/// <summary>
/// Gets similarity of two strings using the most common synset for given string/pos pairs
/// </summary>
/// <param name="string1">First string</param>
/// <param name="pos1">First POS</param>
/// <param name="pos2">Second POS</param>
/// <param name="string2">Second string</param>
/// <param name="strategy">Similarity strategy to use</param>
/// <param name="relations">Relations to use when computing similarity</param>
/// <returns>Similarity</returns>
public float GetSimilarity(string string1, WordNetEngine.POS pos1, string string2, WordNetEngine.POS pos2, Strategy strategy, params WordNetEngine.SynSetRelation[] relations)
{
float similarity = 0;
if (strategy == Strategy.WuPalmer1994Average)
{
// get average similarity across all synsets
int numScores = 0;
foreach (SynSet synset1 in _wordNetEngine.GetSynSets(string1, pos1))
{
foreach (SynSet synset2 in _wordNetEngine.GetSynSets(string2, pos2))
{
similarity += GetSimilarity(synset1, synset2, strategy, relations);
++numScores;
}
}
if (numScores > 0)
{
similarity = similarity / (float)numScores;
}
}
else if (strategy == Strategy.WuPalmer1994Maximum)
{
// get maximum similarity across all synsets
foreach (SynSet synset1 in _wordNetEngine.GetSynSets(string1, pos1))
{
foreach (SynSet synset2 in _wordNetEngine.GetSynSets(string2, pos2))
{
float currSim = GetSimilarity(synset1, synset2, strategy, relations);
if (currSim > similarity)
{
similarity = currSim;
}
}
}
}
else if (strategy == Strategy.WuPalmer1994Minimum)
{
// get minimum similarity across all synsets
similarity = -1;
foreach (SynSet synset1 in _wordNetEngine.GetSynSets(string1, pos1))
{
foreach (SynSet synset2 in _wordNetEngine.GetSynSets(string2, pos2))
{
float currSim = GetSimilarity(synset1, synset2, strategy, relations);
if (similarity == -1 || currSim < similarity)
{
similarity = currSim;
}
}
}
// if we didn't find any synsets, similarity is zero
if (similarity == -1)
{
similarity = 0;
}
}
else if (strategy == Strategy.WuPalmer1994MostCommon)
{
// use most common synsets
SynSet synset1 = _wordNetEngine.GetMostCommonSynSet(string1, pos1);
SynSet synset2 = _wordNetEngine.GetMostCommonSynSet(string2, pos2);
if (synset1 != null && synset2 != null)
{
similarity = GetSimilarity(synset1, synset2, strategy, relations);
}
}
else
{
throw new NotImplementedException("Unimplemented strategy: " + strategy);
}
if (similarity < 0 || similarity > 1)
{
throw new Exception("Invalid similarity: " + similarity);
}
return(similarity);
}
