/// <summary>
/// Desify DataContainer by making sure that each user has at least k items and each item has at least k users
/// </summary>
/// <param name="k"></param>
public void Densify(int k)
{
int removedBasedOnUser, removedBasedOnItem;
int i = 1;
Logger.Current.Info("Densify with min feedback {0}...", k);
Logger.Current.Trace(ToString());
do
{
Logger.Current.Trace("Iteration {0}: ", i);
var toRemove = Feedbacks.GroupBy(f => f.User).Where(g => g.Count() < k)
.SelectMany(g => g);
removedBasedOnUser = 0;
foreach (Feedback f in toRemove)
{
RemoveFeedback(f);
removedBasedOnUser++;
}
Logger.Current.Trace("Removed {0} (user-based)", removedBasedOnUser);
Logger.Current.Trace(ToString());
toRemove = Feedbacks.GroupBy(f => f.Item).Where(g => g.Count() < k)
.SelectMany(g => g);
removedBasedOnItem = 0;
foreach (Feedback f in toRemove)
{
RemoveFeedback(f);
removedBasedOnItem++;
}
Logger.Current.Trace("Removed {0} (item-based)", removedBasedOnItem);
Logger.Current.Trace(ToString() + "\n");
i++;
}while (removedBasedOnUser > 0 || removedBasedOnItem > 0);
Logger.Current.Info("Densify complete with min feedback {0}", k);
}
