public override IList <IRecommendedItem> Recommend(long userID, int howMany, IDRescorer rescorer)
{
IDataModel dataModel = GetDataModel();
int numItems = dataModel.GetNumItems();
List <IRecommendedItem> result = new List <IRecommendedItem>(howMany);
while (result.Count < howMany)
{
var it = dataModel.GetItemIDs();
it.MoveNext();
var skipNum = random.nextInt(numItems);
for (int i = 0; i < skipNum; i++)
{
if (!it.MoveNext())
{
break;
} // skip() ??
}
long itemID = it.Current;
if (dataModel.GetPreferenceValue(userID, itemID) == null)
{
result.Add(new GenericRecommendedItem(itemID, randomPref()));
}
}
return(result);
}
public FixedSizeSamplingIterator(int size, IEnumerator <T> source)
{
this.buf = new List <T>(size);
int n = 0;
RandomWrapper wrapper = RandomUtils.getRandom();
while (source.MoveNext())
{
T current = source.Current;
n++;
if (this.buf.Count < size)
{
this.buf.Add(current);
}
else
{
int num2 = wrapper.nextInt(n);
if (num2 < this.buf.Count)
{
this.buf[num2] = current;
}
}
}
this.enumerator = this.buf.GetEnumerator();
}
protected void shufflePreferences()
{
RandomWrapper wrapper = RandomUtils.getRandom();
for (int i = this.cachedUserIDs.Length - 1; i > 0; i--)
{
int posB = wrapper.nextInt(i + 1);
this.swapCachedPreferences(i, posB);
}
}
public void shuffle()
{
unstagedPreferences = (IPreference[])preferences.Clone();
/// Durstenfeld shuffle
for (int i = unstagedPreferences.Length - 1; i > 0; i--)
{
int rand = random.nextInt(i + 1);
swapCachedPreferences(i, rand);
}
}
protected void shufflePreferences()
{
RandomWrapper random = RandomUtils.getRandom();
/// Durstenfeld shuffle
for (int currentPos = cachedUserIDs.Length - 1; currentPos > 0; currentPos--)
{
int swapPos = random.nextInt(currentPos + 1);
swapCachedPreferences(currentPos, swapPos);
}
}