/// <inheritdoc/>
protected override double GetLogNormalizerOfProduct(StringDictionaryWeightFunction weightFunction)
{
var dict1 = (SortedList <string, Weight>)Dictionary;
var dict2 = (SortedList <string, Weight>)weightFunction.Dictionary;
Weight normalizer = Weight.Zero;
int idx1 = 0, idx2 = 0;
while (idx1 < dict1.Count && idx2 < dict2.Count)
{
int comparisonResult = string.CompareOrdinal(dict1.Keys[idx1], dict2.Keys[idx2]);
if (comparisonResult < 0)
{
++idx1;
}
else if (comparisonResult > 0)
{
++idx2;
}
else
{
normalizer += dict1.Values[idx1] * dict2.Values[idx2];
++idx1;
++idx2;
}
}
return(normalizer.LogValue);
}
/// <inheritdoc/>
public override StringDictionaryWeightFunction Product(StringDictionaryWeightFunction weightFunction)
{
var dict1 = (SortedList <string, Weight>)Dictionary;
var dict2 = (SortedList <string, Weight>)weightFunction.Dictionary;
var resultList = new SortedList <string, Weight>(Math.Min(dict1.Count, dict2.Count), StringComparer.Ordinal);
int idx1 = 0, idx2 = 0;
while (idx1 < dict1.Count && idx2 < dict2.Count)
{
int comparisonResult = string.CompareOrdinal(dict1.Keys[idx1], dict2.Keys[idx2]);
if (comparisonResult < 0)
{
++idx1;
}
else if (comparisonResult > 0)
{
++idx2;
}
else
{
resultList.Add(dict1.Keys[idx1], dict1.Values[idx1] * dict2.Values[idx2]);
++idx1;
++idx2;
}
}
resultList.TrimExcess();
return(new StringDictionaryWeightFunction(resultList));
}