private static double[,] GetNearestNeighborMatrix <T>(List <Group> groups) where T : VectorSimilarity
{
double[,] nearestNeighborGroupMatrix = new double[groups.Count, groups.Count];
foreach (Group groupA in groups)
{
foreach (Article articleA in groupA.Articles)
{
Article nearestNeighbor = null;
Group nearestNeighborGroup = null;
double maxSimilarity = double.MinValue;
foreach (Group groupB in groups.Where(g => g.Id != groupA.Id))
{
foreach (Article articleB in groupB.Articles)
{
VectorSimilarity vs = Activator.CreateInstance <T>();
double similarity = vs.GetSimilarity(articleA, articleB);
if (similarity > maxSimilarity)
{
maxSimilarity = similarity;
nearestNeighbor = articleB;
nearestNeighborGroup = groupB;
}
}
}
articleA.NearestNeighbor = nearestNeighbor;
nearestNeighborGroupMatrix[groupA.Id - 1, nearestNeighborGroup.Id - 1] += 1;
}
}
return(nearestNeighborGroupMatrix);
}
private static List <double> CompareArticles <T>(int articleId, List <Group> groups) where T : VectorSimilarity
{
List <Article> articles = new List <Article>(groups.SelectMany(g => g.Articles));
Article pivot = articles.Where(a => a.Id == articleId).Single();
List <double> similarities = new List <double>(articles.Count);
foreach (Article article in articles)
{
VectorSimilarity vs = Activator.CreateInstance <T>();
similarities.Add(vs.GetSimilarity(article, pivot));
}
return(similarities);
}
private static double CompareGroups(Group a, Group b, Type similarityMethodType)
{
int combinations = 0;
double accumulator = 0;
foreach (Article articleInA in a.Articles)
{
foreach (Article articleInB in b.Articles)
{
VectorSimilarity similarityMethod = (VectorSimilarity)Activator.CreateInstance(similarityMethodType);
accumulator += similarityMethod.GetSimilarity(articleInA, articleInB);
combinations++;
}
}
return(accumulator / combinations);
}