public async Task <RelevancyScoreResult <T> > ScoreAsync <T>(
SearchQueryRelevancyScores <T> query,
string baseUrl,
int resultsToEvaluate)
{
var response = await _searchClient.SearchAsync(
baseUrl,
query.SearchQuery,
resultsToEvaluate);
if (!query.PackageIdToScore.Any() || query.PackageIdToScore.Max(x => x.Value) == 0)
{
return(new RelevancyScoreResult <T>(
0,
query,
response));
}
var patternToScorePairs = new List <KeyValuePair <Regex, int> >();
foreach (var pair in query.PackageIdToScore.Where(x => x.Value > 0))
{
if (WildcardUtility.IsWildcard(pair.Key))
{
patternToScorePairs.Add(new KeyValuePair <Regex, int>(
WildcardUtility.GetPackageIdWildcareRegex(pair.Key),
pair.Value));
}
}
// Determine the score for each of the returns package IDs.
var scores = new List <int>();
for (var i = 0; i < response.Data.Count; i++)
{
var packageId = response.Data[i].Id;
if (query.PackageIdToScore.TryGetValue(packageId, out var score))
{
scores.Add(score);
}
else
{
// It might be that the score map contains wildcards. Let's try those. Execute them from longest to
// shortest. This is a hueristic to perform the most specific ones first.
var match = false;
foreach (var pair in patternToScorePairs.OrderByDescending(x => x.Key.ToString().Length))
{
if (pair.Key.IsMatch(packageId))
{
scores.Add(pair.Value);
patternToScorePairs.Remove(pair);
match = true;
break;
}
}
if (match)
{
continue;
}
scores.Add(0);
}
}
// Determine the ideal scores by taking the top N scores.
var idealScores = query
.PackageIdToScore
.Select(x => x.Value)
.OrderByDescending(x => x)
.Take(resultsToEvaluate);
// Calculate the NDCG.
var resultScore = NDCG(scores, idealScores);
if (resultScore > 1.0)
{
throw new InvalidOperationException("An NDCG score cannot be greater than 1.0. There's a bug!");
}
return(new RelevancyScoreResult <T>(
resultScore,
query,
response));
}
