private List <ProductRating> GetNearestNeighbors(ObjectId productId, int numProducts)
{
List <ProductRating> neighbors = new List <ProductRating>();
int mainProductIndex = ratings.ProductIndexToID.IndexOf(productId);
for (int productIndex = 0; productIndex < ratings.ProductIndexToID.Count; productIndex++)
{
ObjectId searchProductId = ratings.ProductIndexToID[productIndex];
if (productIndex != mainProductIndex)
{
double score = comparer.CompareVectors(transposedRatings[mainProductIndex], transposedRatings[productIndex]);
neighbors.Add(new ProductRating(searchProductId, score));
}
else
{
double score = double.NegativeInfinity;
neighbors.Add(new ProductRating(searchProductId, score));
}
}
neighbors.Sort((c, n) => n.Rating.CompareTo(c.Rating));
return(neighbors.Take(numProducts).ToList());
}
private List <ArticleRating> GetNearestNeighbors(int articleId, int numArticles)
{
List <ArticleRating> neighbors = new List <ArticleRating>();
int mainArticleIndex = ratings.ArticleIndexToID.IndexOf(articleId);
for (int articleIndex = 0; articleIndex < ratings.ArticleIndexToID.Count; articleIndex++)
{
int searchArticleId = ratings.ArticleIndexToID[articleIndex];
double score = comparer.CompareVectors(transposedRatings[mainArticleIndex], transposedRatings[articleIndex]);
neighbors.Add(new ArticleRating(searchArticleId, score));
}
neighbors.Sort((c, n) => n.Rating.CompareTo(c.Rating));
return(neighbors.Take(numArticles).ToList());
}
private List <MenuRating> GetNearestNeighbors(int menuId, int numOfMenus)
{
List <MenuRating> neighbors = new List <MenuRating>();
int mainMenuIndex = ratings.MenuIndexToId.IndexOf(menuId);
for (int menuIndex = 0; menuIndex < ratings.MenuIndexToId.Count; menuIndex++)
{
long searchMenuId = ratings.MenuIndexToId[menuIndex];
double score = comparer.CompareVectors(transposedRatings[mainMenuIndex], transposedRatings[menuIndex]);
neighbors.Add(new MenuRating(searchMenuId, score));
}
neighbors.Sort((c, n) => n.Rating.CompareTo(c.Rating));
return(neighbors.Take(numOfMenus).ToList());
}
private List <UserArticleRatings> GetNearestNeighbors(UserArticleRatings user, int numUsers)
{
List <UserArticleRatings> neighbors = new List <UserArticleRatings>();
for (int i = 0; i < ratings.Users.Count; i++)
{
if (ratings.Users[i].UserID == user.UserID)
{
ratings.Users[i].Score = double.NegativeInfinity;
}
else
{
ratings.Users[i].Score = comparer.CompareVectors(ratings.Users[i].ArticleRatings, user.ArticleRatings);
}
}
var similarUsers = ratings.Users.OrderByDescending(x => x.Score);
return(similarUsers.Take(numUsers).ToList());
}