/// <summary>
/// Constructs a WinLoss calculator
/// </summary>
/// <param name="maxDocsPerQuery">the maximum number of documents per query</param>
/// <param name="sortingAlgorithm">a string describing the sorting algorithm to use</param>
public WinLossCalculator(int maxDocsPerQuery, string sortingAlgorithm)
{
int numThreads = BlockingThreadPool.NumThreads;
_oneTwoThree = Utils.GetIdentityPermutation(maxDocsPerQuery);
_permutationBuffers = new int[numThreads][];
for (int i = 0; i < numThreads; ++i)
{
_permutationBuffers[i] = new int[maxDocsPerQuery];
}
_scoreBuffers = new double[numThreads][];
for (int i = 0; i < numThreads; ++i)
{
_scoreBuffers[i] = new double[maxDocsPerQuery];
}
_comparers = new DcgPermutationComparer[numThreads];
for (int i = 0; i < numThreads; ++i)
{
_comparers[i] = DcgPermutationComparerFactory.GetDcgPermutationFactory(sortingAlgorithm);
}
}
/// <summary>
/// Constructs a DCG calculator
/// </summary>
/// <param name="maxDocsPerQuery">the maximum number of documents per query</param>
/// <param name="sortingAlgorithm">a string describing the sorting algorithm to use</param>
/// <param name="topNDocsForIdealDcg">specifies the ideal DCG@ computation.</param>
public DcgCalculator(int maxDocsPerQuery, string sortingAlgorithm, int topNDocsForIdealDcg = 0)
{
int numThreads = BlockingThreadPool.NumThreads;
_oneTwoThree = Utils.GetIdentityPermutation(maxDocsPerQuery);
_permutationBuffers = new int[numThreads][];
for (int i = 0; i < numThreads; ++i)
{
_permutationBuffers[i] = new int[maxDocsPerQuery];
}
_scoreBuffers = new double[numThreads][];
for (int i = 0; i < numThreads; ++i)
{
_scoreBuffers[i] = new double[maxDocsPerQuery];
}
_comparers = new DcgPermutationComparer[numThreads];
for (int i = 0; i < numThreads; ++i)
{
_comparers[i] = DcgPermutationComparerFactory.GetDcgPermutationFactory(sortingAlgorithm);
// only reorder query/URL pairs, if we have at least two query/URL pairs for reordering
if (topNDocsForIdealDcg > 1)
{
// using lazy initialize for the _secondLevelComparers to make it cheap and easy
// later to test, if re-ordering needs to be computed. This way it also only allocates
// the memory it really needs
if (_secondLevelcomparers == null)
{
_secondLevelcomparers = new DescendingStableIdealComparer[numThreads];
}
_secondLevelcomparers[i] = new DescendingStableIdealComparer(topNDocsForIdealDcg);
}
}
}