCG += ( gain / samePatchCtr ) * markupTrunc;
}
meanNonTruncDCG += ( gain / samePatchCtr ) * markupNonTrunc;
}
public void ComputeDCGs(bool pessimistic, AnnotatedScore[] annScores, out double truncDCG, out double nonTruncDCG)
{
if (pessimistic)
Array.Sort(annScores, new PessimisticAnnotatedScoreComparer());
else
Array.Sort(annScores, new OptimisticAnnotatedScoreComparer());
truncDCG = 0.0;
nonTruncDCG = 0.0;
for (int rank = 0; rank < annScores.Length; ++rank)
{
double markup = DCGScorer.discounts[rank];
double gain = DCGScorer.scoresMap[(int)annScores[rank].label];
if (rank < DCGScorer.truncLevel)
{
truncDCG += markup * gain;
}
nonTruncDCG += markup * gain;
}
}
