public UserNeighbourhood GetUserNeighbourhood(int userId)
{
UserNeighbourhood userNeighbourhood = db.UserNeighbourhoods.Find(userId);
if (userNeighbourhood == null)
{
throw new MissingMemberException();
}
return(userNeighbourhood);
}
private void predictUserPreference(int userID, UserActivityList userprofile, ref List <Activities> prediction_u_i)
{
UserNeighbourhood neighbours = unc.GetUserNeighbourhood(userID);
var similarity = neighbours.similiarity.Split(';').Select(double.Parse).ToList();
var neighbour = neighbours.neighbours.Split(';').Select(int.Parse).ToList();
List <string> allActivities = uac.GetAllActivities();
double averageUserProfile = userprofile.Activities.Sum(x => x.Rating) / userprofile.Activities.Count;
userprofile.Activities.ForEach(x => allActivities.Remove(x.Activity));
foreach (var activity in allActivities)
{
double top = 0;
double bottom = 0;
double rating = 0.0;
for (var i = 0; i < neighbour.Count; i++)
{
if (neighbour[i] != userID)
{
var neighbourProfile = uac.GetUsersActivityList(neighbour[i]);
double avgNProfile = neighbourProfile.Activities.Sum(x => x.Rating) / neighbourProfile.Activities.Count;
double ratingItemNeighbour = 0.0;
if (neighbourProfile.Activities.Exists(x => x.Activity == activity))
{
ratingItemNeighbour = neighbourProfile.Activities.First(x => x.Activity == activity).Rating;
}
top = top + (similarity[i] * (ratingItemNeighbour - avgNProfile));
bottom = bottom + Math.Abs(similarity[i]);
}
}
if (bottom == 0)
{
rating = averageUserProfile;
}
else
{
rating = averageUserProfile + (top / bottom);
}
prediction_u_i.Add(new Activities(activity, rating));
}
}
public void AddUserNeighbourhood(int userId, List <int> neighbours, List <double> similarity)
{
UserNeighbourhood row = db.UserNeighbourhoods.Find(userId);
if (row == null)
{
UserNeighbourhood un = new UserNeighbourhood {
userId = userId, neighbours = string.Join(";", neighbours), similiarity = string.Join(";", similarity)
};
db.UserNeighbourhoods.Add(un);
}
else
{
row.neighbours = string.Join(";", neighbours);
}
row.similiarity = string.Join(";", similarity);
db.SaveChanges();
}
