/// <summary>
/// Gets the similarity.
/// </summary>
/// <param name="patternTokens">The pattern tokens.</param>
/// <param name="targetTokens">The target tokens.</param>
/// <returns></returns>
public double GetSimilarity(string[] patternTokens, string[] targetTokens)
{
var patternWeights = Vocabulary.GetSemanticWeight(patternTokens);
var targetWeights = Vocabulary.GetSemanticWeight(targetTokens);
SimMetric simMetric = SimHelpers.GetSimMetric(InternalTokenSimilarity);
// unit vectorizing
Utils.UnitVectorizing(patternWeights);
Utils.UnitVectorizing(targetWeights);
double finalScore = 0;
for (int p = 0; p < patternTokens.Length; p++)
{
var pattern = patternTokens[p];
if (pattern == null)
{
continue;
}
double maxOverToken = SimHelpers.MinimumScore;
double weightOverToken = 0;
for (int t = 0; t < targetTokens.Length; t++)
{
var target = targetTokens[t];
if (target == null)
{
continue;
}
double currentScore = simMetric(pattern, target);
if (currentScore > DefaultThreshold && currentScore > maxOverToken)
{
maxOverToken = currentScore;
weightOverToken = patternWeights[p] * targetWeights[t];
}
// if score achieves maximum score then breaks the loop and increases the performance
if (Utils.Equals(currentScore, SimHelpers.MaximumScore))
{
break;
}
}
finalScore += weightOverToken * maxOverToken;
}
return(finalScore);
}
/// <summary>
/// Gets the similarity.
/// </summary>
/// <param name="patternTokens">The tokens pattern.</param>
/// <param name="targetTokens">The tokens target.</param>
/// <returns>System.Double.</returns>
public double GetSimilarity(string[] patternTokens, string[] targetTokens)
{
int m = patternTokens.Length;
int n = targetTokens.Length;
SimMetric refSimilarity = SimHelpers.GetSimMetric(InternalTokenSimilarity);
// re-calculate similarity symmetric vs. not symmetric
if (IsSymmetric && m > n)
{
Utils.Swap(ref patternTokens, ref targetTokens);
Utils.Swap(ref m, ref n);
}
double sumOverTokens = 0;
foreach (var pattern in patternTokens)
{
if (pattern == null)
{
continue;
}
double maxOverToken = 0;
foreach (var target in targetTokens)
{
if (target == null)
{
continue;
}
double currentScore = refSimilarity(pattern, target);
// if score achieves maximum score then breaks the loop and increases the performance
if (Utils.Equals(currentScore, SimHelpers.MaximumScore))
{
maxOverToken = SimHelpers.MaximumScore;
break;
}
maxOverToken = Math.Max(maxOverToken, currentScore);
}
sumOverTokens += maxOverToken;
}
return(sumOverTokens / m);
}
/// <summary>
/// Gets the semantic similarity between array of tokens. The position of token in array
/// doesn't have an impact on resulting score.
/// </summary>
/// <param name="tokensPattern">The tokens pattern</param>
/// <param name="tokensTarget">The tokens target.</param>
/// <returns>the score between 0 and 1</returns>
public double GetSimilarity(string[] tokensPattern, string[] tokensTarget)
{
var patternWeights = Vocabulary.GetSemanticWeight(tokensPattern);
var targetWeights = Vocabulary.GetSemanticWeight(tokensTarget);
SimMetric simMetric = SimHelpers.GetSimMetric(InternalTokenSimilarity);
int pLen = tokensPattern.Length;
int tLen = tokensTarget.Length;
// re-calculate similarity symmetric vs. not symmetric
if (IsSymmetric && pLen > tLen)
{
Utils.Swap(ref tokensPattern, ref tokensTarget);
Utils.Swap(ref patternWeights, ref targetWeights);
Utils.Swap(ref pLen, ref tLen);
}
double sumOverTokens = 0;
double sumWeights = 0;
for (int p = 0; p < tokensPattern.Length; p++)
{
string pattern = tokensPattern[p];
double pWeight = patternWeights[p];
if (pattern == null)
{
continue;
}
double maxOverToken = SimHelpers.MinimumScore;
double weightOverToken = Math.Pow(pWeight, 2.0);
for (int t = 0; t < tokensTarget.Length; p++)
{
string target = tokensTarget[t];
double tWeight = targetWeights[t];
if (target == null)
{
continue;
}
double currentScore = simMetric(pattern, target);
if (currentScore > maxOverToken)
{
maxOverToken = currentScore;
weightOverToken = pWeight * tWeight;
}
// if score achieves maximum score then breaks the loop and increases the performance
if (Utils.Equals(currentScore, SimHelpers.MaximumScore))
{
break;
}
}
sumOverTokens += weightOverToken * maxOverToken;
sumWeights += weightOverToken;
}
return(sumOverTokens / sumWeights);
}
