private IDictionary <int, float> Recomend(IDictionary <int, float> userRatings)
{
Dictionary <int, float> Recomendations = new Dictionary <int, float>();
foreach (var itemId in this._Items)
{
if (userRatings.Keys.Contains(itemId))
{
continue; // User has rated this item, just skip it
}
ColoborativeRating itemRating = new ColoborativeRating();
foreach (var userRating in userRatings)
{
if (userRating.Key == itemId)
{
continue;
}
int inputItemId = userRating.Key;
if (_DiffMarix.Contains(itemId, inputItemId))
{
ColoborativeRating diff = _DiffMarix[itemId, inputItemId];
itemRating.Value += diff.Freq * (userRating.Value + diff.AverageValue * ((itemId < inputItemId) ? 1 : -1));
itemRating.Freq += diff.Freq;
}
}
Recomendations.Add(itemId, itemRating.AverageValue);
}
return(Recomendations);
}
private void AddRatings(IDictionary <int, float> filterRatings)
{
foreach (var item1 in filterRatings)
{
int item1Id = item1.Key;
float item1Rating = item1.Value;
_Items.Add(item1.Key);
foreach (var item2 in filterRatings)
{
if (item2.Key <= item1Id)
{
continue; // Eliminate redundancy
}
int item2Id = item2.Key;
float item2Rating = item2.Value;
ColoborativeRating ratingDiff;
if (_DiffMarix.Contains(item1Id, item2Id))
{
ratingDiff = _DiffMarix[item1Id, item2Id];
}
else
{
ratingDiff = new ColoborativeRating();
_DiffMarix[item1Id, item2Id] = ratingDiff;
}
ratingDiff.Value += item1Rating - item2Rating;
ratingDiff.Freq += 1;
}
}
}
